Renate Krüger

Variants in CPA1 are strongly associated with early onset chronic pancreatitis

Chronic pancreatitis is an inflammatory disorder of the pancreas. We analyzed CPA1, encoding carboxypeptidase A1, in subjects with nonalcoholic chronic pancreatitis (cases) and controls in a German discovery set and three replication sets. Functionally impaired variants were present in 29/944 (3.1%) German cases and 5/3,938 (0.1%) controls (odds ratio (OR) = 24.9, P = 1.5 × 10−16). The association was strongest in subjects aged ≤10 years (9.7%; OR = 84.0, P = 4.1 × 10−24). In the replication sets, defective CPA1 variants were present in 8/600 (1.3%) cases and 9/2,432 (0.4%) controls from Europe (P = 0.01), 5/230 (2.2%) cases and 0/264 controls from India (P = 0.02) and 5/247 (2.0%) cases and 0/341 controls from Japan (P = 0.013). The mechanism by which CPA1 variants confer increased pancreatitis risk may involve misfolding-induced endoplasmic reticulum stress rather than elevated trypsin activity, as is seen with other genetic risk factors for this disease.

Diverse stimuli engage different neutrophil extracellular trap pathways

Neutrophils release neutrophil extracellular traps (NETs) which ensnare pathogens and have pathogenic functions in diverse diseases. We examined the NETosis pathways induced by five stimuli; PMA, the calcium ionophore A23187, nigericin, Candida albicans and Group B Streptococcus. We studied NET production in neutrophils from healthy donors with inhibitors of molecules crucial to PMA-induced NETs including protein kinase C, calcium, reactive oxygen species, the enzymes myeloperoxidase (MPO) and neutrophil elastase. Additionally, neutrophils from chronic granulomatous disease patients, carrying mutations in the NADPH oxidase complex or a MPO-deficient patient were examined. We show that PMA, C. albicans and GBS use a related pathway for NET induction, whereas ionophores require an alternative pathway but that NETs produced by all stimuli are proteolytically active, kill bacteria and composed mainly of chromosomal DNA. Thus, we demonstrate that NETosis occurs through several signalling mechanisms, suggesting that extrusion of NETs is important in host defence. DOI: http://dx.doi.org/10.7554/eLife.24437.001

Classification of common variable immunodeficiencies using flow cytometry and a memory B-cell functionality assay.

BACKGROUND The population of patients with common variable immunodeficiency (CVID) comprises a heterogeneous group of patients with different causes of hypogammaglobulinemia predisposing to recurrent infections, higher incidence of autoimmunity, and malignancy. Although memory B cells (memBcs) are key players in humoral defense and their numbers are commonly reduced in these patients, their functionality is not part of any current classification. OBJECTIVE We established and validated a memBc enzyme-linked immunosorbent spot (ELISpot) assay that reveals the capacity of memBcs to develop into antibody-secreting cells and present an idea for a new classification based on this functional capacity. METHODS The memBc ELISpot assay, combined with flow cytometry, was applied to patients with confirmed CVID in comparison with age-matched healthy control subjects. RESULTS Ex vivo frequency of IgG-, IgM-, and IgA-secreting plasmablasts was significantly diminished by 27.2-, 2.4-, and 23.3-fold, respectively, compared with that seen in healthy control subjects. Moreover, in vitro differentiation of memBcs into antibody-secreting cells was 6.1-, 2.6-, and 3.7-fold significantly reduced for IgG-, IgM-, and IgA-secreting cells, respectively. Proliferation of memBcs correlates inversely to immunoglobulin-secreting capacity, suggesting compensatory hyperproliferation. Furthermore, patients with no serum IgA can still have a detectable IgA ELISpot assay result in vitro. Most importantly, the large heterogeneity of memBc function in patients with CVID homogenously grouped by means of fluorescence-activated cell sorting allowed additional subclassification based on memBc/plasmablast function. CONCLUSION These data suggest almost normal memBc/immunoglobulin-secreting plasmablast functionality in some patients if sufficient stimulatory signals are delivered, which might open up opportunities for new therapeutic approaches.

Maternal filaggrin mutations increase the risk of atopic dermatitis in children: an effect independent of mutation inheritance

Epidemiological studies suggest that allergy risk is preferentially transmitted through mothers. This can be due to genomic imprinting, where the phenotype effect of an allele depends on its parental origin, or due to maternal effects reflecting the maternal genomes influence on the child during prenatal development. Loss-of-function mutations in the filaggrin gene (FLG) cause skin barrier deficiency and strongly predispose to atopic dermatitis (AD). We investigated the 4 most prevalent European FLG mutations (c.2282del4, p.R501X, p.R2447X, and p.S3247X) in two samples including 759 and 450 AD families. We used the multinomial and maximum-likelihood approach implemented in the PREMIM/EMIM tool to model parent-of-origin effects. Beyond the known role of FLG inheritance in AD (R1meta-analysis = 2.4, P = 1.0 x 10−36), we observed a strong maternal FLG genotype effect that was consistent in both independent family sets and for all 4 mutations analysed. Overall, children of FLG-carrier mothers had a 1.5-fold increased AD risk (S1 = 1.50, Pmeta-analysis = 8.4 x 10−8). Our data point to two independent and additive effects of FLG mutations: i) carrying a mutation and ii) having a mutation carrier mother. The maternal genotype effect was independent of mutation inheritance and can be seen as a non-genetic transmission of a genetic effect. The FLG maternal effect was observed only when mothers had allergic sensitization (elevated allergen-specific IgE antibody plasma levels), suggesting that FLG mutation-induced systemic immune responses in the mother may influence AD risk in the child. Notably, the maternal effect reported here was stronger than most common genetic risk factors for AD recently identified through genome-wide association studies (GWAS). Our study highlights the power of family-based studies in the identification of new etiological mechanisms and reveals, for the first time, a direct influence of the maternal genotype on the offspring’s susceptibility to a common human disease.

