Costimulatory molecules and cytokine production by T lymphocytes in common variable immunodeficiency disease

Single-cell Atlas of common variable immunodeficiency shows germinal center-associated epigenetic dysregulation in B-cell responses

Common variable immunodeficiency (CVID), the most prevalent symptomatic primary immunodeficiency, displays impaired terminal B-cell differentiation and defective antibody responses. Incomplete genetic penetrance and ample phenotypic expressivity in CVID suggest the participation of additional pathogenic mechanisms. Monozygotic (MZ) twins discordant for CVID are uniquely valuable for studying the contribution of epigenetics to the disease. Here, we generate a single-cell epigenomics and transcriptomics census of naïve-to-memory B cell differentiation in a CVID-discordant MZ twin pair. Our analysis identifies DNA methylation, chromatin accessibility and transcriptional defects in memory B-cells mirroring defective cell-cell communication upon activation. These findings are validated in a cohort of CVID patients and healthy donors. Our findings provide a comprehensive multi-omics map of alterations in naïve-to-memory B-cell transition in CVID and indicate links between the epigenome and immune cell cross-talk. Our resource, publicly available at the Human Cell Atlas, gives insight into future diagnosis and treatments of CVID patients.

Common variable immunodeficiency (CVID) is the most prevalent primary immunodeficiency. Here the authors perform single-cell omics analyses in CVID-discordant monozygotic twins and show epigenetic and transcriptional alterations associated with activation in memory B cells.

Seeking Relevant Biomarkers in Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is the most common symptomatic form of primary immunodeficiency. More than 50% of patients in some series suffer from autoimmune or inflammatory complications (the "CVID+" phenotype), and these are not adequately addressed by current treatments. Despite major advancements in genetics, the pathogenesis of the CVID+ phenotype has remained unexplained for most patients, necessitating the need for relevant biomarkers in both the clinic and research settings. In the clinics, reduced isotype-switched memory B cells (≤ 0.55% of B cells) and reduced T cells (CD4) can be utilized to identify those with increased complication risks. Additionally, condition-specific markers have also been suggested for lymphoma (normal or elevated IgM) and progressive interstitial lung disease (increased BAFF, normal or elevated IgM). Additional biomarkers have provided insights into disease pathogenesis, demonstrating wider systemic inflammation (increased LBP, sCD14, and sCD25; expanded ILC3), mucosal defects (increased zonulin, I-FABP), and perhaps reduced anti-inflammatory capability (reduced HDL) in CVID. Most recently, efforts have revealed elevated circulating bioactive bacterial DNA levels - marking microbial translocation and potentially linking the causation of multiple inflammatory changes previously observed in CVID. The implementation of high throughput profiling techniques may accelerate the search of relevant biomarker profiles in CVID and lead to better clinical risk stratification, revealing disease insights, and identifying potential therapeutic targets.

Trained Immunity Based-Vaccines as a Prophylactic Strategy in Common Variable Immunodeficiency. A Proof of Concept Study

Background. A major concern in the care of common variable immunodeficiency (CVID) patients is the persistence of subclinical or recurrent respiratory tract infections (RRTI) despite adequate trough IgG levels, which impacts the quality of life (QoL) and morbidity. Therefore, the development of new approaches to prevent and treat infection, especially RRTI, is necessary. Objectives. We conducted a clinical observational study from May, 2016 to December, 2017 in 20 CVID patients; ten of these patients had a history of RRTI and received the polybacterial preparation MV130, a trained immunity-based vaccine (TIbV) to assess its impact on their QoL and prognosis. Methods. Subjects with RRTI received MV130 for 3 months and were followed up to 12 months after initiation of the treatment. The primary endpoint was a reduction in RRTI at the end of the study. We analyzed the pharmacoeconomic impact on the RRTI group before and after immunotherapy by estimating the direct and indirect costs, and assessed CVID-QoL and cytokine profile. Specific antibody responses to the bacteria contained in MV130 were measured. Results. The RRTI-group treated with TIbV MV130 showed a significant decrease in infection rate (p = 0.006) throughout the 12 months after initiation of the treatment. A decrease in antibiotic use and unscheduled outpatient visits was observed (p = 0.005 and p = 0.002, respectively). Significant increases in anti-pneumococcus and anti-MV130 IgA antibodies (p = 0.039 both) were detected after 12 months of MV130. Regarding the CVID QoL questionnaire, an overall decrease in the score by more than 50% was observed (p < 0.05) which demonstrated that patients experienced an improvement in their QoL. The pharmacoeconomic analysis showed that the real annual direct costs decreased up to 4 times per patient with the prophylactic intervention (p = 0.005). Conclusion. The sublingual administration of the TIbV MV130 significantly reduced the rate of respiratory infections, antibiotic use and unscheduled visits, while increasing specific IgA responses in CVID patients. Additionally, the CVID population felt that their QoL was improved, and a decrease in expenses derived from health care was predicted.

