Explore the vast range of titles available.

Common variable immunodeficiency disorders (CVID) are an enigmatic group of often heritable conditions, which may manifest for the first time in early childhood or as late as the eighth decade of life. In the last 5 years, next generation sequencing (NGS) has revolutionised identification of genetic disorders. However, despite the best efforts of researchers around the globe, CVID conditions have been slow to yield their molecular secrets. We have previously described the many clinical advantages of identifying the genetic basis of primary immunodeficiency disorders (PIDs). In a minority of CVID patients, monogenic defects have now been identified. If a causative mutation is identified, these conditions are reclassified as CVID-like disorders. Here we discuss recent advances in the genetics of CVID and discuss how NGS can be optimally deployed to identify the causal mutations responsible for the protean clinical manifestations of these conditions. Diagnostic criteria such as the Ameratunga et al. criteria will continue to play an important role in patient management as well as case selection and sequencing strategy design until the genetic conundrum of CVID is solved.

Common variable immunodeficiency disorders (CVIDs) are rare primary immunodeficiency diseases (PIDs) mostly associated with late onset antibody failure leading to immune system failure. Patients with CVID are predisposed to disabling complications such as bronchiectasis and systemic autoimmunity. In recent years a large number of genetic defects have become associated with these disorders. Patients with a causative mutation are deemed to have CVID-like disorders, while those with mutations predisposing to or modifying disease severity remain within the spectrum of CVID as defined by current diagnostic criteria. Next-generation sequencing (NGS) allows simultaneous analysis of multiple genes. Potential mutations identified from NGS are commonly evaluated with the American College of Medical Genetics (ACMG) variant interpretation criteria to determine their pathogenicity (causality). Patients with CVID and CVID-like disorders have marked genetic, allelic, and phenotypic heterogeneity. Although all patients with a CVID phenotype should undergo genetic testing, the complexity of the genetics associated with these disorders is challenging. Variants of unknown significance (VUS) remain a significant barrier to realising the full potential of NGS in CVID and CVID-like disorders. Here we explore the nuances of applying the ACMG criteria to patients with CVID and CVID-like disorders. Close collaboration between the clinician, bioinformatics, and genetics professionals will improve the diagnostic yield from genetic testing and reduce the frequency of VUS.

Primary immunodeficiencies are heritable disorders of immune function. CD19 is a B cell co-receptor important for B cell development, and CD19 deficiency is a known genetic risk factor for a rare form of primary immunodeficiency known as \"common variable immunodeficiency\" (CVID); an antibody deficiency resulting in low levels of serum IgG and IgA. Enteropathies are commonly observed in CVID patients but the underlying reason for this is undefined. Here, we utilize CD19 mice as a model of CVID to test the hypothesis that antibody deficiency negatively impacts gut physiology under steady-state conditions. As anticipated, immune phenotyping experiments demonstrate that CD19 mice develop a severe B cell deficiency in gut-associated lymphoid tissues that result in significant reductions to antibody concentrations in the gut lumen. Antibody deficiency was associated with defective anti-commensal IgA responses and the outgrowth of anaerobic bacteria in the gut. Expansion of anaerobic bacteria coincides with the development of a chronic inflammatory condition in the gut of CD19 mice that results in an intestinal malabsorption characterized by defects in lipid metabolism and transport. Administration of the antibiotic metronidazole to target anaerobic members of the microbiota rescues mice from disease indicating that intestinal malabsorption is a microbiota-dependent phenomenon. Finally, intestinal malabsorption in CD19 mice is a gluten-sensitive enteropathy as exposure to a gluten-free diet also significantly reduces disease severity in CD19 mice. Collectively, these results support an effect of antibody deficiency on steady-state gut physiology that compliment emerging data from human studies linking IgA deficiency with non-infectious complications associated with CVID. They also demonstrate that CD19 mice are a useful model for studying the role of B cell deficiency and gut dysbiosis on gluten-sensitive enteropathies; a rapidly emerging group of diseases in humans with an unknown etiology.

