Subclinical infection and dosing in primary immunodeficiencies.

Efficiency of immunoglobulin G replacement therapy in common variable immunodeficiency: correlations with clinical phenotype and polymorphism of the neonatal Fc receptor.

Comparison of clinical and immunological features and mortality in common variable immunodeficiency and agammaglobulinemia patients

BackgroundInfections caused by bacteria or viruses are frequent in common variable immunodeficiency (CVID) patients due to antibody deficiencies, which may be associated with altered T cell function. CVID patients are frequently in contact with pathogen-associated molecular patterns (PAMPs), leading to the activation of innate immunity through Toll-like receptors (TLR) affecting T cell activation. We evaluated the effect of TLR activation on T cells in CVID patients undergoing intravenous immunoglobulin (IVIg) replacement using synthetic ligands.MethodsExpression of exhaustion, activation and maturation markers on T cells from peripheral blood as well as regulatory T cells and follicular T cells in peripheral blood mononuclear cells (PBMCs) from CVID and healthy individuals were evaluated by flow cytometry. PBMCs cultured with TLR agonists were assessed for intracellular IFN-γ, TNF, IL-10, IL-17a or IL-22 secretion as monofunctional or polyfunctional T cells (simultaneous cytokine secretion) by flow cytometry.ResultsWe found increased expression of the exhaustion marker PD-1 on effector memory CD4+ T cells (CD45RA−CCR7−) in the peripheral blood and increased expression of CD38 in terminally differentiated CD8+ T cells (CD45RA+CCR7−). Furthermore, a decreased frequency of naïve regulatory T cells (CD45RA+Foxp3low), but not of activated regulatory T cells (CD45RA−Foxp3high) was detected in CVID patients with splenomegaly, the non-infectious manifestation in this CVID cohort (43.7 %). Moreover, the frequency of peripheral blood follicular helper T cells (CD3+CD4+CXCR5+PD-1+ICOS+) was similar between the CVID and control groups. Upon in vitro TLR3 activation, a decreased frequency of CD8+ T cells secreting IFN-γ, IL-17a or IL-22 was detected in the CVID group compared to the control group. However, a TLR7/TLR8 agonist and staphylococcal enterotoxin B induced an increased Th22/Tc22 (IL-22+, IFN-γ−, IL-17a−) response in CVID patients. Both TLR2 and TLR7/8/CL097 activation induced an increased response of CD4+ T cells secreting three cytokines (IL-17a, IL-22 and TNF)in CVID patients, whereas CD8+ T cells were unresponsive to these stimuli.ConclusionThe data show that despite the unresponsive profile of CD8+ T cells to TLR activation, CD4+ T cells and Tc22/Th22 cells are responsive, suggesting that activation of innate immunity by TLRs could be a strategy to stimulate CD4+ T cells in CVID.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-016-0900-2) contains supplementary material, which is available to authorized users.

Primary antibody deficiencies (PAD) are a group of disorders characterized by reduced antibody production, leading to a common form of primary immunodeficiency. This group includes specific polysaccharide antibody deficiency, immunoglobulin G subclass deficiency, common variable immunodeficiency (CVID), and agammaglobulinemia. B cell dysfunction is a key feature of PAD, resulting in recurrent respiratory and gastrointestinal infections due to compromised mucosal protection. Preventive measures such as vaccination, prophylactic antibiotics, and immunoglobulin replacement therapy (IRT) have been effective in reducing infections but complications like bronchiectasis, hearing loss, and malnutrition can still occur. Non-infectious complications, including enteropathy, granulomatous lymphocytic interstitial lung disease (GLILD), and secondary hemophagocytic lymphohistiocytosis (HLH), contribute significantly to morbidity and mortality in CVID patients despite IRT. Enteropathy lacks effective treatment options, while GLILD and HLH require early intervention but have diagnostic challenges. Genetic studies have identified over 40 genes linked to PAD, highlighting the complexity of the disorder. Monogenic causes are found in only a small percentage of cases, emphasizing the multifactorial nature of PAD. T cell dysfunction has also been implicated in PAD, beyond the typical B cell abnormalities. CVID patients without a monogenic disease may experience T cell dysregulation, with elevated effector memory T cells and increased IFN-γ response genes. Dysregulated T cells contribute to the activation of monocytes, leading to the production of B cell activating factor (BAFF), which is linked to non-infectious complications, particularly in GLILD patients. To address knowledge gaps in PAD, the thesis aims to improve understanding of the genetic landscape, optimize strategies for preventing infections, and develop treatments for non-infectious complications. Larger cohort studies and clinical trials are needed to establish evidence-based recommendations. Identifying predictive risk factors for specific complications is crucial for effective screening and treatment decisions. T cell functionality is a focus for normalizing non-infectious complications. The thesis is divided into two parts: Diagnosis and pathophysiology of PAD, and Management of PAD. In the first part, various genetic variants associated with PAD are discussed, highlighting the complex interplay of B and T cells in the disease. In the second part, the effectiveness of prophylactic antibiotics and IRT in milder forms of PAD is compared, and treatment options for GLILD are explored, with a focus on corticosteroids as a first-line treatment. Clinical recommendations include using next-generation sequencing for diagnosis, personalized treatment approaches, and intensive monitoring for patients at risk of complications. Standardized treatment approaches for GLILD are also advocated. Collaborative efforts and further research are needed to advance our understanding and management of PAD. In conclusion, this thesis contributes to our understanding of PAD, providing insights into its genetic basis and treatment strategies. However, collaborative research and evidence-based approaches are essential to address remaining knowledge gaps and improve care for patients with this complex disease.

