Candida albicans induces neutrophil extracellular traps and leucotoxic hypercitrullination via candidalysin.

The peptide toxin candidalysin, secreted by Candida albicans hyphae, promotes stimulation of neutrophil extracellular traps (NETs). However, candidalysin alone triggers a distinct mechanism for NET-like structures (NLS), which are more compact and less fibrous than canonical NETs. Candidalysin activates NADPH oxidase and calcium influx, with both processes contributing to morphological changes in neutrophils resulting in NLS formation. NLS are induced by leucotoxic hypercitrullination, which is governed by calcium-induced protein arginine deaminase 4 activation and initiation of intracellular signalling events in a dose- and time-dependent manner. However, activation of signalling by candidalysin does not suffice to trigger downstream events essential for NET formation, as demonstrated by lack of lamin A/C phosphorylation, an event required for activation of cyclin-dependent kinases that are crucial for NET release. Candidalysin-triggered NLS demonstrate anti-Candida activity, which is resistant to nuclease treatment and dependent on the deprivation of Zn2+ . This study reveals that C. albicans hyphae releasing candidalysin concurrently trigger canonical NETs and NLS, which together form a fibrous sticky network that entangles C. albicans hyphae and efficiently inhibits their growth.

Whispers in the wind: Face mask sampling for Mycobacterium tuberculosis detection in children with pulmonary tuberculosis.

BACKGROUND: Recently, face mask sampling (FMS) confirmed detection of Mycobacterium tuberculosis DNA from exhaled breath in adults with TB. To date, no study has evaluated the use of FMS to detect pulmonary Tuberculosis (TB) in children. We developed a method for FMS of M. tuberculosis-specific DNA in children and performed a clinical exploration to assess feasibility in children. METHODS: Face masks were spiked, analysed on GeneXpert-Ultra, qPCR, and tNGS. Children with pulmonary TB were asked to wear three modified FFP2 masks for 30 minutes as part of an exploratory clinical study. RESULTS: Experiments with H37Ra M. tuberculosis strain showed a limit of 95% detection of 3.75 CFU (4.85-3.11; 95%CI) on GeneXpert-Ultra. Ten children with pulmonary TB participated in the clinical study. M. tuberculosis-specific DNA was detected on none of the face masks. CONCLUSIONS: Paediatric FMS has a low limit of detection for M. tuberculosis-specific DNA in vitro. However, M. tuberculosis DNA was not detected in any of thirty masks worn by children with pulmonary TB. This suggests that FMS in this form may not be more effective for detecting M. tuberculosis in children with TB than existing methods.

IRAK1 Duplication in MECP2 Duplication Syndrome Does Not Increase Canonical NF-κB-Induced Inflammation.

PURPOSE: Besides their developmental and neurological phenotype, most patients with MECP2/IRAK1 duplication syndrome present with recurrent and severe infections, accompanied by strong inflammation. Respiratory infections are the most common cause of death. Standardized pneumological diagnostics, targeted anti-infectious treatment, and knowledge of the underlying pathomechanism that triggers strong inflammation are unmet clinical needs. We investigated the influence of IRAK1 overexpression on the canonical NF-κB signaling as a possible cause for excessive inflammation in these patients. METHODS: NF-κB signaling was examined by measuring the production of proinflammatory cytokines and evaluating the IRAK1 phosphorylation and degradation as well as the IκBα degradation upon stimulation with IL-1ß and TLR agonists in SV40-immortalized fibroblasts, PBMCs, and whole blood of 9 patients with MECP2/IRAK1 duplication syndrome, respectively. RESULTS: Both, MECP2/IRAK1-duplicated patients and healthy controls, showed similar production of IL-6 and IL-8 upon activation with IL-1ß and TLR2/6 agonists in immortalized fibroblasts. In PBMCs and whole blood, both patients and controls had a similar response of cytokine production after stimulation with IL-1ß and TLR4/2/6 agonists. Patients and controls had equivalent patterns of IRAK1 phosphorylation and degradation as well as IκBα degradation upon stimulation with IL-1ß. CONCLUSION: Patients with MECP2/IRAK1 duplication syndrome do not show increased canonical NF-κB signaling in immortalized fibroblasts, PBMCs, and whole blood. Therefore, we assume that these patients do not benefit from a therapeutic suppression of this pathway.

