Publications by authors named "Laura Maggi"

97 Publications

Heterogeneous magnitude of immunological memory to SARS-CoV-2 in recovered individuals.

Clin Transl Immunology 2021 6;10(5):e1281. Epub 2021 May 6.

Department of Experimental and Clinical Medicine University of Florence Florence Italy.

Objective: Although the adaptive immune response to SARS-CoV-2 has been characterised in the acute and early convalescent phase of the disease, few studies explore whether natural infection elicits long-lasting immunological memory in recovered individuals. In this work, we aimed to assess the maintenance of immunological memory to SARS-CoV-2.

Methods: We evaluated the long-term virus-specific cellular and humoral immune response in the members of an Italian Serie A football team, who experienced a cluster of COVID-19 in March 2020, which was strictly evaluated in the following months.

Results: Our results highlight a heterogeneous magnitude of immunological memory at 5 months after infection. Indeed, 20% of the subjects displayed a weak cellular and humoral memory to SARS-CoV-2, suggesting that they may be at higher risk of reinfection. In addition, a history of symptomatic COVID-19 was associated with higher levels of SARS-CoV-2-reactive CD4 T cells and specific antibody levels than in asymptomatic individuals.

Conclusion: Collectively, these data demonstrate that immunity to SARS-CoV-2 is maintained five months postinfection even if the magnitude of response is heterogeneous among individuals. This finding suggests that some COVID-19-recovered subjects may benefit from vaccination.
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http://dx.doi.org/10.1002/cti2.1281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8101693PMC
May 2021

T Cell Response Toward Tissue-and Epidermal-Transglutaminases in Coeliac Disease Patients Developing Dermatitis Herpetiformis.

Front Immunol 2021 20;12:645143. Epub 2021 Apr 20.

Department of Experimental and Clinical Medicine, School of Human Health Sciences, University of Florence, Florence, Italy.

The reason why only few coeliac patients develop the cutaneous manifestation of the disease, named dermatitis herpetiformis (DH), is still unknown. Epidermal transglutaminase (TG3) has been described as the main autoantigen of humoral immunity in DH but the mechanisms leading to this autoimmune response remain obscure. Here we characterized T cells from skin, gut and peripheral blood of DH and coeliac disease (CD) patients, evaluated the impact of the gluten-free diet on circulating T lymphocytes' phenotype and investigated antigen specific T cell response toward epidermal and tissue transglutaminase (TG2). DH patients showed an increased frequency of skin-derived T cells producing TNFα when compared to CD patients. Moreover, circulating T cells producing TNFα and IL-17A positively correlated with clinical score of skin disease activity and decreased after gluten-free diet. Finally, TG2 and TG3-specific T cells resulted more reactive to antigens stimulation in DH patients and showed cross reactivity toward the two autoantigens in both the group of patients. Our data suggest a role of TNFα and IL-17A producing cells in the development of DH and, for the first time, show the existence of a crossed T cell response toward the two transglutaminases isoforms, thus suggesting new insights on T cells role in skin damage.
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http://dx.doi.org/10.3389/fimmu.2021.645143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8093623PMC
April 2021

First-dose mRNA vaccination is sufficient to reactivate immunological memory to SARS-CoV-2 in recovered COVID-19 subjects.

J Clin Invest 2021 May 3. Epub 2021 May 3.

Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.

The characterization of the adaptive immune response to COVID-19 vaccination in individuals who recovered from SARS-CoV-2 infection may define current and future clinical practice. To determine the effect of two doses BNT162b2 mRNA COVID-19 vaccination schedule in individuals who recovered from COVID-19 (COVID-19 recovered) compared to naïve subjects, we evaluated SARS-CoV-2 Spike-specific T and B cell responses, as well as specific IgA, IgG, IgM and neutralizing antibodies titers in 22 individuals who received BNT162b2 mRNA COVID-19 vaccine, 11 of which had a previous history of SARS-CoV-2 infection. Evaluations were performed before vaccination and then weekly until 7 days post second injection. Data obtained clearly showed that one vaccine dose is sufficient to increase both cellular and humoral immune response in COVID-19 recovered subjects without any additional improvement after the second dose. On the contrary, the second dose is proved mandatory in naïve ones to further enhance the immune response. These findings were further confirmed at serological level in a larger cohort of naïve (68) and COVID-19 recovered (29) subjects, tested up to 50 days post vaccination. These results question whether a second vaccine injection in COVID-19 recovered subjects is required and indicate that millions of vaccine doses may be redirected to naïve individuals, thus shortening the time to reach herd immunity.
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http://dx.doi.org/10.1172/JCI149150DOI Listing
May 2021

Study of Signal Transduction Pathways by Phospho-Protein Evaluation.

Methods Mol Biol 2021 ;2285:191-200

Department of Experimental and Clinical Medicine and DENOTHE Center, University of Florence, Firenze, Italy.

Flow cytometric evaluation of phosphorylation status of signal transduction molecules is a useful method to study T-cell signaling pathways. As mutations occurring in TCR complex molecules, common gamma chain family's cytokines, their receptors or molecules involved in these pathways can lead to severe immune system defects, the study of T-cell signal transduction can be applied to both basic and clinical/translational research areas. In the present chapter, we show two different protocols for the study of T- cell response to an antigen-like stimulus and to IL-2.
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http://dx.doi.org/10.1007/978-1-0716-1311-5_16DOI Listing
January 2021

Human T-Cell Cloning by Limiting Dilution.

