Confirmation and improvement of criteria for clinical phenotyping in common variable immunodeficiency disorders in replicate cohorts

An Exploratory Approach of Clinically Useful Biomarkers of Cvid by Logistic Regression

Despite advancements in genetic and functional studies, the timely diagnosis of common variable immunodeficiency (CVID) remains a significant challenge. This exploratory study was designed to assess the diagnostic performance of a novel panel of biomarkers for CVID, incorporating the sum of κ+λ light chains, soluble B-cell maturation antigen (sBCMA) levels, switched memory B cells (smB) and the VISUAL score. Comparative analyses utilizing logistic regression were performed against established gold-standard tests, specifically antibody responses. Our research encompassed 88 subjects, comprising 27 CVID, 23 selective IgA deficiency (SIgAD), 20 secondary immunodeficiency (SID) patients and 18 healthy controls. We established the diagnostic accuracy of sBCMA and the sum κ+λ, achieving sensitivity (Se) and specificity (Spe) of 89% and 89%, and 90% and 99%, respectively. Importantly, sBCMA showed strong correlations with all evaluated biomarkers (sum κ+λ, smB cell and VISUAL), whereas the sum κ+λ was uniquely independent from smB cells or VISUAL, suggesting its additional diagnostic value. Through a multivariate tree decision model, specific antibody responses and the sum κ+λ emerged as independent, signature biomarkers for CVID, with the model showcasing an area under the curve (AUC) of 0.946, Se 0.85, and Spe 0.95. This tree-decision model promises to enhance diagnostic efficiency for CVID, underscoring the sum κ+λ as a superior CVID classifier and potential diagnostic criterion within the panel.

High Prevalence of Long COVID in Common Variable Immunodeficiency: An Italian Multicentric Study

The long-term effects of SARS-CoV-2 infection represent a relevant global health problem. Long COVID (LC) is defined as a complex of signs and symptoms developed during or after SARS-CoV-2 infection and lasting > 12 weeks. In common variable immunodeficiency (CVID) patients, we previously reported higher risk of hospitalization and death during SARS-CoV-2 infection, as well as prolonged swab positivity and frequent reinfections. The aim of the present study was to assess the risk of LC in an Italian cohort of CVID patients. We used a translated version of the survey proposed by Centers for Disease Control and Prevention (CDC) to collect data on LC. In the enrolled cohort of 175 CVID patients, we found a high prevalence of LC (65.7%). The most frequent LC symptoms were fatigue (75.7%), arthralgia/myalgia (48.7%), and dyspnea (41.7%). The majority of patients (60%) experienced prolonged symptoms, for at least 6 months after infection. In a multivariate analysis, the presence of complicated phenotype (OR 2.44, 95% CI 1.88-5.03; p = 0.015), obesity (OR 11.17, 95% CI 1.37-90.95; p = 0.024), and female sex (OR 2.06, 95% CI 1.09-3.89; p = 0.024) significantly correlated with the development of LC. In conclusion, in this multicenter observational cohort study, we demonstrated that CVID patients present an increased prevalence of LC when compared to the general population. Improved awareness on the risk of LC in CVID patients could optimize management of this new and alarming complication of SARS-CoV-2 infection.

Impact of Exposure to Vaccination and Infection on Cellular and Antibody Response to SARS-CoV-2 in CVID Patients Through COVID-19 Pandemic

PURPOSE

The purpose of this study is to investigate the kinetics of response against SARS-CoV-2 elicited by vaccination and/or breakthrough infection (occurred after 3 doses of BNT162b2) in a cohort CVID patients.

METHODS

We measured humoral and cellular immunity using quantitative anti-spike antibody (anti-S-IgG) and neutralization assay and specific interferon-gamma release assay (IGRA) before and after the third or fourth dose of BNT162b2 and/or after COVID-19.

