Publications by authors named "Robin Kobbe"

47 Publications

SARS-CoV-2 Reinfection in a Healthcare Worker Despite the Presence of Detectable Neutralizing Antibodies.

Viruses 2021 04 12;13(4). Epub 2021 Apr 12.

German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany.

So far, only a few reports about reinfections with SARS-CoV-2 have been published, and they often lack detailed immunological and virological data. We report about a SARS-CoV-2 reinfection with a genetically distinct SARS-CoV-2 variant in an immunocompetent female healthcare worker that has led to a mild disease course. No obvious viral escape mutations were observed in the second virus variant. The infectious virus was shed from the patient during the second infection episode despite the presence of neutralizing antibodies in her blood. Our data indicate that a moderate immune response after the first infection, but not a viral escape, did allow for reinfection and live virus shedding.
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http://dx.doi.org/10.3390/v13040661DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070424PMC
April 2021

Longitudinal Development of Antibody Responses in COVID-19 Patients of Different Severity with ELISA, Peptide, and Glycan Arrays: An Immunological Case Series.

Pathogens 2021 Apr 6;10(4). Epub 2021 Apr 6.

Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Muehlenberg 1, 14476 Potsdam, Germany.

The current COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). A better understanding of its immunogenicity can be important for the development of improved diagnostics, therapeutics, and vaccines. Here, we report the longitudinal analysis of three COVID-19 patients with moderate (#1) and mild disease (#2 and #3). Antibody serum responses were analyzed using spike glycoprotein enzyme linked immunosorbent assay (ELISA), full-proteome peptide, and glycan microarrays. ELISA immunoglobulin A, G, and M (IgA, IgG, and IgM) signals increased over time for individuals #1 and #2, whereas #3 only showed no clear positive IgG and IgM result. In contrast, peptide microarrays showed increasing IgA/G signal intensity and epitope spread only in the moderate patient #1 over time, whereas early but transient IgA and stable IgG responses were observed in the two mild cases #2 and #3. Glycan arrays showed an interaction of antibodies to fragments of high-mannose and core -glycans, present on the viral shield. In contrast to protein ELISA, microarrays allow for a deeper understanding of IgA, IgG, and IgM antibody responses to specific epitopes of the whole proteome and glycans of SARS-CoV-2 in parallel. In the future, this may help to better understand and to monitor vaccination programs and monoclonal antibodies as therapeutics.
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http://dx.doi.org/10.3390/pathogens10040438DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8067489PMC
April 2021

Phylogenomics of reveals a new lineage and a complex evolutionary history.

Microb Genom 2021 02;7(2)

University of Basel, Basel, Switzerland.

Human tuberculosis (TB) is caused by members of the complex (MTBC). The MTBC comprises several human-adapted lineages known as , as well as two lineages (L5 and L6) traditionally referred to as . Strains of L5 and L6 are largely limited to West Africa for reasons unknown, and little is known of their genomic diversity, phylogeography and evolution. Here, we analysed the genomes of 350 L5 and 320 L6 strains, isolated from patients from 21 African countries, plus 5 related genomes that had not been classified into any of the known MTBC lineages. Our population genomic and phylogeographical analyses showed that the unclassified genomes belonged to a new group that we propose to name MTBC lineage 9 (L9). While the most likely ancestral distribution of L9 was predicted to be East Africa, the most likely ancestral distribution for both L5 and L6 was the Eastern part of West Africa. Moreover, we found important differences between L5 and L6 strains with respect to their phylogeographical substructure and genetic diversity. Finally, we could not confirm the previous association of drug-resistance markers with lineage and sublineages. Instead, our results indicate that the association of drug resistance with lineage is most likely driven by sample bias or geography. In conclusion, our study sheds new light onto the genomic diversity and evolutionary history of , and highlights the need to consider the particularities of each MTBC lineage for understanding the ecology and epidemiology of TB in Africa and globally.
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http://dx.doi.org/10.1099/mgen.0.000477DOI Listing
February 2021

A distinct CD38+CD45RA+ population of CD4+, CD8+, and double-negative T cells is controlled by FAS.

J Exp Med 2021 Feb;218(2)

Department of General Paediatrics, Clinic Oldenburg, Oldenburg, Germany.

The identification and characterization of rare immune cell populations in humans can be facilitated by their growth advantage in the context of specific genetic diseases. Here, we use autoimmune lymphoproliferative syndrome to identify a population of FAS-controlled TCRαβ+ T cells. They include CD4+, CD8+, and double-negative T cells and can be defined by a CD38+CD45RA+T-BET- expression pattern. These unconventional T cells are present in healthy individuals, are generated before birth, are enriched in lymphoid tissue, and do not expand during acute viral infection. They are characterized by a unique molecular signature that is unambiguously different from other known T cell differentiation subsets and independent of CD4 or CD8 expression. Functionally, FAS-controlled T cells represent highly proliferative, noncytotoxic T cells with an IL-10 cytokine bias. Mechanistically, regulation of this physiological population is mediated by FAS and CTLA4 signaling, and its survival is enhanced by mTOR and STAT3 signals. Genetic alterations in these pathways result in expansion of FAS-controlled T cells, which can cause significant lymphoproliferative disease.
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http://dx.doi.org/10.1084/jem.20192191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7658692PMC
February 2021

SARS Coronavirus-2 variant tracing within the first Coronavirus Disease 19 clusters in northern Germany.

Clin Microbiol Infect 2021 Jan 29;27(1):130.e5-130.e8. Epub 2020 Sep 29.

Institute for Medical Microbiology, Virology and Hygiene, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany. Electronic address:

Objectives: Investigation whether in depth characterization of virus variant patterns can be used for epidemiological analysis of the first severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection clusters in Hamburg, Germany.

Methods: Metagenomic RNA-sequencing and amplicon-sequencing and subsequent variant calling in 25 respiratory samples from SARS-CoV-2 infected patients involved in the earliest infection clusters in Hamburg.

