Publications by authors named "Christine Falk"

157 Publications

Genetic Correction of IL-10RB Deficiency Reconstitutes Anti-Inflammatory Regulation in iPSC-Derived Macrophages.

J Pers Med 2021 Mar 20;11(3). Epub 2021 Mar 20.

Institute of Experimental Hematology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.

Patient material from rare diseases such as very early-onset inflammatory bowel disease (VEO-IBD) is often limited. The use of patient-derived induced pluripotent stem cells (iPSCs) for disease modeling is a promising approach to investigate disease pathomechanisms and therapeutic strategies. We successfully developed VEO-IBD patient-derived iPSC lines harboring a mutation in the IL-10 receptor β-chain (IL-10RB) associated with defective IL-10 signaling. To characterize the disease phenotype, healthy control and VEO-IBD iPSCs were differentiated into macrophages. IL-10 stimulation induced characteristic signal transducer and activator of transcription 3 (STAT3) and suppressor of cytokine signaling 3 () downstream signaling and anti-inflammatory regulation of lipopolysaccharide (LPS)-mediated cytokine secretion in healthy control iPSC-derived macrophages. In contrast, IL-10 stimulation of macrophages derived from patient iPSCs did not result in STAT3 phosphorylation and subsequent expression, recapitulating the phenotype of cells from patients with IL-10RB deficiency. In line with this, LPS-induced cytokine secretion (e.g., IL-6 and tumor necrosis factor-α (TNF-α)) could not be downregulated by exogenous IL-10 stimulation in VEO-IBD iPSC-derived macrophages. Correction of the IL-10RB defect via lentiviral gene therapy or genome editing in the adeno-associated virus integration site 1 () safe harbor locus led to reconstitution of the anti-inflammatory response. Corrected cells showed IL-10RB expression, IL-10-inducible phosphorylation of STAT3, and subsequent expression. Furthermore, LPS-mediated TNF-α secretion could be modulated by IL-10 stimulation in gene-edited VEO-IBD iPSC-derived macrophages. Our established disease models provide the opportunity to identify and validate new curative molecular therapies and to investigate phenotypes and consequences of additional individual IL-10 signaling pathway-dependent VEO-IBD mutations.
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http://dx.doi.org/10.3390/jpm11030221DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003874PMC
March 2021

Influenza A virus-induced thymus atrophy differentially affects dynamics of conventional and regulatory T-cell development in mice.

Eur J Immunol 2021 Feb 26. Epub 2021 Feb 26.

Department of Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany.

Foxp3 Treg cells, which are crucial for maintenance of self-tolerance, mainly develop within the thymus, where they arise from CD25 Foxp3 or CD25 Foxp3 Treg cell precursors. Although it is known that infections can cause transient thymic involution, the impact of infection-induced thymus atrophy on thymic Treg (tTreg) cell development is unknown. Here, we infected mice with influenza A virus (IAV) and studied thymocyte population dynamics post infection. IAV infection caused a massive, but transient thymic involution, dominated by a loss of CD4 CD8 double-positive (DP) thymocytes, which was accompanied by a significant increase in the frequency of CD25 Foxp3 tTreg cells. Differential apoptosis susceptibility could be experimentally excluded as a reason for the relative tTreg cell increase, and mathematical modeling suggested that enhanced tTreg cell generation cannot explain the increased frequency of tTreg cells. Yet, an increased death of DP thymocytes and augmented exit of single-positive (SP) thymocytes was suggested to be causative. Interestingly, IAV-induced thymus atrophy resulted in a significantly reduced T-cell receptor (TCR) repertoire diversity of newly produced tTreg cells. Taken together, IAV-induced thymus atrophy is substantially altering the dynamics of major thymocyte populations, finally resulting in a relative increase of tTreg cells with an altered TCR repertoire.
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http://dx.doi.org/10.1002/eji.202048981DOI Listing
February 2021

Pilot Study Using Machine Learning to Identify Immune Profiles for the Prediction of Early Virological Relapse After Stopping Nucleos(t)ide Analogues in HBeAg-Negative CHB.

Hepatol Commun 2021 Jan 5;5(1):97-111. Epub 2020 Nov 5.

Department of Gastroenterology, Hepatology, and Endocrinology Hannover Medical School Hannover Germany.

Treatment with nucleos(t)ide analogues (NAs) may be stopped after 1-3 years of hepatitis B virus DNA suppression in hepatitis B e antigen (HBeAg)-negative patients according to Asian Pacific Association for the Study of Liver and European Association for the Study of Liver guidelines. However, virological relapse (VR) occurs in most patients. We aimed to analyze soluble immune markers (SIMs) and use machine learning to identify SIM combinations as predictor for early VR after NA discontinuation. A validation cohort was used to verify the predictive power of the SIM combination. In a analysis of a prospective, multicenter therapeutic vaccination trial (ABX-203, NCT02249988), hepatitis B surface antigen, hepatitis B core antigen, and 47 SIMs were repeatedly determined before NA was stopped. Forty-three HBeAg-negative patients were included. To detect the highest predictive constellation of host and viral markers, a supervised machine learning approach was used. Data were validated in a different cohort of 49 patients treated with entecavir. VR (hepatitis B virus DNA ≥ 2,000 IU/mL) occurred in 27 patients. The predictive value for VR of single SIMs at the time of NA stop was best for interleukin (IL)-2, IL-17, and regulated on activation, normal T cell expressed and secreted (RANTES/CCL5) with a maximum area under the curve of 0.65. Hepatitis B core antigen had a higher predictive power than hepatitis B surface antigen but lower than the SIMs. A supervised machine-learning algorithm allowed a remarkable improvement of early relapse prediction in patients treated with entecavir. The combination of IL-2, monokine induced by interferon (MIG)/chemokine (C-C motif) ligand 9 (CCL9), RANTES/CCL5, stem cell factor (SCF), and TNF-related apoptosis-inducing ligand (TRAIL) was reliable in predicting VR (0.89; 95% confidence interval: 0.5-1.0) and showed viable results in the validation cohort (0.63; 0.1-0.99). Host immune markers such as SIMs appear to be underestimated in guiding treatment cessation in HBeAg-negative patients. Machine learning can help find predictive SIM patterns that allow a precise identification of patients particularly suitable for NA cessation.
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http://dx.doi.org/10.1002/hep4.1626DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789842PMC
January 2021

Mutation-specific effects of NRAS oncogenes in colorectal cancer cells.

Adv Biol Regul 2021 01 31;79:100778. Epub 2020 Dec 31.

Laboratory of Molecular Tumor Pathology and Cancer Systems Biology, Institute of Pathology, Charité Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany; German Cancer Consortium (DKTK), German Cancer Research Center, Im Neuenheimer Feld 280, D-69120, Heidelberg, Germany; Comprehensive Cancer Center, Charité Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany. Electronic address:

In colorectal cancer (CRC), the prevalence of NRAS mutations (5-9%) is inferior to that of KRAS mutations (40-50%). NRAS mutations feature lately during tumour progression and drive resistance to anti-EGFR therapy in KRAS wild-type tumours. To elucidate specific functions of NRAS mutations in CRC, we expressed doxycycline-inducible G12D and Q61K mutations in the CRC cell line Caco-2. A focused phospho-proteome analysis based on the Bio-Plex platform, which interrogated the activity of MAPK, PI3K, mTOR, STAT, p38, JNK and ATF2, did not reveal significant differences between Caco-2 cells expressing NRAS, NRAS and KRAS. However, phenotypic read-outs were different. The NRAS Q61K mutation promoted anchorage-independent proliferation and tumorigenicity, similar to features driven by canonical KRAS mutations. In contrast, expression of NRAS resulted in reduced proliferation and apoptosis. At the transcriptome level, we saw upregulation of cytokines and chemokines. IL1A, IL11, CXCL8 (IL-8) and CCL20 exhibited enhanced secretion into the culture medium. In addition, RNA sequencing results indicated activation of the IL1-, JAK/STAT-, NFκB- and TNFα signalling pathways. These results form the basis for an NRAS-driven inflammatory phenotype in CRC.
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http://dx.doi.org/10.1016/j.jbior.2020.100778DOI Listing
January 2021

Case Report: Daratumumab in a Patient With Severe Refractory Anti-NMDA Receptor Encephalitis.