A substantial proportion of common variable immunodeficiency (CVID) patients has duodenal inflammation of largely unknown etiology. However, because of its histologic similarities with celiac disease, gluten sensitivity has been proposed as a potential mechanism. We aimed to elucidate the role of the duodenal microenvironment in the pathogenesis of duodenal inflammation in CVID by investigating the transcriptional, proteomic, and microbial signatures of duodenal biopsy samples in CVID. DNA, total RNA, and protein were isolated from snap-frozen pieces of duodenal biopsy samples from CVID (with and without duodenal inflammation), healthy controls, and patients with celiac disease (untreated). RNA sequencing, mass spectrometry-based proteomics, and 16S ribosomal DNA sequencing (bacteria) were then performed. CVID separated from controls in regulation of transcriptional response to lipopolysaccharide and cellular immune responses. These differences were independent of mucosal inflammation. Instead, CVID patients with duodenal inflammation displayed alterations in transcription of genes involved in response to viral infections. Four proteins were differently regulated between CVID patients and healthy controls-DBNL, TRMT11, GCHFR, and IGHA2-independent of duodenal inflammation. Despite similar histology, there were major differences in CVID with duodenal inflammation and celiac disease both at the RNA and protein level. No significant difference was observed in the bacterial gut microbial signature between CVID, celiac, and healthy controls. Our findings suggest the existence of altered functions of the duodenal epithelium, particularly in response to lipopolysaccharide and viruses. The latter finding was related to duodenal inflammation, suggesting that viruses, not gluten sensitivity, could be related to duodenal inflammation in CVID.

To the Editor Primary antibody deficiency syndromes (PADs) comprise an heterogeneous group of disorders characterized by low immunoglobulin serum levels. PADs encompass a wide range of disorders with Selective IgA deficiency (SIgAD) and Common Variable Immunodeficiency (CVID) being the more frequent ones. The incidence of SIgAD varies notably depending on ethnicity, while CVID presents an estimated incidence of 1:10.000–1:25.000; both may affect pediatric and adult patients. Regarding CVID, the genetic landscape is continuously becoming broader, involving genes encoding for, among others, TACI, BAFFR, CD19, CD20, CD21, CD81 and LRBA [1]. Mutations in TACI, the most frequently mutated gene in CVID, may be present in almost 8–10 % of affected patients [1]. TACI genetic variants have also been associated with SIgAD. TACI together with BAFFR and BCMA, are members of the Tumor Necrosis Factor Receptor (TNFR) superfamily. They are only expressed on B cells, as known so far, and their ligation to BAFF (all three) or APRIL (only TACI and BCMA) affects B cell homeostasis. Mutations in TACI associated with CVID abrogate the receptor’s expression on B cells as well as its capacity to bind APRIL. Homozygous deletions in the BAFFR gene on the other hand are very rare. Only two adult onset patients affected with complete BAFFR deficiency and hypogammaglobulinemia have been reported so far [2]. Mutations in BAFFR not resulting in lack of BAFFR expression have also been reported in CVID patients [3]. The P21R mutation in BAFFR was recently reported to alter the multimerization of BAFFR on B cell surface, contributing to common variable immunodeficiency [4]. So far, mutations in BAFFR have not been associated with SIgAD. We report on three family members (father and two daughters) affected with Common Variable Immunodeficiency (patient 1), selective IgA deficiency (Patient 2) and Hypo-IgM (father) that carry the monoallelic P21R/H159Y mutations in TNFRSF13C associated with reduced BAFFR expression on B cells suggesting that the P21R/H159Y monoallelic mutations may contribute to primary antibody deficiency with variable immunological presentation. The immunological data of the reported patients are summarized in Fig. 1a. All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individuals (or their parents in case of pediatric patients) participating in this study. In brief, patient 1 presented a history of recurrent respiratory infections starting at the age of 2 years. Her clinical history was complicated by an episode of meningitis and mastoiditis at the age of 5 years. During this admission, immunological work-up showed hypogammaglobulinemia, normal peripheral B cell percentages, absent humoral response to vaccinations leading to the diagnosis of CVID. Patient 2, the sister of patient 1, presented occasional gastrointestinal and respiratory infections and was evaluated due to positive family history for CVID. IgA serum levels were below the threshold of * Vassilios Lougaris vlougaris@yahoo.co.uk