Results: Amplikon sequencing and cluster analyses of these SARS-CoV-2 sequences allowed the identification of the first infection cluster and five non-related infection clusters occurring at the beginning of the viral entry of SARS-CoV-2 in the Hamburg metropolitan region. Viral genomics together with epidemiological analyses revealed that the index patient acquired the infection in northern Italy and transmitted it to two out of 134 contacts. Single nucleotide polymorphisms clearly distinguished the virus variants of the index and other clusters and allowed us to track in which sequences worldwide these mutations were first described. Minor variant analyses identified the transmission of intra-host variants in the index cluster and household clusters.

Conclusions: SARS-CoV-2 variant tracing allows the identification of infection clusters and the follow up of infection chains occurring in the population. Furthermore, the follow up of minor viral variants in infection clusters can provide further resolution on transmission events indistinguishable at a consensus sequence level.
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http://dx.doi.org/10.1016/j.cmi.2020.09.034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7524521PMC
January 2021

Characterization of the clinical and immunologic phenotype and management of 157 individuals with 56 distinct heterozygous NFKB1 mutations.

J Allergy Clin Immunol 2020 10 9;146(4):901-911. Epub 2020 Apr 9.

Primary Immunodeficiencies Unit, Hospital Dona Estefania, Centro Hospitalar de Lisboa Central, Lisbon, Portugal.

Background: An increasing number of NFKB1 variants are being identified in patients with heterogeneous immunologic phenotypes.

Objective: To characterize the clinical and cellular phenotype as well as the management of patients with heterozygous NFKB1 mutations.

Methods: In a worldwide collaborative effort, we evaluated 231 individuals harboring 105 distinct heterozygous NFKB1 variants. To provide evidence for pathogenicity, each variant was assessed in silico; in addition, 32 variants were assessed by functional in vitro testing of nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB) signaling.

Results: We classified 56 of the 105 distinct NFKB1 variants in 157 individuals from 68 unrelated families as pathogenic. Incomplete clinical penetrance (70%) and age-dependent severity of NFKB1-related phenotypes were observed. The phenotype included hypogammaglobulinemia (88.9%), reduced switched memory B cells (60.3%), and respiratory (83%) and gastrointestinal (28.6%) infections, thus characterizing the disorder as primary immunodeficiency. However, the high frequency of autoimmunity (57.4%), lymphoproliferation (52.4%), noninfectious enteropathy (23.1%), opportunistic infections (15.7%), autoinflammation (29.6%), and malignancy (16.8%) identified NF-κB1-related disease as an inborn error of immunity with immune dysregulation, rather than a mere primary immunodeficiency. Current treatment includes immunoglobulin replacement and immunosuppressive agents.

Conclusions: We present a comprehensive clinical overview of the NF-κB1-related phenotype, which includes immunodeficiency, autoimmunity, autoinflammation, and cancer. Because of its multisystem involvement, clinicians from each and every medical discipline need to be made aware of this autosomal-dominant disease. Hematopoietic stem cell transplantation and NF-κB1 pathway-targeted therapeutic strategies should be considered in the future.
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http://dx.doi.org/10.1016/j.jaci.2019.11.051DOI Listing
October 2020

Successful Immunochemotherapy for Burkitt Lymphoma During Pregnancy as a Bridge to Postpartum High-Dose Methotrexate Therapy: A Case Report and Review of the Literature.

Clin Lymphoma Myeloma Leuk 2020 06 25;20(6):e284-e290. Epub 2019 Dec 25.

Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

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http://dx.doi.org/10.1016/j.clml.2019.12.012DOI Listing
June 2020

Intravenous Artesunate for Imported Severe Malaria in Children Treated in Four Tertiary Care Centers in Germany: A Retrospective Study.

Pediatr Infect Dis J 2019 11;38(11):e295-e300

Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

Background: Intravenous artesunate (ivA) is the standard treatment for severe malaria. Data systematically evaluating the use of ivA in pediatric patients outside malaria-endemic regions are limited. The aim of this case series was to summarize efficacy and safety of ivA for imported severe malaria in children in Germany.

Methods: Our retrospective case series included pediatric patients with imported severe malaria treated with at least 1 dose of ivA (Artesun, Guilin Pharmaceutical; Shanghai, China) at 4 German tertiary care centers. Severe malaria was defined according to World Health Organization criteria.

Results: Between 2010 and 2018, 14 children with a median [interquartile range (IQR)] age of 6 (1;9.5) years were included. All children were of African descent. All but 2 patients had Plasmodium falciparum malaria; 1 child had P. vivax malaria and 1 child had P. falciparum and P. vivax co-infection. Median (IQR) parasitemia at admission in patients with P. falciparum was 9.5% (3;16.5). Patients were treated with 1-10 [median (IQR) 3 (3;4)] doses ivA. All but one patient received a full course of oral antimalarial treatment. Parasite clearance was achieved within 2-4 days, with the exception of 1 patient with prolonged clearance of peripheral parasitemia. Three patients experienced posttreatment hemolysis but none needed blood transfusion. Otherwise ivA was safe and well tolerated.

Conclusions: ivA was highly efficacious in this pediatric cohort. We observed episodes of mild to moderate posttreatment hemolysis in approximately one-third of patients. The legal status and usage of potentially lifesaving ivA should be evaluated in Europe.
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http://dx.doi.org/10.1097/INF.0000000000002417DOI Listing
November 2019

The German National Registry of Primary Immunodeficiencies (2012-2017).

Front Immunol 2019 19;10:1272. Epub 2019 Jul 19.

Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, Ludwig-Maximilians-University Munich, Munich, Germany.

