T cell phenotypes in patients with common variable immunodeficiency disorders: associations with clinical phenotypes in comparison with other groups with recurrent infections

Evaluation of Frequency of CMV Replication and Disease Complications Reveals New Cellular Defects and a Time Dependent Pattern in CVID Patients

PURPOSE

Common Variable Immunodeficiency (CVID) is characterized by hypogammaglobulinemia and failure of specific antibody production due to B-cell defects. However, studies have documented various T-cell abnormalities, potentially linked to viral complications. The frequency of Cytomegalovirus (CMV) replication in CVID cohorts is poorly studied. To address this gap in knowledge, we set up an observational study with the objectives of identifying CVID patients with active viraemia (CMV, Epstein-Barr virus (EBV)), evaluating potential correlations with immunophenotypic characteristics, clinical outcome, and the dynamic progression of clinical phenotypes over time.

METHODS

31 CVID patients were retrospectively analysed according to viraemia, clinical and immunologic characteristics. 21 patients with non CVID humoral immunodeficiency were also evaluated as control.

RESULTS

Active viral replication of CMV and/or EBV was observed in 25% of all patients. CMV replication was detected only in CVID patients (16%). CVID patients with active viral replication showed reduced HLA-DR+ NK counts when compared with CMV-DNA negative CVID patients. Viraemic patients had lower counts of LIN-DNAMbright and LIN-CD16+ inflammatory lymphoid precursors which correlated with NK-cell subsets. Analysis of the dynamic progression of CVID clinical phenotypes over time, showed that the initial infectious phenotype progressed to complicated phenotypes with time. All CMV viraemic patients had complicated disease.

CONCLUSION

Taken together, an impaired production of inflammatory precursors and NK activation is present in CVID patients with active viraemia. Since "Complicated" CVID occurs as a function of disease duration, there is need for an accurate evaluation of this aspect to improve classification and clinical management of CVID patients.

Target genes regulated by CLEC16A intronic region associated with common variable immunodeficiency

BACKGROUND

CLEC16A intron 19 has been identified as a candidate locus for common variable immunodeficiency (CVID).

OBJECTIVES

This study sought to elucidate the molecular mechanism by which variants at the CLEC16A intronic locus may contribute to the pathogenesis of CVID.

METHODS

The investigators performed fine-mapping of the CLEC16A locus in a CVID cohort, then deleted the candidate functional SNP in T-cell lines by the CRISPR-Cas9 technique and conducted RNA-sequencing to identify target gene(s). The interactions between the CLEC16A locus and its target genes were identified using circular chromosome conformation capture. The transcription factor complexes mediating the chromatin interactions were determined by proteomic approach. The molecular pathways regulated by the CLEC16A locus were examined by RNA-sequencing and reverse phase protein array.

RESULTS

This study showed that the CLEC16A locus is an enhancer regulating expression of multiple target genes including a distant gene ATF7IP2 through chromatin interactions. Distinct transcription factor complexes mediate the chromatin interactions in an allele-specific manner. Disruption of the CLEC16A locus affects the AKT signaling pathway, as well as the molecular response of CD4+ T cells to immune stimulation.

CONCLUSIONS

Through multiomics and targeted experimental approaches, this study elucidated the underlying target genes and signaling pathways involved in the genetic association of CLEC16A with CVID, and highlighted plausible molecular targets for developing novel therapeutics.

Studying the cellular basis of small bowel enteropathy using high-parameter flow cytometry in mouse models of primary antibody deficiency

Background

Primary immunodeficiencies are heritable defects in immune system function. Antibody deficiency is the most common form of primary immunodeficiency in humans, can be caused by abnormalities in both the development and activation of B cells, and may result from B-cell-intrinsic defects or defective responses by other cells relevant to humoral immunity. Inflammatory gastrointestinal complications are commonly observed in antibody-deficient patients, but the underlying immune mechanisms driving this are largely undefined.

Methods

In this study, several mouse strains reflecting a spectrum of primary antibody deficiency (IgA-/-, Aicda-/-, CD19-/- and JH -/-) were used to generate a functional small-bowel-specific cellular atlas using a novel high-parameter flow cytometry approach that allows for the enumeration of 59 unique cell subsets. Using this cellular atlas, we generated a direct and quantifiable estimate of immune dysregulation. This estimate was then used to identify specific immune factors most predictive of the severity of inflammatory disease of the small bowel (small bowel enteropathy).

Results

Results from our experiments indicate that the severity of primary antibody deficiency positively correlates with the degree of immune dysregulation that can be expected to develop in an individual. In the SI of mice, immune dysregulation is primarily explained by defective homeostatic responses in T cell and invariant natural killer-like T (iNKT) cell subsets. These defects are strongly correlated with abnormalities in the balance between protein (MHCII-mediated) versus lipid (CD1d-mediated) antigen presentation by intestinal epithelial cells (IECs) and intestinal stem cells (ISCs), respectively.

Conclusions

Multivariate statistical approaches can be used to obtain quantifiable estimates of immune dysregulation based on high-parameter flow cytometry readouts of immune function. Using one such estimate, we reveal a previously unrecognized tradeoff between iNKT cell activation and type 1 immunity that underlies disease in the small bowel. The balance between protein/lipid antigen presentation by ISCs may play a crucial role in regulating this balance and thereby suppressing inflammatory disease in the small bowel.

Epigenetic immune cell quantification for diagnostic evaluation and monitoring of patients with inborn errors of immunity and secondary immune deficiencies

BACKGROUND

Early detection and monitoring of primary immunodeficiencies (PID) in humans require quantitative determination of immune cells from fresh blood analyzed by flow cytometry. However, epigenetic immune cell quantification allows analysis from fresh, frozen, or dried blood samples. We demonstrate the utility of epigenetic immune cell quantification for patients with PID.

METHODS

Epigenetic quantification of basic lymphocyte subpopulations of 259 samples from PID patients were compared to flow cytometric data. Epigenetic analysis was extended to T-cell subsets (Treg, Th17, Tfh, PD-1+, CCR6+) and memory B-cells and compared between venous EDTA and dried blood.

RESULTS

A high correlation of >0.9 was observed for basic T- and B-cell subsets. Extended epigenetic analysis showed quantitative trends within PID subgroups, but individually these varied substantially within these groups. Epigenetic analysis of dried blood samples was equivalent to EDTA blood.

CONCLUSION

Epigenetic immune cell quantification is suitable for immune cell profiling in PID patients.

Unraveling the Natural History of Good's Syndrome: A Progressive Adult Combined Immunodeficiency

BACKGROUND

Good's syndrome (GS) is a rare immune deficiency described almost 6 decades ago. Despite numerous published individual case reports and data collected in cross-sectional studies of small cohorts, the natural history and long-term outcomes of this disease remain unknown.

OBJECTIVE

We aimed to determine the clinical and laboratory evolution of 8 adults diagnosed with GS and consecutively evaluated between 1983 and 2023.

METHODS

In this prospective, longitudinal cohort study, newly diagnosed patients with GS were followed through repeated measures of clinical, immune, and hematologic changes, as well as targeted genetic screening.

RESULTS

All patients reported a healthy childhood and adolescence with symptom onset during the third or fourth decade of life. All presented to our center with recurrent bacterial sinopulmonary infections, thymoma, hypogammaglobulinemia, and absence of B cells. The median age of GS diagnosis was 57 years. During follow-up, immunoglobin replacement therapy effectively minimized sinopulmonary infections. However, the majority experienced severe and systemic viral or fungal infections, 3 developed basal cell carcinomas, and 5 had progressive bronchiectasis and persistent splenomegaly. The most notable clinical feature was opportunistic infections and in vitro evidence of cellular immune deficiency, which resulted in the death of 2 individuals. We also report a statistically significant, multidecade progressive decline in lymphocytes, platelets, hemoglobin, and red blood cells in our cohort, suggesting gradual bone marrow failure.

CONCLUSIONS

Knowledge of the unique phenotype and temporal evolution of GS has allowed us to develop a more comprehensive diagnostic framework. It can be investigated as part of broader research into disease pathophysiology.

STAT expression and TFH1 cells in CVID granulomatosis and sarcoidosis: immunological and histopathological comparisons

Granulomatous disease is a serious complication of common variable immunodeficiency (CVID-GD) that occurs in 8-22% of these patients and can mimic sarcoidosis, with which it shares certain clinical, biological, and radiological features. However, few studies to date have compared the two pathologies immunologically and histologically. Therefore, we analyzed the immunological-histological findings for different tissue samples from ten patients with CVID-GD and compared them to those of biopsy-proven sarcoidosis. Specifically, we wanted to know whether or not the signaling abnormalities observed in sarcoidosis granulomas are also present in CVID-GD. Morphological differences were found between CVID-GD histology and classical sarcoidosis: mainly, the former's notable lymphoid hyperplasia associated with granulomas not observed in the latter. All CVID-GD involved organs contained several follicular helper-T (TFH) cells within the granulomatosis, while those cells were inconstantly and more weakly expressed in sarcoidosis. Moreover, CVID and sarcoidosis granulomas expressed the phosphorylated-signal transducer and activator of transcription (pSTAT)1 and pSTAT3 factors, regardless of the organ studied and without any significant difference between entities. Our results suggest that the macrophage-activation mechanism in CVID resembles that of sarcoidosis, thereby suggesting that Janus kinase (JAK)-STAT-pathway blockade might be useful in currently difficult-to-treat CVID-GD.