Front Neurol 2020 22;11:602102. Epub 2020 Dec 22.

Department of Neurology, Hannover Medical School, Hanover, Germany.

Anti-NMDA receptor encephalitis is the most common type of antibody mediated autoimmune encephalitis (AIE). Patients often develop neuropsychiatric symptoms and seizures, women are affected about four times more than men, and in about 50% the disease is associated with a neoplasia, especially teratomas of the ovary. We describe the case of a 20-year-old woman suffering from a severe therapy refractory course of anti-NMDA receptor encephalitis. Treatment included glucocorticoids, plasma exchange, intravenous immunoglobulins, rituximab, and bortezomib without clinical improvement. Due to a therapy refractive course 28 weeks after disease onset, the patient received 10 cycles of daratumumab. Therapy escalation was performed with the anti-CD38 monoclonal antibody daratumumab as off label treatment, based on the therapy of refractory myeloma and led to an improvement of her clinical status. She spent about 200 days on the intensive care unit, followed by several weeks on the intermediate care unit with close follow ups every 4-6 weeks afterward. During follow-up, the patient was able to resume everyday and self-care activities, reflected by the modified Rankin scale (mRS) and Barthel index. Because this disease is potentially life threatening and can lead to irreversible brain atrophy, development of further therapy strategies are of great importance. Our case describes a successful treatment for therapy refractory anti-NMDA receptor encephalitis using the anti-CD38 antibody daratumumab.
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http://dx.doi.org/10.3389/fneur.2020.602102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7782967PMC
December 2020

Sex matters: COVID-19 in kidney transplantation.

Kidney Int 2021 03 5;99(3):555-558. Epub 2021 Jan 5.

Canadian Donation and Transplantation Research Program, Edmonton, Alberta, Canada; Division of Nephrology, Department of Medicine, McGill University, Montreal, Quebec, Canada; Centre for Outcomes Research, Research Institute of McGill University Health Centre, Montreal, Quebec, Canada. Electronic address:

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http://dx.doi.org/10.1016/j.kint.2020.12.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7783460PMC
March 2021

Extracellular vesicles from human multipotent stromal cells protect against hearing loss after noise trauma in vivo.

Clin Transl Med 2020 Dec;10(8):e262

GMP Unit, Spinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI-TReCS), Paracelsus Medical University (PMU), Salzburg, Austria.

The lack of approved anti-inflammatory and neuroprotective therapies in otology has been acknowledged in the last decades and recent approaches are heralding a new era in the field. Extracellular vesicles (EVs) derived from human multipotent (mesenchymal) stromal cells (MSC) can be enriched in vesicular secretome fractions, which have been shown to exert effects (eg, neuroprotection and immunomodulation) of their parental cells. Hence, MSC-derived EVs may serve as novel drug candidates for several inner ear diseases. Here, we provide first evidence of a strong neuroprotective potential of human stromal cell-derived EVs on inner ear physiology. In vitro, MSC-EV preparations exerted immunomodulatory activity on T cells and microglial cells. Moreover, local application of MSC-EVs to the inner ear significantly attenuated hearing loss and protected auditory hair cells from noise-induced trauma in vivo. Thus, EVs derived from the vesicular secretome of human MSC may represent a next-generation biological drug that can exert protective therapeutic effects in a complex and nonregenerating organ like the inner ear.
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http://dx.doi.org/10.1002/ctm2.262DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7752163PMC
December 2020

Distinct systemic cytokine networks in symptomatic and asymptomatic carotid stenosis.

Sci Rep 2020 12 15;10(1):21963. Epub 2020 Dec 15.

Division of Vascular and Endovascular Surgery, Department of Cardiothoracic-, Transplantation- and Vascular Surgery, Hannover Medical School, Hannover, Germany.

Inflammatory processes are crucial in atherosclerosis and atherothrombosis. This study aimed to identify a cytokine-pattern that is associated with plaque-vulnerability or symptomatic state in comprehensively investigated patients with symptomatic (sCS) and asymptomatic carotid stenosis (aCS). Twenty-two patients with sCS and twenty-four patients with aCS undergoing carotid endarterectomy (CEA) were considered. A cytokine-panel was measured in plasma-specimens prior to surgery and at a 90 day follow-up. Doppler-ultrasound detecting microembolic signals (MES) in the ipsilateral middle cerebral artery was performed. Carotid plaques were analysed regarding histopathological criteria of plaque-vulnerability and presence of chemokine receptor CXCR4. Correction for multiple comparisons and logistic regression analysis adjusting for vascular risk factors, grade of stenosis, antithrombotic and statin pretreatment were applied. In sCS-patients higher plasma-levels of Fractalkine (CXCL1), IFN-α2, IL-1β, IL-2, IL-3, IL-7 were found compared to aCS-patients. CXCR4-expression on inflammatory cells was more evident in sCS- compared to aCS-plaques and was associated with vulnerability-criteria. In contrast, plasma-cytokine-levels were not related to CXCR4-expression or other vulnerability-criteria or MES. However, in both groups distinct inter-cytokine correlation patterns, which persisted at follow-up and were more pronounced in the sCS-group could be detected. In conclusion, we identified a distinct cytokine/chemokine-network in sCS-patients with elevated and closely correlated mediators of diverse functions.
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http://dx.doi.org/10.1038/s41598-020-78941-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7738491PMC
December 2020

Effect of everolimus-based drug regimens on CMV-specific T-cell functionality after renal transplantation: 12-month ATHENA subcohort-study results.

Eur J Immunol 2020 Dec 11. Epub 2020 Dec 11.

Department of Transplant and Infection Immunology, Saarland University, Homburg, Germany.

Post-transplant cytomegalovirus (CMV) infections and increased viral replication are associated with CMV-specific T-cell anergy. In the ATHENA-study, de-novo everolimus (EVR) with reduced-exposure tacrolimus (TAC) or cyclosporine (CyA) showed significant benefit in preventing CMV infections in renal transplant recipients as compared to standard TAC + mycophenolic acid (MPA). However, immunomodulatory mechanisms for this effect remain largely unknown. Ninety patients from the ATHENA-study completing the 12-month visit on-treatment (EVR + TAC n = 28; EVR + CyA n = 19; MPA + TAC n = 43) were included in a posthoc analysis. Total lymphocyte subpopulations were quantified. CMV-specific CD4 T cells were determined after stimulation with CMV-antigen, and cytokine-profiles and various T-cell anergy markers were analyzed using flow cytometry. While 25.6% of MPA + TAC-treated patients had CMV-infections, no such events were reported in EVR-treated patients. Absolute numbers of lymphocyte subpopulations were comparable between arms, whereas the percentage of regulatory T cells was significantly higher with EVR + CyA versus MPA + TAC (p = 0.019). Despite similar percentages of CMV-specific T cells, their median expression of CTLA-4 and PD-1 was lower with EVR + TAC (p < 0.05 for both) or EVR + CyA (p = 0.045 for CTLA-4) compared with MPA + TAC. Moreover, mean percentages of multifunctional CMV-specific T cells were higher with EVR + TAC (27.2%) and EVR + CyA (29.4%) than with MPA + TAC (19.0%). In conclusion, EVR-treated patients retained CMV-specific T-cell functionality, which may contribute to enhanced protection against CMV infections.
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http://dx.doi.org/10.1002/eji.202048855DOI Listing
December 2020

Plasma Acute Phase Proteins as Predictors of Chronic Lung Allograft Dysfunction in Lung Transplant Recipients.