The German PID-NET registry was founded in 2009, serving as the first national registry of patients with primary immunodeficiencies (PID) in Germany. It is part of the European Society for Immunodeficiencies (ESID) registry. The primary purpose of the registry is to gather data on the epidemiology, diagnostic delay, diagnosis, and treatment of PIDs. Clinical and laboratory data was collected from 2,453 patients from 36 German PID centres in an online registry. Data was analysed with the software Stata® and Excel. The minimum prevalence of PID in Germany is 2.72 per 100,000 inhabitants. Among patients aged 1-25, there was a clear predominance of males. The median age of living patients ranged between 7 and 40 years, depending on the respective PID. Predominantly antibody disorders were the most prevalent group with 57% of all 2,453 PID patients (including 728 CVID patients). A gene defect was identified in 36% of patients. Familial cases were observed in 21% of patients. The age of onset for presenting symptoms ranged from birth to late adulthood (range 0-88 years). Presenting symptoms comprised infections (74%) and immune dysregulation (22%). Ninety-three patients were diagnosed without prior clinical symptoms. Regarding the general and clinical diagnostic delay, no PID had undergone a slight decrease within the last decade. However, both, SCID and hyper IgE- syndrome showed a substantial improvement in shortening the time between onset of symptoms and genetic diagnosis. Regarding treatment, 49% of all patients received immunoglobulin G (IgG) substitution (70%-subcutaneous; 29%-intravenous; 1%-unknown). Three-hundred patients underwent at least one hematopoietic stem cell transplantation (HSCT). Five patients had gene therapy. The German PID-NET registry is a precious tool for physicians, researchers, the pharmaceutical industry, politicians, and ultimately the patients, for whom the outcomes will eventually lead to a more timely diagnosis and better treatment.
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http://dx.doi.org/10.3389/fimmu.2019.01272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6659583PMC
October 2020

Impact of refugee influx on the epidemiology of late-presenting HIV-infected pregnant women and mother-to-child transmission: comparing a southern and northern medical centre in Germany.

Infection 2019 Oct 12;47(5):847-852. Epub 2019 Jun 12.

Division of Paediatric Infectious Diseases, Dr. von Hauner Children's Hospital, University Hospital, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany.

Purpose: Due to early antenatal screening and treatment, HIV mother-to-child transmission (MTCT) rarely occurs in Germany. The study aimed to investigate the impact on prevalence of HIV infection in the antenatal population and the incidence of late-presenting HIV-infected mothers attributable to increased numbers of refugees.

Methods: Retrospective analysis and comparison were performed for all deliveries in HIV-infected pregnant women presenting to medical care in Munich (southern Germany) and Hamburg (northern Germany) covering two time periods, A (2010-2012) and B (2013-2015).

Results: In Munich, deliveries in HIV-infected pregnant women increased 1.6-fold from period A (n = 50) to B (n = 79) with late-presenting cases rising significantly from 2% (1/50) in period A to 13% (10/79) in B. In contrast, late-presenting cases in Hamburg decreased from 14% (14/100) in period A to 7% (7/107) in B, while the total number of HIV-infected women giving birth remained stable. From 2010 to 2015, one late-presenting pregnant woman transmitted HIV in Munich by presumed in utero mode of infection (case reviewed here), while no MTCT occurred in Hamburg.

Conclusions: HIV infections diagnosed late in pregnancy and leading to delayed ART initiation are rising in Munich compared to Hamburg. Antenatal care of HIV-infected pregnant women in Munich appears to have been more affected by the recent refugee influx than Hamburg. Our study highlights the importance of screening all pregnant women for HIV early in pregnancy and providing timely health care access for pregnant refugees and asylum seekers to effectively prevent MTCT in Germany.
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http://dx.doi.org/10.1007/s15010-019-01332-3DOI Listing
October 2019

Reducing Hematologic Toxicity With Short Course Postexposure Prophylaxis With Zidovudine for HIV-1 Exposed Infants With Low Transmission Risk.

Pediatr Infect Dis J 2019 07;38(7):727-730

Department of Paediatric Oncology, Hematology and Clinical Immunology, Center for Child and Adolescent Health, Heinrich Heine University, Düsseldorf, Germany.

Using retrospectively collected data from 383 infants born to HIV-1-infected mothers receiving antiretroviral therapy, we compared transmission rates and hematologic toxicity between infants receiving 2-week (short course) versus longer duration zidovudine postexposure prophylaxis. Short course resulted in lower hematologic toxicity without evidence of increased vertical transmission risk.
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http://dx.doi.org/10.1097/INF.0000000000002357DOI Listing
July 2019

Clinical and Immunological Phenotype of Patients With Primary Immunodeficiency Due to Damaging Mutations in .

Front Immunol 2019 19;10:297. Epub 2019 Mar 19.

Faculty of Medicine, Center for Chronic Immunodeficiency (CCI), Medical Center, University of Freiburg, Freiburg, Germany.

Non-canonical NF-κB-pathway signaling is integral in immunoregulation. Heterozygous mutations in have recently been established as a molecular cause of common variable immunodeficiency (CVID) and DAVID-syndrome, a rare condition combining deficiency of anterior pituitary hormone with CVID. Here, we investigate 15 previously unreported patients with primary immunodeficiency (PID) from eleven unrelated families with heterozygous -mutations including eight patients with the common p.Arg853 nonsense mutation and five patients harboring unique novel C-terminal truncating mutations. In addition, we describe the clinical phenotype of two patients with proximal truncating mutations. Cohort analysis extended to all 35 previously published -cases revealed occurrence of early-onset PID in 46/50 patients (mean age of onset 5.9 years, median 4.0 years). ACTH-deficiency occurred in 44%. Three mutation carriers have deceased, four developed malignancies. Only two mutation carriers were clinically asymptomatic. In contrast to typical CVID, most patients suffered from early-onset and severe disease manifestations, including clinical signs of T cell dysfunction e.g., chronic-viral or opportunistic infections. In addition, 80% of patients suffered from (predominately T cell mediated) autoimmune (AI) phenomena (alopecia > various lymphocytic organ-infiltration > diarrhea > arthritis > AI-cytopenia). Unlike in other forms of CVID, auto-antibodies or lymphoproliferation were not common hallmarks of disease. Immunophenotyping showed largely normal or even increased quantities of naïve and memory CD4 or CD8 T-cells and normal T-cell proliferation. NK-cell number and function were also normal. In contrast, impaired B-cell differentiation and hypogammaglobinemia were consistent features of -associated disease. In addition, an array of lymphocyte subpopulations, such as regulatory T cell, Th17-, cTFH-, NKT-, and MAIT-cell numbers were decreased. We conclude that heterozygous damaging mutations in represent a distinct PID entity exceeding the usual clinical spectrum of CVID. Impairment of the non-canonical NF-κB pathways affects function and differentiation of numerous lymphocyte-subpopulations and thus causes a heterogeneous, more severe form of PID phenotype with early-onset. Further characteristic features are multifaceted, primarily T cell-mediated autoimmunity, such as alopecia, lymphocytic organ infiltration, and in addition frequently ACTH-deficiency.
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http://dx.doi.org/10.3389/fimmu.2019.00297DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6435015PMC
May 2020

BCL11B mutations in patients affected by a neurodevelopmental disorder with reduced type 2 innate lymphoid cells.