Common variable immunodeficiency (CVID) patients have markedly decreased immune response to vaccinations. In this study we evaluated humoral and T cell-mediated responses against severe acute respiratory syndrome coronavirus-2 (SARS-Cov-2) with additional flow cytometric changes in CVID patients receiving booster vaccination with BNT162b2 after two ChAdOx1 nCoV-19. The BNT162b2 vaccine raised the anti-spike protein S immunoglobulin G over the cut-off value from 70% to 83% in CVID, anti-neutralizing antibody had been raised over a cut-off value from 70% to 80% but levels after boosting were significantly less in both tests than in healthy controls (*p=0.02; **p=0.009 respectively). Anti-SARS-CoV-2 immunoglobulin A became less positive in CVID after boosting, but the difference was not significant. The cumulative interferon-γ positive T cell response by ELISpot was over the cut-off value in 53% of the tested individuals and raised to 83% after boosting. This and flow cytometric control of cumulative CD4+ and CD8+ virus-specific T cell absolute counts in CVID were also statistically not different from healthy individuals after boosting. Additional flow cytometric measures for CD45+ lymphocytes, CD3+, and CD19+ cells have not shown significant differences from controls except for lower CD4+T cell counts at both time points (**p=0.003; **p=0.002), in parallel CD4+ virus-specific T-cell ratio was significantly lower in CVID patients at the first time point (*p: 0.03). After boosting, in more than 33% of both CVID patients and also in their healthy controls we detected a decrease in absolute CD45+, CD3+, CD3+CD4+, and CD3+CD8+, CD19+, and CD16+56+ cell counts. CD16+CD56+ cell counts were significantly lower compared to controls before and after boosting (*p=0.02, *p=0.02). CVID patients receiving immunosuppressive therapy throughout the previous year or autologous stem cell transplantation two years before vaccination had worse responses in anti-spike, anti-neutralizing antibody, CD3+CD4+T, CD19+ B, and natural killer cell counts than the whole CVID group. Vaccinations had few side effects. Based on these data, CVID patients receiving booster vaccination with BNT162b2 after two ChadOx1 can effectively elevate the levels of protection against COVID-19 infection, but the duration of the immune response together with COVID-19 morbidity data needs further investigation among these patients.