J Inflamm Res 2020 30;13:1021-1028. Epub 2020 Nov 30.

CHU de Nantes, Centre National De Référence Mucoviscidose Nantes-Roscoff, Nantes, France.

Cumulating reports suggest that acute phase proteins (APPs) have diagnostic and prognostic value in different clinical conditions. Among others, APPs are proposed to serve as markers that help to control the outcome of transplant recipients. Here, we questioned whether plasma concentrations of APPs mirror the development of chronic lung allograft dysfunction (CLAD). We performed blinded analysis of serial plasma samples retrospectively collected from 35 lung transplanted patients, of whom 25 developed CLAD and 10 remained stable during the follow-up period of 3 to 4.5 years. Albumin (ALB), alpha1-antitrypsin (AAT), high sensitivity C-reactive protein (CRPH), antithrombin-3 (AT3), ceruloplasmin (CER), and alpha2-macroglobulin (A2MG) were measured by the nephelometric method. We found that within the first six months post-transplantation, levels of A2MG, CER and AAT were higher in stable patients relative to those who later developed CLAD. Moreover, in stable patient's plasma CRPH levels decreased during the follow-up period whereas opposite, in those developing CLAD, the CRPH gradually increased. The ALB levels became significantly lower at the end of the follow-up period in CLAD relative to a stable group. A logistic regression model based on A2MG, CER and AT3 at cut-offs levels of ≥175.5 mg/dL, ≥37.8 mg/dL and ≥27.35 mg/dL enabled to discriminate between stable and CLAD patients with a sensitivity of 87.5%, 100% and 62.5%, and specificity of 65.9%, 72.7% and 79.5%, respectively. We identified A2MG (below 175.5 mg/dL) as an independent predictor of CLAD (hazard ratio 11.5, 95% CI (1.5-91.3), p<0.021). Our findings suggest that profiles of certain APPs may help to predict the development of lung dysfunction at the very early stages after transplantation.
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http://dx.doi.org/10.2147/JIR.S272662DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7721309PMC
November 2020

CRELD1 modulates homeostasis of the immune system in mice and humans.

Nat Immunol 2020 12 9;21(12):1517-1527. Epub 2020 Nov 9.

Genomics and Immunoregulation, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.

CRELD1 is a pivotal factor for heart development, the function of which is unknown in adult life. We here provide evidence that CRELD1 is an important gatekeeper of immune system homeostasis. Exploiting expression variance in large human cohorts contrasting individuals with the lowest and highest CRELD1 expression levels revealed strong phenotypic, functional and transcriptional differences, including reduced CD4 T cell numbers. These findings were validated in T cell-specific Creld1-deficient mice. Loss of Creld1 was associated with simultaneous overactivation and increased apoptosis, resulting in a net loss of T cells with age. Creld1 was transcriptionally and functionally linked to Wnt signaling. Collectively, gene expression variance in large human cohorts combined with murine genetic models, transcriptomics and functional testing defines CRELD1 as an important modulator of immune homeostasis.
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http://dx.doi.org/10.1038/s41590-020-00811-2DOI Listing
December 2020

Combined high-throughput library screening and next generation RNA sequencing uncover microRNAs controlling human cardiac fibroblast biology.

J Mol Cell Cardiol 2021 01 28;150:91-100. Epub 2020 Oct 28.

Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany; REBIRTH Excellence Cluster, Hannover Medical School, Hannover, Germany. Electronic address:

Background: Myocardial fibrosis is a hallmark of the failing heart, contributing to the most common causes of deaths worldwide. Several microRNAs (miRNAs, miRs) controlling cardiac fibrosis were identified in recent years; however, a more global approach to identify miRNAs involved in fibrosis is missing.

Methods And Results: Functional miRNA mimic library screens were applied in human cardiac fibroblasts (HCFs) to identify annotated miRNAs inducing proliferation. In parallel, miRNA deep sequencing was performed after subjecting HCFs to proliferating and resting stimuli, additionally enabling discovery of novel miRNAs. In-depth in vitro analysis confirmed the pro-fibrotic nature of selected, highly conserved miRNAs miR-20a-5p and miR-132-3p. To determine downstream cellular pathways and their role in the fibrotic response, targets of the annotated miRNA candidates were modulated by synthetic siRNA. We here provide evidence that repression of autophagy and detoxification of reactive oxygen species by miR-20a-5p and miR-132-3p explain some of their pro-fibrotic nature on a mechanistic level.

Conclusion: We here identified both miR-20a-5p and miR-132-3p as crucial regulators of fibrotic pathways in an in vitro model of human cardiac fibroblast biology.
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http://dx.doi.org/10.1016/j.yjmcc.2020.10.008DOI Listing
January 2021

Knockout-Induced Pluripotent Stem Cells for Disease and Therapy Modeling of IL-10-Associated Primary Immunodeficiencies.

Hum Gene Ther 2021 Jan 11;32(1-2):77-95. Epub 2021 Jan 11.

Institute of Experimental Hematology.

Samples from patients with rare diseases, such as primary immunodeficiencies, are often limited, which hampers careful analysis of the pathomechanisms involved in immune cell dysregulation. To overcome this issue, induced pluripotent stem cells (iPSCs) represent an almost inexhaustible cell source and thus provide an excellent opportunity to generate disease models for rare diseases and to validate new therapeutic approaches. To obtain a better understanding of primary immunodeficiencies associated with the interleukin (IL)-10 signaling pathway, for example, very-early-onset inflammatory bowel disease (VEO-IBD), we generated genetic knockouts (KOs) of IL-10RA (IL-10 receptor α-chain) and IL-10RB (IL-10 receptor β-chain) as well as the downstream targets of the IL-10-receptor (IL-10R) signal transducers and activators of transcription (STAT)1 and STAT3 via an sgRNA (single-guide RNA)-CRISPR-Cas9-expressing lentiviral system. IL-10 signaling-associated KO models and a VEO-IBD patient-derived iPSC clone were differentiated into macrophages for disease models. IL-10R- or STAT3-deficient disease models showed no IL-10-induced or expression, whereas lipopolysaccharide (LPS) stimulation induced IL-10R independently of and expression. Cytokine secretion profiles from iPSC-derived macrophage disease models showed that IL-10 was involved in many inflammatory cytokine secretions, which indicated formation of both anti- and proinflammatory macrophage phenotypes. Macrophage-secreted cytokines were separated into IL-10R- and STAT3-dependent (IL-6, TNF-α), or into IL-10R-, STAT1-, and STAT3-dependent cytokines (CCL2, CXCL10). Importantly, lentiviral correction restored IL-10-mediated regulation of LPS-induced cytokine secretion in corrected IL-10RB, STAT1, and VEO-IBD patient-derived disease models. Furthermore, treatment of IL-10RB-deficient macrophages with anti-inflammatory small molecules (SB202190, filgotinib) reduced proinflammatory cytokine secretion patterns. Taken together, the described iPSC KO models gave new insights into the pathomechanisms of immune cell dysregulation and served as model systems to test potential therapeutic approaches, including lentiviral gene therapy and targeted small-molecule treatment.
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http://dx.doi.org/10.1089/hum.2020.235DOI Listing
January 2021

The global response to the COVID-19 pandemic: how have immunology societies contributed?

Nat Rev Immunol 2020 10 10;20(10):594-602. Epub 2020 Sep 10.

National Institute for Communicable Diseases, a division of the National Health Laboratory Service, Johannesburg, South Africa.