Brain 2018 08;141(8):2299-2311

Département de Génétique, Hôpital La Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.

The transcription factor BCL11B is essential for development of the nervous and the immune system, and Bcl11b deficiency results in structural brain defects, reduced learning capacity, and impaired immune cell development in mice. However, the precise role of BCL11B in humans is largely unexplored, except for a single patient with a BCL11B missense mutation, affected by multisystem anomalies and profound immune deficiency. Using massively parallel sequencing we identified 13 patients bearing heterozygous germline alterations in BCL11B. Notably, all of them are affected by global developmental delay with speech impairment and intellectual disability; however, none displayed overt clinical signs of immune deficiency. Six frameshift mutations, two nonsense mutations, one missense mutation, and two chromosomal rearrangements resulting in diminished BCL11B expression, arose de novo. A further frameshift mutation was transmitted from a similarly affected mother. Interestingly, the most severely affected patient harbours a missense mutation within a zinc-finger domain of BCL11B, probably affecting the DNA-binding structural interface, similar to the recently published patient. Furthermore, the most C-terminally located premature termination codon mutation fails to rescue the progenitor cell proliferation defect in hippocampal slice cultures from Bcl11b-deficient mice. Concerning the role of BCL11B in the immune system, extensive immune phenotyping of our patients revealed alterations in the T cell compartment and lack of peripheral type 2 innate lymphoid cells (ILC2s), consistent with the findings described in Bcl11b-deficient mice. Unsupervised analysis of 102 T lymphocyte subpopulations showed that the patients clearly cluster apart from healthy children, further supporting the common aetiology of the disorder. Taken together, we show here that mutations leading either to BCL11B haploinsufficiency or to a truncated BCL11B protein clinically cause a non-syndromic neurodevelopmental delay. In addition, we suggest that missense mutations affecting specific sites within zinc-finger domains might result in distinct and more severe clinical outcomes.
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http://dx.doi.org/10.1093/brain/awy173DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6061686PMC
August 2018

Universal screening for latent and active tuberculosis (TB) in asylum seeking children, Bochum and Hamburg, Germany, September 2015 to November 2016.

Euro Surveill 2018 03;23(12)

University Children`s Hospital Bochum- Germany, Department of Pulmonology, Bochum, Germany.

BackgroundIn Germany, the incidence of tuberculosis (TB) in children has been on the rise since 2009. High numbers of foreign-born asylum seekers have contributed considerably to the disease burden. Therefore, effective screening strategies for latent TB infection (LTBI) and active TB in asylum seeking children are needed. Our aim was to investigate the prevalence of LTBI and active TB in asylum seeking children up to 15 years of age in two geographic regions in Germany. Screening for TB was performed in children in asylum seeker reception centres by tuberculin skin test (TST) or interferon gamma release assay (IGRA). Children with positive results were evaluated for active TB. Additionally, country of origin, sex, travel time, TB symptoms, TB contact and Bacille Calmette-Guérin (BCG) vaccination status were registered. Of 968 screened children 66 (6.8%) had TB infection (58 LTBI, 8 active TB). LTBI prevalence was similar in children from high (Afghanistan) and low (Syria) incidence countries (8.7% vs 6.4%). There were no differences regarding sex, age or travel time between infected and non-infected children. Children under the age of 6 years were at higher risk of progression to active TB (19% vs 2% respectively, p=0,07). Most children (7/8) with active TB were asymptomatic at the time of diagnosis. None of the children had been knowingly exposed to TB. Asylum seeking children from high and low incidence countries are both at risk of developing LTBI or active TB. Universal TB screening for all asylum seeking children should be considered.
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http://dx.doi.org/10.2807/1560-7917.ES.2018.23.12.17-00536DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6205260PMC
March 2018

Targeted Gene Panel Sequencing for Early-onset Inflammatory Bowel Disease and Chronic Diarrhea.