The GAIN Registry - a New Prospective Study for Patients with Multi-organ Autoimmunity and Autoinflammation.

Patient registries are a very important and essential tool for investigating rare diseases, as most physicians only see a limited number of cases during their career. Diseases of multi-organ autoimmunity and autoinflammation are especially challenging, as they are characterized by diverse clinical phenotypes and highly variable expressivity. The GAIN consortium (German multi-organ Auto Immunity Network) developed a dataset addressing these challenges. ICD-11, HPO, and ATC codes were incorporated to document various clinical manifestations and medications with a defined terminology. The GAIN dataset comprises detailed information on genetics, phenotypes, medication, and laboratory values. Between November 2019 and July 2022, twelve centers from Europe have registered 419 patients with multi-organ autoimmunity or autoinflammation. The median age at onset of symptoms was 13 years (IQR 3-28) and the median delay from onset to diagnosis was 5 years (IQR 1-14). Of 354 (84.5%) patients who were genetically tested, 248 (59.2%) had a defined monogenetic cause. For 87 (20.8%) patients, no mutation was found and for 19 (4.5%), the result was pending. The most common gene affected was NFkB1 (48, 11.5%), and the second common was CTLA4 (40, 9.5%), both genetic patient groups being fostered by specific research projects within GAIN. The GAIN registry may serve as a valuable resource for research in the inborn error of immunity community by providing a platform for etiological and diagnostic research projects, as well as observational trials on treatment options.

Prospective Newborn Screening for SCID in Germany: A First Analysis by the Pediatric Immunology Working Group (API).

BACKGR OUND: T-cell receptor excision circle (TREC)-based newborn screening (NBS) for severe combined immunodeficiencies (SCID) was introduced in Germany in August 2019. METHODS: Children with abnormal TREC-NBS were referred to a newly established network of Combined Immunodeficiency (CID) Clinics and Centers. The Working Group for Pediatric Immunology (API) and German Society for Newborn Screening (DGNS) performed 6-monthly surveys to assess the TREC-NBS process after 2.5 years. RESULTS: Among 1.9 million screened newborns, 88 patients with congenital T-cell lymphocytopenia were identified (25 SCID, 17 leaky SCID/Omenn syndrome (OS)/idiopathic T-cell lymphocytopenia, and 46 syndromic disorders). A genetic diagnosis was established in 88%. Twenty-six patients underwent hematopoietic stem cell transplantation (HSCT), 23/26 within 4 months of life. Of these, 25/26 (96%) were alive at last follow-up. Two patients presented with in utero onset OS and died after birth. Five patients with syndromic disorders underwent thymus transplantation. Eight syndromic patients deceased, all from non-immunological complications. TREC-NBS missed one patient, who later presented clinically, and one tracking failure occurred after an inconclusive screening result. CONCLUSION: The German TREC-NBS represents the largest European SCID screening at this point. The incidence of SCID/leaky SCID/OS in Germany is approximately 1:54,000, very similar to previous observations from North American and European regions and countries where TREC-NBS was implemented. The newly founded API-CID network facilitates tracking and treatment of identified patients. Short-term HSCT outcome was excellent, but NBS and transplant registries will remain essential to evaluate the long-term outcome and to compare results across the rising numbers of TREC-NBS programs across Europe.

Performance of QuantiFERON-TB Gold Plus assays in paediatric tuberculosis: a multicentre PTBNET study.