Methods Mol Biol 2021 ;2285:165-172

Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.

Human T cells represent a heterogeneous population, including cells with different phenotypical and function properties. Despite, in the last years, several technologies were developed to investigate phenotypical properties of T cells at single cell level, in vitro T cell clone 's culture remains the only way to perform functional study on T cells at single cell levels. Here, we describe the method to obtain human T cell clones by limiting dilution in the presence of feeder cells and to maintain them in culture for further investigations.
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http://dx.doi.org/10.1007/978-1-0716-1311-5_14DOI Listing
January 2021

Activated IL-6 signaling contributes to the pathogenesis of, and is a novel therapeutic target for, CALR-mutated MPNs.

Blood Adv 2021 Apr;5(8):2184-2195

Center of Research and Innovation of Myeloproliferative Neoplasms (CRIMM), Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.

Calreticulin (CALR), an endoplasmic reticulum-associated chaperone, is frequently mutated in myeloproliferative neoplasms (MPNs). Mutated CALR promotes downstream JAK2/STAT5 signaling through interaction with, and activation of, the thrombopoietin receptor (MPL). Here, we provide evidence of a novel mechanism contributing to CALR-mutated MPNs, represented by abnormal activation of the interleukin 6 (IL-6)-signaling pathway. We found that UT7 and UT7/mpl cells, engineered by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) to express the CALR type 1-like (DEL) mutation, acquired cytokine independence and were primed to the megakaryocyte (Mk) lineage. Levels of IL-6 messenger RNA (mRNA), extracellular-released IL-6, membrane-associated glycoprotein 130 (gp130), and IL-6 receptor (IL-6R), phosphorylated JAK1 and STAT3 (p-JAK1 and p-STAT3), and IL-6 promoter region occupancy by STAT3 all resulted in increased CALR DEL cells in the absence of MPL stimulation. Wild-type, but not mutated, CALR physically interacted with gp130 and IL-6R, downregulating their expression on the cell membrane. Agents targeting gp130 (SC-144), IL-6R (tocilizumab [TCZ]), and cell-released IL-6 reduced proliferation of CALR DEL as well as CALR knockout cells, supporting a mutated CALR loss-of-function model. CD34+ cells from CALR-mutated patients showed increased levels of IL-6 mRNA and p-STAT3, and colony-forming unit-Mk growth was inhibited by either SC144 or TCZ, as well as an IL-6 antibody, supporting cell-autonomous activation of the IL-6 pathway. Targeting IL-6 signaling also reduced colony formation by CD34+ cells of JAK2V617F-mutated patients. The combination of TCZ and ruxolitinib was synergistic at very low nanomolar concentrations. Overall, our results suggest that target inhibition of IL-6 signaling may have therapeutic potential in CALR, and possibly JAK2V617F, mutated MPNs.
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http://dx.doi.org/10.1182/bloodadvances.2020003291DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8095134PMC
April 2021

Selecting antidepressants according to a drug-by-environment interaction: A comparison of fluoxetine and minocycline effects in mice living either in enriched or stressful conditions.

Behav Brain Res 2021 Jun 26;408:113256. Epub 2021 Mar 26.

Center for Behavioral Sciences and Mental Health, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161, Rome, Italy. Electronic address:

Selective serotonin reuptake inhibitors (SSRIs) are the first-line treatment for major depressive disorder. It has been recently proposed that these drugs, by enhancing neural plasticity, amplify the influences of the living conditions on mood. Consequently, SSRI outcome depends on the quality of the environment, improving symptomatology mainly in individuals living in favorable conditions. In adverse conditions, drugs with a different mechanism of action might have higher efficacy. The antibiotic minocycline, with neuroprotective and anti-inflammatory properties, has been recently proposed as a novel potential antidepressant treatment. To explore the drug-by-environment interaction, we compared the effects on depressive-like behavior and neural plasticity of the SSRI fluoxetine and minocycline in enriched and stressful conditions. We first exposed C57BL/6 adult female mice to 14 days of chronic unpredictable mild stress to induce a depressive-like profile. Afterward, mice received vehicle, fluoxetine, or minocycline for 21 days, while exposed to either enriched or stressful conditions. During the first five days, fluoxetine led to an improvement in enrichment but not in stress. By contrast, minocycline led to an improvement in both conditions. After 21 days, all groups showed a significant improvement in enrichment while fluoxetine worsened the depressive like behavior in stress. The effects of the drugs on neural plasticity, measured as long-term potentiation, were also environment-dependent. Overall, we show that the environment affects fluoxetine but not minocycline outcome, indicating that the latter represents a potential alternative to SSRIs to treat depressed patients living in adverse conditions. From a translation perspective, our finding call for considering the drug-by-environment interaction to select the most effective pharmacological treatment.
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http://dx.doi.org/10.1016/j.bbr.2021.113256DOI Listing
June 2021

Metabolomic/lipidomic profiling of COVID-19 and individual response to tocilizumab.

PLoS Pathog 2021 02 1;17(2):e1009243. Epub 2021 Feb 1.

Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino, Florence, Italy.