Inflamm Bowel Dis 2017 12;23(12):2109-2120

1Institute of Clinical Molecular Biology, Kiel University, Kiel, Germany; 2Center for Chronic Immunodeficiency (CCI), DZIF Satellite Center, Medical Center, Faculty of Medicine, Germany; 3Paediatric Gastroenterology, Klinikum Nürnberg, Nuremberg, Germany; 4Laboratory of Applied Molecular Biology and Immunology, University of Abou-Bekr Belkaïd, Tlemcen, Algeria; 5Department of Pediatrics, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; 6Clinic of Pediatric Allergy and Immunology, Marmara University Pendik Training and Research Hospital, Istanbul, Turkey; 7Department of Gastroenterology and Clinical Nutrition, Birmingham Children's Hospital, Birmingham, United Kingdom; 8Department of Paediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 9Department of Immunology, Royal Free Hospital, London, United Kingdom; 10Primary Immunodeficiencies Unit, Hospital Dona Estefania, Pediatric University Hospital, and CEDOC, Chronic Diseases Research Center, NOVA Medical School, Lisbon, Portugal; 11Department of Pediatric Gasteroentrology and Hepatology, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 12Helios Kliniken, Childrens Hospital, Krefeld, Germany; 13Pediatrics Department, Faculty of Medicine, Cairo University, Cairo, Egypt; 14Paediatric Gastroenterology/Hepatology, University of Freiburg, Freiburg, Germany; 15Institute of Medical Microbiology and Hygiene, University of Freiburg, Freiburg, Germany; 16Department of Pediatrics, University Medical Center Dresden, Technische Universität Dresden, Dresden, Germany; 17Department of Medicine II, University Hospital and Medical Faculty, University Freiburg, Freiburg, Germany; 18Department of Paediatrics, Centre for Diagnosis and Treatment of Primary Immunodeficiencies, Jessenius Faculty of Medicine, Commenius University in Bratislava, Martin, Slovakia; 19Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey; 20Department of Allergy and Clinical Immunology, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 21Pediatric Immunology Division, Uludag University Medical Faculty, Department of Pediatrics, Bursa, Turkey; 22Dr. von Hauner Children's Hospital, Department of Pediatrics, Ludwig-Maximilians-Universität Munich, Munich, Germany; 23Center for Chronic Immunodeficiency (CCI), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; 24Center for Pediatrics, Department of Pediatric Hematology and Oncology, University Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; 25Department of Paediatric Immunology and Infectious Diseases, Our Lady's Children's Hospital, Dublin, Ireland; 26Department of Immunology, Mofid Children Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 27Department of Paediatric Gastroenterology, St. George's Healthcare NHS Trust and University of London, London, United Kingdom; 28Department of Gastroenterology and Clinical Nutrition, Marmara University Medical Faculty, Istanbul, Turkey; 29Service of Clinical Laboratory, Division of Immunology, San Pedro De Alcántara Hospital, Cáceres, Spain; 30Bone Marrow Failure Group, Division of Pediatric Hematology and Oncology, University of Freiburg, Germany; 31Children's Hospital, University of Bonn, Germany; 32University College London Institute of Immunity and Transplantation, Royal Free Campus, London, United Kingdom; 33Department of Paediatrics, St. George's Hospital, University of London, London, United Kingdom; 34Department of Pediatrics, Universitair Ziekenhuis Brussel, Brussels, Belgium; 35Pediatric Pneumology and Immunology, Department of Immunology, Charité University Medicine Labor Berlin Charité Vivantes GmbH, Berlin, Germany; 36Department of Medicine I, University Medical Center Dresden, Technische Universität Dresden, Dresden, Germany; 37Center for Regenerative Therapies, Technische Universität Dresden, Dresden, Germany; and 38Institute of Laboratory Medicine, Brandenburg Hospital, Brandenburg Medical School, Brandenburg/Havel, Germany.

Background: In contrast to adult-onset inflammatory bowel disease (IBD), where many genetic loci have been shown to be involved in complex disease etiology, early-onset IBD (eoIBD) and associated syndromes can sometimes present as monogenic conditions. As a result, the clinical phenotype and ideal disease management in these patients often differ from those in adult-onset IBD. However, due to high costs and the complexity of data analysis, high-throughput screening for genetic causes has not yet become a standard part of the diagnostic work-up of eoIBD patients.

Methods: We selected 28 genes of interest associated with monogenic IBD and performed targeted panel sequencing in 71 patients diagnosed with eoIBD or early-onset chronic diarrhea to detect causative variants. We compared these results to whole-exome sequencing (WES) data available for 25 of these patients.

Results: Target coverage was significantly higher in the targeted gene panel approach compared with WES, whereas the cost of the panel was considerably lower (approximately 25% of WES). Disease-causing variants affecting protein function were identified in 5 patients (7%), located in genes of the IL10 signaling pathway (3), WAS (1), and DKC1 (1). The functional effects of 8 candidate variants in 5 additional patients (7%) are under further investigation. WES did not identify additional causative mutations in 25 patients.

Conclusions: Targeted gene panel sequencing is a fast and effective screening method for monogenic causes of eoIBD that should be routinely established in national referral centers.
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http://dx.doi.org/10.1097/MIB.0000000000001235DOI Listing
December 2017

Plasma cell deficiency in human subjects with heterozygous mutations in Sec61 translocon alpha 1 subunit (SEC61A1).

J Allergy Clin Immunol 2018 04 4;141(4):1427-1438. Epub 2017 Aug 4.

Center for Chronic Immunodeficiency, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; Institute of Immunity and Transplantation, UCL, London, United Kingdom. Electronic address:

Background: Primary antibody deficiencies (PADs) are the most frequent primary immunodeficiencies in human subjects. The genetic causes of PADs are largely unknown. Sec61 translocon alpha 1 subunit (SEC61A1) is the major subunit of the Sec61 complex, which is the main polypeptide-conducting channel in the endoplasmic reticulum membrane. SEC61A1 is a target gene of spliced X-box binding protein 1 and strongly induced during plasma cell (PC) differentiation.

Objective: We identified a novel genetic defect and studied its pathologic mechanism in 11 patients from 2 unrelated families with PADs.

Methods: Whole-exome and targeted sequencing were conducted to identify novel genetic mutations. Functional studies were carried out ex vivo in primary cells of patients and in vitro in different cell lines to assess the effect of SEC61A1 mutations on B-cell differentiation and survival.

Results: We investigated 2 families with patients with hypogammaglobulinemia, severe recurrent respiratory tract infections, and normal peripheral B- and T-cell subpopulations. On in vitro stimulation, B cells showed an intrinsic deficiency to develop into PCs. Genetic analysis and targeted sequencing identified novel heterozygous missense (c.254T>A, p.V85D) and nonsense (c.1325G>T, p.E381*) mutations in SEC61A1, segregating with the disease phenotype. SEC61A1-V85D was deficient in cotranslational protein translocation, and it disturbed the cellular calcium homeostasis in HeLa cells. Moreover, SEC61A1-V85D triggered the terminal unfolded protein response in multiple myeloma cell lines.

Conclusion: We describe a monogenic defect leading to a specific PC deficiency in human subjects, expanding our knowledge about the pathogenesis of antibody deficiencies.
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http://dx.doi.org/10.1016/j.jaci.2017.06.042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5797495PMC
April 2018

Case report - atypical hemolytic uremic syndrome triggered by influenza B.

BMC Nephrol 2017 Mar 20;18(1):96. Epub 2017 Mar 20.

University Medical Center Hamburg-Eppendorf, Martinistr. 52, D-20246, Hamburg, Germany.