RATIONALE: In 2016, a new interferon-gamma release assay (IGRA) was introduced, QuantiFERON-TB Gold Plus (QFT-Plus), claimed to have improved sensitivity in active tuberculosis (TB). OBJECTIVES: This study aimed to determine the performance of QFT-Plus, compared with previous generation IGRAs and the tuberculin skin test (TST), in children with TB in Europe. METHODS: Multicentre, ambispective cohort study within the Paediatric Tuberculosis Network European Trials Group (ptbnet), a dedicated paediatric TB research network comprising >300 members, capturing TB cases <18 years-of-age diagnosed between January 2009 and December 2019. MEASUREMENTS AND MAIN RESULTS: 1001 TB cases from 16 countries were included (mean age (IQR) 5.6 (2.4-12.1) years). QFT-Plus was performed in 358, QFT Gold in-Tube (QFT-GIT) in 600, T-SPOT.TB in 58 and TST in 636 cases. The overall test sensitivities were: QFT-Plus 83.8% (95% CI 80.2% to 87.8%), QFT-GIT 85.5% (95% CI 82.7% to 88.3%), T-SPOT.TB 77.6% (95% CI 66.9% to 88.3%) and TST (cut-off ≥10 mm) 83.3% (95% CI 83.3% to 86.2%). There was a trend for tests to have lower sensitivity in patients with miliary and/or central nervous system (CNS) TB (73.1%, 70.9%, 63.6% and 43.5%, respectively), and in immunocompromised patients (75.0%, 59.6%, 45.5% and 59.1%, respectively). CONCLUSIONS: The results indicate that the latest generation IGRA assay, QFT-Plus, does not perform better than previous generation IGRAs or the TST in children with TB disease. Overall, tests performed worse in CNS and miliary TB, and in immunocompromised children. None of the tests evaluated had sufficiently high sensitivity to be used as a rule-out test in children with suspected TB.

When malignancy hits twice - synchronous gastric carcinoma and non-Hodgkin-B-cell lymphoma in a patient with common variable immunodeficiency.

Patients with common variable immunodeficiency (CVID) generally bear a higher risk of non Hodgkin B-cell lymphomas and solid tumors, in particular gastric adenocarcinoma.Here we report a case of a 58-year-old male CVID patient who developed both malignancies within a very short period, as documented by two subsequent esophagogastroduodenoscopies performed within 4 months. While the first upper gastrointestinal endoscopy for routine surveillance purposes was uneventful, the second one after developing unexplained weight loss revealed two new neoplastic lesions in the stomach. The histological evaluation revealed a poorly differentiated adenocarcinoma infiltrating the muscularis propria forcing gastrectomy as well as a high-grade B-non-Hodgkin-lymphoma with detection of a MYC- and BCL6-translocation, necessitating chemotherapy with R-CHOP.This case emphasizes the necessity of high awareness for gastric neoplasia in patients with CVID and highlights the need of a standardized yet not established endoscopic surveillance protocol for this vulnerable group.

Treatment and Outcome in Children With Tuberculous Meningitis: A Multicenter Pediatric Tuberculosis Network European Trials Group Study.

BACKGROUND: Currently, data on treatment, outcome, and prognostic factors in children with tuberculous meningitis (TBM) in Europe are limited. To date, most existing data on TBM originate from adult studies, or studies conducted in low-resource settings. METHODS: We designed a multicenter, retrospective study involving 27 pediatric healthcare institutions in 9 European countries via an established pediatric TB research network, before and after the 2014 revision of World Health Organization (WHO) dosing recommendations. RESULTS: Of 118 children, 39 (33.1%) had TBM grade 1, 68 (57.6%) grade 2, and 11 (9.3%) grade 3. Fifty-eight (49.1%) children received a standard 4-drug treatment regimen; other commonly used drugs included streptomycin, prothionamide, and amikacin. Almost half of the patients (48.3%; 56/116) were admitted to intensive care unit, with a median stay of 10 (interquartile range [IQR] 4.5-21.0) days. Of 104 children with complete outcome data, 9.6% (10/104) died, and only 47.1% (49/104) recovered fully. Main long-term sequelae included spasticity of 1 or more limbs and developmental delay both in 19.2% (20/104), and seizure disorder in 17.3% (18/104). Multivariate regression analyses identified microbiological confirmation of TBM, the need for neurosurgical intervention, and mechanical ventilation as risk factors for unfavorable outcome. CONCLUSIONS: There was considerable heterogeneity in the use of TB drugs in this cohort. Despite few children presenting with advanced disease and the study being conducted in a high-resource setting, morbidity and mortality were high. Several risk factors for poor outcome were identified, which may aid prognostic predictions in children with TBM in the future.