The COVID-19 pandemic is shining a spotlight on the field of immunology like never before. To appreciate the diverse ways in which immunologists have contributed, Nature Reviews Immunology invited the president of the International Union of Immunological Societies and the presidents of 15 other national immunology societies to discuss how they and their members responded following the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
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http://dx.doi.org/10.1038/s41577-020-00428-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7483049PMC
October 2020

Senolytics prevent mt-DNA-induced inflammation and promote the survival of aged organs following transplantation.

Nat Commun 2020 08 27;11(1):4289. Epub 2020 Aug 27.

Division of Transplant Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

Older organs represent an untapped potential to close the gap between demand and supply in organ transplantation but are associated with age-specific responses to injury and increased immunogenicity, thereby aggravating transplant outcomes. Here we show that cell-free mitochondrial DNA (cf-mt-DNA) released by senescent cells accumulates with aging and augments immunogenicity. Ischemia reperfusion injury induces a systemic increase of cf-mt-DNA that promotes dendritic cell-mediated, age-specific inflammatory responses. Comparable events are observed clinically, with the levels of cf-mt-DNA elevated in older deceased organ donors, and with the isolated cf-mt-DNA capable of activating human dendritic cells. In experimental models, treatment of old donor animals with senolytics clear senescent cells and diminish cf-mt-DNA release, thereby dampening age-specific immune responses and prolonging the survival of old cardiac allografts comparable to young donor organs. Collectively, we identify accumulating cf-mt-DNA as a key factor in inflamm-aging and present senolytics as a potential approach to improve transplant outcomes and availability.
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http://dx.doi.org/10.1038/s41467-020-18039-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7453018PMC
August 2020

Alpha-Toxin Limits Type 1 While Fostering Type 3 Immune Responses.

Front Immunol 2020 7;11:1579. Epub 2020 Aug 7.

Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany.

can cause life-threatening diseases, and hospital- as well as community-associated antibiotic-resistant strains are an emerging global public health problem. Therefore, prophylactic vaccines or immune-based therapies are considered as alternative treatment opportunities. To develop such novel treatment approaches, a better understanding of the bacterial virulence and immune evasion mechanisms and their potential effects on immune-based therapies is essential. One important staphylococcal virulence factor is alpha-toxin, which is able to disrupt the epithelial barrier in order to establish infection. In addition, alpha-toxin has been reported to modulate other cell types including immune cells. Since CD4 T cell-mediated immunity is required for protection against infection, we were interested in the ability of alpha-toxin to directly modulate CD4 T cells. To address this, murine naïve CD4 T cells were differentiated into effector T cell subsets in the presence of alpha-toxin. Interestingly, alpha-toxin induced death of Th1-polarized cells, while cells polarized under Th17 conditions showed a high resistance toward increasing concentrations of this toxin. These effects could neither be explained by differential expression of the cellular alpha-toxin receptor ADAM10 nor by differential activation of caspases, but might result from an increased susceptibility of Th1 cells toward Ca-mediated activation-induced cell death. In accordance with the findings, an alpha-toxin-dependent decrease of Th1 and concomitant increase of Th17 cells was observed during bacteremia. Interestingly, corresponding subsets of innate lymphoid cells and γδ T cells were similarly affected, suggesting a more general effect of alpha-toxin on the modulation of type 1 and type 3 immune responses. In conclusion, we have identified a novel alpha-toxin-dependent immunomodulatory strategy of , which can directly act on CD4 T cells and might be exploited for the development of novel immune-based therapeutic approaches to treat infections with antibiotic-resistant strains.
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http://dx.doi.org/10.3389/fimmu.2020.01579DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7427519PMC
August 2020

In Vitro Effects of Biofilm on Peri-Implant Soft Tissue Cells.

Cells 2020 05 15;9(5). Epub 2020 May 15.

Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.

Human gingival epithelial cells (HGEps) and fibroblasts (HGFs) are the main cell types in peri-implant soft tissue. HGEps are constantly exposed to bacteria, but HGFs are protected by connective tissue as long as the mucosa-implant seal is intact. is one of the commensal bacteria, is highly abundant at healthy implant sites, and might modulate soft tissue cells-as has been described for other streptococci. We have therefore investigated the effects of the biofilm on HGEps and HGFs. HGEps or HGFs were grown separately on titanium disks and responded to challenge with biofilm. HGFs were severely damaged after 4 h, exhibiting transcriptional inflammatory and stress responses. In contrast, challenge with only induced a mild transcriptional inflammatory response in HGEps, without cellular damage. HGFs were more susceptible to the biofilm than HGEps. The pro-inflammatory interleukin 6 (IL-6) was attenuated in HGFs, as was interleukin 8 (CXCL8) in HGEps. This indicates that can actively protect tissue. In conclusion, commensal biofilms can promote homeostatic tissue protection, but only if the implant-mucosa interface is intact and HGFs are not directly exposed.
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http://dx.doi.org/10.3390/cells9051226DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290395PMC
May 2020

Relevance of inducible nitric oxide synthase for immune control of subspecies infection in mice.

Virulence 2020 12;11(1):465-481

Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany.

subspecies (MAP) causes Johne's disease (JD), an incurable chronic intestinal bowel disease in ruminants. JD occurs worldwide and causes enormous economic burden in dairy industry. Research on JD pathobiology is hampered by its complexity which cannot completely be mimicked by small animal models. As a model the mouse allows dissecting some pathogenicity features of MAP. However, for unknown reasons MAP exhibits reduced growth in granulomas of infected mice compared to other subspecies. Here, we characterized immune reactions of MAP-infected C57BL/6 mice. After infection, mice appeared fully immunocompetent. A strong antigen-specific T cell response was elicited indicated by IFNγ production of splenic T cells re-stimulated with MAP antigens. Function of splenic dendritic cells and proliferation of adoptively transferred antigen-specific CD4 T cells was unaltered. Isolated splenic myeloid cells from infected mice revealed that MAP resides in CD11b macrophages. Importantly, sorted CD11bCD11c cells expressed high level of type 2 nitric oxide synthase (NOS2) but only low levels of pro- and anti-inflammatory cytokines. Correspondingly, MAP-infected MAC2 expressing myeloid cells in spleen and liver granuloma displayed strong expression of NOS2. In livers of infected mice higher bacterial loads, more granuloma and larger areas of tissue damage were observed 5 weeks post infection compared to wild type mice. , MAP was sensitive to NO released by a NO-donor. Thus, a strong T cell response and concomitant NOS2/NO activity appears to control MAP infection, but allows development of chronicity and pathogen persistence. A similar mechanism might explain persistence of MAP in ruminants.
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http://dx.doi.org/10.1080/21505594.2020.1763055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7239028PMC
December 2020

Differential effects of Belatacept on virus-specific memory versus de novo allo-specific T cell responses of kidney transplant recipients and healthy donors.

Transpl Immunol 2020 08 21;61:101291. Epub 2020 Apr 21.