The current pandemic emergence of novel coronavirus disease (COVID-19) poses a relevant threat to global health. SARS-CoV-2 infection is characterized by a wide range of clinical manifestations, ranging from absence of symptoms to severe forms that need intensive care treatment. Here, plasma-EDTA samples of 30 patients compared with age- and sex-matched controls were analyzed via untargeted nuclear magnetic resonance (NMR)-based metabolomics and lipidomics. With the same approach, the effect of tocilizumab administration was evaluated in a subset of patients. Despite the heterogeneity of the clinical symptoms, COVID-19 patients are characterized by common plasma metabolomic and lipidomic signatures (91.7% and 87.5% accuracy, respectively, when compared to controls). Tocilizumab treatment resulted in at least partial reversion of the metabolic alterations due to SARS-CoV-2 infection. In conclusion, NMR-based metabolomic and lipidomic profiling provides novel insights into the pathophysiological mechanism of human response to SARS-CoV-2 infection and to monitor treatment outcomes.
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http://dx.doi.org/10.1371/journal.ppat.1009243DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7877736PMC
February 2021

The IL-33/ST2 pathway is not essential to Th2 stimulation but is key for modulation and survival during chronic infection with Schistosoma mansoni in mice.

Cytokine 2021 Feb 16;138:155390. Epub 2020 Dec 16.

Laboratório de Esquistossomose e Imunohelmintologia, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. Electronic address:

Morbidity during chronic schistosomiasis has been associated with the induction and modulation of type-2 granulomatous inflammatory response induced by antigens secreted by the eggs, which become trapped in capillary venules of the host tissues, especially in the liver and intestines. IL-33, an alarmin released after cell damage, binds to its ST2 (suppressor of tumorigenicity 2) receptor, expressed in an variety of immune cells, including ILC2 and macrophages, and stimulates the early production of IL-5 and IL-13, which leads to eosinophil infiltration and activation of a Th2 response. However, the role of IL-33/ST2 activation on Schistosoma-induced granuloma formation and modulation is mostly unknown. In the current work, we comparatively evaluated the immune response and granuloma formation in wild-type BALB/c (WT) and BALB/c mice genetically deficient in the IL-33 receptor (ST2) experimentally infected with Schistosoma mansoni. Mice were infected with 25 or 50 S. mansoni cercariae and followed for up to 14 weeks to assess mortality. Mice from each experimental group were comparatively evaluated for parasite burden, liver immune response, and granuloma appearance during acute and chronic schistosomiasis. Our data showed that the number of circulating worms and eggs retained in the liver and eliminated in the feces was similar in WT and ST2 infected mice, but infected ST2 mice presented an enhanced rate of mortality. Interestingly, the production of type-2 cytokines by soluble egg antigens (SEA)-stimulated spleen cells, the serum concentrations of IL-5 and Immunoglobulin (Ig)-E, and the level of parasite-reactive IgG1 were similar in infected mice of both experimental groups. The concentrations of IL-4, IL-5, IL-13, and IFN-γ in liver homogenate of infected mice also did not differ between the strains at acute schistosomiasis, but there was a significant increase in IL-17 levels in ST2 infected mice at this phase. On the other hand, IL-4, IL-13, IL-10, IL-17, and IFN-γ concentrations were reduced and the ratios of IL-4/IFN-γ and IL-17/IFN-γ were higher in liver homogenate of chronically infected ST2 mice, suggesting unbalanced Th2 and Th17 responses. Moreover, liver granulomas of ST2 mice were larger and disorganized, showing an intense cellular infiltrate, rich in eosinophils and neutrophils. Our results suggest that the absence of the IL-33/ST2 pathway is not essential for the Schistosoma-induced Th2 response, but is necessary to prevent host mortality by modulating granuloma-mediated pathology.
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http://dx.doi.org/10.1016/j.cyto.2020.155390DOI Listing
February 2021

Pulmonary vascular improvement in severe COVID-19 patients treated with tocilizumab.

Immunol Lett 2020 12 5;228:122-128. Epub 2020 Nov 5.

Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Immunology and Cell Therapy Unit, Careggi University Hospital, Florence, Italy. Electronic address:

As of October 2020 management of Coronavirus disease 2019 (COVID-19) is based on supportive care and off-label or compassionate-use therapies. On March 2020 tocilizumab - an anti-IL-6 receptor monoclonal antibody - was suggested as immunomodulatory treatment in severe COVID-19 because hyperinflammatory syndrome occurs in many patients similarly to the cytokine release syndrome that develops after CAR-T cell therapy. In our retrospective observational study, 20 severe COVID-19 patients requiring intensive care were treated with tocilizumab in addition to standard-of-care therapy (SOC) and compared with 13 COVID-19 patients receiving only SOC. Clinical respiratory status, inflammatory markers and vascular radiologic score improved after one week from tocilizumab administration. On the contrary, these parameters were stable or worsened in patients receiving only SOC. Despite major study limitations, improvement of alveolar-arterial oxygen gradient as well as vascular radiologic score after one week may account for improved pulmonary vascular perfusion and could explain the more rapid recovery of COVID-19 patients receiving tocilizumab compared to controls.
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http://dx.doi.org/10.1016/j.imlet.2020.10.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7644186PMC
December 2020

Cell-mediated and humoral adaptive immune responses to SARS-CoV-2 are lower in asymptomatic than symptomatic COVID-19 patients.