Extended clinical and immunological phenotype and transplant outcome in CD27 and CD70 deficiency.

Biallelic mutations in the genes encoding CD27 or its ligand CD70 underlie inborn errors of immunity (IEIs) characterized predominantly by Epstein-Barr virus (EBV)-associated immune dysregulation, such as chronic viremia, severe infectious mononucleosis, hemophagocytic lymphohistiocytosis (HLH), lymphoproliferation, and malignancy. A comprehensive understanding of the natural history, immune characteristics, and transplant outcomes has remained elusive. Here, in a multi-institutional global collaboration, we collected the clinical information of 49 patients from 29 families (CD27, n = 33; CD70, n = 16), including 24 previously unreported individuals and identified a total of 16 distinct mutations in CD27, and 8 in CD70, respectively. The majority of patients (90%) were EBV+ at diagnosis, but only ∼30% presented with infectious mononucleosis. Lymphoproliferation and lymphoma were the main clinical manifestations (70% and 43%, respectively), and 9 of the CD27-deficient patients developed HLH. Twenty-one patients (43%) developed autoinflammatory features including uveitis, arthritis, and periodic fever. Detailed immunological characterization revealed aberrant generation of memory B and T cells, including a paucity of EBV-specific T cells, and impaired effector function of CD8+ T cells, thereby providing mechanistic insight into cellular defects underpinning the clinical features of disrupted CD27/CD70 signaling. Nineteen patients underwent allogeneic hematopoietic stem cell transplantation (HSCT) prior to adulthood predominantly because of lymphoma, with 95% survival without disease recurrence. Our data highlight the marked predisposition to lymphoma of both CD27- and CD70-deficient patients. The excellent outcome after HSCT supports the timely implementation of this treatment modality particularly in patients presenting with malignant transformation to lymphoma.

Pilot study to identify missed opportunities for prevention of childhood tuberculosis.

Tuberculosis (TB) in exposed children can be prevented with timely contact tracing and preventive treatment. This study aimed to identify potential barriers and delays in the prevention of childhood TB in a low-incidence country by assessing the management of children subsequently diagnosed with TB. A pilot retrospective cohort study included children (< 15 years) treated for TB between 2009 and 2016 at a tertiary care hospital in Berlin, Germany. Clinical data on cases and source cases, information on time points of the diagnostic work up, and preventive measures were collected and analyzed. Forty-eight children (median age 3 years [range 0.25-14]) were included; 36 had been identified through contact tracing, the majority (26; 72.2%) being < 5 years. TB source cases were mostly family members, often with advanced disease. Thirty children (83.3%) did not receive prophylactic or preventive treatment, as TB was already prevalent when first presented. Three cases developed TB despite preventive or prophylactic treatment; in three cases (all < 5 years), recommendations had not been followed. Once TB was diagnosed in source cases, referral, assessment, TB diagnosis, and treatment were initiated in most children in a timely manner with a median duration of 18 days (interquartile range 6-60, range 0-252) between diagnosis of source case and child contact (information available for 35/36; 97.2%). In some cases, notable delays in follow-up occurred. CONCLUSION: Prompt diagnosis of adult source cases appears to be the most important challenge for childhood TB prevention. However, improvement is also needed in the management of exposed children. WHAT IS KNOWN: • Following infection with Mycobacterium tuberculosis, young children have a high risk of progression to active and severe forms of tuberculosis (TB). • The risk of infection and disease progression can be minimized by prompt identification of TB-exposed individuals and initiation of prophylactic or preventive treatment. WHAT IS NEW: • We could show that there are avoidable time lags in diagnosis in a relevant proportion of children with known TB exposure. • Delayed diagnosis of adult source cases, losses in follow-up examinations, and delay in referral to a specialized TB clinic of TB-exposed children, especially among foreign-born children, appear to be the main issue in this German pediatric study cohort.