Institute of Transplant Immunology, Hannover Medical School, Hannover, Germany; DZIF, German Center for Infectious Diseases, TTU-IICH Hannover-Braunschweig site, Germany. Electronic address:

Belatacept, Nulojix®, inhibits the interaction of CD28 on naïve T cells with B7.1/B7.2 (CD80/86) on antigen presenting cells, leading to T cell hyporesponsiveness and anergy and is approved as immunosuppressive drug in kidney transplantation. Due to its specificity for B7.1/2 molecules, side effects are reduced compared to other immunosuppressive drugs like calcineurin- and mTOR-inhibitors. Kidney transplant recipients under Belatacept-based immunosuppression presented with superior renal function and similar graft survival seven years after transplantation compared to cyclosporine treatment. However, de novo Belatacept-based immunosuppression was associated with increased risk of early rejections and viral (EBV) infections in clinical trials, especially in EBV-naïve patients. Since there is no vaccination against EBV infection available, EBV-derived virus like particles (EBV-VLPs) are currently developed as vaccine strategy. Here, we investigated the immunosuppressive effects of Belatacept compared to calcineurin- and mTOR inhibitors on allo- versus virus-specific T cells and the potency of EBV-VLPs to induce virus-specific T cell responses in vitro. Using PBMC of kidney recipients and healthy donors, we could demonstrate selective inhibition of allo-specific de novo T cell responses but not virus-specific memory T cell responses by Belatacept, as measured by IFN-γ production. In contrast, calcineurin inhibitors suppressed IFN-γ production of virus-specific memory CD8 T cells completely. These results experimentally confirm the concept that Belatacept blocks CD28-mediated costimulation in newly primed naïve T cells but does not interfere with memory T cell responses being already independent from CD28-mediated costimulation. Additionally, we could show that EBV-VLPs induce a significant though weak IFN-γ-mediated T cell response in vitro in both kidney recipients and healthy donors. In summary, we demonstrated that immunosuppression of kidney recipients by Belatacept may primarily suppress de novo allo-specific T cell responses sparing virus-specific memory T cells. Moreover, EBV-VLPs could represent a novel strategy for vaccination of immunocompromised renal transplant recipients to prevent EBV reactivation especially under Belatacept-based immunosuppression.
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http://dx.doi.org/10.1016/j.trim.2020.101291DOI Listing
August 2020

Early host-microbe interaction in a peri-implant oral mucosa-biofilm model.

Cell Microbiol 2020 08 14;22(8):e13209. Epub 2020 May 14.

Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Hannover, Germany.

The host-microbe relationship is pivotal for oral health as well as for peri-implant diseases. Peri-implant mucosa and commensal biofilm play important roles in the maintenance of host-microbe homeostasis, but little is known about how they interact. We have therefore investigated the early host-microbe interaction between commensal multispecies biofilm (Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, Porphyromonas gingivalis) and organotypic peri-implant mucosa using our three-dimensional model. After 24 hr, biofilms induced weak inflammatory reaction in the peri-implant mucosa by upregulation of five genes related to immune response and increased secretion of IL-6 and CCL20. Biofilm volume was reduced which might be explained by secretion of β-Defensins-1, -2, and CCL20. The specific tissue reaction without intrinsic overreaction might contribute to intact mucosa. Thus, a relationship similar to homeostasis and oral health was established within the first 24 hr. In contrast, the mucosa was damaged and the bacterial distribution was altered after 48 hr. These were accompanied by an enhanced immune response with upregulation of additional inflammatory-related genes and increased cytokine secretion. Thus, the homeostasis-like relationship was disrupted. Such profound knowledge of the host-microbe interaction at the peri-implant site may provide the basis to improve strategies for prevention and therapy of peri-implant diseases.
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http://dx.doi.org/10.1111/cmi.13209DOI Listing
August 2020

Extracorporeal cytokine removal in severe CAR-T cell associated cytokine release syndrome.

J Crit Care 2020 06 19;57:124-129. Epub 2020 Feb 19.

Department of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany. Electronic address:

Purpose: Life-threatening complications of CD-19 Chimeric antigen receptor - T (CAR-T) cells such as the cytokine release syndrome (CRS)) have been reported. Treatment is limited to IL-6 blockade and steroids although global removal of elevated soluble inflammatory factors might be more effective.

Methods: Clinical course of a CRS patient treated with extracorporeal cytokine adsorption (Cytosorb®). A panel of 48 cytokines, chemokines and endothelial markers has been analyzed longitudinally. Ex vivo stimulation of endothelial cells to visualize (immunocytochemistry) and quantify (ECIS, TER) endothelial barrier effects.

Results: Following CAR-T cell application a 65 years old male developed grade 4 CRS with refractory shock (3 vasopressors) and severe capillary leakage (+37 L/24 h resuscitation). Treatment included IL-6 blockade, methylprednisolone and additionally Cytosorb hemoperfusion. While multiple soluble inflammatory factors were elevated and most of them decreased by more than 50% following Cytosorb, markers of endothelial injury increased steadily (e.g. Angpt-2/Angpt-1) leading to profound endothelial activation and leakage in ex vivo assays.

Conclusion: This is the first reported use of cytokine adsorption for CRS showing efficacy in absorption of various cytokines but not endothelial growth factors. A randomized controlled trial to evaluate additional Cytosorb treatment in CRS is currently recruiting at our institution (NCT04048434).
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http://dx.doi.org/10.1016/j.jcrc.2020.02.010DOI Listing
June 2020

MAIT Cells Are Enriched and Highly Functional in Ascites of Patients With Decompensated Liver Cirrhosis.

Hepatology 2020 10 13;72(4):1378-1393. Epub 2020 Oct 13.

Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.

Background And Aims: Patients with advanced liver cirrhosis have an increased susceptibility to infections. As part of the cirrhosis-associated immune dysfunction, mucosal-associated invariant T (MAIT) cells, which have the capacity to respond to bacteria, are severely diminished in circulation and liver tissue. However, MAIT cell presence and function in the peritoneal cavity, a common anatomical site for infections in cirrhosis, remain elusive. In this study, we deliver a comprehensive investigation of the immune compartment present in ascites of patients with decompensated liver cirrhosis, and focus especially on MAIT cells.

Approach And Results: To study this, matched peripheral blood and ascites fluid were collected from 35 patients with decompensated cirrhosis, with or without spontaneous bacterial peritonitis (SBP). MAIT cell phenotype and function were analyzed using high-dimensional flow cytometry, and the obtained data were compared with the blood samples of healthy controls (n = 24) and patients with compensated cirrhosis (n = 11). We found circulating MAIT cells to be severely decreased in patients with cirrhosis as compared with controls. In contrast, in ascites fluid, MAIT cells were significantly increased together with CD14 CD16 monocytes, innate lymphoid cells, and natural killer cells. This was paralleled by elevated levels of several pro-inflammatory cytokines and chemokines in ascites fluid as compared with plasma. Peritoneal MAIT cells displayed an activated tissue-resident phenotype, and this was corroborated by increased functional responses following stimulation with E. coli or interleukin (lL)-12 + IL-18 as compared with circulating MAIT cells. During SBP, peritoneal MAIT cell frequencies increased most among all major immune cell subsets, suggestive of active homing of MAIT cells to the site of infection.

Conclusions: Despite severely diminished MAIT cell numbers and impaired phenotype in circulation, peritoneal MAIT cells remain abundant, activated, and highly functional in decompensated cirrhosis and are further enriched in SBP. This suggests that peritoneal MAIT cells could be of interest for immune-intervention strategies in patients with decompensated liver cirrhosis and SBP.
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http://dx.doi.org/10.1002/hep.31153DOI Listing
October 2020

Recirculating IL-1R2 Tregs fine-tune intrathymic Treg development under inflammatory conditions.

Cell Mol Immunol 2021 Jan 27;18(1):182-193. Epub 2020 Jan 27.

Department of Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany.