Eur J Immunol 2020 Dec 9;50(12):2013-2024. Epub 2020 Nov 9.

Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.

The characterization of cell-mediated and humoral adaptive immune responses to SARS-CoV-2 is fundamental to understand COVID-19 progression and the development of immunological memory to the virus. In this study, we detected T-cells reactive to SARS-CoV-2 proteins M, S, and N, as well as serum virus-specific IgM, IgA, IgG, in nearly all SARS-CoV-2 infected individuals, but not in healthy donors. Virus-reactive T cells exhibited signs of in vivo activation, as suggested by the surface expression of immune-checkpoint molecules PD1 and TIGIT. Of note, we detected antigen-specific adaptive immune response both in asymptomatic and symptomatic SARS-CoV-2 infected subjects. More importantly, symptomatic patients displayed a significantly higher magnitude of both cell-mediated and humoral adaptive immune response to the virus, as compared to asymptomatic individuals. These findings suggest that an uncontrolled adaptive immune response contribute to the development of the life-threatening inflammatory phase of the disease. Finally, this study might open the way to develop effective vaccination strategies.
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http://dx.doi.org/10.1002/eji.202048915DOI Listing
December 2020

Quantitative and qualitative alterations of circulating myeloid cells and plasmacytoid DC in SARS-CoV-2 infection.

Immunology 2020 12 6;161(4):345-353. Epub 2020 Oct 6.

Flow Cytometry Diagnostic Center and Immunotherapy (CDCI), AOU Careggi, Florence, Italy.

SARS-CoV-2 is responsible for a new infectious disease (COVID-19) in which individuals can either remain asymptomatic or progress from mild to severe clinical conditions including acute respiratory distress syndrome and multiple organ failure. The immune mechanisms that potentially orchestrate the pathology in SARS-CoV-2 infection are complex and only partially understood. There is still paucity of data on the features of myeloid cells involved in this viral infection. For this reason, we investigated the different activation status profiles and the subset distribution of myeloid cells and their correlation with disease progression in 40 COVID-19 patients at different stages of disease. COVID-19 patients showed a decrease in the absolute number of plasmacytoid and myeloid dendritic cells, different subset distribution of monocytes and different activation patterns of both monocytes and neutrophils, coupled to a significant reduction of HLA-DR monocyte levels. We found that some of these alterations are typical of all COVID-19 patients, while some others vary at different stages of the disease and correlate with biochemical parameters of inflammation. Collectively, these data suggest that not only the lymphoid, but also the myeloid compartment, is severely affected by SARS-CoV-2 infection.
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http://dx.doi.org/10.1111/imm.13254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7692244PMC
December 2020

Disseminated Mycobacterium xenopi in an Adult with IL-12Rβ1 Deficiency.

J Clin Immunol 2020 11 27;40(8):1166-1170. Epub 2020 Aug 27.

Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134, Florence, FI, Italy.

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http://dx.doi.org/10.1007/s10875-020-00848-wDOI Listing
November 2020

Plasticity and regulatory mechanisms of human ILC2 functions.

Immunol Lett 2020 11 18;227:109-116. Epub 2020 Aug 18.

Department of Experimental and Clinical Medicine and DENOTHE Center, University of Florence, Florence, 50134, Italy.

Human group 2 innate lymphoid cells (ILC2) represent the innate counterpart of Th2 cells and cooperate with them in helminths protection and in the pathogenesis of allergic diseases. Some reports described ILC2 plasticity and few studies investigated the cellular and molecular mechanisms regulating human ILC2 functions. The aim of this study is to define how immune deviation and immune regulation control human ILC2-mediated immune response. Human circulating ILC2 were expanded in vitro and then cultured in presence of IL-12 or IL-1β plus IL-23 or co-coltured in presence of circulating CD4+CD25highFoxp3+Treg. IL-12 induces IFN-γ production and upregulation of T-bet mRNA level on human circulating ILC2 whereas IL-1β and IL-23 mediate IL-22 production and upregulation of RORC mRNA level. In all these conditions, GATA-3 mRNA level is not reduced and the typical type 2 cytokines are only partially reduced. Moreover, "modulated" ILC2 have reduced ability to induce IgE producing by B cells. ILC2 proliferation, cytokines production and CD154 expression were inhibited by CD4+CD25highFoxp3+ Treg cells. TGF-β reduced CD154 expression on ILC2 stimulated with IL-25/IL-33. This study defines possible cellular and molecular mechanisms responsible for modulation and inhibition of human ILC2 activity. These results may be useful in the development of strategies aimed to dampen ILC2 function in type-2 mediated diseases.
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http://dx.doi.org/10.1016/j.imlet.2020.08.004DOI Listing
November 2020

Compassionate use of JAK1/2 inhibitor ruxolitinib for severe COVID-19: a prospective observational study.

Leukemia 2021 04 19;35(4):1121-1133. Epub 2020 Aug 19.

Center Research Innovation of Myeloproliferative Neoplasms (CRIMM), SOD Hematology, University of Florence and AOU Careggi, Florence, Italy.