Daily subcutaneous administration of human C1 inhibitor in a child with hereditary angioedema type 1.

Giuliana Giardino; Domenico Somma; Emilia Cirillo; Giuseppina Ruggiero; Giuseppe Terrazzano; Valentina Rubino; Matilde Valeria Ursini; Donatella Vairo; Raffaele Badolato; Rita Carsetti; Antonio Leonardi; Anne Puel & Claudio Pignata Department of Translational Medical Sciences, Federico II University; Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, Naples; Department of Science, University of Basilicata, Potenza; International Institute of Genetics and Biophysics, IGBCNR, Naples; Department of Molecular and Translational Medicine, Institute of Molecular Medicine ‘Angelo Nocivelli’, University of Brescia and SpedaliCivili of Brescia; Department of Clinical and Experimental Sciences, Pediatrics Clinic and Institute of Molecular Medicine ‘Angelo Nocivelli’, University of Brescia and SpedaliCivili of Brescia, Brescia; Research Center, Ospedale Pediatrico Bambino Ges u (IRCCS), Rome, Italy; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM, UMR; Imagine Institute, Paris Descartes University, Paris, France E-mail: pignata@unina.it DOI:10.1111/pai.12496

Fatal case of ataxia-telangiectasia complicated by severe epistaxis due to nasal telangiectasia in a 12-year-old boy

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Pyoderma outbreak among kindergarten families: Association with a Panton-Valentine leukocidin (PVL)-producing S. aureus strain

Objectives We report on an outbreak of skin and soft tissue infections (SSTI) among kindergarten families. We analyzed the transmission route and aimed to control the outbreak. Methods The transmission route was investigated by nasal screening for Panton-Valentine leukocidin (PVL)-producing Staphylococcus aureus (PVL-SA), subsequent microbiological investigation including whole genome sequencing and a questionnaire-based analysis of epidemiological information. The control measures included distribution of outbreak information to all individuals at risk and implementation of a Staphylococcus aureus decontamination protocol. Results Individuals from 7 of 19 families were either colonized or showed signs of SSTI such as massive abscesses or eye lid infections. We found 10 PVL-SA isolates in 9 individuals. In the WGS-analysis all isolates were found identical with a maximum of 17 allele difference. The clones were methicillin-susceptible but cotrimoxazole resistant. In comparison to PVL-SAs from an international strain collection, the outbreak clone showed close genetical relatedness to PVL-SAs from a non-European country. The questionnaire results showed frequent travels of one family to this area. The results also demonstrated likely transmission via direct contact between families. After initiation of Staphylococcus aureus decontamination no further case was detected. Conclusions Our outbreak investigation showed the introduction of a PVL-SA strain into a kindergarten likely as a result of international travel and further transmission by direct contact. The implementation of a Staphylococcus aureus decontamination protocol was able to control the outbreak.

Positive Kappa-Deleting Recombination Excision Circles (KREC) Newborn Screening in a Neonate With Intrauterine Exposure to Rituximab

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/sji.12627 This article is protected by copyright. All rights reserved. DR. RENATE KRÜGER (Orcid ID : 0000-0001-8728-9385)To the Editor: Neonatal screening for primary immunodeficiency disorders with severe T cell and/or B cell lymphopenia at birth (e.g. severe combined immunodeficiency and x-linked agammaglobulinemia) have been evaluated in several countries worldwide. A triplex PCR method allows quantitation of T cell receptor excision circles (TREC) and kappa-deleting recombination excision circles (KREC) copies from a single punch of a DBS (Guthrie card). Nondetectable or markedly reduced numbers of KREC copies in blood samples taken within the first week of life are indicative of a severe B cell lymphopenia (reviewed in ref. [1]). Rituximab (RTX), a chimeric monoclonal anti-CD20 IgG1 antibody, is approved for treatment of B cellmediated malignancies and autoimmune disorders. An exposure to RTX results in selective and sustained depletion of CD20-positive B cell subpopulations. Treatment during pregnancy and pregnancy outcomes have been described in case reports (reviewed in ref. [2]) and case series of >100 woman [3]. Due to placental transfer of RTX, neonates with intrauterine exposure during the second trimester and/or third trimester of pregnancy show a marked reduction in CD20-positive B cells during the first weeks of life with an increase in B cell numbers as well as immunoglobulin levels to normal values at the age of 6 months (reviewed in ref. [2]). We hypothesized that neonatal KREC screening in newborns exposed to RTX within the second and third trimesters of pregnancy should result in a positive (abnormal) screening result due to RTX-induced depletion of peripheral B cells.

Corrigendum to ‘Panton-Valentine Leucocidin (PVL) Staphylococcus aureus a position statement from the International Society of Chemotherapy’ [International Journal of Antimicrobial Agents 51/1 (2018) 16-25]

The authors regret that the author name Silvano Esposito was published incorrectly. The authors would like to apologise for any inconvenience caused.

Scabies, Periorbital Cellulitis and Recurrent Skin Abscesses due to Panton-Valentine Leukocidin-Positive Staphylococcus aureus Mimic Hyper IgE Syndrome in an Infant

We describe the clinical course of a 2-month-old infant who was evaluated for autosomal dominant Hyper IgE Syndrome based on eczema, periorbital cellulitis, skin abscesses, increased total IgE levels and blood eosinophilia. However, scabies and nasal colonization by Panton-Valentine Leucocidin-positive S. aureus were eventually diagnosed. After specific treatment, the child was asymptomatic.