Studying the cellular basis of small bowel enteropathy using high-parameter flow cytometry in mouse models of primary antibody deficiency

Background

Primary immunodeficiencies are heritable defects in immune system function. Antibody deficiency is the most common form of primary immunodeficiency in humans, can be caused by abnormalities in both the development and activation of B cells, and may result from B-cell-intrinsic defects or defective responses by other cells relevant to humoral immunity. Inflammatory gastrointestinal complications are commonly observed in antibody-deficient patients, but the underlying immune mechanisms driving this are largely undefined.

Methods

In this study, several mouse strains reflecting a spectrum of primary antibody deficiency (IgA -/- , Aicda -/- , CD19 -/- and J H -/- ) were used to generate a functional small-bowel-specific cellular atlas using a novel high-parameter flow cytometry approach that allows for the enumeration of 59 unique cell subsets. Using this cellular atlas, we generated a direct and quantifiable estimate of immune dysregulation. This estimate was then used to identify specific immune factors most predictive of the severity of inflammatory disease of the small bowel (small bowel enteropathy).

Results

Results from our experiments indicate that the severity of primary antibody deficiency positively correlates with the degree of immune dysregulation that can be expected to develop in an individual. In the SI of mice, immune dysregulation is primarily explained by defective homeostatic responses in T cell and invariant natural killer-like T (iNKT) cell subsets. These defects are strongly correlated with abnormalities in the balance between protein (MHCII-mediated) versus lipid (CD1d-mediated) antigen presentation by intestinal epithelial cells (IECs) and intestinal stem cells (ISCs), respectively.

Conclusions

Multivariate statistical approaches can be used to obtain quantifiable estimates of immune dysregulation based on high-parameter flow cytometry readouts of immune function. Using one such estimate, we reveal a previously unrecognized tradeoff between iNKT cell activation and type 1 immunity that underlies disease in the small bowel. The balance between protein/lipid antigen presentation by ISCs may play a crucial role in regulating this balance and thereby suppressing inflammatory disease in the small bowel.

Influence of Splenomegaly and Splenectomy on the Immune Cell Profile of Patients with Common Variable Immunodeficiency Disease

PURPOSE

About 25% of patients with common variable immunodeficiency disease (CVID) have splenomegaly, necessitating sometimes splenectomy whom consequences on the immunological profile of CVID patients have never been studied. We analyzed 11 CVID patients' comprehensive blood immune cell phenotypes pre- and post-splenectomy.

METHODS

Flow cytometry analyses of immune cell populations.

RESULTS

Among 89 CVID cohort patients, 41 with splenomegaly, splenomegaly was strongly associated with granulomatous disease, autoimmune disorders, lymphoid hyperplasia, and/or portal hypertension. CVID patients with splenomegaly have significant peripheral lymphopenia (p = 0.001), and significantly fewer peripheral class-switched memory B cells (smBs) (p = 0.001), CD4+ T lymphocytes (p = 0.001), NK (p = 0.0001) and dendritic cells (p ≤ 0.01), and significantly more circulating CD4+ and CD8+ (p = 0.00001) T cell subset activation (p = 0.00005), than CVID patients without splenomegaly. Examination of splenectomy impact on circulating lymphocyte subset distributions demonstrated the drastically enhanced total circulating lymphocyte count post-splenectomy, predominantly B lymphocytes and CD8+ T cells. However, splenectomy did not change B cell distribution, with smBs remaining persistently low, in contrast to complete inversion of the circulating T cell composition, with reversal of the CD4+/CD8+ ratio suggesting that amplification of the CD8+ T cell compartment is a CVID characteristic in patients with splenomegaly. Our results highlight this CD8+ amplification in CVID-splenomegaly patients that might be explained by a homing effect to the spleen and/or possible chronic virus replication, which in turn could induce T cell expansions.

CONCLUSION

Splenectomizing CVID patients with splenomegaly restores the absolute circulating lymphocyte count, suggesting that the decreased T cell count in the presence of splenomegaly cannot be used as an exclusive criterion for combined immunodeficiency.

Cluster analysis of flowcytometric immunophenotyping with extended T cell subsets in suspected immunodeficiency

BACKGROUND

Patients with immunodeficiencies commonly experience diagnostic delays resulting in morbidity. There is an unmet need to identify patients earlier, especially those with high risk for complications. Compared to immunoglobulin quantification and flowcytometric B cell subset analysis, expanded T cell subset analysis is rarely performed in the initial evaluation of patients with suspected immunodeficiency. The simultaneous interpretation of multiple immune variables, including lymphocyte subsets, is challenging.

OBJECTIVE

To evaluate the diagnostic value of cluster analyses of immune variables in patients with suspected immunodeficiency.

METHODS

Retrospective analysis of 38 immune system variables, including seven B cell and sixteen T cell subpopulations, in 107 adult patients (73 with immunodeficiency, 34 without) evaluated at a tertiary outpatient immunology clinic. Correlation analyses of individual variables, k-means cluster analysis with evaluation of the classification into "no immunodeficiency" versus "immunodeficiency" and visual analyses of hierarchical heatmaps were performed.

RESULTS

Binary classification of patients into groups with and without immunodeficiency was correct in 54% of cases with the full data set and increased to 69% and 75% of cases, respectively, when only 16 variables with moderate (p < .05) or 7 variables with strong evidence (p < .01) for a difference between groups were included. In a cluster heatmap with all patients but only moderately differing variables and a heatmap with only immunodeficient patients restricted to T cell variables alone, segregation of most patients with common variable immunodeficiency and combined immunodeficiency was observed.

CONCLUSION

Cluster analyses of immune variables, including detailed lymphocyte flowcytometry with T cell subpopulations, may support clinical decision making for suspected immunodeficiency in daily practice.

In-depth immune profiling reveals advanced B- and T-cell differentiation to be associated with Th1-driven immune dysregulation in common variable immunodeficiency

Common variable immunodeficiency (CVID) is an inborn error of immunity characterized by low levels of antibodies. In addition to infections, many patients also suffer from T-helper 1-driven immune dysregulation, which is associated with increased mortality. The aim of this study was to perform in-depth characterization of the T and the B cell compartments in a well-defined cohort of patients affected by CVID and correlate the findings to the level of clinical immune dysregulation. We used mass cytometry, targeted proteomics, flow cytometry and functional assays to delineate the immunological phenotype of 15 CVID-affected patients with different levels of immune dysregulation. Unbiased clustering of T cell mass cytometry data correlated with CVID-related immune dysregulation and plasma protein profiles. Expanded CXCR3+ T-bet-expressing B cells correlated with effector memory CD4+ T cell clusters, and increased plasma levels of CXCR3-ligands. Our findings indicate an interplay between B cells and T cells in CVID-related immune dysregulation and provide a better understanding of the underlying pathological mechanisms.

In-depth blood immune profiling of Good syndrome patients

Introduction

Good syndrome (GS) is a rare adult-onset immunodeficiency first described in 1954. It is characterized by the coexistence of a thymoma and hypogammaglobulinemia, associated with an increased susceptibility to infections and autoimmunity. The classification and management of GS has been long hampered by the lack of data about the underlying immune alterations, a controversy existing on whether it is a unique diagnostic entity vs. a subtype of Common Variable Immune Deficiency (CVID).

Methods

Here, we used high-sensitive flow cytometry to investigate the distribution of up to 70 different immune cell populations in blood of GS patients (n=9) compared to age-matched CVID patients (n=55) and healthy donors (n=61).

Results

All 9 GS patients displayed reduced B-cell counts -down to undetectable levels (<0.1 cells/μL) in 8/9 cases-, together with decreased numbers of total CD4+ T-cells, NK-cells, neutrophils, and basophils vs. age-matched healthy donors. In contrast, they showed expanded TCRγδ+ T-cells (p ≤ 0.05). Except for a deeper B-cell defect, the pattern of immune cell alteration in blood was similar in GS and (age-matched) CVID patients. In depth analysis of CD4+ T-cells revealed significantly decreased blood counts of naïve, central memory (CM) and transitional memory (TM) TCD4+ cells and their functional compartments of T follicular helper (TFH), regulatory T cells (Tregs), T helper (Th)2, Th17, Th22, Th1/Th17 and Th1/Th2 cells. In addition, GS patients also showed decreased NK-cell, neutrophil, basophil, classical monocyte and of both CD1c+ and CD141+ myeloid dendritic cell counts in blood, in parallel to an expansion of total and terminal effector TCRγδ+ T-cells. Interestingly, those GS patients who developed hypogammaglobulinemia several years after the thymoma presented with an immunological and clinical phenotype which more closely resembled a combined immune humoral and cellular defect, with poorer response to immunoglobulin replacement therapy, as compared to those in whom the thymoma and hypogammaglobulinemia were simultaneously detected.

Discussion

Our findings provide a more accurate definition of the immune cell defects of GS patients and contribute to a better discrimination among GS patients between those with a pure B-cell defect vs. those suffering from a combined immunodeficiency with important consequences on the diagnosis and management of the disease.