RESULTS

In CVID, 58.3% seroconverted after 2 doses that increased to 77.8% after 3 doses. Between the second and third dose, there was a decline in humoral compartment that led to titers below the cutoff of 1:10 (MNA90%) in CVID. This was paralleled by a significantly lower proportion (30%) and reduced magnitude of the residual cellular response among CVID. The third dose achieved a lower titer of anti-S and nAb against the Wuhan strain than HC and significantly decreased the rate of those showing solely a positive neutralizing activity and those with simultaneous negativity of IGRA and nAbs; the differences in IGRA were overall reduced with respect to HC. At further sampling after breakthrough SARS-COV-2 infection, mostly in the omicron era, or fourth dose, 6 months after the last event, the residual nAb titer to Wuhan strain was still significantly higher in HC, while there was no significant difference of nAbs to BA.1. The rate of IGRA responders was 65.5% in CVID and 90.5% in HC (p=0.04), while the magnitude of response was similar. None of CVID had double negativity to nAbs and IGRA at the last sampling.

CONCLUSION

This data shows an increase of adaptive immunity in CVID after mRNA vaccination in parallel to boosters, accrual number of exposures and formation of hybrid immunity.

Dysimmunity in common variable immunodeficiency is associated with alterations in oral, respiratory, and intestinal microbiota

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency characterized by decreased immunoglobulins and recurrent infections. Its aetiology remains unknown, and some patients present with severe non-infectious autoimmune or inflammatory complications with elevated associated morbimortality. Recently, intestinal dysbiosis has been proposed as a driver of immune dysregulation. In this study, we assessed the oral, respiratory, and gastrointestinal microbiota of 41 CVID patients (24 with dysimmune and 17 with infection complications) and 15 healthy volunteers using 16S rRNA gene sequencing to explore associations between microbiome profiles and CVID phenotypes. Profound differences in the composition of the microbiota in saliva, sputum, and stool were detected between dysimmune CVID patients and healthy individuals. Globally, respiratory species diversity and faecal bacterial richness were lower in CVID individuals with immune complications. Although a single species could not be identified as a robust predictor of dysimmunity, a combination of around 5-7 bacterial species in each type of sample could predict this severe phenotype with an accuracy of around 90% in the study population. Our study provides new insights into these previously unexplored but highly interrelated ecological niches among themselves and with patient profiles. Our data suggest that this disease-related systemic dysbiosis could be implicated in the immune dysregulation associated with severe cases of CVID.

Non-infectious Pulmonary Complications in Children with Primary Immunodeficiency

Primary immune deficiency (PID) is a large group of diseases characterized by defective immune function, leading to recurrent infections, and immune dysregulation. Clinical presentations, severity, and complications differ for each disease, based on the components of the immune system that are impacted. When patients with PID present with respiratory symptoms, infections should be initially suspected, investigated, and promptly managed. However, non-infectious complications of PID also frequently occur and can lead to significant morbidity and mortality. They can involve both the upper and lower respiratory systems, resulting in various presentations that mimic infectious diseases. Thus, clinicians should be able to detect these conditions and make an appropriate referral to an immunologist and a pulmonologist for further management. In this article, we use case-based scenarios to review the differential diagnosis, investigation, and multidisciplinary treatment of non-infectious pulmonary complications in patients with primary immune deficiencies.

The efficacy and safety of systemic corticosteroids as first line treatment for granulomatous lymphocytic interstitial lung disease

BACKGROUND

Granulomatous and lymphocytic interstitial lung disease (gl-ILD) is a major cause of morbidity and mortality among patients with common variable immunodeficiency. Corticosteroids are recommended as first-line treatment for gl-ILD, but evidence for their efficacy is lacking.

OBJECTIVES

This study analyzed the effect of high-dose corticosteroids (≥0.3 mg/kg prednisone equivalent) on gl-ILD, measured by high-resolution computed tomography (HRCT) scans, and pulmonary function test (PFT) results.

METHODS

Patients who had received high-dose corticosteroids but no other immunosuppressive therapy at the time (n = 56) and who underwent repeated HRCT scanning or PFT (n = 39) during the retrospective and/or prospective phase of the Study of Interstitial Lung Disease in Primary Antibody Deficiency (STILPAD) were included in the analysis. Patients without any immunosuppressive treatment were selected as controls (n = 23). HRCT scans were blinded, randomized, and scored using the Hartman score. Differences between the baseline and follow-up HRCT scans and PFT were analyzed.

RESULTS

Treatment with high-dose corticosteroids significantly improved HRCT scores and forced vital capacity. Carbon monoxide diffusion capacity significantly improved in both groups. Of 18 patients, for whom extended follow-up data was available, 13 achieved a long-term, maintenance therapy independent remission. All patients with relapse were retreated with corticosteroids, but only one-fifth of them responded. Two opportunistic infections were found in the corticosteroid treatment group, while overall infection rate was similar between cohorts.