Overwhelming inflammatory reactions contribute to respiratory distress in patients with COVID-19. Ruxolitinib is a JAK1/JAK2 inhibitor with potent anti-inflammatory properties. We report on a prospective, observational study in 34 patients with COVID-19 who received ruxolitinib on a compassionate-use protocol. Patients had severe pulmonary disease defined by pulmonary infiltrates on imaging and an oxygen saturation ≤ 93% in air and/or PaO2/FiO2 ratio ≤ 300 mmHg. Median age was 80.5 years, and 85.3% had ≥ 2 comorbidities. Median exposure time to ruxolitinib was 13 days, median dose intensity was 20 mg/day. Overall survival by day 28 was 94.1%. Cumulative incidence of clinical improvement of ≥2 points in the ordinal scale was 82.4% (95% confidence interval, 71-93). Clinical improvement was not affected by low-flow versus high-flow oxygen support but was less frequent in patients with PaO2/FiO2 < 200 mmHg. The most frequent adverse events were anemia, urinary tract infections, and thrombocytopenia. Improvement of inflammatory cytokine profile and activated lymphocyte subsets was observed at day 14. In this prospective cohort of aged and high-risk comorbidity patients with severe COVID-19, compassionate-use ruxolitinib was safe and was associated with improvement of pulmonary function and discharge home in 85.3%. Controlled clinical trials are necessary to establish efficacy of ruxolitinib in COVID-19.
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http://dx.doi.org/10.1038/s41375-020-01018-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7437386PMC
April 2021

Th17 lymphocyte-dependent degradation of joint cartilage by synovial fibroblasts in a humanized mouse model of arthritis and reversal by secukinumab.

Eur J Immunol 2021 01 9;51(1):220-230. Epub 2020 Aug 9.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy.

How T-helper (Th) lymphocyte subpopulations identified in synovial fluid from patients with juvenile idiopathic arthritis (JIA) (Th17, classic Th1, or nonclassic Th1) drive joint damage is of great interest for the possible use of biological drugs that inhibit the specific cytokines. Our objective was to clarify the role of such Th subpopulations in the pathogenesis of articular cartilage destruction by synovial fibroblasts (SFbs), and the effect of Th17 blockage in an animal model. SFbs were isolated from healthy subjects and patients with JIA, and peripheral blood Th lymphocytes subsets were obtained from healthy subjects. Fragments of human cartilage from healthy subjects in a collagen matrix containing JIA or normal SFbs grafted underskin in SCID mice were used to measure cartilage degradation under the effects of Th supernatants. JIA SFbs overexpress MMP9 and MMP2 and Th17 induce both MMPs in normal SFbs, while nonclassic Th1 upregulate urokinase plasminogen activator (uPA) activity. In vitro invasive phenotype of normal SFbs is stimulated with conditioned medium of Th17 and nonclassic-Th1. In the in vivo "inverse wrap" model, normal SFbs stimulated with supernatants of Th17-lymphocytes and nonclassic Th1 produced a cartilage invasion and degradation similar to JIA SFbs. Secukinumab inhibits the cartilage damage triggered by factors produced by Th17.
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http://dx.doi.org/10.1002/eji.202048773DOI Listing
January 2021

Impaired immune cell cytotoxicity in severe COVID-19 is IL-6 dependent.

J Clin Invest 2020 09;130(9):4694-4703

Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.

BACKGROUNDCoronavirus disease 19 (COVID-19) is an emerging infectious disease caused by SARS-CoV-2. Antiviral immune response is crucial to achieve pathogen clearance; however, in some patients an excessive and aberrant host immune response can lead to an acute respiratory distress syndrome. The comprehension of the mechanisms that regulate pathogen elimination, immunity, and pathology is essential to better characterize disease progression and widen the spectrum of therapeutic options.METHODSWe performed a flow cytometric characterization of immune cell subsets from 30 patients with COVID-19 and correlated these data with clinical outcomes.RESULTSPatients with COVID-19 showed decreased numbers of circulating T, B, and NK cells and exhibited a skewing of CD8+ T cells toward a terminally differentiated/senescent phenotype. In agreement, CD4+ T and CD8+ T, but also NK cells, displayed reduced antiviral cytokine production capability. Moreover, a reduced cytotoxic potential was identified in patients with COVID-19, particularly in those who required intensive care. The latter group of patients also showed increased serum IL-6 levels that inversely correlated to the frequency of granzyme A-expressing NK cells. Off-label treatment with tocilizumab restored the cytotoxic potential of NK cells.CONCLUSIONThe association between IL-6 serum levels and the impairment of cytotoxic activity suggests the possibility that targeting this cytokine may restore antiviral mechanisms.FUNDINGThis study was supported by funds from the Department of Experimental and Clinical Medicine of University of Florence (the ex-60% fund and the "Excellence Departments 2018-2022 Project") derived from Ministero dell'Istruzione, dell'Università e della Ricerca (Italy).
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http://dx.doi.org/10.1172/JCI138554DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7456250PMC
September 2020

Human T cells interacting with HNSCC-derived mesenchymal stromal cells acquire tissue-resident memory like properties.

Eur J Immunol 2020 10 2;50(10):1571-1579. Epub 2020 Jun 2.

Department of Experimental and Clinical Medicine, University of Florence, Firenze, Italy.