Clinical utility of measuring CD4+ T follicular cells in patients with immune dysregulation

Mechanistic studies of autoimmune disorders have identified circulating T follicular helper (cTfh) cells as drivers of autoimmunity. However, the quantification of cTfh cells is not yet used in clinical practice due to the lack of age-stratified normal ranges and the unknown sensitivity and specificity of this test for autoimmunity. We enrolled 238 healthy participants and 130 patients with common and rare disorders of autoimmunity or autoinflammation. Patients with infections, active malignancy, or any history of transplantation were excluded. In 238 healthy controls, median cTfh percentages (range 4.8%-6.2%) were comparable among age groups, sexes, races, and ethnicities, apart from a significantly lower percentages in children less than 1 year of age (median 2.1%, CI: 0.4%-6.8, p < 0.0001). Among 130 patients with over 40 immune regulatory disorders, a cTfh percentage exceeding 12% had 88% sensitivity and 94% specificity for differentiating disorders with adaptive immune cell dysregulation from those with predominantly innate cell defects. This threshold had a sensitivity of 86% and specificity of 100% for active autoimmunity and normalized with effective treatment. cTfh percentages exceeding 12% distinguish autoimmunity from autoinflammation, thereby differentiating two endotypes of immune dysregulation with overlapping symptoms and different therapies.

Cytokine dysregulation despite immunoglobulin replacement therapy in common variable immunodeficiency (CVID)

Introduction

Common variable immunodeficiency (CVID) is the most prevalent symptomatic primary immunodeficiency. CVID is a heterogeneous disorder with a presumed multifactorial etiology. Intravenous or subcutaneous immunoglobulin replacement therapy (IgRT) can prevent severe infections but not underlying immune dysregulation.

Methods

In this study, we evaluated the serum concentrations of proinflammatory (TNF-α, IL-1β, IL-6) and immunoregulatory cytokines (IL-10), as well as lipopolysaccharide (LPS) and soluble CD14 (sCD14) in CVID individuals with infectious only (INF-CVID), and those with additional systemic autoimmune and inflammatory disorders (NIC-CVID), and healthy donors (HD).

Results

Our results showed increased serum concentrations of TNF-α, IL-1β, IL-6, and IL-10 in both INF-CVID and NIC-CVID subjects compared to HD. However, elevations of TNF-α, IL-1β, IL-6, and IL-10 were significantly more marked in NIC-CVID than INF-CVID. Additionally, LPS concentrations were increased only in NIC-CVID but not in INF-CVID compared to HD. Circulating levels of sCD14 were significantly increased in NIC-CVID compared to both INF-CVID and HD.

Discussion

These findings indicate persistent cytokine dysregulation despite IgRT in individuals with CVID. Moreover, the circulating cytokine profile reveals the heterogeneity of immune dysregulation in different subgroups of CVID subjects.

Guardians of Immunity: Advances in Primary Immunodeficiency Disorders and Management

Primary immunodeficiency disorders (PIDs) are a heterogeneous group of genetic conditions profoundly impacting immune function. The investigation spans various PID categories, offering insights into their distinct pathogenic mechanisms and clinical manifestations. Within the adaptive immune system, B-cell, T-cell, and combined immunodeficiencies are dissected, emphasizing their critical roles in orchestrating effective immune responses. In the realm of the innate immune system, focus is directed toward phagocytes and complement deficiencies, underscoring the pivotal roles of these components in initial defense against infections. Furthermore, the review delves into disorders of immune dysregulation, encompassing hemophagocytic lymphohistiocytosis (HLH), autoimmune lymphoproliferative syndrome (ALPS), immune dysregulation, polyendocrinopathy, enteropathy, and X-linked(IPEX), and autoimmunity polyendocrinopathy candidiasis-ectodermal dystrophy(APECED), elucidating the intricate interplay between immune tolerance and autoimmunity prevention. Diagnostic strategies for PIDs are explored, highlighting advancements in genetic and molecular techniques that enable precise identification of underlying genetic mutations and alterations in immune function. We have also outlined treatment modalities for PIDs, which often entail a multidisciplinary approach involving immunoglobulin replacement, antimicrobial prophylaxis, and, in select cases, hematopoietic stem cell transplantation. Emerging therapies, including gene therapy, hold promise for targeted interventions. In essence, this review encapsulates the complexity of PIDs, emphasizing the critical importance of early diagnosis and tailored therapeutic interventions. As research advances, a clearer understanding of these disorders emerges, fostering optimism for enhanced patient care and management in the future.

Characterization of infectious and non-infectious gastrointestinal disease in common variable immunodeficiency: analysis of 114 patient cohort

Common Variable Immunodeficiency (CVID), a complex primary immunodeficiency syndrome defined by defective B cell responses to infection and vaccination, has heterogeneous clinical manifestations. Gastrointestinal (GI) complications in CVID, both infectious and non-infectious, can cause significant impairment leading to malabsorption and frank malnutrition. In order to better characterize the spectrum of GI disease associated with CVID, we describe 114 patients with GI disease (15.6%) from our 728 patient single center CVID cohort. Norovirus, Giardia and Cytomegalovirus were the most frequently isolated infectious pathogens. CVID enteropathy was the most encountered GI diagnosis based on endoscopy, with only a minority of patients having Crohn's disease (6.1%) or ulcerative colitis/proctitis (4.5%). Concurrent autoimmunity (30.7%), lung disease (18.4%) and malignancy (8.7%) were also present in significant proportion of subjects. Lastly, 16 of 47 (34%) who underwent whole exome sequencing demonstrated a culprit gene defect associated with CVID.

Unraveling the Role of Toll-like Receptors in the Immunopathogenesis of Selected Primary and Secondary Immunodeficiencies

The human immune system is a complex network of cells, tissues, and molecules that work together to defend the body against pathogens and maintain overall health. However, in some individuals, the immune system fails to function correctly, leading to immunodeficiencies. Immunodeficiencies can be classified into primary (PID) and secondary (SID) types, each with distinct underlying causes and manifestations. Toll-like receptors (TLRs), as key components of the immune system, have been implicated in the pathogenesis of both PID and SID. In this study, we aim to unravel the intricate involvement of TLR2, TLR4, TLR3, TLR7, TLR8, and TLR9 in the immunopathogenesis of common variable immunodeficiency-CVID (as PID)-and chronic lymphocytic leukemia-CLL (as SID). The obtained results indicate a significant increase in the percentage of all tested subpopulations of T lymphocytes and B lymphocytes showing positive expression of all analyzed TLRs in patients with CVID and CLL compared to healthy volunteers, constituting the control group, which is also confirmed by analysis of the concentration of soluble forms of these receptors in the plasma of patients. Furthermore, patients diagnosed with CVID are characterized by the percentage of all lymphocytes showing positive expression of the tested TLR2, TLR4, TLR3, and TLR9 and their plasma concentrations in relation to patients with CLL. By investigating the functions and interactions of TLRs within the immune system, we seek to shed light on their critical role in the development and progression of these immunodeficiencies. Through a comprehensive analysis of the literature and presented experimental data, we hope to deepen our understanding of the complex mechanisms by which TLRs contribute to the pathogenesis of PID and SID. Ultimately, our findings may provide valuable insights into developing targeted therapeutic strategies to mitigate the impact of these disorders on those affected by immunodeficiency.

SARS-CoV-2 Infection and Response to COVID-19 Vaccination in Patients With Primary Immunodeficiencies

Primary immunodeficiencies (PIDs) are heterogeneous, rare disorders that increase susceptibility to infection and/or immune dysregulation. Individuals with certain PIDs are at high risk of severe or fatal outcomes from SARS-CoV-2 infections (the causative agent of COVID-19), either due to the underlying PID and/or due to the presence of comorbidities such as severe lung and liver disease. Vaccination remains the primary strategy to protect individuals with PID from COVID-19. However, populations with PID exhibit variable vaccine seroresponse rates, antibody titers, and neutralization activity depending on the type of PID and/or COVID-19 vaccine, and consequently, are at an elevated risk of severe disease. In this article, we review the COVID-19 burden in patients with PIDs and focus in-depth on findings from patients with predominantly antibody deficiencies or combined immunodeficiencies. We conclude by providing COVID-19 vaccination recommendations for this population.

Clinical utility of measuring CD4 + T follicular cells in patients with immune dysregulation

Mechanistic studies of autoimmune disorders have identified circulating T follicular helper (cTfh) cells as drivers of autoimmunity. However, the quantification of cTfh cells is not yet used in clinical practice due to the lack of age-stratified normal ranges and the unknown sensitivity and specificity of this test for autoimmunity. We enrolled 238 healthy participants and 130 patients with common and rare disorders of autoimmunity or autoinflammation. Patients with infections, active malignancy, or any history of transplantation were excluded. In 238 healthy controls, median cTfh percentages (range 4.8% - 6.2%) were comparable among age groups, sexes, races, and ethnicities, apart from a significantly lower percentages in children less than 1 year of age (median 2.1%, CI: 0.4% - 6.8, p< 0.0001). Among 130 patients with over 40 immune regulatory disorders, a cTfh percentage exceeding 12% had 88% sensitivity and 94% specificity for differentiating disorders with adaptive immune cell dysregulation from those with predominantly innate cell defects. This threshold had a sensitivity of 86% and specificity of 100% for active autoimmunity and normalized with effective treatment. cTfh percentages exceeding 12% distinguish autoimmunity from autoinflammation, thereby differentiating two endotypes of immune dysregulation with overlapping symptoms and different therapies.