Despite immunoglobulin replacement (IgRT) therapy, some patients with primary antibody deficiency (PAD) continue to develop respiratory infections. Recurrent and severe respiratory infections, particularly pneumonia, can lead to significant morbidity and mortality. Therefore, we sought to determine the risk factors of developing pneumonia in PAD patients, already receiving IgRT. We evaluated clinical and laboratory features of PAD patients enrolled in the US Immune Deficiency Network (USIDNET) registry by April 2017. Patients were included if they met the following criteria: (1) PAD diagnosis (common variable immunodeficiency (CVID), agammaglobulinemia, hypogammaglobinemia, and specific antibody deficiency (SAD) and (2) available data on infections before and after IgRT. Patients were excluded if they were not receiving IgRT, or if no pre/post infections data were available. Descriptive and multivariable logistic regression analyses were used to identify factors associated with pneumonia post-IgRT. A total of 1232 patients met the inclusion criteria. Following IgRT, 218 patients (17.7%) were reported to have at least one pneumonia episode. Using multivariate logistic regression analysis, we found a statistically significant increased risk of pneumonia in patients with asthma (OR: 2.55, 95% CI (1.69-3.85), p < 0.001) bronchiectasis (OR: 3.94, 95% CI (2.29-6.80), p < 0.001), interstitial lung disease (ILD) (OR: 3.28, 95%CI (1.43-7.56), p < 0.005), splenomegaly (OR: 2.02, 95%CI (1.08-3.76), p < 0.027), allergies (OR: 2.44, 95% CI [1.44-4.13], p = 0.001), and patients who were not on immunosuppressives (OR: 1.61; 95%CI [1.06-2.46]; p = 0.027). For every 50 unit increase in IgA, the odds of reporting pneumonia post IgRT decreased (OR: 0.86, 95% CI [0.73-1.02], p = 0.062). Infectious organisms were reported in 35 of 218 patients who reported pneumonia after IgRT. Haemophilus influenzae was the most frequently reported (n = 11, 31.43%), followed by Streptococcus pneumoniae (n = 7, 20.00%). Our findings suggest PAD patients with chronic and structural lung disease, splenomegaly, and allergies were associated with persistent pneumonia. However, our study is limited by the cross-sectional nature of the USIDNET database and limited longitudinal data. Further studies are warranted to identify susceptible causes and explore targeted solutions for prevention and associated morbidity and mortality. Patients with primary antibody deficiency with structural lung disease, allergies, and splenomegaly are associated with persistent pneumonia post-IgRT.

The work presented in the first section of this thesis describes how a novel homozygous P440S mutation in LCK results in decreased LCK protein expression and defective TCR signaling. The severe signaling defect impedes thymocyte development, which results in T cell lymphopenia. We find P440S Treg development and function to be compromised, however the loss of T cell function is only partial in conventional T cells. This residual activity in mutant conventional T cells drives the development of intestinal inflammation in P440S mice. In contrast, Lck knock out mice do not develop any intestinal inflammation, despite sharing similar central and peripheral T cell defects. These results indicate that a complete loss of Lck expression and function results in only a state of immunodeficiency, whereas the residual mutant Lck expression and function produces immunodeficiency with immune dysregulation. In the second section of this thesis, we describe our efforts to identify perturbations in both immune cell subsets and antigen receptor signal transduction within a subset of common variable immunodeficiency (CVID) patients with granulomatous lymphocytic interstitial lung disease (GLILD). We determined that CVID patients, regardless of GLILD status, demonstrate increased frequency of HLADR+CD4+ T cells, CD57+CD8+ T cells, and CD21lo B cells when compared to healthy controls. However, CVID patients with GLILD demonstrated discordant antigen receptor signaling events within these subsets of activated lymphocytes. These findings suggest that while increased frequencies of activated lymphocyte subsets may be a common finding in CVID and CVID/GLILD, the downstream cellular function is only disturbed in CVID/GLILD. Our findings provide a cohesive picture of the phenotypic and signaling differences amongst healthy vs. CVID vs. CVID/GLILD individuals, setting up a foundation to identify specific pathways that may be aberrantly signaling in CVID/GLILD patients to better guide personalized therapy.

Abnormalities in peripheral blood B cell subsets have been identified in common variable immunodeficiency (CVID) patients and classification systems based upon their numbers have been proposed to predict the clinical features. We analysed B lymphocyte subsets by multi-colour flow cytometry (MFC) in a cohort of well-characterized CVID patients to look at their clinical relevance and validate the published association of different classification criteria (Freiburg, Paris and Euroclass) with clinical manifestations. CVID patients had a reduced proportion of total and switched memory B cells (MBC, swMBC) compared to normal controls (P < 0·0006). Patients classified in Freiburg Ia had a higher prevalence of granulomatous diseases (P = 0·0034). The previously published associations with autoimmune diseases could not be confirmed. The Euroclass classification was not predictive of clinical phenotypes. The absolute numbers of all B cell subsets were reduced in CVID patients compared to controls. There was a significant linear correlation between low absolute total B cells and MBC with granulomatous disease (P < 0·05) and a trend towards lower B cells in patients with autoimmune diseases (P = 0·07). Absolute number of different B cell subsets may be more meaningful than their relative percentages in assessing the risk of granulomatous diseases and possibly autoimmunity.