The vast majority of Foxp3 regulatory T cells (Tregs) are generated in the thymus, and several factors, such as cytokines and unique thymic antigen-presenting cells, are known to contribute to the development of these thymus-derived Tregs (tTregs). Here, we report the existence of a specific subset of Foxp3 Tregs within the thymus that is characterized by the expression of IL-1R2, which is a decoy receptor for the inflammatory cytokine IL-1. Detailed flow cytometric analysis of the thymocytes from Foxp3xRAG1 reporter mice revealed that the IL-1R2 Tregs are mainly RAG1 and CCR6CCR7, demonstrating that these Tregs are recirculating cells entering the thymus from the periphery and that they have an activated phenotype. In the spleen, the majority of IL-1R2 Tregs express neuropilin-1 (Nrp-1) and Helios, suggesting a thymic origin for these Tregs. Interestingly, among all tissues studied, the highest frequency of IL-1R2 Tregs was observed in the thymus, indicating preferential recruitment of this Treg subset by the thymus. Using fetal thymic organ cultures (FTOCs), we demonstrated that increased concentrations of exogenous IL-1β blocked intrathymic Treg development, resulting in a decreased frequency of CD25Foxp3 tTregs and an accumulation of CD25Foxp3 Treg precursors. Interestingly, the addition of IL-1R2 Tregs, but not IL-1R2 Tregs, to reaggregated thymic organ cultures (RTOCs) abrogated the IL-1β-mediated blockade, demonstrating that these recirculating IL-1R2 Tregs can quench IL-1 signaling in the thymus and thereby maintain thymic Treg development even under inflammatory conditions.
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http://dx.doi.org/10.1038/s41423-019-0352-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7853075PMC
January 2021

Six-year experience with treatment of early donor-specific anti-HLA antibodies in pediatric lung transplantation using a human immunoglobulin-based protocol.

Pediatr Pulmonol 2020 03 7;55(3):754-764. Epub 2020 Jan 7.

Department of Cardiothoracic, Transplant and Vascular Surgery, Hannover Medical School, Hannover, Germany.

Objectives: Experience with the treatment of early donor-specific anti-HLA antibodies (eDSA) after lung transplantation in children is very limited. At our institution, we have treated patients with eDSA since 2013 with successive infusions of intravenous human immunoglobulins (IVIG), combined in some cases with a single dose of Rituximab and plasmapheresis (therapeutic plasma exchange [tPE]) or immunoabsorption. The aim of this study was to present the 6-year results of IVIG-based therapy in pediatric lung recipients.

Methods: Records of pediatric (<18 years old) patients transplanted at our institution between 01/2013 and 03/2019 were reviewed. Outcomes were compared between patients with eDSA treated with IVIG (IVIG group) and without eDSA (control group). Median (interquartile range [IQR]) follow-up amounted to 28 (12-52) months.

Results: During the study period, 66 lung-transplanted pediatric patients were included, of which 27 (41%) formed the IVIG group and 38 (57%) the control group. Among the IVIG patients, 14 (52%) patients showed concomitant graft dysfunction (possible clinical antibody-mediated rejection). The median time to eDSA detection was 24 (14-63) days after transplantation. eDSA were cleared in 25 (96%) of the 26 patients which completed treatment. At 3 years, graft survival (%) was 73 vs 85 (P = .65); freedom (%) from chronic lung allograft rejection (CLAD) was 89 vs 78 (P = .82); and from infection 47 vs 31 (P = .15), in IVIG vs control patients, respectively.

Conclusions: After lung transplantation, an IVIG-based treatment for eDSA yielded high eDSA clearance. IVIG and control patients showed similar CLAD-free and graft survival.
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http://dx.doi.org/10.1002/ppul.24639DOI Listing
March 2020

Increased frequency of CD4 CD25 CD127 T cells early after lung transplant is associated with improved graft survival - a retrospective study.

Transpl Int 2020 May 31;33(5):503-516. Epub 2020 Jan 31.

Department of Cardiothoracic, Transplant and Vascular Surgery, Hannover Medical School, Hannover, Germany.

In this retrospective study, we analyzed the presence of any association of three CD4 CD25 regulatory T-cell subpopulations at 3 weeks after lung transplantation with the later incidence of chronic lung allograft dysfunction and graft survival. Among lung-transplanted patients between January 2009 and April 2018, only patients with sufficient T-cell measurements at 3 weeks after transplantation were included into the study. Putative regulatory T cells were defined as CD4 CD25 T cells, detected in peripheral blood and further analyzed for CD127 , FoxP3 , and CD152 using fluorescence-activated cell sorting (FACS) analysis. Associations of regulatory T cells with chronic lung allograft dysfunction (CLAD) and graft survival were evaluated using Cox analysis. During the study period, 724 (71%) patients were included into the study. Freedom from chronic lung allograft dysfunction (CLAD) and graft survival amounted to 66% and 68% at 5 years. At the multivariable analysis, increasing frequencies of CD127 were associated with better freedom from CLAD (hazard ratio for each 1% increase of %CD127 , HR = 0.989, 95% CI = 0.981-0.996, P = 0.003) and better graft survival (HR = 0.991, 95% CI = 0.984-0.999, P = 0.026). A higher frequency of CD127 regulatory T cells in peripheral blood early after lung transplantation estimated a protective effect against chronic lung allograft dysfunction, mortality, and re-transplantation.
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http://dx.doi.org/10.1111/tri.13568DOI Listing
May 2020

The immunogenic potential of bacterial flagella for Salmonella-mediated tumor therapy.

Int J Cancer 2020 07 7;147(2):448-460. Epub 2020 Jan 7.

Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany.

Genetically engineered Salmonella Typhimurium are potent vectors for prophylactic and therapeutic measures against pathogens as well as cancer. This is based on the potent adjuvanticity that supports strong immune responses. The physiology of Salmonella is well understood. It simplifies engineering of both enhanced immune-stimulatory properties as well as safety features, thus, resulting in an appropriate balance between attenuation and efficacy for clinical applications. A major virulence factor of Salmonella is the flagellum. It is also a strong pathogen-associated molecular pattern recognized by extracellular and intracellular receptors of immune cells of the host. At the same time, it represents a serious metabolic burden. Accordingly, the bacteria evolved tight regulatory mechanisms that control flagella synthesis in vivo. Here, we systematically investigated the immunogenicity and adjuvant properties of various flagella mutants of Salmonella in vitro and in a mouse cancer model in vivo. We found that mutants lacking the flagellum-specific ATPase FliHIJ or the inner membrane ring FliF displayed the greatest stimulatory capacity and strongest antitumor effects, while remaining safe in vivo. Scanning electron microscopy revealed the presence of outer membrane vesicles in the ΔfliF and ΔfliHIJ mutants. Finally, the combination of the ΔfliF and ΔfliHIJ mutations with our previously described attenuated and immunogenic background strain SF102 displayed strong efficacy against the highly resistant cancer cell line RenCa. We thus conclude that manipulating flagella biosynthesis has great potential for the construction of highly efficacious and versatile Salmonella vector strains.
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http://dx.doi.org/10.1002/ijc.32807DOI Listing
July 2020

Long-term follow-up in peripartum cardiomyopathy patients with contemporary treatment: low mortality, high cardiac recovery, but significant cardiovascular co-morbidities.

Eur J Heart Fail 2019 12 13;21(12):1534-1542. Epub 2019 Nov 13.

Department of Cardiology and Angiology, Hannover Medical School, Hannover, Germany.

Aims: Peripartum cardiomyopathy (PPCM) establishes late in pregnancy or in the first postpartum months. Many patients recover well within the first year, but long-term outcome studies on morbidity and mortality are rare. Here, we present 5-year follow-up data of a German PPCM cohort.

Methods And Results: Five-year follow-up data were available for 66 PPCM patients (mean age 34 ± 5 years) with a mean left ventricular ejection fraction (LVEF) of 26 ± 9% at diagnosis. Ninety-eight percent initially received standard heart failure therapy (beta-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and/or mineralocorticoid receptor antagonists), and 86% were additionally treated with dopamine D2 receptor agonists (mainly bromocriptine) and anticoagulation. After 1 year, mean LVEF had improved to 50 ± 11% (n = 48) and further increased to 54 ± 7% at 5-year follow-up with 72% of patients having achieved full cardiac recovery (LVEF >50%). At 5-year follow-up, only three patients (5%) displayed no recovery, of whom one had died. However, 20% had arterial hypertension and 17% arrhythmias, including paroxysmal supraventricular tachycardia, ventricular tachycardia, or ventricular fibrillation. Moreover, 70% were still on at least one heart failure drug. Subsequent pregnancy occurred in 16 patients with two abortions and 14 uneventful pregnancies. Mean LVEF was 55 ± 7% at 5-year follow-up in these patients.