Treatment of inflammatory complications in common variable immunodeficiency (CVID): current concepts and future perspectives

INTRODUCTION

Patients with Common variable immunodeficiency (CVID) have a high frequency of inflammatory complications like autoimmune cytopenias, interstitial lung disease and enteropathy. These patients have poor prognosis and effective, timely and safe treatment of inflammatory complications in CVID are essential, but guidelines and consensus on therapy are often lacking.

AREAS COVERED

This review will focus on current medical treatment of inflammatory complications in CVID and point out some future perspectives based on literature indexed in PubMed. There are a number of good observational studies and case reports on treatment of specific complications but randomized controlled trials are scarce.

EXPERT OPINION

In clinical practice, the most urgent issues that need to be addressed are the preferred treatment of GLILD, enteropathy and liver disease. Treating the underlying immune dysregulation and immune exhaustion in CVID is an alternative approach that potentially could alleviate these and other organ-specific inflammatory complications. Therapies of potential interest and wider use in CVID include mTOR-inhibitors like sirolimus, JAK-inhibitors like tofacitinib, the monoclonal IL-12/23 antibody ustekinumab, the anti-BAFF antibody belimumab and abatacept. For all inflammatory complications, there is a need for prospective therapeutic trials, preferably randomized controlled trials, and multi-center collaborations with larger cohorts of patients will be essential.

Role of Protein Kinase A Activation in the Immune System with an Emphasis on Lipopolysaccharide-Responsive and Beige-like Anchor Protein in B Cells

Cyclic AMP-dependent protein kinase A (PKA) is a ubiquitous enzymatic complex that is involved in a broad spectrum of intracellular receptor signaling. The activity of PKA depends on A-kinase anchoring proteins (AKAPs) that attach to PKAs close to their substrates to control signaling. Although the relevance of PKA-AKAP signaling in the immune system is evident in T cells, its relevance in B and other immune cells remains relatively unclear. In the last decade, lipopolysaccharide-responsive and beige-like anchor protein (LRBA) has emerged as an AKAP that is ubiquitously expressed in B and T cells, specifically after activation. A deficiency of LRBA leads to immune dysregulation and immunodeficiency. The cellular mechanisms regulated by LRBA have not yet been investigated. Therefore, this review summarizes the functions of PKA in immunity and provides the most recent information regarding LRBA deficiency to deepen our understanding of immune regulation and immunological diseases.

Cellular immunity in COVID-19 and other infections in Common variable immunodeficiency

COVID-19 has shed light on the role of cellular immunity in the absence of humoral response in different patient groups. Common variable immunodeficiency (CVID) is characterized by impaired humoral immunity but also an underlying T-cell dysregulation. The impact of T-cell dysregulation on cellular immunity in CVID is not clear, and this review summarizes available literature on cellular immunity in CVID with a particular focus on COVID-19. Overall mortality of COVID-19 in CVID is difficult to assess, but seems not significantly elevated, and risk factors for severe disease mirrors that of the general population, including lymphopenia. Most CVID patients have a significant T-cell response to COVID-19 disease with possible cross-reactivity to endemic coronaviruses. Several studies find a significant but impaired cellular response to basal COVID-19 mRNA vaccination that is independent of an antibody response. CVID patients with infection only have better cellular responses to vaccine in one study, but there is no clear association to T-cell dysregulation. Cellular response wane over time but responds to a third booster dose of vaccine. Opportunistic infection as a sign of impaired cellular immunity in CVID is rare but is related to the definition of the disease. CVID patients have a cellular response to influenza vaccine that in most studies is comparable to healthy controls, and annual vaccination against seasonal influenza should be recommended. More research is required to clarify the effect of vaccines in CVID with the most immediate issue being when to booster the COVID-19 vaccine.

Autoimmune disorders associated with common variable immunodeficiency: prediction, diagnosis, and treatment

INTRODUCTION

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency. Due to the wide spectrum of the CVID manifestations, the differential diagnosis becomes complicated, ends in a diagnostic delay and increased morbidity and mortality rates. Autoimmunity is one of the important complications associated with CVID. While immunoglobulin replacement therapy has considerably decreased the mortality rate in CVID patients, mainly infection-related mortality, other complications such as autoimmunity appeared prevalent and, in some cases, life threatening.

AREAS COVERED

In this article, genetics, responsible immune defects, autoimmune manifestations in different organs, and the diagnosis and treatment processes in CVID patients are reviewed, after searching the literature about these topics.

EXPERT OPINION

Considering the many phenotypes of CVID and the fact that it remained undiagnosed until older ages, it is important to include various manifestations of CVID in the differential diagnosis. Due to the different manifestations of CVID, including autoimmune diseases, interdisciplinary collaboration of physicians from different fields is highly recommended, as discussed in the manuscript. Meanwhile, it is important to determine which patients could benefit from genetic diagnostic studies since such studies are not necessary for establishing the diagnosis of CVID.

B Cell Subsets in Colombian Adults with Predominantly Antibody Deficiencies, Bronchiectasis or Recurrent Pneumonia

Aim: To evaluate and describe lymphocyte populations’ and B cell subsets’ frequencies in patients presenting with Predominantly antibody deficiencies (PAD) and diagnosed with bronchiectasis or recurrent pneumonia seen in Cali (Colombian Southwest region). Materials and Methods: 16 subjects with PAD, 20 subjects with pulmonary complications (bronchiectasis or recurrent pneumonia) and 20 healthy donors (HD). Controls and probands between 14 and 64 years old, regardless of gender were included. Lymphocyte populations (T, B and NK cells) and B cell subsets were evaluated in peripheral blood mononuclear cells using flow cytometry, T/B/NK reagent and the pre-germinal center antibody panel proposed by the EUROflow consortium were used. EUROclass and the classification proposed by Driessen et al. were implemented. Results: CVID patients exhibited increase absolute numbers of CD8+ T cells and reduce NK cells as compare with HD, other PAD cases or pulmonary complications. PAD B cell subsets were disturbed when compared to the age range-matched healthy donors. Among B cell subsets, the memory B cell compartment was the most affected, especially switched memory B cells. Four participants were classified as B- and two CVID as smB-Trnorm and smB-21low groups according to EUROclass classification. The most frequent patterns proposed by Driessen et al. were B cell production and germinal center defect. Conclusions: B cell subsets, especially memory B cells, are disturbed in PAD patients from Southwestern Colombia. To the best of our knowledge this is the most comprehensive study of B cell subsets in Colombian adults.

Lymphocyte alterations in patients with Common Variable Immunodeficiency (CVID) and autoimmune manifestations

INTRODUCTION

Autoimmunity is a common feature in CVID patients. To date the mechanisms leading to the development of such complications are not fully elucidated.

MATERIALS AND METHODS

Data from 122 CVID patients subdivided in three groups based on the absence of autoimmunity (n-AI) or the presence of hematologic autoimmune phenomena (Cy-AI) or non-hematologic autoimmune phenomena (n-Cy-AI) were evaluated.

RESULTS

We identified a total of 128 autoimmune manifestations in 55/122 patients (45.1%). 30/122 (24.6%) patients presented hematologic autoimmune phenomena while 29/122 (23.8%) presented gastrointestinal autoimmune involvement. Immune thrombocytopenia was the most common manifestation (27/122; 22.1%), followed by autoimmune hemolytic anemia (18/122; 14.8%) and autoimmune enteropathy (17/122; 13.9%). Cy-AI patients displayed higher CD4⁺ effector memory and terminally differentiated CD8⁺ cells with lower percentages of naïve and recent thymic emigrants (RTEs) CD4⁺ cells and a significant expansion of the CD19^hiCD21^low population.

CONCLUSIONS

CVID patients developing autoimmune cytopenias display characteristic immune phenotypic features.

Autoimmune Cytopenias in Common Variable Immunodeficiency Are a Diagnostic and Therapeutic Conundrum: An Update

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency (PID). CVID is a heterogenous condition and clinical manifestations may vary from increased susceptibility to infections to autoimmune manifestations, granulomatous disease, polyclonal lymphoproliferation, and increased risk of malignancy. Autoimmune manifestations may, at times, be the first and only clinical presentation of CVID, resulting in diagnostic dilemma for the treating physician.

Autoimmune cytopenias (autoimmune haemolytic anaemia and/or thrombocytopenia) are the most common autoimmune complications seen in patients with CVID. Laboratory investigations such as antinuclear antibodies, direct Coomb’s test and anti-platelet antibodies may not be useful in patients with CVID because of lack of specific antibody response. Moreover, presence of autoimmune cytopenias may pose a significant therapeutic challenge as use of immunosuppressive agents can be contentious in these circumstances. It has been suggested that serum immunoglobulins must be checked in all patients presenting with autoimmune cytopenia such as immune thrombocytopenia or autoimmune haemolytic anaemia.