Incomplete penetrance for isolated congenital asplenia in humans with mutations in translated and untranslated RPSA exons.

Isolated congenital asplenia (ICA) is the only known human developmental defect exclusively affecting a lymphoid organ. In 2013, we showed that private deleterious mutations in the protein-coding region of RPSA, encoding ribosomal protein SA, caused ICA by haploinsufficiency with complete penetrance. We reported seven heterozygous protein-coding mutations in 8 of the 23 kindreds studied, including 6 of the 8 multiplex kindreds. We have since enrolled 33 new kindreds, 5 of which are multiplex. We describe here 11 new heterozygous ICA-causing RPSA protein-coding mutations, and the first two mutations in the 5'-UTR of this gene, which disrupt mRNA splicing. Overall, 40 of the 73 ICA patients (55%) and 23 of the 56 kindreds (41%) carry mutations located in translated or untranslated exons of RPSA. Eleven of the 43 kindreds affected by sporadic disease (26%) carry RPSA mutations, whereas 12 of the 13 multiplex kindreds (92%) carry RPSA mutations. We also report that 6 of 18 (33%) protein-coding mutations and the two (100%) 5'-UTR mutations display incomplete penetrance. Three mutations were identified in two independent kindreds, due to a hotspot or a founder effect. Finally, RPSA ICA-causing mutations were demonstrated to be de novo in 7 of the 23 probands. Mutations in RPSA exons can affect the translated or untranslated regions and can underlie ICA with complete or incomplete penetrance.

Risk Factors for Complicated Lymphadenitis Caused by Nontuberculous Mycobacteria in Children.

Nontuberculous mycobacteria (NTM) are an emerging cause of infections, including chronic lymphadenitis in children. To identify risk factors for NTM lymphadenitis, particularly complicated disease, we collected epidemiologic, clinical, and microbiological data on 138 cases of NTM lymphadenitis in children across 13 centers in Germany and Austria. We assessed lifestyle factors but did not identify specific risk behaviors. We noted that more cases of NTM lymphadenitis occurred during cold months than during warm months. Moreover, we noted female sex and age <5.5 years as potential risk factors. Complete extirpation of the affected lymph node appeared to be the best therapeutic measure. We integrated the study data to develop a simple risk score to predict unfavorable clinical outcomes for NTM lymphadenitis.

T Cell Impairment Is Predictive for a Severe Clinical Course in NEMO Deficiency.

PURPOSE: NEMO-deficient patients present with variable degrees of immunodeficiency. Accordingly, treatment ranges from antibiotic prophylaxis and/or IgG-substitution to allogenic hematopoietic stem cell transplantation (HSCT). The correct estimation of the immunodeficiency is essential to avoid over- as well as under-treatment. We compare the immunological phenotype of a NEMO-deficient patient with a newly-described splice site mutation that causes truncation of the NEMO zinc-finger (ZF) domain and a severe clinical course with the immunological phenotype of three NEMO-deficient patients with missense mutations and milder clinical courses and all previously published patients. METHODS: Lymphocyte subsets, proliferation, and intracellular NEMO-expression were assessed by FACS. NF-κB signal transduction was determined by measuring IκBα-degradation and the production of cytokines upon stimulation with TNF-α, IL-1ß, and TLR-agonists in immortalized fibroblasts and whole blood, respectively. RESULTS: The patient with truncated ZF-domain of NEMO showed low levels of IgM and IgG, reduced class-switched memory B cells, almost complete skewing towards naïve CD45RA+ T cells, impaired T cell proliferation as well as cytokine production upon stimulation with TNF-α, IL-1ß, and TLR-agonists. He suffered from severe infections (sepsis, pneumonia, osteomyelitis) during infancy. In contrast, three patients with missense mutations in IKBKG presented neither skewing of T cells towards naïvety nor impaired T cell proliferation. They are stable on prophylactic IgG-substitution or even off any prophylactic treatment. CONCLUSION: The loss of the ZF-domain and the impaired T cell proliferation accompanied by almost complete persistence of naïve T cells despite severe infections are suggestive for a profound immunodeficiency. Allogenic HSCT should be considered early for these patients before chronic sequelae occur.