Autoimmune enteropathy (AIE) and common variable immunodeficiency (CVID) can both manifest as chronic diarrhea and small intestinal villous atrophy, making their differentiation challenging. To explore the similarities and differences in the clinical manifestations, laboratory tests, pathological features, and long-term prognoses between these two diseases. This retrospective study included 26 AIE patients and 29 CVID patients with gastrointestinal (GI) involvement who were admitted to our center from June 2012 to May 2024, with all their medical records reviewed. Differences between the two diseases were evaluated via statistical tests. Compared with CVID patients, AIE patients experienced a shorter duration of severe diarrhea, greater weight loss, and more severe hypoalbuminemia and electrolyte imbalances. Furthermore, CVID patients exhibited a notable history of recurrent respiratory infections; significantly lower serum levels of IgG, IgM, and IgA; a marked decrease in B-cell and CD4 + T-cell counts; and a significant inversion of the CD4 + /CD8 + ratio within peripheral blood lymphocyte subsets. Endoscopically, AIE patients are more likely to present with active inflammatory changes, such as erosions and hyperemia. On the basis of histopathological analysis of 23 AIE patients and 24 CVID patients, AIE patients presented with reduced goblet and Paneth cells, pronounced neutrophilic infiltration, and more frequent apoptotic bodies, while CVID patients demonstrated reduced plasma cells and deep crypt lymphocytosis. The diagnostic efficiency of the five pathological items in the duodenum (AUC 0.937), which includes goblet cell and Paneth cell reduction, was greater than that of the four-item combination (AUC 0.622). Long-term follow-up indicated that patients with both conditions were prone to diarrhea relapse, and CVID patients showed a slightly longer median relapse-free survival than did AIE patients. Although AIE patients and CVID patients share many similarities, they exhibit significant differences. A thorough medical history, laboratory tests, and endoscopic and histopathological results provide compelling evidence for their differential diagnosis. Key Points • Both AIE and CVID with gastrointestinal involvement are immune-mediated diseases characterized by chronic diarrhea and small intestinal villi atrophy, making clinical diagnosis difficult. • AIE and CVID have different characteristics that can be used to distinguish them, especially pathological findings.

Controller medications and their effects on asthma exacerbations temporally associated with upper respiratory infections

Immunoglobulin treatment in primary antibody deficiency

Sera from 77 patients with common variable immunodeficiency (CVID) were tested for GB virus C (GBV-C) RNA, because they are prone to unexplained chronic hepatitis, and from 28 patients with X-linked agammaglobulinemia (XLA) who have a similar primary antibody deficiency but are not prone to hepatitis. Eight CVID and 8 XLA patients were positive; 6 positive CVID and 3 XLA patients had abnormal liver enzymes, explained in 3 by either hepatitis B or C virus infection. Most patients tested had antibodies to the E2 antigen of GBV-C, apparently passively acquired from their immunoglobulin therapy. The high prevalence of GBV-C viremia in CVID and XLA patients is probably explained by their long-term exposure to blood products. Our data indicate that GBV-C does not cause chronic hepatitis in immunocompromised XLA patients and is not the cause of chronic non-B or -C hepatitis in the majority of CVID patients.

Background: Common variable immunodeficiency (CVID) is one of the most prevalent symptomatic primary immunodeficiencies (PIDs), which manifest a wide clinical variability such as gastrointestinal (GI) disorder.Patients and Methods: A total of 240 patients with CVID were enrolled in this study. The patients were evaluated for demographic data, clinical manifestations, and immunologic profile.Results: In demographic data, the frequency of consanguinity and mortality rate were higher in patients with GI manifestation than those without GI manifestation. History of GI manifestations was evident in 147 patients (61.3%). The most common GI manifestation in patients with CVID was chronic diarrhea (29.6%). The prevalence of GI disease was 59 of 102 (57.8%) in female patients and 88 of 138 (63.8%) in male patients. The frequency of recurrent infection was higher in patients with GI manifestation than in those without GI manifestation. Also, CVID patients with GI manifestations had lower WBC and CD4+ T cells than patients without GI manifestations.Conclusion: CVID patients are at increased risk of infectious conditions in the GI tract; hence GI manifestations are one of the most important presentations in CVID patients which can appear as a first manifestation or appear during the course of disease.