Tissue-resident memory (Trm) cells are specialized components of both CD4+ and CD8+ T cell subsets that persist in peripheral nonlymphoid tissues following infections and provide fast response in case of a secondary invasion by the same pathogen. Trm cells express the surface markers CD69, CD103, and the immune checkpoint molecule PD-1. Trm cells develop not only in the context of infections but also in tumors, where they can provide a line of defense as suggested by the positive correlation between the frequency of tumor-infiltrating Trm cells and patients' survival. Trm cells persistence in peripheral tissues depends on their adaptation to the local microenvironment and the presence of survival factors, mainly IL-7, IL-15, and Notch ligands. However, the cell sources of these factors are largely unknown, especially in the context of tumors. Here, we show that head-neck squamous cell carcinoma (HNSCC) is enriched in CD4+ and CD8+ T cells with a Trm phenotype. Moreover, we show that mesenchymal stromal cells that accumulate in HNSCC are a source of survival factors and allow proper expression of Trm-typical markers in a VCAM1-dependent manner.
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http://dx.doi.org/10.1002/eji.202048544DOI Listing
October 2020

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

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

Flow Cytometry Laboratory, Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, German Research Center for Environmental Health, München, 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

Biological and clinical significance of T helper 17 cell plasticity.

Immunology 2019 12 14;158(4):287-295. Epub 2019 Oct 14.

Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.

Mature T helper (Th) effector cells originate following antigen recognition by naive T precursors. The maturation process is accompanied by the acquisition of specific effector functions that distinguish at least three different T helper subsets: Th1, Th2 and Th17. In general, maturation of somatic cells is accompanied by terminal differentiation. However, accumulating evidence shows that effector T cells retain a certain degree of plasticity. This is especially true for Th17 cells, which have been shown to converge towards other phenotypes in response to specific microenvironmental pressure. In this review we will discuss the experimental evidence that supports the hypothesis of Th17 plasticity, with particular emphasis on the generation of Th17-derived 'non-classic' Th1 cells, and the molecular networks that control it. Moreover, we will consider why Th17 plasticity is important for host protection, but also why it can have pathogenic functions during chronic inflammation. Regarding the last point, we will discuss a possible role for biological drugs in the control of Th17 plasticity and disease course.
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http://dx.doi.org/10.1111/imm.13124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6856928PMC
December 2019

Biologicals targeting type 2 immunity: Lessons learned from asthma, chronic urticaria and atopic dermatitis.

Eur J Immunol 2019 09 12;49(9):1334-1343. Epub 2019 Aug 12.

Department of Experimental and Clinical Medicine and DENOTHE Center, University of Florence, Florence, Italy.

During the last decades, progression of research has led to great achievements for treatment and therapy of several disabling disorders, particularly in the field of chronic inflammatory diseases. The increased knowledge of the molecular mechanisms operating in such diseases has represented the first step in this process, and the discovery of molecules able to interfere with the natural history of the diseases, has been the second. This review is focused on the effects of biologics on type 2 diseases such as asthma, chronic urticaria and atopic dermatitis, both biologics just approved for clinical application and also those that are currently undergoing clinical trials. We will also discuss aspects and emphasize clinical trials and recently published studies, as well as research that is currently in the progress, which will be highly relevant for basic immunologists. Likewise, we will cover aspects that are pertinent for clinical immunologists and highlight translational studies that are evaluating novel biologicals in animal models.
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http://dx.doi.org/10.1002/eji.201948156DOI Listing
September 2019

Interplay between inflammation and neural plasticity: Both immune activation and suppression impair LTP and BDNF expression.

Brain Behav Immun 2019 10 4;81:484-494. Epub 2019 Jul 4.

Department of Physiology and Pharmacology, Laboratory Affiliated to Istituto Pasteur-Italy, Sapienza University of Rome, Italy. Electronic address:

An increasing number of studies show that both inflammation and neural plasticity act as key players in the vulnerability and recovery from psychiatric disorders and neurodegenerative diseases. However, the interplay between these two players has been limitedly explored. In fact, while a few studies reported an immune activation, others conveyed an immune suppression, associated with an impairment in neural plasticity. Therefore, we hypothesized that deviations in inflammatory levels in both directions may impair neural plasticity. We tested this hypothesis experimentally, by acute treatment of C57BL/6 adult male mice with different doses of two inflammatory modulators: lipopolysaccharide (LPS), an endotoxin, and ibuprofen (IBU), a nonselective cyclooxygenase inhibitor, which are respectively a pro- and an anti-inflammatory agent. The results showed that LPS and IBU have different effects on behavior and inflammatory response. LPS treatment induced a reduction of body temperature, a decrease of body weight and a reduced food and liquid intake. In addition, it led to increased levels of inflammatory markers expression, both in the total hippocampus and in isolated microglia cells, including Interleukin (IL)-1β, and enhanced the concentration of prostaglandin E (PGE). On the other hand, IBU increased the level of anti-inflammatory markers, decreased tryptophan 2,3-dioxygenase (TDO2), the first step in the kynurenine pathway known to be activated during inflammatory conditions, and PGE levels. Though LPS and IBU administration differently affected mediators related with pro- or anti-inflammatory responses, they produced overlapping effects on neural plasticity. Indeed, higher doses of both LPS and IBU induced a statistically significant decrease in the amplitude of long-term potentiation (LTP), in Brain-Derived Neurotrophic Factor (BDNF) expression levels and in the phosphorylation of the AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor subunit GluR1, compared to the control group. Such effect appears to be dose-dependent since only the higher, but not the lower, dose of both compounds led to a plasticity impairment. Overall, the present findings indicate that acute treatment with pro- and anti-inflammatory agents impair neural plasticity in a dose dependent manner.
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http://dx.doi.org/10.1016/j.bbi.2019.07.003DOI Listing
October 2019

The protease systems and their pathogenic role in juvenile idiopathic arthritis.