Incidence of SCID in Germany from 2014 to 2015 an ESPED* Survey on Behalf of the API*** Erhebungseinheit für Seltene Pädiatrische Erkrankungen in Deutschland (German Paediatric Surveillance Unit) ** Arbeitsgemeinschaft Pädiatrische Immunologie.

PURPOSE: Severe combined immunodeficiencies (SCID) are a heterogeneous group of fatal genetic disorders, in which the immune response is severely impaired. SCID can be cured if diagnosed early. We aim to determine the incidence of clinically defined SCID cases, acquire data of reported cases and evaluate their possible prediction by newborn screening, before introduction of a general screening program in Germany. METHODS: The German Surveillance Unit for rare Paediatric Diseases (ESPED) prospectively queried the number of incident SCID cases in all German paediatric hospitals in 2014 and 2015. Inclusion criteria were (1) opportunistic or severe infections or clinical features associated with SCID (failure to thrive, lacking thymus or lymphatic tissue, dysregulation of the immune system, graft versus host reaction caused by maternal T cells), (2) dysfunctional T cell immunity or proof of maternal T cells and (3) exclusion of a secondary immunodeficiency such as human immunodeficiency virus (HIV) infection. In a capture-recapture analysis, cases were matched with cases reported to the European Society for Immunodeficiencies (ESID). RESULTS: Fifty-eight patients were initially reported to ESPED, 24 reports could be confirmed as SCID, 21 patients were less than 1 year old at time of diagnosis. One SCID case was reported to ESID only. The estimated incidence of SCID in Germany is 1.6/100,000 (1:62,500) per year in children less than 1 year of age. Most patients reported were symptomatic and mortality in regard to reported outcome was high (29% (6/22)). The majority of incident SCID cases were considered to be probably detectable by newborn screening. CONCLUSIONS: SCID is a rare disease with significant mortality. Newborn screening may give the opportunity to improve the prognosis in a significant number of children with SCID.

Performance of immune-based and microbiological tests in children with tuberculosis meningitis in Europe: a multicentre Paediatric Tuberculosis Network European Trials Group (ptbnet) study.

INTRODUCTION: Tuberculous meningitis (TBM) is often diagnostically challenging. Only limited data exist on the performance of interferon-γ release assays (IGRA) and molecular assays in children with TBM in routine clinical practice, particularly in the European setting. METHODS: Multicentre, retrospective study involving 27 healthcare institutions providing care for children with tuberculosis (TB) in nine European countries. RESULTS: Of 118 children included, 54 (45.8%) had definite, 38 (32.2%) probable and 26 (22.0%) possible TBM; 39 (33.1%) had TBM grade 1, 68 (57.6%) grade 2 and 11 (9.3%) grade 3. Of 108 patients who underwent cranial imaging 90 (83.3%) had at least one abnormal finding consistent with TBM. At the 5-mm cut-off the tuberculin skin test had a sensitivity of 61.9% (95% CI 51.2-71.6%) and at the 10-mm cut-off 50.0% (95% CI 40.0-60.0%). The test sensitivities of QuantiFERON-TB and T-SPOT.TB assays were 71.7% (95% CI 58.4-82.1%) and 82.5% (95% CI 58.2-94.6%), respectively (p=0.53). Indeterminate results were common, occurring in 17.0% of QuantiFERON-TB assays performed. Cerebrospinal fluid (CSF) cultures were positive in 50.0% (95% CI 40.1-59.9%) of cases, and CSF PCR in 34.8% (95% CI 22.9-43.7%). In the subgroup of children who underwent tuberculin skin test, IGRA, CSF culture and CSF PCR simultaneously, 84.4% had at least one positive test result (95% CI 67.8%-93.6%). CONCLUSIONS: Existing immunological and microbiological TB tests have suboptimal sensitivity in children with TBM, with each test producing false-negative results in a substantial proportion of patients. Combining immune-based tests with CSF culture and CSF PCR results in considerably higher positive diagnostic yields, and should therefore be standard clinical practice in high-resource settings.