Conclusion: Our PPCM collective treated with standard therapy for heart failure, dopamine D2 receptor agonists, and anticoagulation displays a high and stable long-term recovery rate with low mortality at 5-year follow-up. However, long-term use of cardiovascular medication, persisting or de novo hypertension and arrhythmias were frequent.
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http://dx.doi.org/10.1002/ejhf.1624DOI Listing
December 2019

In peripartum cardiomyopathy plasminogen activator inhibitor-1 is a potential new biomarker with controversial roles.

Cardiovasc Res 2020 Sep;116(11):1875-1886

Department of Cardiology and Angiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625 Hannover, Germany.

Aims: Peripartum cardiomyopathy (PPCM) is a life-threatening heart disease occurring in previously heart-healthy women. A common pathomechanism in PPCM involves the angiostatic 16 kDa-prolactin (16 kDa-PRL) fragment, which via NF-κB-mediated up-regulation of microRNA-(miR)-146a induces vascular damage and heart failure. We analyse whether the plasminogen activator inhibitor-1 (PAI-1) is involved in the pathophysiology of PPCM.

Methods And Results: In healthy age-matched postpartum women (PP-Ctrl, n = 53, left ventricular ejection fraction, LVEF > 55%), PAI-1 plasma levels were within the normal range (21 ± 10 ng/mL), but significantly elevated (64 ± 38 ng/mL, P < 0.01) in postpartum PPCM patients at baseline (BL, n = 64, mean LVEF: 23 ± 8%). At 6-month follow-up (n = 23), PAI-1 levels decreased (36 ± 14 ng/mL, P < 0.01 vs. BL) and LVEF (49 ± 11%) improved. Increased N-terminal pro-brain natriuretic peptide and Troponin T did not correlate with PAI-1. C-reactive protein, interleukin (IL)-6 and IL-1β did not differ between PPCM patients and PP-Ctrl. MiR-146a was 3.6-fold (P < 0.001) higher in BL-PPCM plasma compared with PP-Ctrl and correlated positively with PAI-1. In BL-PPCM serum, 16 kDa-PRL coprecipitated with PAI-1, which was associated with higher (P < 0.05) uPAR-mediated NF-κB activation in endothelial cells compared with PP-Ctrl serum. Cardiac biopsies and dermal fibroblasts from PPCM patients displayed higher PAI-1 mRNA levels (P < 0.05) than healthy controls. In PPCM mice (due to a cardiomyocyte-specific-knockout for STAT3, CKO), cardiac PAI-1 expression was higher than in postpartum wild-type controls, whereas a systemic PAI-1-knockout in CKO mice accelerated peripartum cardiac fibrosis, inflammation, heart failure, and mortality.

Conclusion: In PPCM patients, circulating and cardiac PAI-1 expression are up-regulated. While circulating PAI-1 may add 16 kDa-PRL to induce vascular impairment via the uPAR/NF-κB/miR-146a pathway, experimental data suggest that cardiac PAI-1 expression seems to protect the PPCM heart from fibrosis. Thus, measuring circulating PAI-1 and miR-146a, together with an uPAR/NF-κB-activity assay could be developed into a specific diagnostic marker assay for PPCM, but unrestricted reduction of PAI-1 for therapy may not be advised.
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http://dx.doi.org/10.1093/cvr/cvz300DOI Listing
September 2020

Impact of immunosuppressive therapy on brain derived cytokines after liver transplantation.

Transpl Immunol 2020 02 24;58:101248. Epub 2019 Oct 24.

Department of Neurology, Hannover Medical School, Hannover, Germany; Integrated Research and Treatment Centre Transplantation (IFB-Tx), Hannover Medical School, Hannover, Germany.

Background: While acute neurotoxic side effects of calcineurin inhibitors (CNI) are well-known, data upon long-term effects on brain structure and function are sparse. We hypothesize that long-term CNI therapy affects the neuroimmune system, thereby, increasing the risk of neurodegeneration. Here, we measured the impact of CNI therapy on plasma levels of brain- and T cell-derived cytokines in a cohort of patients after liver transplantation (LT).

Methods: Levels of T cell-mediated cytokines (e.g. Interferon-γ (IFN-γ)) and brain-derived cytokines (e.g. brain derived neurotrophic factor (BDNF), platelet derived growth factor (PDGF)) were measured by multiplex assays in plasma of 82 patients about 10 years after LT (17 with CNI free, 35 with CNI low dose, 30 with standard dose CNI immunosuppression) and 33 healthy controls. Data were related to psychometric test results and parameters of cerebral magnetic resonance imaging.

Results: IFN-γ levels were significantly higher in the CNI free LT patient group (p=0.027) compared to healthy controls. BDNF levels were significantly lower in LT patients treated with CNI (CNI low: p<0.001; CNI standard: p=0.016) compared to controls. PDGF levels were significantly lower in the CNI low dose group (p=0.004) and for PDGF-AB/BB also in the CNI standard dose group (p=0.029) compared to controls. BDNF and PDGF negatively correlated with cognitive function and brain volume (p<0.05) in the CNI low dose group.

Conclusion: Our results imply that long-term treatment with CNI suppresses BDNF and PDGF expression, both crucial for neuronal signaling, cell survival and synaptic plasticity and thereby may lead to cognitive dysfunction and neurodegeneration.
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http://dx.doi.org/10.1016/j.trim.2019.101248DOI Listing
February 2020

Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition).