It has been observed that patients with CVID and autoimmune cytopenias have a different clinical and immunological profile as compared to patients with CVID who do not have an autoimmune footprint. Monogenic defects have been identified in 10-50% of all patients with CVID depending upon the population studied. Monogenic defects are more likely to be identified in patients with CVID with autoimmune complications. Common genetic defects that may lead to CVID with an autoimmune phenotype include nuclear factor kappa B subunit 1 (NF-kB1), Lipopolysaccharide (LPS)-responsive beige-like anchor protein (LRBA), cytotoxic T lymphocyte antigen 4 (CTLA4), Phosphoinositide 3-kinase (PI3K), inducible T-cell costimulatory (ICOS), IKAROS and interferon regulatory factor-2 binding protein 2 (IRF2BP2).

In this review, we update on recent advances in pathophysiology and management of CVID with autoimmune cytopenias.

T Cell Abnormalities in X-Linked Agammaglobulinaemia: an Updated Review

X-linked agammaglobulinaemia (XLA) is a primary immunodeficiency (PID) resulting from a defect in the B cell development. It has conventionally been thought that T cells play a major role in the development and function of the B cell compartment. However, it has also been shown that B cells and T cells undergo bidirectional interactions and B cells also influence the structure and function of the T cell compartment. Patients with XLA offer a unique opportunity to understand the effect of absent B cells on the T cell compartment. In this review, we provide an update on abnormalities in the T cell compartment in patients with XLA. Studies have shown impaired memory T cells, follicular helper T cells, T regulatory cells and T helper 17 in patients with XLA. In addition, these patients have also been reported to have abnormal delayed cell-mediated immune responses and vaccine-specific T cell-mediated immune responses; defective T helper cell polarization and impaired T cell receptor diversity. At present, the clinical significance of these T cell abnormalities has not been studied in detail. However, these abnormalities may result in an increased risk of viral infections, autoimmunity, autoinflammation and possibly chronic lung disease. Abnormal response to SARS-Cov2 vaccine in patients with XLA and prolonged persistence of SARS-Cov2 virus in the respiratory tract of these patients may be related to abnormalities in the T cell compartment.

Distinct CD8 T Cell Populations with Differential Exhaustion Profiles Associate with Secondary Complications in Common Variable Immunodeficiency

Purpose

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immunodeficiency, with heterogeneous clinical presentation. Our goal was to analyze CD8 T cell homeostasis in patients with infection only CVID, compared to those additionally affected by dysregulatory and autoimmune phenomena.

Methods

We used flow and mass cytometry evaluation of peripheral blood of 40 patients with CVID and 17 healthy donors.

Results

CD8 T cells are skewed in patients with CVID, with loss of naïve and increase of effector memory stages, expansion of cell clusters with high functional exhaustion scores, and a highly activated population of cells with immunoregulatory features, producing IL-10. These findings correlate to clinically widely used B cell-based EURO classification. Features of exhaustion, including loss of CD127 and CD28, and expression of TIGIT and PD-1 in CD8 T cells are strongly associated with interstitial lung disease and autoimmune cytopenias, whereas CD8 T cell activation with elevated HLA-DR and CD38 expression predict non-infectious diarrhea.

Conclusion

We demonstrate features of advanced differentiation, exhaustion, activation, and immunoregulatory capabilities within CD8 T cells of CVID patients. Assessment of CD8 T cell phenotype may allow risk assessment of CVID patients and provide new insights into CVID pathogenesis, including a better understanding of mechanisms underlying T cell exhaustion and regulation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10875-022-01291-9.

Clinical and Phenotypic Characterization of Common Variable Immunodeficiency Diagnosed in Younger and Older Adults

PURPOSE

Common variable immunodeficiency (CVID) is the most prevalent symptomatic immunodeficiency in adults. Little is known about the manifestations of CVID presenting in older adults. Herein, we performed a phenotypic characterization of patients diagnosed older than age 40.

METHODS

A retrospective chart review of 79 patients seen at UF Health between 2006 and 2020 with a verified diagnosis of CVID per the ICON 2016 criteria was conducted. Patients were classified according to four phenotypes: no-disease-related complications, autoimmune cytopenias, polyclonal lymphoproliferation, and unexplained enteropathy. Patients diagnosed with CVID from age 2 to 40 (n = 41, "younger cohort") were compared to patients diagnosed with CVID age 41 and older (n = 38, "older cohort").

RESULTS

Among the younger cohort, pathologic genetic variants, positive family history for immunodeficiency, autoimmunity (49% vs 24%, p = 0.03), and splenomegaly (46% vs 16%, p = 0.004) were more common, as was the "autoimmune cytopenias" phenotype (24% vs 3%, p = 0.007). Among the older cohort, lymphoma (11% vs 0%, p = 0.049) and the "no disease-related complications" phenotype (79% vs 57%, p = 0.03) were more commonly seen. Comorbidities such as bronchiectasis (27% vs 21%, p = 0.61), GI involvement (34% vs 24%, p = 0.33), and GLILD (5% vs 8%, p = 0.67) were equally present among both the younger and older cohorts, respectively.

CONCLUSION

The lower incidence of autoimmunity and splenomegaly, as well as overlapping clinical features with immunosenescence, may make diagnosing CVID in older patients more challenging; however, the disease is not more indolent as the risks for lymphoma, bronchiectasis, and GLILD are similar to those of younger patients.

Integrating Clinics, Laboratory, and Imaging for the Diagnosis of Common Variable Immunodeficiency-Related Granulomatous-Lymphocytic Interstitial Lung Disease

Background

Granulomatous–lymphocytic interstitial lung disease (GLILD) is a distinct clinic-radio-pathological interstitial lung disease (ILD) that develops in 9% to 30% of patients with common variable immunodeficiency (CVID). Often related to extrapulmonary dysimmune disorders, it is associated with long-term lung damage and poorer clinical outcomes. The aim of this study was to explore the potential use of the integration between clinical parameters, laboratory variables, and developed CT scan scoring systems to improve the diagnostic accuracy of non-invasive tools.

Methods

A retrospective cross-sectional study of 50 CVID patients was conducted in a referral unit of primary immune deficiencies. Clinical variables including demographics and comorbidities; analytical parameters including immunoglobulin levels, lipid metabolism, and lymphocyte subpopulations; and radiological and lung function test parameters were collected. Baumann’s GLILD score system was externally validated by two observers in high-resolution CT (HRCT) scans. We developed an exploratory predictive model by elastic net and Bayesian regression, assessed its discriminative capacity, and internally validated it using bootstrap resampling.

Results

Lymphadenopathies (adjusted OR 9.42), splenomegaly (adjusted OR 6.25), Baumann’s GLILD score (adjusted OR 1.56), and CD8+ cell count (adjusted OR 0.9) were included in the model. The larger range of values of the validated Baumann’s GLILD HRCT scoring system gives it greater predictability. Cohen’s κ statistic was 0.832 (95% CI 0.70–0.90), showing high concordance between both observers. The combined model showed a very good discrimination capacity with an internally validated area under the curve (AUC) of 0.969.

Conclusion

Models integrating clinics, laboratory, and CT scan scoring methods may improve the accuracy of non-invasive diagnosis of GLILD and might even preclude aggressive diagnostic tools such as lung biopsy in selected patients.

Immunophenotypic and functional analysis of lymphocyte subsets in common variable immunodeficiency patients without monogenic defects

Common variable immunodeficiency (CVID) is accompanied by various lymphocyte abnormalities believed to be mostly responsible for disease features in patients with no diagnosed monogenic defects. Here, we evaluated the association of B and T lymphocyte abnormalities with the incidence of CVID. Twenty-six genetically unsolved CVID patients were examined for B and T lymphocyte subsets by flow cytometry and CD4⁺ T cell proliferation by Carboxyfluorescein succinimidyl ester (CFSE) test. We detected a reduction in total, naive, memory B cells and plasmablasts, and also total, naive, central memory and regulatory CD4⁺ T cells, besides naive CD8⁺ T cells. There were an increase in CD21^low and transitional B cells, effector memory (EM) and terminally differentiated effector memory (T_EMRA ) CD4⁺ T cell subsets as well as total, EM, T_EMRA , activated and cytotoxic CD8⁺ T cells among non-monogenic CVID patients. CD4⁺ T cells proliferation response was reduced regarding both division index and percent divided. In conclusion, regarding the similarity of lymphocyte abnormalities between patients without genetic defects and those with monogenic defects, genetic mutations are not responsible for these specific lymphocyte changes. However, the novel correlations observed between lymphocyte alterations among genetically unsolved CVID patients may serve as a guide to predict the potential of future CVID development for hypogammaglobulinemia children.

Autoimmune Cytopenias and Dysregulated Immunophenotype Act as Warning Signs of Inborn Errors of Immunity: Results From a Prospective Study

Inborn errors of immunity (IEI) are genetic disorders characterized by a wide spectrum of clinical manifestations, ranging from increased susceptibility to infections to significant immune dysregulation. Among these, primary immune regulatory disorders (PIRDs) are mainly presenting with autoimmune manifestations, and autoimmune cytopenias (AICs) can be the first clinical sign. Significantly, AICs in patients with IEI often fail to respond to first-line therapy. In pediatric patients, autoimmune cytopenias can be red flags for IEI. However, for these cases precise indicators or parameters useful to suspect and screen for a hidden congenital immune defect are lacking. Therefore, we focused on chronic/refractory AIC patients to perform an extensive clinical evaluation and multiparametric flow cytometry analysis to select patients in whom PIRD was strongly suspected as candidates for genetic analysis. Key IEI-associated alterations causative of STAT3 GOF disease, IKAROS haploinsufficiency, activated PI3Kδ syndrome (APDS), Kabuki syndrome and autoimmune lymphoproliferative syndrome (ALPS) were identified. In this scenario, a dysregulated immunophenotype acted as a potential screening tool for an early IEI diagnosis, pivotal for appropriate clinical management and for the identification of new therapeutic targets.