Impaired polysaccharide responsiveness without agammaglobulinaemia in three patients with hypomorphic mutations in Bruton Tyrosine Kinase-No detection by newborn screening for primary immunodeficiencies.

Hypomorphic mutations in the gene encoding Bruton tyrosine kinase (BTK) may result in milder phenotypes and delayed diagnosis of B-cell related immunodeficiencies due to residual BTK function. Newborn screening for kappa-deleting-recombination-excision circles (KRECs) reliably identifies classical X-linked agammaglobulinaemia (XLA) patients with profound B-cell lymphopenia at birth but has not been evaluated in patients with residual BTK function. We aimed to evaluate clinical findings, BTK function and KREC copy numbers in three patients with BTK mutations presenting with impaired polysaccharide responsiveness without agammaglobulinaemia. One patient had an invasive pneumococcal infection at the age of 4 years. All three patients (two brothers) had visible tonsils, normal to slightly decreased immunoglobulin G levels, undetectable pneumococcal antibodies despite pneumococcal conjugate vaccinations, no antibody response after a diagnostic polysaccharide vaccination as well as profound B-cell lymphopenia with residual B-cell differentiation. BTK mutations were identified by Sanger sequencing. BTK staining and phosphorylation assays were performed on peripheral B cells. KREC copy numbers were determined from dried blood spots obtained within the first week of life as well as once at the age of 8, 6 and 3 years, respectively. BTK staining showed residual protein expression. Also, residual BTK activity could be demonstrated. KREC copy numbers from dried blood spots were above the threshold set for detection of patients with profound B-cell lymphopenia. Male patients with impaired polysaccharide responsiveness should be evaluated for B-cell lymphopenia followed by BTK analyses irrespective of immunoglobulin levels or tonsil size.

Hereditary angioedema in children and adolescents - A consensus update on therapeutic strategies for German-speaking countries.

BACKGROUND/METHODS: At a consensus meeting in August 2018, pediatricians and dermatologists from German-speaking countries discussed the therapeutic strategy for the treatment of pediatric patients with type I and II hereditary angioedema due to C1 inhibitor deficiency (HAE-C1-INH) for Germany, Austria, and Switzerland, taking into account the current marketing approval status. HAE-C1-INH is a rare disease that usually presents during childhood or adolescence with intermittent episodes of potentially life-threatening angioedema. Diagnosis as early as possible and an optimal management of the disease are important to avoid ineffective therapies and to properly treat swelling attacks. This article provides recommendations for developing appropriate treatment strategies in the management of HAE-C1-INH in pediatric patients in German-speaking countries. An overview of available drugs in this age-group is provided, together with their approval status, and study results obtained in adults and pediatric patients. RESULTS/CONCLUSION: Currently, plasma-derived C1 inhibitor concentrates have the broadest approval status and are considered the best available option for on-demand treatment of HAE-C1-INH attacks and for short- and long-term prophylaxis across all pediatric age-groups in German-speaking countries. For on-demand treatment of children aged 2 years and older, recombinant C1-INH and bradykinin-receptor antagonist icatibant are alternatives. For long-term prophylaxis in adolescents, the parenteral kallikrein inhibitor lanadelumab has recently been approved and can be recommended due to proven efficacy and safety.