CONCLUSIONS

Induction therapy with high-dose corticosteroids improved HRCT scans and PFT results of patients with gl-ILD and achieved long-term remission in 42% of patients. It was not associated with major side effects. Low-dose maintenance therapy provided no benefit and efficacy was poor in relapsing disease.

A beacon in the dark: COVID-19 course in CVID patients from two European countries: Different approaches, similar outcomes

Background

CVID patients present an increased risk of prolonged SARS-CoV-2 infection and re-infection and a higher COVID-19-related morbidity and mortality compared to the general population. Since 2021, different therapeutic and prophylactic strategies have been employed in vulnerable groups (vaccination, SARS-CoV-2 monoclonal antibodies and antivirals). The impact of treatments over the last 2 years has not been explored in international studies considering the emergence of viral variants and different management between countries.

Methods

A multicenter retrospective/prospective real-life study comparing the prevalence and outcomes of SARS-CoV-2 infection between a CVID cohort from four Italian Centers (IT-C) and one cohort from the Netherlands (NL-C), recruiting 773 patients.

Results

329 of 773 CVID patients were found positive for SARS-CoV-2 infection between March 1^st, 2020 and September 1^st 2022. The proportion of CVID patients infected was comparable in both national sub-cohorts. During all waves, chronic lung disease, "complicated" phenotype, chronic immunosuppressive treatment and cardiovascular comorbidities impacted on hospitalization, whereas risk factors for mortality were older age, chronic lung disease, and bacterial superinfections. IT-C patients were significantly more often treated, both with antivirals and mAbs, than NL-C patients. Outpatient treatment, available only in Italy, started from the Delta wave. Despite this, no significant difference was found for COVID-19 severity between the two cohorts. However, pooling together specific SARS-CoV-2 outpatient treatments (mAbs and antivirals), we found a significant effect on the risk of hospitalization starting from Delta wave. Vaccination with ≥ 3 doses shortened RT-PCR positivity, with an additional effect only in patients receiving antivirals.

Conclusions

The two sub-cohorts had similar COVID-19 outcomes despite different treatment approaches. This points out that specific treatment should now be reserved for selected subgroups of CVID patients, based on pre-existing conditions.

Common Variable Immunodeficiency: More Pathways than Roads to Rome

Fifty years have elapsed since the term common variable immunodeficiency (CVID) was introduced to accommodate the many and varied antibody deficiencies being identified in patients with suspected inborn errors of immunity (IEIs). Since then, how the term is understood and applied for diagnosis and management has undergone many revisions, though controversy persists on how exactly to define and classify CVID. Many monogenic disorders have been added under its aegis, while investigations into polygenic, epigenetic, and somatic contributions to CVID susceptibility have gained momentum. Expansion of the overall IEI landscape has increasingly revealed genotypic and phenotypic overlap between CVID and various other immunological conditions, while increasingly routine genotyping of CVID patients continues to identify an incredible diversity of pathophysiological mechanisms affecting even single genes. Though many questions remain to be answered, the lessons we have already learned from CVID biology have greatly informed our understanding of adaptive, but also innate, immunity.

Lymphoid stromal cells - potential implications for the pathogenesis of CVID

Non-hematopoietic lymphoid stromal cells (LSC) maintain lymph node architecture and form niches allowing the migration, activation, and survival of immune cells. Depending on their localization in the lymph node, these cells display heterogeneous properties and secrete various factors supporting the different activities of the adaptive immune response. LSCs participate in the transport of antigen from the afferent lymph as well as in its delivery into the T and B cell zones and organize cell migration via niche-specific chemokines. While marginal reticular cells (MRC) are equipped for initial B-cell priming and T zone reticular cells (TRC) provide the matrix for T cell-dendritic cell interactions within the paracortex, germinal centers (GC) only form when both T- and B cells successfully interact at the T-B border and migrate within the B-cell follicle containing the follicular dendritic cell (FDC) network. Unlike most other LSCs, FDCs are capable of presenting antigen via complement receptors to B cells, which then differentiate within this niche and in proximity to T follicular helper (T_FH) cells into memory and plasma cells. LSCs are also implicated in maintenance of peripheral immune tolerance. In mice, TRCs induce the alternative induction of regulatory T cells instead of T_FH cells by presenting tissue-restricted self-antigens to naïve CD4 T cells via MHC-II expression. This review explores potential implications of our current knowledge of LSC populations regarding the pathogenesis of humoral immunodeficiency and autoimmunity in patients with autoimmune disorders or common variable immunodeficiency (CVID), the most common form of primary immunodeficiency in humans.