Authors:
Andrea Cossarizza Hyun-Dong Chang Andreas Radbruch Andreas Acs Dieter Adam Sabine Adam-Klages William W Agace Nima Aghaeepour Mübeccel Akdis Matthieu Allez Larissa Nogueira Almeida Giorgia Alvisi Graham Anderson Immanuel Andrä Francesco Annunziato Achille Anselmo Petra Bacher Cosima T Baldari Sudipto Bari Vincenzo Barnaba Joana Barros-Martins Luca Battistini Wolfgang Bauer Sabine Baumgart Nicole Baumgarth Dirk Baumjohann Bianka Baying Mary Bebawy Burkhard Becher Wolfgang Beisker Vladimir Benes Rudi Beyaert Alfonso Blanco Dominic A Boardman Christian Bogdan Jessica G Borger Giovanna Borsellino Philip E Boulais Jolene A Bradford Dirk Brenner Ryan R Brinkman Anna E S Brooks Dirk H Busch Martin Büscher Timothy P Bushnell Federica Calzetti Garth Cameron Ilenia Cammarata Xuetao Cao Susanna L Cardell Stefano Casola Marco A Cassatella Andrea Cavani Antonio Celada Lucienne Chatenoud Pratip K Chattopadhyay Sue Chow Eleni Christakou Luka Čičin-Šain Mario Clerici Federico S Colombo Laura Cook Anne Cooke Andrea M Cooper Alexandra J Corbett Antonio Cosma Lorenzo Cosmi Pierre G Coulie Ana Cumano Ljiljana Cvetkovic Van Duc Dang Chantip Dang-Heine Martin S Davey Derek Davies Sara De Biasi Genny Del Zotto Gelo Victoriano Dela Cruz Michael Delacher Silvia Della Bella Paolo Dellabona Günnur Deniz Mark Dessing James P Di Santo Andreas Diefenbach Francesco Dieli Andreas Dolf Thomas Dörner Regine J Dress Diana Dudziak Michael Dustin Charles-Antoine Dutertre Friederike Ebner Sidonia B G Eckle Matthias Edinger Pascale Eede Götz R A Ehrhardt Marcus Eich Pablo Engel Britta Engelhardt Anna Erdei Charlotte Esser Bart Everts Maximilien Evrard Christine S Falk Todd A Fehniger Mar Felipo-Benavent Helen Ferry Markus Feuerer Andrew Filby Kata Filkor Simon Fillatreau Marie Follo Irmgard Förster John Foster Gemma A Foulds Britta Frehse Paul S Frenette Stefan Frischbutter Wolfgang Fritzsche David W Galbraith Anastasia Gangaev Natalio Garbi Brice Gaudilliere Ricardo T Gazzinelli Jens Geginat Wilhelm Gerner Nicholas A Gherardin Kamran Ghoreschi Lara Gibellini Florent Ginhoux Keisuke Goda Dale I Godfrey Christoph Goettlinger Jose M González-Navajas Carl S Goodyear Andrea Gori Jane L Grogan Daryl Grummitt Andreas Grützkau Claudia Haftmann Jonas Hahn Hamida Hammad Günter Hämmerling Leo Hansmann Goran Hansson Christopher M Harpur Susanne Hartmann Andrea Hauser Anja E Hauser David L Haviland David Hedley Daniela C Hernández Guadalupe Herrera Martin Herrmann Christoph Hess Thomas Höfer Petra Hoffmann Kristin Hogquist Tristan Holland Thomas Höllt Rikard Holmdahl Pleun Hombrink Jessica P Houston Bimba F Hoyer Bo Huang Fang-Ping Huang Johanna E Huber Jochen Huehn Michael Hundemer Christopher A Hunter William Y K Hwang Anna Iannone Florian Ingelfinger Sabine M Ivison Hans-Martin Jäck Peter K Jani Beatriz Jávega Stipan Jonjic Toralf Kaiser Tomas Kalina Thomas Kamradt Stefan H E Kaufmann Baerbel Keller Steven L C Ketelaars Ahad Khalilnezhad Srijit Khan Jan Kisielow Paul Klenerman Jasmin Knopf Hui-Fern Koay Katja Kobow Jay K Kolls Wan Ting Kong Manfred Kopf Thomas Korn Katharina Kriegsmann Hendy Kristyanto Thomas Kroneis Andreas Krueger Jenny Kühne Christian Kukat Désirée Kunkel Heike Kunze-Schumacher Tomohiro Kurosaki Christian Kurts Pia Kvistborg Immanuel Kwok Jonathan Landry Olivier Lantz Paola Lanuti Francesca LaRosa Agnès Lehuen Salomé LeibundGut-Landmann Michael D Leipold Leslie Y T Leung Megan K Levings Andreia C Lino Francesco Liotta Virginia Litwin Yanling Liu Hans-Gustaf Ljunggren Michael Lohoff Giovanna Lombardi Lilly Lopez Miguel López-Botet Amy E Lovett-Racke Erik Lubberts Herve Luche Burkhard Ludewig Enrico Lugli Sebastian Lunemann Holden T Maecker Laura Maggi Orla Maguire Florian Mair Kerstin H Mair Alberto Mantovani Rudolf A Manz Aaron J Marshall Alicia Martínez-Romero Glòria Martrus Ivana Marventano Wlodzimierz Maslinski Giuseppe Matarese Anna Vittoria Mattioli Christian Maueröder Alessio Mazzoni James McCluskey Mairi McGrath Helen M McGuire Iain B McInnes Henrik E Mei Fritz Melchers Susanne Melzer Dirk Mielenz Stephen D Miller Kingston H G Mills Hans Minderman Jenny Mjösberg Jonni Moore Barry Moran Lorenzo Moretta Tim R Mosmann Susann Müller Gabriele Multhoff Luis Enrique Muñoz Christian Münz Toshinori Nakayama Milena Nasi Katrin Neumann Lai Guan Ng Antonia Niedobitek Sussan Nourshargh Gabriel Núñez José-Enrique O'Connor Aaron Ochel Anna Oja Diana Ordonez Alberto Orfao Eva Orlowski-Oliver Wenjun Ouyang Annette Oxenius Raghavendra Palankar Isabel Panse Kovit Pattanapanyasat Malte Paulsen Dinko Pavlinic Livius Penter Pärt Peterson Christian Peth Jordi Petriz Federica Piancone Winfried F Pickl Silvia Piconese Marcello Pinti A Graham Pockley Malgorzata Justyna Podolska Zhiyong Poon Katharina Pracht Immo Prinz Carlo E M Pucillo Sally A Quataert Linda Quatrini Kylie M Quinn Helena Radbruch Tim R D J Radstake Susann Rahmig Hans-Peter Rahn Bartek Rajwa Gevitha Ravichandran Yotam Raz Jonathan A Rebhahn Diether Recktenwald Dorothea Reimer Caetano Reis e Sousa Ester B M Remmerswaal Lisa Richter Laura G Rico Andy Riddell Aja M Rieger J Paul Robinson Chiara Romagnani Anna Rubartelli Jürgen Ruland Armin Saalmüller Yvan Saeys Takashi Saito Shimon Sakaguchi Francisco Sala-de-Oyanguren Yvonne Samstag Sharon Sanderson Inga Sandrock Angela Santoni Ramon Bellmàs Sanz Marina Saresella Catherine Sautes-Fridman Birgit Sawitzki Linda Schadt Alexander Scheffold Hans U Scherer Matthias Schiemann Frank A Schildberg Esther Schimisky Andreas Schlitzer Josephine Schlosser Stephan Schmid Steffen Schmitt Kilian Schober Daniel Schraivogel Wolfgang Schuh Thomas Schüler Reiner Schulte Axel Ronald Schulz Sebastian R Schulz Cristiano Scottá Daniel Scott-Algara David P Sester T Vincent Shankey Bruno Silva-Santos Anna Katharina Simon Katarzyna M Sitnik Silvano Sozzani Daniel E Speiser Josef Spidlen Anders Stahlberg Alan M Stall Natalie Stanley Regina Stark Christina Stehle Tobit Steinmetz Hannes Stockinger Yousuke Takahama Kiyoshi Takeda Leonard Tan Attila Tárnok Gisa Tiegs Gergely Toldi Julia Tornack Elisabetta Traggiai Mohamed Trebak Timothy I M Tree Joe Trotter John Trowsdale Maria Tsoumakidou Henning Ulrich Sophia Urbanczyk Willem van de Veen Maries van den Broek Edwin van der Pol Sofie Van Gassen Gert Van Isterdael René A W van Lier Marc Veldhoen Salvador Vento-Asturias Paulo Vieira David Voehringer Hans-Dieter Volk Anouk von Borstel Konrad von Volkmann Ari Waisman Rachael V Walker Paul K Wallace Sa A Wang Xin M Wang Michael D Ward Kirsten A Ward-Hartstonge Klaus Warnatz Gary Warnes Sarah Warth Claudia Waskow James V Watson Carsten Watzl Leonie Wegener Thomas Weisenburger Annika Wiedemann Jürgen Wienands Anneke Wilharm Robert John Wilkinson Gerald Willimsky James B Wing Rieke Winkelmann Thomas H Winkler Oliver F Wirz Alicia Wong Peter Wurst Jennie H M Yang Juhao Yang Maria Yazdanbakhsh Liping Yu Alice Yue Hanlin Zhang Yi Zhao Susanne Maria Ziegler Christina Zielinski Jakob Zimmermann Arturo Zychlinsky

Eur J Immunol 2019 Oct;49(10):1457-1973

Max Planck Institute for Infection Biology, Berlin, Germany.

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.
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http://dx.doi.org/10.1002/eji.201970107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7350392PMC
October 2019