Safety of tenofovir during pregnancy: early growth outcomes and hematologic side effects in HIV-exposed uninfected infants.

Intrauterine exposure to zidovudine-based combination antiretroviral therapy (cART) can cause severe anemia within the first weeks of life. Tenofovir disoproxil fumarate (TDF)-based regimens may have less hematologic side effects but may affect growth parameters. This study aimed to assess the safety of TDF for prevention of mother-to-child transmission (PMTCT) in HIV-exposed uninfected infants regarding early growth outcomes and hematologic side effects. Our retrospective observational cohort study included children born (n = 232) to HIV-infected mothers (n = 228) on cART. Blood counts were compared at birth, 4-6 weeks, and 3, 12 and 18 months of age. Growth parameters were measured at birth and 12 and 18 months of age. Data were analyzed according to treatment group (TDF and non-TDF cART regimes). The median hemoglobin (Hgb) was significantly lower in the non-TDF-based group at birth (15.4 g/dl vs. 16.9 g/dl; **p = 0.002) and at 4-6 weeks of age (9.9 g/dl vs. 10.4 g/dl; **p = 0.004). The mean corpuscular volume was higher in the non-TDF-based group (109 fl vs. 105 fl; ***p < 0.001) as well at 4-6 weeks (102 fl vs. 95 fl; ***p < 0.001). In the TDF-based group, a higher proportion of neutropenia (grade 2 and higher) compared to the non-TDF-group (21.4% vs. 11%; *p = 0.015) was observed at three months of age. This effect was transient. There was no difference in growth.Conclusions: TDF appears to have no major side effects in our cohort. Transient anemia was observed more commonly with non-TDF regimens. However, our research suggests a potential delayed effect of TDF on neutrophils at 3 months of age.What is Known:• TDF is suspected to affect the growth of HIV-exposed uninfected infants.• Non-TDF-based cART regimes for prevention of mother-to-child transmission of HIV often result in transient anemia in the infant.What is New:• TDF appears to have no major side effects regarding the growth of HIV-exposed uninfected infants.• Our research suggests a potential delayed effect of TDF on neutrophils at 3 months of age in these infants.

Periorbital infections and conjunctivitis due to Panton-Valentine Leukocidin (PVL) positive Staphylococcus aureus in children.

BACKGROUND: Colonisation with Panton-Valentine Leukocidin expressing strains of Staphylococcus aureus (PVL + SA) is characterised by recurrent skin and soft tissue infections. While periorbital and orbital infections are common in children and frequently caused by S. aureus the role of PVL + SA in recurrent eye infections has not been studied. This study aimed to detect and report frequency and recurrence of periorbital or orbital infections as additional symptoms of PVL + SA colonisation in children. METHODS: We conducted a retrospective cohort study of pediatric patients who were treated for PVL + SA skin and soft tissue infection in our in- and outpatient clinics in Berlin, Germany from January 2012 to January 2017. We identified cases with periorbital or orbital infections in the year prior to the first PVL + SA evidence. In these cases, we conducted follow-up interviews by phone to determine recurrence of symptoms after the completion of decolonisation procedures. RESULTS: Fifty pediatric patients (age range: one week to 17 years) were evaluated and treated for PVL + SA infections in the reported time period. 19 patients (38%) reported periorbital infection or conjunctivitis, with recurrent hordeola as the most frequent finding (n = 9; 18%). Reappearance of hordeola (n = 5) was associated with recurrence of skin and soft tissue infections and/or de novo detection of PVL + SA. No further hordeola or other eye infections occurred after successful decolonisation. CONCLUSION: Our findings suggest a frequent involvement of periorbital skin in children with PVL + SA infections. Pediatric patients with recurrent periorbital infections might benefit from PVL + SA screening and consecutive decolonisation procedures.

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 genome's 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.