Lymphoma as an Exclusion Criteria for CVID Diagnosis Revisited

PURPOSE

Hypogammaglobulinemia in a context of lymphoma is usually considered as secondary and prior lymphoma remains an exclusion criterion for a common variable immunodeficiency (CVID) diagnosis. We hypothesized that lymphoma could be the revealing symptom of an underlying primary immunodeficiency (PID), challenging the distinction between primary and secondary hypogammaglobulinemia.

METHODS

Within a French cohort of adult patients with hypogammaglobulinemia, patients who developed a lymphoma either during follow-up or before the diagnosis of hypogammaglobulinemia were identified. These two chronology groups were then compared. For patients without previous genetic diagnosis, a targeted next-generation sequencing of 300 PID-associated genes was performed.

RESULTS

A total of forty-seven patients had developed 54 distinct lymphomas: non-Hodgkin B cell lymphoma (67%), Hodgkin lymphoma (26%), and T cell lymphoma (7%). In 25 patients, lymphoma developed prior to the diagnosis of hypogammaglobulinemia. In this group of patients, Hodgkin lymphoma was overrepresented compared to the group of patients in whom lymphoma occurred during follow-up (48% versus 9%), whereas MALT lymphoma was absent (0 versus 32%). Despite the histopathological differences, both groups presented with similar characteristics in terms of age at hypogammaglobulinemia diagnosis, consanguinity rate, or severe T cell defect. Overall, genetic analyses identified a molecular diagnosis in 10/47 patients (21%), distributed in both groups and without peculiar gene recurrence. Most of these patients presented with a late onset combined immunodeficiency (LOCID) phenotype.

CONCLUSION

Prior or concomitant lymphoma should not be used as an exclusion criteria for CVID diagnosis, and these patients should be investigated accordingly.

Genomic crossroads between non-Hodgkin's lymphoma and common variable immunodeficiency

Common variable immunodeficiency (CVID) represents the largest group of primary immunodeficiencies that may manifest with infections, inflammation, autoimmunity, and cancer, mainly B-cell non-Hodgkin's lymphoma (NHL). Indeed, NHL may result from chronic or recurrent infections and has, therefore, been recognized as a clinical phenotype of CVID, although rare. The more one delves into the mechanisms involved in CVID and cancer, the stronger the idea that both pathologies can be a reflection of the same primer events observed from different angles. The potential effects of germline variants on specific somatic modifications in malignancies suggest that it might be possible to anticipate critical events during tumor development. In the same way, a somatic alteration in NHL could be conditioning a similar response at the transcriptional level in the shared signaling pathways with genetic germline alterations in CVID. We aimed to explore the genomic substrate shared between these entities to better characterize the CVID phenotype immunodeficiency in NHL. By means of an in-silico approach, we interrogated the large, publicly available datasets contained in cBioPortal for the presence of genes associated with genetic pathogenic variants in a panel of 50 genes recurrently altered in CVID and previously described as causative or disease-modifying. We found that 323 (25%) of the 1,309 NHL samples available for analysis harbored variants of the CVID spectrum, with the most recurrent alteration presented in NHL occurring in PIK3CD (6%) and STAT3 (4%). Pathway analysis of common gene alterations showed enrichment in inflammatory, immune surveillance, and defective DNA repair mechanisms similar to those affected in CVID, with PIK3R1 appearing as a central node in the protein interaction network. The co-occurrence of gene alterations was a frequent phenomenon. This study represents an attempt to identify common genomic grounds between CVID and NHL. Further prospective studies are required to better know the role of genetic variants associated with CVID and their reflection on the somatic pathogenic variants responsible for cancer, as well as to characterize the CVID-like phenotype in NHL, with the potential to influence early CVID detection and therapeutic management.