Background: Influenza A infections have been described to cause secondary hemolytic uremic syndrome and to trigger atypical hemolytic uremic syndrome (aHUS) in individuals with an underlying genetic complement dysregulation. To date, influenza B has not been reported to trigger aHUS.

Case Presentation: A 6-month-old boy presented with hemolytic uremic syndrome triggered by influenza B infection. Initially the child recovered spontaneously. When he relapsed Eculizumab treatment was initiated, resulting in complete and sustained remission. A pathogenic mutation in membrane cofactor protein (MCP) was detected.

Conclusion: Influenza B is a trigger for aHUS and might be underreported as such. Influenza vaccination may protect patients at risk.
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http://dx.doi.org/10.1186/s12882-017-0512-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5358041PMC
March 2017

Hypereosinophilic Syndrome After Liver Transplantation: A Case Report and a Review of the Literature.

Transplantation 2017 05;101(5):e166-e169

1 Department of Pediatrics, University-Medical Centre Hamburg-Eppendorf, Germany. 2 Department of Pediatric Infectious Diseases, University-Medical Centre Hamburg-Eppendorf, Germany. 3 Department of Pediatric Gastroenterology, Hepatology and Liver Transplantation, University-Medical Centre Hamburg-Eppendorf, Germany. 4 Institute of Pathology, University-Medical Centre Hamburg-Eppendorf, Germany. 5 Department of Pediatric Nephrology and Kidney Transplantation, University-Medical Centre Hamburg-Eppendorf, Germany. 6 Department of Pediatrics, Heidberg-Hospital, Hamburg, Germany.

Persistently elevated eosinophil granulocytes in the peripheral blood in children is challenging because of a complex diagnosis especially after solid organ transplantation and can lead to difficulties in finding an underlying causative factor.We report a 12-year-old boy who developed severe hypereosinophilia 11 years after liver transplantation due to biliary atresia. Accompanying symptoms were recurrent fever, fatigue, elevated liver enzymes, abdominal pain, and significant weight loss. After exclusion of secondary causes of eosinophilia, an idiopathic hypereosinophilic syndrome (I-HES) was diagnosed. Treatment with prednisolone resulted in an immediate response with rapid reduction of eosinophils, normalization of liver enzymes, and amelioration of any clinical symptoms. A hypereosinophilic syndrome in patients after liver transplantation is rare, and a broad differential diagnosis has to be considered. Prednisolone may lead to a prompt amelioration of eosinophilia and associated symptoms.
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http://dx.doi.org/10.1097/TP.0000000000001721DOI Listing
May 2017

Dolutegravir in breast milk and maternal and infant plasma during breastfeeding.

AIDS 2016 11;30(17):2731-2733

aDepartment of Pediatrics, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany bDepartment of Pharmacy, Radboud University Medical Center cRadboud Institute for Health Sciences, Nijmegen, The Netherlands dHeinrich Pette Institute - Leibniz Institute for Experimental Virology eGerman Center for Infection Research (DZIF) fDepartment of Obstetrics and Fetal Medicine, University Medical Center Hamburg-Eppendorf gDepartment of Medicine, Infectious Disease Unit, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

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http://dx.doi.org/10.1097/QAD.0000000000001259DOI Listing
November 2016

Hyperactive mTOR pathway promotes lymphoproliferation and abnormal differentiation in autoimmune lymphoproliferative syndrome.

Blood 2016 07 20;128(2):227-38. Epub 2016 Apr 20.

Department of Internal Medicine 5, Haematology and Oncology, University Hospital Erlangen, Erlanger, Germany;

Autoimmune lymphoproliferative syndrome (ALPS) is a human disorder characterized by defective Fas signaling, resulting in chronic benign lymphoproliferation and accumulation of TCRαβ(+) CD4(-) CD8(-) double-negative T (DNT) cells. Although their phenotype resembles that of terminally differentiated or exhausted T cells, lack of KLRG1, high eomesodermin, and marginal T-bet expression point instead to a long-lived memory state with potent proliferative capacity. Here we show that despite their terminally differentiated phenotype, human ALPS DNT cells exhibit substantial mitotic activity in vivo. Notably, hyperproliferation of ALPS DNT cells is associated with increased basal and activation-induced phosphorylation of serine-threonine kinases Akt and mechanistic target of rapamycin (mTOR). The mTOR inhibitor rapamycin abrogated survival and proliferation of ALPS DNT cells, but not of CD4(+) or CD8(+) T cells in vitro. In vivo, mTOR inhibition reduced proliferation and abnormal differentiation by DNT cells. Importantly, increased mitotic activity and hyperactive mTOR signaling was also observed in recently defined CD4(+) or CD8(+) precursor DNT cells, and mTOR inhibition specifically reduced these cells in vivo, indicating abnormal programming of Fas-deficient T cells before the DNT stage. Thus, our results identify the mTOR pathway as a major regulator of lymphoproliferation and aberrant differentiation in ALPS.
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http://dx.doi.org/10.1182/blood-2015-11-685024DOI Listing
July 2016

Common variable immunodeficiency, impaired neurological development and reduced numbers of T regulatory cells in a 10-year-old boy with a STAT1 gain-of-function mutation.

Gene 2016 Jul 6;586(2):234-8. Epub 2016 Apr 6.

Department of Psychosomatic Medicine and Psychotherapy, University of Göttingen, Germany. Electronic address:

Recently, gain-of-function (GOF) mutations in the gene encoding signal transducer and activator of transcription 1 (STAT1) have been associated with chronic mucocutaneous candidiasis (CMC). This case report describes a 10-year-old boy presenting with signs of common variable immunodeficiency (CVID), failure to thrive, impaired neurological development, and a history of recurrent mucocutaneous Candida infections. Sequencing of the STAT1 gene identified a heterozygous missense mutation in exon 7 encoding the STAT1 coiled-coil domain (c.514T>C, p.Phe172Leu). In addition to hypogammaglobulinemia with B-cell deficiency, and a low percentage of Th17 cells, immunological analysis of the patient revealed a marked depletion of forkhead-box P3(+)-expressing regulatory T cells (Tregs). In vitro stimulation of T cells from the patient with interferon-α (IFNα) and/or IFNɣ resulted in a significantly increased expression of STAT1-regulated target genes such as MIG1, IRF1, MX1, MCP1/CCL2, IFI-56K, and CXCL10 as compared to IFN-treated cells from a healthy control, while no IFNα/ɣ-mediated up-regulation of the FOXP3 gene was found. These data demonstrate that the STAT1 GOF mutation F172L, which results in impaired stability of the antiparallel STAT1 dimer conformation, is associated with inhibited Treg cell development and neurological symptoms.
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http://dx.doi.org/10.1016/j.gene.2016.04.006DOI Listing
July 2016

The Extended Clinical Phenotype of 26 Patients with Chronic Mucocutaneous Candidiasis due to Gain-of-Function Mutations in STAT1.