T-follicular helper cell expansion and chronic T-cell activation are characteristic immune anomalies in Evans syndrome

Pediatric Evans syndrome (pES) is increasingly identified as the presenting manifestation of several inborn errors of immunity. Despite an improved understanding of genetic defects in pES, the underlying immunobiology of pES is poorly defined, and characteristic diagnostic immune parameters are lacking. We describe the immune characteristics of 24 patients with pES and compared them with 22 patients with chronic immune thrombocytopenia (cITP) and 24 healthy controls (HCs). Compared with patients with cITP and HC, patients with pES had increased circulating T-follicular helper cells (cTfh), increased T-cell activation, and decreased naïve CD4+ T cells for age. Despite normal or high immunoglobulin G (IgG) in most pES at presentation, class-switched memory B cells were decreased. Within the cTfh subset, we noted features of postactivation exhaustion with upregulation of several canonical checkpoint inhibitors. T-cell receptor β chain (TCR-β) repertoire analysis of cTfh cells revealed increased oligoclonality in patients with pES compared with HCs. Among patients with pES, those without a known gene defect had a similar characteristic immune abnormality as patients with defined genetic defects. Similarly, patients with pES with normal IgG had similar T-cell abnormalities as patients with low IgG. Because genetic defects have been identified in less than half of patients with pES, our findings of similar immune abnormalities across all patients with pES help establish a common characteristic immunopathology in pES, irrespective of the underlying genetic etiology.

The Effects of Stimulation with PMA/Ionomycin on CD4+ T cell Proliferation and Surface CD4 Molecule Modulation of Patients with LRBA Deficiency and CVID with the Unsolved Genetic Defect

BACKGROUND

Common variable immunodeficiency (CVID) is the most prevalent symptomatic primary immunodeficiencies. LPS-responsive beige-like anchor protein (LRBA) deficiency is a combined immunodeficiency characterized by a CVID-like phenotype. Affected patients by LRBA and CVID present a wide range of clinical manifestations, including hypogammaglobulinemia, recurrent infections, autoimmunity, as well as T cell abnormality.

METHODS

The study population comprised of patients with CVID (n=10), LRBA deficiency (n=11), and healthy controls (n=12). CD4+ T cell frequency and CD4 MFI (mean fluorescence intensity) were evaluated using flow cytometry before and after stimulation with PMA/ION.

RESULTS

The frequencies of CD4+ T cells were significantly lower in patients with LRBA deficiency than in HCs before and after treatment. In the unstimulated state, the CD4+ T cells frequency in CVID patients was significantly lower than in HCs. There were no statistically significant differences between patients and healthy individuals in CD4+ T cell proliferation. Compared to HCs, LRBA and CVID patients showed a lower CD4 MFI in unstimulated conditions. Furthermore, CD4 MFI decreased in both patients and the control group following activation.

CONCLUSION

Despite the reported decrease in CD4+ T cell frequency in patients with CVID and LRBA deficiency, our findings demonstrated that their CD4+ T cells have a normal proliferative response to stimuli similar to healthy individuals.

Naïve Regulatory T Cell Subset Is Altered in X-Linked Agammaglobulinemia

The interplay between T- and B-cell compartments during naïve, effector and memory T cell maturation is critical for a balanced immune response. Primary B-cell immunodeficiency arising from X-linked agammaglobulinemia (XLA) offers a model to explore B cell impact on T cell subsets, starting from the thymic selection. Here we investigated characteristics of naïve and effector T cell subsets in XLA patients, revealing prominent alterations in the corresponding T-cell receptor (TCR) repertoires. We observed immunosenescence in terms of decreased diversity of naïve CD4⁺ and CD8⁺ TCR repertoires in XLA donors. The most substantial alterations were found within naïve CD4⁺ subsets, and we have investigated these in greater detail. In particular, increased clonality and convergence, along with shorter CDR3 regions, suggested narrower focused antigen-specific maturation of thymus-derived naïve T_reg (CD4⁺CD45RA⁺CD27⁺CD25⁺) in the absence of B cells - normally presenting diverse self and commensal antigens. The naïve T_reg proportion among naïve CD4 T cells was decreased in XLA patients, supporting the concept of impaired thymic naïve T_reg selection. Furthermore, the naïve T_reg subset showed prominent differences at the transcriptome level, including increased expression of genes specific for antigen-presenting and myeloid cells. Altogether, our findings suggest active B cell involvement in CD4 T cell subsets maturation, including B cell-dependent expansion of the naïve Treg TCR repertoire that enables better control of self-reactive T cells.

B cells promote CD8 T cell primary and memory responses to subunit vaccines

The relationship between B cells and CD4 T cells has been carefully studied, revealing a collaborative effort in which B cells promote the activation, differentiation, and expansion of CD4 T cells while the so-called “helper” cells provide signals to B cells, influencing their class switching and fate. Interactions between B cells and CD8 T cells are not as well studied, although CD8 T cells exhibit an accelerated contraction after certain infections in B-cell-deficient mice. Here, we find that B cells significantly enhance primary CD8 T cell responses after vaccination. Moreover, memory CD8 numbers and function are impaired in B-cell-deficient animals, leading to increased susceptibility to bacterial challenge. We also show that interleukin-27 production by B cells contributes to their impact on primary, but not memory, CD8 responses. Better understanding of the interactions between CD8 T cells and B cells may aid in the design of more effective future vaccine strategies.

Generating cytotoxic CD8 T cell responses with vaccines can greatly improve their efficacy, but inducing adequate numbers of these cells can be challenging. Klarquist et al. reveal that the magnitude, persistence, and function of CD8 T cell vaccine responses depend on B cells.

Decreased ATM Function Causes Delayed DNA Repair and Apoptosis in Common Variable Immunodeficiency Disorders

PURPOSE

Common variable immunodeficiency disorders (CVID) is characterized by low/absent serum immunoglobulins and susceptibility to bacterial infection. Patients can develop an infections-only phenotype or a complex disease course with inflammatory, autoimmune, and/or malignant complications. We hypothesized that deficient DNA repair mechanisms may be responsible for the antibody deficiency and susceptibility to inflammation and cancer in some patients.

METHODS

Germline variants were identified following targeted sequencing of n = 252 genes related to DNA repair in n = 38 patients. NanoString nCounter PlexSet assay measured gene expression in n = 20 CVID patients and n = 7 controls. DNA damage and apoptosis were assessed by flow cytometry in n = 34 CVID patients and n = 11 controls.

RESULTS

Targeted sequencing supported enrichment of rare genetic variants in genes related to DNA repair pathways with novel and rare likely pathogenic variants identified and an altered gene expression signature that distinguished patients from controls and complex patients from those with an infections-only phenotype. Consistent with this, flow cytometric analyses of lymphocytes following DNA damage revealed a subset of CVID patients whose immune cells have downregulated ATM, impairing the recruitment of other repair factors, delaying repair and promoting apoptosis.

CONCLUSION

These data suggest that germline genetics and altered gene expression predispose a subset of CVID patients to increased sensitivity to DNA damage and reduced DNA repair capacity.

Patients with Common Variable Immunodeficiency Complicated by Autoimmune Phenomena Have Lymphopenia and Reduced Treg, Th17, and NK Cells

Most patients with primary immune deficiency suffer from recurrent infections; however, paradoxical autoimmune phenomena can also manifest. The aim of this study was to identify immunological markers of autoimmune phenomena associated with common variable immunodeficiency (CVID). The study included 33 adults with CVID divided into two groups: (1) those with noninfectious autoimmune complications (CVID-C (n = 24)) and (2) those with only infectious symptoms (CVID-OI (n = 9)). Flow cytometry of peripheral blood was performed and compared with systemic lupus erythematosus (SLE) patients (n = 17) and healthy controls (n = 20). We found that all lymphocytes were lower in CVID-C and SLE. NK cells were lowest in CVID-C. Th17 cells were significantly reduced in CVID-C and SLE. Tregs were significantly lower in CVID-C and SLE. Bregs did not significantly differ between any groups. Class-switched memory B cells were significantly lower in CVID-C and CVID-OI. Lastly, plasmablasts were significantly higher in SLE. Among the T cell subsets, CVID-C patients had lower naive and recent thymic emigrant CD4+ T cells. In conclusion, reduced Treg, Th17, and NK cells are features of CVID with autoimmune complications, and class-switched memory B cells can help distinguish patients with different causes of autoimmunity. Future studies are needed to confirm whether reductions of Treg, Th17, and NK cells might be a biomarker of more complicated CVID cases.