How I approach: The workup and management of patients with progressive transformation of the germinal center

Progressive transformation of the germinal center (PTGC) is a common and underrecognized cause of pediatric lymphadenopathy. PTGC may be associated with numerous systemic medical conditions that require further workup and management, including malignancy, autoimmune conditions, lymphoproliferative conditions, immunodeficiency, and infection. Given the breadth and rarity of the associated conditions, workup should be tailored to the individual patient and occur in a tiered approach. Patients with PTGC require ongoing follow-up, given their long-term risk of malignancy and recurrent PTGC.

Evaluation of Laboratory and Sonographic Parameters for Detection of Portal Hypertension in Patients with Common Variable Immunodeficiency

Timely detection of portal hypertension as a manifestation in a subgroup of patients with common variable immunodeficiency (CVID) represents a challenge since it is usually not associated with liver cirrhosis. To identify relevant markers for portal hypertension, we evaluated clinical history, laboratory parameters, and abdominal ultrasound including liver elastography and biomarkers of extracellular matrix formation. Twenty seven (6%) of 479 CVID patients presented with clinically significant portal hypertension as defined by either the presence of esophageal varices or ascites. This manifestation occurred late during the course of the disease (11.8 years after first diagnosis of CVID) and was typically part of a multiorgan disease and associated with a high mortality (11/27 patients died during follow up). The strongest association with portal hypertension was found for splenomegaly with a longitudinal diameter of > 16 cm. Similarly, most patients presented with a liver stiffness measurement (LSM) of above 6.5 kPa, and a LSM above 20 kPa was always indicative of manifest portal hypertension. Additionally, many laboratory parameters including Pro-C4 were significantly altered in patients with portal hypertension without clearly increasing the discriminatory power to detect non-cirrhotic portal hypertension in CVID. Our data suggest that a spleen size above 16 cm and an elevated liver stiffness above 6.5 kPa should prompt further evaluation of portal hypertension and its sequelae, but earlier and better liquid biomarkers of this serious secondary complication in CVID are needed.

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.

Intravenous Immunoglobulins Promote an Expansion of Monocytic Myeloid-Derived Suppressor Cells (MDSC) in CVID Patients

Common variable immunodeficiency disorders (CVID), the most common primary immune deficiency, includes heterogeneous syndromes characterized by hypogammaglobulinemia and impaired antibody responses. CVID patients frequently suffer from recurrent infections and inflammatory conditions. Currently, immunoglobulin replacement therapy (IgRT) is the first-line treatment to prevent infections and aminorate immune alterations in CVID patients. Intravenous Immunoglobulin (IVIg), a preparation of highly purified poly-specific IgG, is used for treatment of immunodeficiencies as well as for autoimmune and inflammatory disorders, as IVIg exerts immunoregulatory and anti-inflammatory actions on innate and adaptive immune cells. To determine the mechanism of action of IVIg in CVID in vivo, we determined the effect of IVIg infusion on the transcriptome of peripheral blood mononuclear cells from CVID patients, and found that peripheral blood monocytes are primary targets of IVIg in vivo, and that IVIg triggers the acquisition of an anti-inflammatory gene profile in human monocytes. Moreover, IVIg altered the relative proportions of peripheral blood monocyte subsets and enhanced the proportion of CD14⁺ cells with a transcriptional, phenotypic, and functional profile that resembles that of monocytic myeloid-derived suppressor cells (MDSC). Therefore, our results indicate that CD14 + MDSC-like cells might contribute to the immunoregulatory effects of IVIg in CVID and other inflammatory disorders.

Monitoring patients with uncomplicated common variable immunodeficiency: a systematic review

BACKGROUND

Non-infectious complications have become a major cause of morbidity and mortality in patients with Common Variable Immunodeficiency (CVID). The monitoring of patients with CVID prior to the development of non-infectious complications is not well defined.

OBJECTIVE

Our objectives were to systematically review the current literature on the monitoring of CVID patients without non-infectious complications and to develop recommendations for such monitoring.

METHODS

MEDLINE and EMBASE were searched from January 1^st, 2000 to March 25^th, 2021. Studies on any aspects of CVID monitoring were included. Studies that included only children, on monitoring CVID patients with existing non-infectious complications, or in the format of case reports were excluded.