Autoimmun Rev 2019 Aug 8;18(8):761-766. Epub 2019 Jun 8.

Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy.

Numerous proteases produced by synovial cells of arthritic joints, chondrocytes, macrophages and polymorphonuclear cells have been identified as responsible for the joint damage in rheumatoid arthritis. There are few scientific contributions aimed to identify similar mechanisms in the joints of patients with juvenile idiopathic arthritis. Recently, some mechanisms emerged, triggered by the TH17 and TH1/TH17 lymphocytes, which could shed new light on unexpected pathogenic pathways of joint damage in the JIA, mainly regarding the RANK-RANKL pathway. Other novelties are linked to the mechanisms of acidification of the synovial fluid, which create a microenvironment suitable for the extracellular activity of lysosomal enzymes. Some biological drugs currently used in the therapy of JIA can interfere with these mechanisms.
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http://dx.doi.org/10.1016/j.autrev.2019.06.010DOI Listing
August 2019

Th17 and Th1 Lymphocytes in Oligoarticular Juvenile Idiopathic Arthritis.

Front Immunol 2019 14;10:450. Epub 2019 Mar 14.

Department of Experimental and Clinical Medicine and DENOTHE Center, University of Florence, Florence, Italy.

In the last years much attention has focused on the Th17 and Th1 phenotypes and on their pathogenic role in juvenile idiopathic arthritis, investigating how the cytokines produced by T helper cells act on resident cells on the synovia and which signal transduction pathways regulate Th17 cells proliferation and plasticity. In this context, an important milestone was represented by the identification of the non-classic Th1 phenotype, developed from the shift of Th17 cells. The cytokine TNF-α, beyond its well-known proinflammatory activity is involved in this process and this is one of the reasons why the TNF-α inhibitors are widely used in the treatment of juvenile idiopathic arthritis patients.
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http://dx.doi.org/10.3389/fimmu.2019.00450DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6428030PMC
June 2020

Human neutrophils activated via TLR8 promote Th17 polarization through IL-23.

J Leukoc Biol 2019 06 28;105(6):1155-1165. Epub 2019 Feb 28.

Department of Medicine, Section of General Pathology, University of Verona, Verona, Italy.

Human neutrophils contribute to the regulation of inflammation via the generation of a range of cytokines that affect all elements of the immune system. Here, we investigated their ability to express some of the members of the IL-12 family after incubation with TLR8 agonists. Highly pure human neutrophils were thus incubated for up to 48 h with or without R848, or other TLR8 agonists, to then measure the expression levels of transcripts and proteins for IL-12 family member subunits by RNA-seq, reverse transcription quantitative PCR, and ELISA. We show a TLR8-mediated inducible expression of IL-12B and IL-23A, but not IL-12A, mRNA, which occurs via chromatin remodeling (as assessed by ChIP-seq), and subsequent production of IL-23 and IL-12B, but no IL-12, proteins. Induction of IL-23 requires endogenous TNF-α, as both mRNA and protein levels were blocked in TLR8-activated neutrophils via a TNF-α-neutralizing Ab. We also show that supernatants from TLR8-activated neutrophils, but not autologous monocytes, induce the differentiation of Th17 cells from naïve T cells in an IL-23-dependent fashion. This study unequivocally demonstrates that highly pure human neutrophils express and produce IL-23, further supporting the key roles played by these cells in the important IL-17/IL-23 network and Th17 responses.
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http://dx.doi.org/10.1002/JLB.MA0818-308RDOI Listing
June 2019

Combined Fluoxetine and Metformin Treatment Potentiates Antidepressant Efficacy Increasing IGF2 Expression in the Dorsal Hippocampus.

Neural Plast 2019 21;2019:4651031. Epub 2019 Jan 21.

Center for Behavioral Sciences and Mental Health, Istituto Superiore di Sanità, Rome, Italy.

An increasing number of studies show that selective serotonin reuptake inhibitors (SSRIs) exert their therapeutic action, at least in part, by amplifying the influence of the living environment on mood. As a consequence, when administered in a favorable environment, SSRIs lead to a reduction of symptoms, but in stressful conditions, they show limited efficacy. Therefore, novel therapeutic approaches able to neutralize the influence of the stressful environment on treatment are needed. The aim of our study was to test whether, in a mouse model of depression, the combined administration of SSRI fluoxetine and metformin, a drug able to improve the metabolic profile, counteracts the limited efficacy of fluoxetine alone when administered in stressful conditions. Indeed, metabolic alterations are associated to both the onset of major depression and the antidepressant efficacy. To this goal, adult C57BL/6 male mice were exposed to stress for 6 weeks; the first two weeks was aimed at generating a mouse model of depression. During the remaining 4 weeks, mice received one of the following treatments: vehicle, fluoxetine, metformin, or a combination of fluoxetine and metformin. We measured liking- and wanting-type anhedonia as behavioral phenotypes of depression and assessed the expression levels of selected genes involved in major depressive disorder and antidepressant response in the dorsal and ventral hippocampus, which are differently involved in the depressive symptomatology. The combined treatment was more effective than fluoxetine alone in ameliorating the depressive phenotype after one week of treatment. This was associated to an increase in IGF2 mRNA expression and enhanced long-term potentiation, specifically in the dorsal hippocampus, at the end of treatment. Overall, the present results show that, when administered in stressful conditions, the combined fluoxetine and metformin treatment may represent a more effective approach than fluoxetine alone in a short term. Finally, our findings highlight the relevance of polypharmacological strategy as effective interventions to increase the efficacy of the antidepressant drugs currently available.
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http://dx.doi.org/10.1155/2019/4651031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6360645PMC
May 2019

Microglia shape presynaptic properties at developing glutamatergic synapses.