Lymphocytes subsets in correlation with clinical profile in CVID patients without monogenic defects

Objectives: Common variable immunodeficiency (CVID) patients experience clinical manifestations rather than recurrent respiratory infections including autoimmunity, enteropathy, and lymphoproliferation. We evaluated the correlation of lymphocyte subpopulations with such manifestations.Methods: Twenty-six genetically unsolved CVID patients were subdivided into four phenotypes: infection only (IO), autoimmunity (AI), chronic enteropathy (CE), and lymphoproliferative disorders (LP) and examined for lymphocyte subsets by flow cytometry and TCD4⁺ proliferation by Carboxyfluorescein succinimidyl ester (CFSE) test.Results: We detected reduced memory B and increased total, effector memory (EM), cytotoxic, and activated TCD8⁺ in IO, AI and CE, decreased plasmablasts, total and naive TCD4⁺, Regulatory TCD4⁺ (Treg) and naive TCD8⁺ in IO and CE, elevated CD21^low B and terminally differentiated effector memory (T_EMRA) TCD8⁺ in IO and AI, increased helper T (Th2) and Th17 in IO, decreased Th1 in AI and defective total and naive B and central memory (CM) TCD4⁺ in CE. IO showed reduced TCD4⁺ proliferation response.Conclusions: In genetically unsolved CVID patients, increased Th2 and Th17 and reduced Treg is associated with IO, increased CD21^low B and T_EMRA TCD8⁺ and reduced Th1 is contributed to AI and reduced total and naive B, CM TCD4⁺ and naive TCD8⁺ and expanded total TCD8⁺ is correlated with CE.

Shared Pathogenetic Features Between Common Variable Immunodeficiency and Sjögren's Syndrome: Clues for a Personalized Medicine

Common variable immunodeficiency disorders (CVID) are a group of rare diseases of the immune system and the most common symptomatic primary antibody deficiency in adults. The “variable” aspect of CVID refers to the approximately half of the patients who develop non-infective complications, mainly autoimmune features, in particular organ specific autoimmune diseases including thyroiditis, and cytopenias. Among these associated conditions, the incidence of lymphoma, including mucosal associated lymphoid tissue (MALT) type, is increased. Although these associated autoimmune disorders in CVID are generally attributed to Systemic Lupus Erythematosus (SLE), we propose that Sjogren’s syndrome (SS) is perhaps a better candidate for the associated disease. SS is an autoimmune disorder characterized by the lymphocytic infiltrates of lacrimal and salivary glands, leading to dryness of the eyes and mouth. Thus, it is a lymphocyte aggressive disorder, in contrast to SLE where pathology is generally attributed to auto-antibody and complement activation. Although systemic lupus erythematosus (SLE) shares these features with SS, a much higher frequency of MALT lymphoma distinguishes SS from SLE. Also, the higher frequency of germ line encoded paraproteins such as the monoclonal rheumatoid factor found in SS patients would be more consistent with the failure of B-cell VDJ switching found in CVID; and in contrast to the hypermutation that characterizes SLE autoantibodies. Thus, we suggest that SS may fit as a better “autoimmune” association with CVID. Examining the common underlying biologic mechanisms that promote lymphoid infiltration by dysregulated lymphocytes and lymphoma in CVID may provide new avenues for treatment in both the diseases. Since the diagnosis of SLE or rheumatoid arthritis is usually based on specific autoantibodies, the associated autoimmune features of CVID patients may not be recognized in the absence of autoantibodies.

Variable immunodeficiency score upfront analytical link (VISUAL), a proposal for combined prognostic score at diagnosis of common variable immunodeficiency

The broad and heterogeneous clinical spectrum that characterizes common variable immunodeficiency (CVID) is associated with quite different disease course and prognosis, highlighting the need to develop tools that predict complications. We developed a multianalyte VISUAL score (variable immunodeficiency score upfront analytical link) aimed to predict severity using individual CVID patient data at baseline of a cohort of 50 CVID patients from two different centers in Portugal and Spain. We retrospectively applied VISUAL to the CVID clinical severity scores proposed by Ameratunga and Grimbacher after 15 years follow-up of our cohort. VISUAL score at CVID diagnosis showed adequate performance for predicting infectious and non-infectious severe complications (Cluster B). Compared to switched memory B lymphocyte phenotype alone, VISUAL provided a more accurate identification of clinically meaningful outcome, with significantly higher sensitivity (85% vs 55%, p = 0.01), and negative predictive value (77% vs 58%) and AUC of the ROC curves (0.72 vs 0.64), with optimal cut-off level of 10. For every increase of 1 point in the VISUAL scale, the odds of being in the higher risk category (Cluster B) increased in 1.3 (p = 0.005) for Ameratunga's severity score and 1.26 (p = 0.004) for Grimbacher's severity score. At diagnosis of CVID, VISUAL score ≥ 10 showed 8.94-fold higher odds of severe prognosis than below this threshold. Kaplan-Meier estimates for the VISUAL ≥ 10 points showed significantly earlier progression to Cluster B than those with VISUAL < 10 (p = 0.0002). This prognostic laboratory score might allow close monitoring and more aggressive treatment in patients with scores ≥ 10 on a personalized basis approach. Further studies are needed to prospectively validate VISUAL score.

Beyond monogenetic rare variants: tackling the low rate of genetic diagnoses in predominantly antibody deficiency

Predominantly antibody deficiency (PAD) is the most prevalent form of primary immunodeficiency, and is characterized by broad clinical, immunological and genetic heterogeneity. Utilizing the current gold standard of whole exome sequencing for diagnosis, pathogenic gene variants are only identified in less than 20% of patients. While elucidation of the causal genes underlying PAD has provided many insights into the cellular and molecular mechanisms underpinning disease pathogenesis, many other genes may remain as yet undefined to enable definitive diagnosis, prognostic monitoring and targeted therapy of patients. Considering that many patients display a relatively late onset of disease presentation in their 2nd or 3rd decade of life, it is questionable whether a single genetic lesion underlies disease in all patients. Potentially, combined effects of other gene variants and/or non-genetic factors, including specific infections can drive disease presentation. In this review, we define (1) the clinical and immunological variability of PAD, (2) consider how genetic defects identified in PAD have given insight into B-cell immunobiology, (3) address recent technological advances in genomics and the challenges associated with identifying causal variants, and (4) discuss how functional validation of variants of unknown significance could potentially be translated into increased diagnostic rates, improved prognostic monitoring and personalized medicine for PAD patients. A multidisciplinary approach will be the key to curtailing the early mortality and high morbidity rates in this immune disorder.

Combined immunodeficiency (CVID and CD4 lymphopenia) is associated with a high risk of malignancy among adults with primary immune deficiency

Primary immunodeficiency disorders (PID) are a group of heterogeneous disorders characterized by recurrent infections, autoimmunity, increased lymphoproliferative disorders and other malignancies. PID is classified into cellular or humoral disorders or a combination of both. We evaluated the clinical differences among adult patients with three variants of PID: common variable immunodeficiency (CVID), idiopathic CD4 lymphopenia (ICL) and combined immunodeficiency (CID). We retrospectively compared demographics, immunological characteristics, clinical presentations and outcomes of CVID, CID and ICL patients followed from 2012 to 2018. In our cohort, we identified 44 adult patients diagnosed with CVID (22), CID (11) and ICL (11). Malignancy was associated with CID, as seven of 11 patients in this group were diagnosed with malignancy compared to CVID (three of 22) or ICL (two of 11) (P = 0·002 and 0·03, respectively). Malignancies were also linked to male gender [odds ratio (OR) = 5, 95% confidence interval (CI) = 1·12-22·18) P = 0·0342] and a low ratio of CD4/CD8 < 0·8 (OR = 5·1, 95% CI = 1·22-21·28, P = 0·025). Among CID and ICL, two of 11 patients died in each group, while no death was documented among CVID group (P = 0·04). Autoimmune manifestations did not differ between groups. Similarly, the rate of infections was similar between groups, although infectious agents vary. CID is associated with a high risk of malignancy compare to CVID or ICL. Among adults with PID, male gender, low CD4 and a CD4/CD8 ratio of < 0·8 may serve as risk factors of concomitant malignancy. Surveillance of lymphocyte subpopulations should be considered for all adults.

Transcriptomics analysis for the identification of potential age-related genes and cells associated with three major urogenital cancers

Age is one of the most important risk factors of the occurrence for tumor patients. The majority of patients with urogenital cancers are the elderly, whose clinical characteristics are greatly affected by age and ageing. Our study aimed to explore age-related genes, cells, and biological changes in three common urogenital cancers via integrative bioinformatics analysis. First, mRNA (count format) and clinical data for bladder cancer, prostate cancer and renal cell carcinoma were downloaded from the Cancer Genome Atlas (TCGA). Through the comparison of clinicopathological characteristics, genes expression and cells infiltration between the old group and the young group, it was found that the clinical characteristics, genes and cells in the tumor microenvironment of different ages were quite different. And 4 key cells, 14 hub genes and some potential pathways were identified and considered as important factors. More importantly, we analyzed the differential landscape of the genes and cells from different perspectives, and confirmed its importance. In conclusion, we identified genes and cell types associated with age-related changes in the tumour microenvironment in urogenital cancer patients. These genes and cell types may play a critical role in the age-associated differences in clinicopathological characteristics among urogenital cancers, thus providing a link between ageing and cancer occurrence. The findings of this study may pave the way for the development of age-tailored approaches to treat cancer and other age-related diseases.