Common Variable Immunodeficiency (CVID), the most prevalent symptomatic primary immunodeficiency, is frequently associated with severe inflammatory complications that determine its morbidity and mortality. We hypothesize that Helicobacter pylori (HP), a very common worldwide infection, may contribute to the clinical and immune phenotype of CVID. We stratified 41 CVID patients into HP+ (n=26) and HPneg (n=15) groups, according to previous urease breath test and/or gastric biopsies, and compared their clinical manifestations and immune profile evaluated by flow cytometry. No genetic variants with known potential impact in HP infection were found upon WES/WGS. Gastric complications were significantly more frequent in HP+ patients. Importantly, the six CVID patients with gastric cancer were infected with HP. In contrast, a significantly higher frequency of cytopenias was observed in the HPneg. Moreover, HP+ did not feature higher prevalence of organ auto-immunity, as well as of lung, liver or intestinal inflammatory manifestations. We observed the same B-cell profiles in HP+ and HPneg groups, accompanied by marked CD4 and CD8 T-cell activation, increased IFNγ production, and contraction of naïve compartments. Notably, HP+ patients featured low CD25 despite preserved Foxp3 levels in CD4 T cells. Overall, HP impact in CVID inflammatory complications was mainly restricted to the gastric mucosa, contributing to increased incidence of early onset gastric cancer. Thus, early HP screening and eradication should be performed in all CVID patients irrespective of symptoms.

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.

[This corrects the article DOI: 10.3389/fimmu.2021.767188.].

The life span of patients with primary and secondary immunodeficiency is increasing due to recent improvements in therapeutic strategies. While the incidence of primary immunodeficiencies (PIDs) is 1:10,000 births, that of secondary immunodeficiencies are more common and are associated with posttransplantation immune dysfunction, with immunosuppressive medication for human immunodeficiency virus or with human T-cell lymphotropic virus infection. After infection, malignancy is the most prevalent cause of death in both children and adults with (PIDs). PIDs more often associated with cancer include common variable immunodeficiency (CVID), Wiskott-Aldrich syndrome, ataxia-telangiectasia, and severe combined immunodeficiency. This suggests that a protective immune response against both infectious non-self-(pathogens) and malignant self-challenges (cancer) exists. The increased incidence of cancer has been attributed to defective elimination of altered or \"transformed\" cells and/or defective immunity towards cancer cells. The concept of aberrant immune surveillance occurring in PIDs is supported by evidence in mice and from patients undergoing immunosuppression after transplantation. Here, we discuss the importance of PID defects in the development of malignancies and the current limitations associated with molecular pathogenesis of these diseases and emphasize the need for further knowledge of how specific mutations can modulate the immune system to alter immunosurveillance and thereby play a key role in the etiology of malignancies in PID patients.

Background Vaccination prevents severe morbidity and mortality from COVID-19 in the general population. The immunogenicity and efficacy of SARS-CoV-2 vaccines in patients with antibody deficiency is poorly understood. Objectives COVID-19 in patients with antibody deficiency (COV-AD) is a multi-site UK study that aims to determine the immune response to SARS-CoV-2 infection and vaccination in patients with primary or secondary antibody deficiency, a population that suffers from severe and recurrent infection and does not respond well to vaccination. Methods Individuals on immunoglobulin replacement therapy or with an IgG less than 4 g/L receiving antibiotic prophylaxis were recruited from April 2021. Serological and cellular responses were determined using ELISA, live-virus neutralisation and interferon gamma release assays. SARS-CoV-2 infection and clearance were determined by PCR from serial nasopharyngeal swabs. Results A total of 5.6% ( n  = 320) of the cohort reported prior SARS-CoV-2 infection, but only 0.3% remained PCR positive on study entry. Seropositivity, following two doses of SARS-CoV-2 vaccination, was 54.8% ( n  = 168) compared with 100% of healthy controls ( n  = 205). The magnitude of the antibody response and its neutralising capacity were both significantly reduced compared to controls. Participants vaccinated with the Pfizer/BioNTech vaccine were more likely to be seropositive (65.7% vs. 48.0%, p  = 0.03) and have higher antibody levels compared with the AstraZeneca vaccine (IgGAM ratio 3.73 vs. 2.39, p  = 0.0003). T cell responses post vaccination was demonstrable in 46.2% of participants and were associated with better antibody responses but there was no difference between the two vaccines. Eleven vaccine-breakthrough infections have occurred to date, 10 of them in recipients of the AstraZeneca vaccine. Conclusion SARS-CoV-2 vaccines demonstrate reduced immunogenicity in patients with antibody deficiency with evidence of vaccine breakthrough infection.