Variable immunodeficiency study: Evaluation of two European cohorts within a variety of clinical phenotypes

INTRODUCTION

Given the wide heterogeneity of common variable immunodeficiency (CVID), several groups have proposed clinical and immunological classifications to better define follow-up and prognostic algorithms. The present study aims to validate recent clinical and laboratory algorithms, based on different combinations of CVID biomarkers, to provide more personalized treatment and follow-up strategies.

METHODS

We analysed clinical and immunological features of 80 patients with suspected or diagnosed CVID, in two reference centres of Portugal and Spain. Clinical manifestations were categorized into clinical phenotyping proposed by Chapel et al. [1] that included cytopenia; polyclonal lymphocytic infiltration; unexplained enteropathy; and no disease-related complications.

RESULTS

76% of patients in our cohort entered one of the four categories of clinical phenotyping, without overlap (cytopenia; polyclonal lymphocytic infiltration; unexplained enteropathy; and no disease-related complications). The most prominent phenotype was "cytopenia" (40%) followed by "polyclonal lymphocytic infiltration" (19%). The remaining 24% patients of our cohort had overlap of 2 clinical phenotypes (cytopenia and unexplained enteropathy mainly). A delay of CVID diagnosis in more than 6 years presented 3.7-fold higher risk of developing lymphoproliferation and/or malignancy (p < 0.05), and was associated with increased CD8⁺CD45RO ⁺ T-lymphocytes (p < 0.05). An association between decreased switched-memory B cells with lymphoproliferation and malignancy was observed (p < 0.03 and p < 0.05, respectively). CD4 ⁺ T-lymphocytopenia correlated with autoimmune phenotype, with 30% prevalence (p < 0.05). HLA-DR7 expression was related to CVID onset in early life in our patients (13 vs 25 years), and DQ2.5 or DQ2.2 with unexplained enteropathy (p < 0.05).

CONCLUSIONS

The phenotypic and genetic study is crucial for an adequate clinical orientation of CVID patients. In these two independent cohorts of patients, classification based in clinical and laboratory algorithms, provides more personalized treatment and follow-up strategies.

Chemokine, cytokine and type I interferon production induced by Toll-like receptor activation in common variable immune deficiency

Common variable immunodeficiency (CVID) is the most common symptomatic primary antibody deficiency and is associated with recurrent infections and chronic inflammatory diseases. We evaluated the ability of Toll-like receptor (TLR) ligands to induce secretion of chemokines, cytokines and type I interferons by peripheral blood mononuclear cells (PBMCs) from CVID patients. High levels of CXCL10, CCL2, CXCL9, CCL5, CXCL8, and IL-6 were detected in sera of CVID patients compared with healthy controls. Increased chemokine levels were observed in unstimulated PBMCs, but after stimulation with TLR2 and TLR4 agonists, equivalent chemokine and pro-inflammatory cytokine secretion, as in healthy controls, was observed, whereas TLR4 agonist induced a decreased secretion of CCL2 and CXCL8 and increased secretion of TNF. Decreased IFN-α secretion induced by TLR7/TLR8 activation was observed in CVID, which was recovered with TLR9 signaling. Our findings revealed that TLR9 activation has an adjuvant effect on the altered type I response in CVID.