J Clin Immunol 2016 Jan 25;36(1):73-84. Epub 2015 Nov 25.

Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium.

Purpose: Gain-of-function (GOF) mutations in the signal transducer and activator of transcription 1 (STAT1) result in unbalanced STAT signaling and cause immune dysregulation and immunodeficiency. The latter is often characterized by the susceptibility to recurrent Candida infections, resulting in the clinical picture of chronic mucocutaneous candidiasis (CMC). This study aims to assess the frequency of GOF STAT1 mutations in a large international cohort of CMC patients.

Methods: STAT1 was sequenced in genomic DNA from 57 CMC patients and 35 healthy family members. The functional relevance of nine different STAT1 variants was shown by flow cytometric analysis of STAT1 phosphorylation in patients' peripheral blood cells (PBMC) after stimulation with interferon (IFN)-α, IFN-γ or interleukin-27 respectively. Extended clinical data sets were collected and summarized for 26 patients.

Results: Heterozygous mutations within STAT1 were identified in 35 of 57 CMC patients (61%). Out of 39 familial cases from 11 families, 26 patients (67%) from 9 families and out of 18 sporadic cases, 9 patients (50%) were shown to have heterozygous mutations within STAT1. Thirteen distinct STAT1 mutations are reported in this paper. Eight of these mutations are known to cause CMC (p.M202V, p.A267V, p.R274W, p.R274Q, p.T385M, p.K388E, p.N397D, and p.F404Y). However, five STAT1 variants (p.F172L, p.Y287D, p.P293S, p.T385K and p.S466R) have not been reported before in CMC patients.

Conclusion: STAT1 mutations are frequently observed in patients suffering from CMC. Thus, sequence analysis of STAT1 in CMC patients is advised. Measurement of IFN- or IL-induced STAT1 phosphorylation in PBMC provides a fast and reliable diagnostic tool and should be carried out in addition to genetic testing.
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http://dx.doi.org/10.1007/s10875-015-0214-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4718942PMC
January 2016

The ESPID/ESWI Joint Symposium - A strong vote for universal influenza vaccination in children in Europe.

Authors:
Robin Kobbe

Vaccine 2015 Dec 16;33(49):6967-9. Epub 2015 Sep 16.

Department of Paediatrics, Infectious Diseases and Immunity, University Medical Centre Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. Electronic address:

During this year's 33rd annual meeting in Leipzig, Germany, the European Society of Paediatric Infectious Diseases (ESPID) jointly together with the European Scientific Working group on Influenza (ESWI), organized a staged debate on the motion of universal annual immunization of children against influenza as a cost-effective health intervention in Europe. Six invited speakers, all experts in the field of influenza vaccination, who were not necessary confident with their given position of pro or contra, battled each other with short oral presentations to convince the audience to vote for or against the motion.
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http://dx.doi.org/10.1016/j.vaccine.2015.09.018DOI Listing
December 2015

Risk of Rotavirus Vaccination for Children with SCID.

Pediatr Infect Dis J 2015 Jan;34(1):114-5

Department of Paediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany Robert-Koch-Institute, Berlin, Germany Kliniken der Stadt Köln gGmbH, Institut für Hygiene, Köln-Merheim, Germany Klinken der Stadt Köln gGmbH, Institut für Pathologie, Furth, Germany Department for Paediatric Haematology and Oncology, University Medical Center Hamburg-Eppendorf, Bone Marrow Transplantation Unit, Hamburg, Germany Klinken der Stadt Köln gGmbH, Institut für Pathologie, Furth, Germany Department of Paediatrics, University Medical Center, Hamburg-Eppendorf, Hamburg, Germany.

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http://dx.doi.org/10.1097/INF.0000000000000507DOI Listing
January 2015

Geographically weighted regression of land cover determinants of Plasmodium falciparum transmission in the Ashanti Region of Ghana.

Int J Health Geogr 2014 Sep 30;13:35. Epub 2014 Sep 30.

Bernhard-Nocht-Institute for Tropical Medicine, Research Group Infectious Disease Epidemiology, Hamburg, Germany.

Background: Malaria is a mosquito-borne parasitic disease that causes severe mortality and morbidity, particularly in Sub-Saharan Africa. As the vectors predominantly bite between dusk and dawn, risk of infection is determined by the abundance of P. falciparum infected mosquitoes in the surroundings of the households. Remote sensing is commonly employed to detect associations between land use/land cover (LULC) and mosquito-borne diseases. Due to challenges in LULC identification and the fact that LULC merely functions as a proxy for mosquito abundance, assuming spatially homogenous relationships may lead to overgeneralized conclusions.

Methods: Data on incidence of P. falciparum parasitaemia were recorded by active and passive follow-up over two years. Nine LULC types were identified through remote sensing and ground-truthing. Spatial associations of LULC and P. falciparum parasitaemia rate were described in a semi-parametric geographically weighted Poisson regression model.

Results: Complete data were available for 878 individuals, with an annual P. falciparum rate of 3.2 infections per person-year at risk. The influences of built-up areas (median incidence rate ratio (IRR): 0.94, IQR: 0.46), forest (median IRR: 0.9, IQR: 0.51), swampy areas (median IRR: 1.15, IQR: 0.88), as well as banana (median IRR: 1.02, IQR: 0.25), cacao (median IRR: 1.33, IQR: 0.97) and orange plantations (median IRR: 1.11, IQR: 0.68) on P. falciparum rate show strong spatial variations within the study area. Incorporating spatial variability of LULC variables increased model performance compared to the spatially homogenous model.