Glia 2019 01 11;67(1):53-67. Epub 2018 Nov 11.

Department of Physiology and Pharmacology, Sapienza University, Rome, Italy.

Deficient neuron-microglia signaling during brain development is associated with abnormal synaptic maturation. However, the precise impact of deficient microglia function on synaptic maturation and the mechanisms involved remain poorly defined. Here we report that mice defective in neuron-to-microglia signaling via the fractalkine receptor (Cx3cr1 KO) show reduced microglial branching and altered motility and develop widespread deficits in glutamatergic neurotransmission. We characterized the functional properties of CA3-CA1 synapses in hippocampal slices from these mice and found that they display altered glutamatergic release probability, maintaining immature properties also at late developmental stages. In particular, CA1 synapses of Cx3cr1 KO show (i) immature AMPA/NMDA ratio across developmental time, displaying a normal NMDA component and a defective AMPA component of EPSC; (ii) defective functional connectivity, as demonstrated by reduced current amplitudes in the input/output curve; and (iii) greater facilitation in the paired pulse ratio (PPR), suggesting decreased release probability. In addition, minimal stimulation experiments revealed that excitatory synapses have normal potency, but an increased number of failures, confirming a deficit in presynaptic release. Consistently, KO mice were characterized by higher number of silent synapses in comparison to WT. The presynaptic deficits were corrected by performing experiments in conditions of high release probability (Ca /Mg ratio 8), where excitatory synapses showed normal synaptic multiplicity, AMPA/NMDA ratio, and proportion of silent synapses. These results establish that neuron-microglia interactions profoundly influence the functional maturation of excitatory presynaptic function.
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http://dx.doi.org/10.1002/glia.23508DOI Listing
January 2019

Omalizumab dampens type 2 inflammation in a group of long-term treated asthma patients and detaches IgE from FcεRI.

Eur J Immunol 2018 12 9;48(12):2005-2014. Epub 2018 Oct 9.

Department of Experimental and Clinical Medicine and DENOTHE Center, University of Florence, Florence, Italy.

Even if omalizumab is broadly used in the treatment of severe, allergic asthma, the immunological effects in long-term treated patients have not been fully elucidated. To this aim, a cohort of 15 allergic asthmatic patients treated with omalizumab for at least three years was compared with 12 allergic asthma patients treated with standard therapy. Omalizumab treated asthmatic patients showed lower frequencies of circulating plasmacytoid DCs, and lower CD154 expression on CD4 T-helper cells than the control group. Moreover, basophils and DCs from omalizumab-treated patients had lower surface expression of IgE compared to the control group. In a longitudinal evaluation of two patients that started omalizumab treatment, we show that FcεRI free of IgE were evident on basophils just after four weeks of drug administration. Finally, in vitro experiments with basophils obtained from healthy donors confirm that omalizumab is able to detach IgE from high affinity IgE receptors. Collectively these data indicate that long-term omalizumab treatment dampens type 2 inflammation acting on different cell types that play a pivotal role in the pathogenesis of allergic asthma. Moreover, we have identified a further mechanism of action of omalizumab, such as the ability to detach IgE from its receptor.
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http://dx.doi.org/10.1002/eji.201847668DOI Listing
December 2018

Eomes controls the development of Th17-derived (non-classic) Th1 cells during chronic inflammation.

Eur J Immunol 2019 01 22;49(1):79-95. Epub 2018 Nov 22.

Department of Experimental and Clinical Medicine and DENOTHE Center, University of Florence, Firenze, Italy.

It is well accepted that Th17 cells are a highly plastic cell subset that can be easily directed toward the Th1 phenotype in vitro and also in vivo during inflammation. However, there is an ongoing debate regarding the reverse plasticity (conversion from Th1 to Th17). We show here that ectopic ROR-γt expression can restore or initiate IL-17 expression by non-classic or classic Th1 cells, respectively, while common pro-Th17 cytokine cocktails are ineffective. This stability of the Th1 phenotype is at least partially due to the presence of a molecular machinery governed by the transcription factor Eomes, which promotes IFN-γ secretion while inhibiting the expression of ROR-γt and IL-17. By using a mouse model of T cell-dependent colitis we demonstrate that Eomes controls non-classic Th1 cell development also in vivo and promotes their pathogenic potential. Eomes expression associates to a highly inflammatory phenotype also in patients with juvenile idiopathic arthritis. Indeed, it favors the acquisition of a cytotoxic signature, and promotes the development of IFN-γ GM-CSF cells that have been described to be pathogenic in chronic inflammatory disorders.
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http://dx.doi.org/10.1002/eji.201847677DOI Listing
January 2019