Cytokines in common variable immunodeficiency as signs of immune dysregulation and potential therapeutic targets - a review of the current knowledge

Common variable immunodeficiency (CVID) is characterized by low levels of circulating immunoglobulins and compromised specific antibody response leading to frequent infections. Cytokines play an important role in the orchestration of the antibody response. Several previous studies have attempted to identify distinct cytokines responsible for the inflammatory changes and different manifestations of CVID, but there are conflicting results regarding the cytokine profiles in CVID patients. In light of this, an extensive review regarding the level of various cytokines and their potential therapeutic role in CVID patients was performed. This review delineates the contribution of interleukin (IL)-1, IL-2, IL-4, IL-5, IL-6, IL-7, IL-10, IL-12, IL-21, interferons, tumor necrosis factor (TNF)-α, IL-17, APRIL (a proliferation inducing ligand) and BAFF (B cell activating factor) in CVID disease and outline their potential therapeutic implications in these patients.

Immunophenotypic Analysis of B Lymphocytes in Patients with Common Variable Immunodeficiency: Identification of CD23 as a Useful Marker in the Definition of the Disease

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by the failure of B lymphocytes differentiation leading to deficient immunoglobulins secretion. The identified genetic defects account only for a minority of cases. The importance of B cells immunophenotyping in the classification of CVID is known. This procedure can identify alterations on the cell surface molecules expression that could explain some immunological disorders characteristic of CVID. Moreover, some immunophenotypical aspects can correlate with clinical features of the disease. We used this procedure to analyze a cohort of 23 patients affected by CVID, in order to identify the novel alterations of B cells and to find the possible correlations with clinical features. Circulating B cells were studied by flow cytometry incubating whole blood with specific antibodies for B cell surface molecules including CD27, IgM, IgD, CD21, and CD23. We compared the population of “switched memory” IgD− CD27+ B lymphocytes with the population of “switched memory” IgM− IgD− CD23− CD27+ B cells. These last B cells were reduced in patients compared to healthy controls; moreover, IgM− IgD− CD23− CD27+ B cells were lower than IgD− CD27+ B cells in patients with CVID. The reduction of this subset of B lymphocytes correlates more tightly than IgD− CD27+ B cells with lymphadenopathy and airways infections. In conclusion, our findings may help in better identifying patients with CVID.

Defective B cell response to TLR9 ligand (CpG-ODN), Streptococcus pneumoniae and Haemophilus influenzae extracts in common variable immunodeficiency patients

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by hypogammaglobulinaemia and antibody deficiency to both T dependent and independent antigens. Patients suffer from recurrent sinopulmonary infections mostly caused by Streptococcus pneumoniae and Haemophilus influenzae, but also gastrointestinal or autoimmune symptoms. Their response to vaccination is poor or absent. In this study we investigated B cell activation induced by the TLR9 specific ligand (CpG-ODN) and bacterial extracts from S. pneumoniae and H. influenzae known to stimulate several TLR. We found that B cells from CVID patients express lower levels of CD86 after stimulation with CpG-ODN, S. pneumoniae and H. influenzae extracts in combination with anti-IgM antibody and also display a lower proliferative index when stimulated with bacterial extracts. Our results point to a broad TLR signalling defect in B lymphocytes from CVID patients that may be related to the hypogammaglobulinaemia and poor response to vaccination characteristic of these patients.

Interleukin-21 restores immunoglobulin production ex vivo in patients with common variable immunodeficiency and selective IgA deficiency

Interleukin-21 (IL-21) is an important promoter for differentiation of human B cells into immunoglobulin (Ig)–secreting cells. The objective of this study was to evaluate an IL-21–based approach to induce immunoglobulin production in B cells from patients with common variable immunodeficiency (CVID) or selective IgA deficiency (IgAD). We show that a combination of IL-21, IL-4, and anti-CD40 stimulation induces class-switch recombination to IgG and IgA and differentiation of Ig-secreting cells, consisting of both surface IgG+ (sIgG+) and sIgA+ B cells and CD138+ plasma cells, in patients with CVID or IgAD. Stimulation with IL-21 was far more effective than stimulation with IL-4 or IL-10. Moreover, spontaneous apoptosis of CD19+ B cells from patients with CVID or IgAD was prevented by a combination of IL-21, IL-4, and anti-CD40 stimulation. Analysis of IL-21 and IL-21 receptor (IL-21R) mRNA expression upon anti-CD3 stimulation of T cells, however, showed no evidence for defective IL-21 expression in CVID patients and sequencing of the coding regions of the IL21 gene did not reveal any mutations, suggesting a regulatory defect. Thus, our work provides an initial basis for a potential therapeutic role of IL-21 to reconstitute immunoglobulin production in CVID and IgAD.