Conclusions: The observed spatial variability of LULC influence in parasitaemia would have been masked by traditional Poisson regression analysis assuming a spatially constant influence of all variables. We conclude that the spatially varying effects of LULC on P. falciparum parasitaemia may in fact be associated with co-factors not captured by remote sensing, and suggest that future studies assess small-scale spatial variation of vegetation to circumvent generalised assumptions on ecological associations that may in fact be artificial.
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http://dx.doi.org/10.1186/1476-072X-13-35DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4192530PMC
September 2014

Open-source genomic analysis of Shiga-toxin-producing E. coli O104:H4.

N Engl J Med 2011 Aug 27;365(8):718-24. Epub 2011 Jul 27.

Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg–Eppendorf, Hamburg, Germany.

An outbreak caused by Shiga-toxin–producing Escherichia coli O104:H4 occurred in Germany in May and June of 2011, with more than 3000 persons infected. Here, we report a cluster of cases associated with a single family and describe an open-source genomic analysis of an isolate from one member of the family. This analysis involved the use of rapid, bench-top DNA sequencing technology, open-source data release, and prompt crowd-sourced analyses. In less than a week, these studies revealed that the outbreak strain belonged to an enteroaggregative E. coli lineage that had acquired genes for Shiga toxin 2 and for antibiotic resistance.
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http://dx.doi.org/10.1056/NEJMoa1107643DOI Listing
August 2011

Follow-up survey of children who received sulfadoxine-pyrimethamine for intermittent preventive antimalarial treatment in infants.

J Infect Dis 2011 Feb 20;203(4):556-60. Epub 2010 Dec 20.

Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.

Recently, the World Health Organization emphasized the potential benefit of intermittent preventive treatment in infants (IPTi) to control malaria and officially recommended implementation of IPTi with sulfadoxine-pyrimethamine (SP) in areas with moderate and high transmission, where SP resistance is not high. As reported rebound effects make further observation mandatory, we performed a survey of participants of a former IPTi trial. Malariometric parameters were similar in the SP and the placebo group. In contrast, anti-Plasmodium falciparum lysate immunoglobulin G antibody levels, a proxy measure for preceding malaria episodes, remained lower in the SP arm. The most likely explanation is a lower overall exposure to parasitic antigens after IPTi.
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http://dx.doi.org/10.1093/infdis/jiq079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3071230PMC
February 2011

IL3 variant on chromosomal region 5q31-33 and protection from recurrent malaria attacks.

Hum Mol Genet 2011 Mar 10;20(6):1173-81. Epub 2011 Jan 10.

Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, D-20359 Hamburg, Germany.

Using segregation analyses, control of malaria parasites has previously been linked to a major gene within the chromosomal region 5q31-33, but also to complex genetic factors in which effects are under substantial age-dependent influence. However, the responsible gene variants have not yet been identified for this chromosomal region. In order to perform association analyses of 5q31-33 locus candidate single nucleotide polymorphisms (SNPs), 1015 children were recruited at the age of 3 months and followed monthly until the age of 2 years in an area holoendemic for Plasmodium falciparum malaria in Ghana. Quantitative (incidence rates of malaria episodes) and qualitative phenotypes (i.e. 'more than one malaria episode' or 'not more than one malaria episode') were used in population- and family-based analyses. The strongest signal was observed for the interleukin 3 gene (IL3) SNP rs40401 (P = 3.4 × 10(-7), P(c)= 1.4 × 10(-4)). The IL3 genotypes rs40401(CT) and rs40401(TT) were found to exert a protective effect of 25% [incidence rate ratio (IRR) 0.75, P = 4.1 × 10(-5)] and 33% (IRR 0.67, P = 3.2 × 10(-8)), respectively, against malaria attacks. The association was confirmed in transmission disequilibrium tests (TDT, qTDT). The results could argue for a role of IL3 in the pathophysiology of falciparum malaria.
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http://dx.doi.org/10.1093/hmg/ddq562DOI Listing
March 2011

Multiplicity of Plasmodium falciparum infection following intermittent preventive treatment in infants.

Malar J 2010 Aug 26;9:244. Epub 2010 Aug 26.

Institute of Tropical Medicine and International Health, Charité - University Medicine, Berlin, Germany.

Background: Intermittent preventive treatment in infants with sulphadoxine-pyrimethamine (IPTi-SP) reduces malaria morbidity by 20% to 33%. Potentially, however, this intervention may compromise the acquisition of immunity, including the tolerance towards multiple infections with Plasmodium falciparum.

Methods: Plasmodium falciparum isolates were obtained from children participating in two Ghanaian IPTi-SP trials (Tamale, Afigya Sekyere) at 15 months of age, i.e., six months after they had received the second dose of IPTi-SP or placebo. By typing the polymorphic merozoite surface protein 1 (msp1) and msp2 genes, multiplicity of infection (MOI) was assessed in 389 isolates. A total of additional 133 samples were collected in Tamale at 3, 6, 9, and 12 months of age. Comparisons of MOI between groups were done by non-parametric statistical tests.

Results: The number of distinguishable P. falciparum clones (MOI) ranged between one and six. Mean MOI in Tamale was stable at 2.13 - 2.17 during the first year of life, and increased to 2.57 at age 15 months (P = 0.01). At no age did MOI differ between the IPTi-SP and placebo groups (each, P ≥ 0.5). At 15 months of age, i.e., six months after the second dose, MOI was very similar for children who had received IPTi or placebo (means, 2.25 vs. 2.33; P = 0.55) as was the proportion of polyclonal infections (69.6% vs. 69.7%; P = 0.99). Adjusting for study site, current and prior malaria, parasite density, and season did not change this finding.

Conclusions: IPTi-SP appears to have no impact on the multiplicity of infection during infancy and thereafter. This suggests that tolerance of multiple infections, a component of protective immunity in highly endemic areas, is not affected by this intervention.
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http://dx.doi.org/10.1186/1475-2875-9-244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2939622PMC
August 2010