From infections to autoimmunity: Diagnostic challenges in common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most common clinically significant primary antibody deficiency diagnosed in adults. The early symptoms are not specific. They include common infections, mainly of the respiratory tract, caused by typical microorganisms, so cases can be missed in primary care. In the majority of patients increased susceptibility to infections coexists with signs or symptoms of autoimmunity, inflammation or polyclonal lymphoproliferation, which can divert diagnosis from immune deficiency. The overall incidence of malignancy is increased in CVID and certain cancers are significantly more common. Lymphomas and gastric carcinoma are the most frequently reported malignancies in CVID, so a high index of suspicion is recommended. Diagnostic delay in CVID is seen worldwide. The main goal of this paper is to increase the awareness about CVID among health care professionals. We aim to present features which can be helpful in CVID diagnosis in order to shorten the “latency” of proper management of CVID patients. We review clinical symptoms, complications and laboratory abnormalities of CVID. Immunoglobulin replacement therapy is regarded as the cornerstone of pharmacological intervention. New modes of Ig application, mainly subcutaneously and via the hyaluronidase-facilitated subcutaneous route, help to adjust therapy to patients’ needs and preferences. Still there remain unmet needs. It remains to be seen whether CVID complications can be avoided by earlier diagnosis, treatment and thorough monitoring in the context of increased risk of malignancy. Development of patient tailored protocols depending on the clinical phenotype and risk factors might be more appropriate. The most important consideration is to diagnose suspected cases and stratify patients in a precise and timely way. Work is needed to define features predictive of unfavorable prognosis.

Infectious Complications Reporting in Common Variable Immunodeficiency: A Systematic Review and Meta-analysis

Objectives

Common variable immunodeficiency (CVID) is a heterogeneous disorder characterized by hypogammaglobulinemia and increased susceptibility to recurrent infections.

Methods

We searched PubMed, Web of Science, and Scopus databases to find eligible studies from the earliest available date to January 2018 with standard keywords. Pooled estimates of the infection prevalence and the corresponding 95% confidence intervals were calculated using random-effects models.

Results

We found that pneumonia (67.7%) was the most prevalent infection followed by upper respiratory tract (59.0%) and gastrointestinal infections (36.3%). Furthermore, bacterial complications (41.7%) were higher in CVID patients compared to viral (25.4%), parasitic (18.8%), or fungal (3.4%) infections. Patients with longer age at diagnosis presented with fewer disease comorbidities. There was an inverse correlation between T lymphocyte count and viral infections. Moreover, we found that immunoglobulin M (IgM) serum level was inversely correlated with hepatitis C and gastrointestinal infections, and IgG serum level was inversely correlated with infectious arthritis. Higher numbers of CD4 and CD8 T cells were associated with the lower frequencies of otitis media. CVID patients with infections had significantly lower percentages of CD3 T cells. In contrast, higher percentages of CD19 lymphocytes were found in CVID patients who had a history of infections.

Conclusions

Our findings demonstrated that in addition to hypogammaglobulinemia, patients with CVID have an imbalance in the frequency of T lymphocytes, which is in parallel with the higher frequency of infectious complications.

Primary Humoral Immune Deficiencies: Overlooked Mimickers of Chronic Immune-Mediated Gastrointestinal Diseases in Adults

In recent years, the incidence of immune-mediated gastrointestinal disorders, including celiac disease (CeD) and inflammatory bowel disease (IBD), is increasingly growing worldwide. This generates a need to elucidate the conditions that may compromise the diagnosis and treatment of such gastrointestinal disorders. It is well established that primary immunodeficiencies (PIDs) exhibit gastrointestinal manifestations and mimic other diseases, including CeD and IBD. PIDs are often considered pediatric ailments, whereas between 25 and 45% of PIDs are diagnosed in adults. The most common PIDs in adults are the selective immunoglobulin A deficiency (SIgAD) and the common variable immunodeficiency (CVID). A trend to autoimmunity occurs, while gastrointestinal disorders are common in both diseases. Besides, the occurrence of CeD and IBD in SIgAD/CVID patients is significantly higher than in the general population. However, some differences concerning diagnostics and management between enteropathy/colitis in PIDs, as compared to idiopathic forms of CeD/IBD, have been described. There is an ongoing discussion whether CeD and IBD in CVID patients should be considered a true CeD and IBD or just CeD-like and IBD-like diseases. This review addresses the current state of the art of the most common primary immunodeficiencies in adults and co-occurring CeD and IBD.

Application of Flow Cytometry in Predominantly Antibody Deficiencies

Predominantly antibody deficiencies (PADs) are a heterogeneous group of primary immunodeficiency disorders (PIDs), consisting of recurrent infections, autoimmunity, inflammation, and other immune complications. In the recent years, several immunological and genetic defects have been recognized in PADs. Currently, 45 distinct PAD disorders with 40 different genetic defects have been identified based on the 2019 IUIS classification. Genetic analysis is helpful for diagnosing PIDs; however, genetic studies are expensive, time-consuming, and unavailable everywhere. Flow cytometry is a highly sensitive tool for evaluating the immune system and diagnosing PADs. In addition to cell populations and subpopulations assay, flow cytometry can measure cell surface, intracellular and intranuclear proteins, biological changes associated with specific immune defects, and certain functional immune abnormalities. These capabilities help in rapid diagnostic and prognostic assessment as well as in evaluating the pathogenesis of PADs. For the first time, this review particularly provides an overview of the application of flow cytometry for diagnosis, immunophenotyping, and determining the pathogenesis of PADs.

Pathogenesis of immune thrombocytopenia in common variable immunodeficiency

Immune Thrombocitopenic Purpura (ITP) is an autoimmune disease characterized by antibody-mediated platelet destruction and variable reduced platelet production. Besides antibody-mediated platelet destruction, new pathogenic mechanisms have been reported to be involved in reducing platelet count. Among these, desialylation is one of the most recent and innovative mechanisms that has been found to be implied, at least in part, in non-antibody mediated platelet clearance. Common Variable Immunodeficiency (CVID) is the most common Primary Immunodeficiency seen in clinical practice. About 25-30% of CVID patients are affected by autoimmune manifestation, among which ITP is the most common. Little is know about pathophysiological mechanisms that lead to ITP in CVID. Given the poor antibody production typical of CVID patients, we aimed at verifying whether platelet desialylation could be responsible for CVID associated thrombocytopenia. According to our results, we may suggest that in CVID patients, ITP is due to a decreased bone marrow platelets production, rather than an increased peripheral platelet destruction, which is more common in patients with primary ITP. An increased platelet desialylation does not appear to be implicated in the thrombocytopenia secondary to CVID, while it is implicated in the pathogenesis of primary ITP. Nevertheless an intriguing aspect has emerged from this study: regardless the presence of thrombocytopenia, the majority of CVID patients present a double platelet population as far as desialylation concerns, whilst no one of the healthy donors and of the patients with primary ITP shows a similar characteristic.

Autologous Stem Cell Transplantation in Common Variable Immunodeficiency: A Case of Successful Treatment of Severe Refractory Autoimmune Encephalitis

Common variable immunodeficiency (CVID) is the most common primary immunodeficiency in adults. It is associated with hypogammaglobulinemia, recurring infections and autoimmune phenomena. Treatment includes immunoglobulin substitution and immunosuppressants. Autoimmune neurological manifestations of CVID are rare and occur predominantly as granulomatous disease. We report the case of a 35-year-old woman with CVID who developed autoimmune encephalitis as demonstrated by double cerebral biopsy. Infectious or malignant causes could be excluded. Despite intensive immunosuppressive therapy with common regimens no significant improvement could be achieved. Ultimately, an autologous hematopoietic stem cell transplantation (HSCT) was performed, resulting in lasting complete remission of the encephalitis. To our knowledge, this is the first report of refractory autoimmune phenomena in CVID treated by autologous HSCT.

Preserved Cellular Immunity Upon Influenza Vaccination in Most Patients with Common Variable Immunodeficiency

BACKGROUND

Vaccination against influenza is recommended for patients with common variable immunodeficiency (CVID), although humoral immune responses in these patients are impaired and the evidence of effective T-cell responses in CVID is not well established.

OBJECTIVE

To determine plasmablast and T-cellular vaccination responses against influenza in patients with CVID.

METHODS

Patients with CVID and healthy controls were vaccinated with the quadrivalent vaccine Influsplit Tetra 2018/2019. Before and 1 week after vaccination plasmablasts and circulating inducible costimulator-expressing T follicular helper cells were measured to determine positive vaccine responses in these patients. In addition, antigen-specific T cells were determined by their upregulation of CD25 and OX40 after in vitro restimulation with the vaccine.

RESULTS

Most healthy controls but only 1 patient with CVID mounted a positive humoral immune response, measured by an increase in plasmablasts 1 week after vaccination. In contrast, most patients with CVID showed an increase in inducible costimulator⁺ T follicular helper cells and/or an increase in antigen-specific CD25⁺OX40⁺ T cells 1 week after vaccination, demonstrating a positive T-cellular immune response.

CONCLUSIONS

Despite the remaining challenge of accurately assessing the complexity of T-cell responses, the recommendation of vaccinating patients with CVID against influenza is reasonable.