A decreased frequency of regulatory T cells in patients with common variable immunodeficiency

Introduction

Common variable immunodeficiency disorder (CVID) is a heterogeneous syndrome, characterized by deficient antibody production and recurrent bacterial infections in addition abnormalities in T cells. CD4⁺CD25^high regulatory T cells (Treg) are essential modulators of immune responses, including down-modulation of immune response to pathogens, allergens, cancer cells and self-antigens.

Objective

In this study we set out to investigate the frequency of Treg cells in CVID patients and correlate with their immune activation status.

Materials and Methods

Sixteen patients (6 males and 10 females) with CVID who had been treated with regular intravenous immunoglobulin and 14 controls were enrolled. Quantitative analyses of peripheral blood mononuclear cells (PBMC) were performed by multiparametric flow cytometry using the following cell markers: CD38, HLA-DR, CCR5 (immune activation); CD4, CD25, FOXP3, CD127, and OX40 (Treg cells); Ki-67 and IFN-γ (intracellular cytokine).

Results

A significantly lower proportion of CD4⁺CD25^highFOXP3 T cells was observed in CVID patients compared with healthy controls (P<0.05). In addition to a higher proportion of CD8⁺ T cells from CVID patients expressing the activation markers, CD38⁺ and HLA-DR⁺ (P<0.05), we observed no significant correlation between Tregs and immune activation.

Conclusion

Our results demonstrate that a reduction in Treg cells could have impaired immune function in CVID patients.

Proinflammatory cytokine gene single nucleotide polymorphisms in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a heterogeneous group of primary immunodeficiency diseases. Cytokine production could be affected in CVID patients, whereas its alteration could be due to genetic polymorphisms within coding and promoter regions of the cytokine genes. This study was performed to analyse the proinflammatory cytokine single nucleotide polymorphisms in CVID. The allele and genotype frequencies of a number polymorphic genes coding tumour necrosis factor (TNF)-alpha, interleukin (IL)-1alpha, IL-1beta, IL-1R, IL-1RA and IL-6 were investigated and compared between two groups of CVID patients and controls. The IL-6 GA genotype at position nt565 was significantly over-represented in the patient group (P<0.001), while the IL-6 GG genotype at position -174 (P=0.006) and the GG genotype at position nt565 (P<0.001) were significantly lower than controls. The TNF-alpha AG genotype at position -308 in the patient group was increased significantly in comparison with controls (P=0.027), but the GG genotype at the same position was significantly decreased (P=0.011). IL-6 CA and GA haplotypes were the most frequent haplotypes in the patients (P<0.005), whereas TNF-alpha GA (P=0.002) and IL-6 GG (P<0.001) haplotypes were decreased significantly in the patients in comparison with controls. Cytokine single nucleotide polymorphisms could have a role in pathophysiology of CVID. High production of TNF-alpha is expected in some CVID patients based on the frequency of genotypes/haplotypes of these cytokine gene polymorphisms.

Increased serum levels of soluble CD30 in patients with common variable immunodeficiency and its clinical implications

Common variable immunodeficiency (CVID) is a heterogeneous group of disorders, characterized by hypogammaglobulinemia and increased susceptibility to recurrent pyogenic infections, autoimmunity, and malignancies. Twenty-five cases with CVID (18 male and 7 female) and 25 healthy volunteers were investigate in this study. Soluble CD30 (sCD30) serum levels of the subjects were measured and compared. Serum levels of sCD30 in the patients with CVID were significantly increased in comparison with controls (36.93 +/- 32.38 vs 5.27 +/- 1.32 U/ml, P < 0.001). The group of patients with splenomegaly and reversed ratio of CD3+CD4+ T cells/CD3+CD8+ T cells had the highest serum levels of sCD30 (66.01 +/- 43.34 U/ml) in comparison with other patients (P = 0.010). High levels of sCD30 in the CVID patients with splenomegaly and the presence of lymphoma in a patient with the highest level of sCD30 may suggest a soluble form of this marker as a prognostic tool in such diseases.