RESULTS

Nine studies on CVID monitoring, including 3 cohort studies, 3 experts' opinions, 2 consensus statements and a single guideline report were identified. These studies revealed that clinical assessment and bloodwork were preformed every 6 to 12 months in asymptomatic patients. Some centers performed computerized tomography scan of the chest every 2-5 years to identify chronic lung disease, although the majority did chest imaging in accordance with clinical indications. Pulmonary function tests were done annually at most centers. Most studies did not address the role of abdominal imaging to screen for liver diseases or endoscopy to screen for gastric cancer in asymptomatic patients with uncomplicated CVID.

CONCLUSIONS

There is paucity of evidence-based information to guide the routine monitoring of CVID patients without non-infectious complications. Prospective studies are needed to determine the best monitoring practices in this group of patients.

Systemic Lupus Erythematosus and Common Variable Immunodeficiency

ABSTRACT

Systemic lupus erythematosus (SLE) and common variable immunodeficiency (CVID) are both conditions defined by immune system dysfunction: one hyperactive, the other hypoactive. Although uncommon, these diseases can coexist in the same individual. This review aims to assess the state of the literature on the relationship between SLE and CVID, particularly when workup for CVID should be considered in individuals with SLE and how CVID in individuals with SLE should be treated.

Granulomatous-Lymphocytic Interstitial Lung Disease Mimicking Sarcoidosis

Common variable immunodeficiency (CVID) is one of the most common primary immunodeficiency disorders characterized by hypogammaglobulinemia and inadequate antibody response to immunizations. The impaired antibody response occurs due to the failure of B cells to differentiate into plasma cells resulting in low immunoglobulins levels and increased frequency of infections. Granulomatous and Lymphocytic Interstitial Lung Disease (GLILD) is a non-infectious complication of CVID that is seen in 10-30% of cases. GLILD is a multisystem inflammatory disease involving the lungs, lymph node, liver, spleen and gastrointestinal tract that mimics sarcoidosis. This report describes a series of cases who presented with dyspnea, recurrent respiratory infections or autoimmunity and on further evaluation revealed features suggestive of GLILD. There is very limited understanding of GLILD in terms of clinical presentation, the histo-pathological logical findings, and the diagnostic criteria by itself are limited. A diagnosis of GLILD is established in cases of CVID when there is evidence of lymphoproliferation, cytopenia, autoimmune processes and a lung biopsy demonstrating lymphocytic interstitial pneumonia, follicular bronchiolitis, lymphoid hyperplasia, and/or non-necrotizing granulomas. We review the treatment strategies, including replacement of immunoglobulin and agents targeting B and T lymphocytes. Systematic characterization of GLILD cases and long term follow up studies are sorely needed to understand the natural history of GLILD.

Common variable immunodeficiency disorders: What generalists should know

Primary immune deficiency disorders (PIDDs) are common and underdiagnosed. Predominant antibody deficiencies (PADs) are the most common type of immune deficiency and comprise 55% of the immune deficiencies diagnosed.^[1] Although immunoglobulin A (IgA) deficiency remains the most common type of PID, common variable immunodeficiency disorders remain the most common symptomatic PID for which medical therapy is sought.

Autoimmunity in Primary Immunodeficiency Disorders: An Updated Review on Pathogenic and Clinical Implications

During the last years, studies investigating the intriguing association between immunodeficiency and autoimmunity led to the discovery of new monogenic disorders, the improvement in the knowledge of the pathogenesis of autoimmunity, and the introduction of targeted treatments. Autoimmunity is observed with particular frequency in patients with primary antibody deficiencies, such as common variable immunodeficiency (CVID) and selective IgA deficiency, but combined immunodeficiency disorders (CIDs) and disorders of innate immunity have also been associated with autoimmunity. Among CIDs, the highest incidence of autoimmunity is described in patients with autoimmune polyendocrine syndrome 1, LRBA, and CTLA-4 deficiency, and in patients with STAT-related disorders. The pathogenesis of autoimmunity in patients with immunodeficiency is far to be fully elucidated. However, altered germ center reactions, impaired central and peripheral lymphocyte negative selection, uncontrolled lymphocyte proliferation, ineffective cytoskeletal function, innate immune defects, and defective clearance of the infectious agents play an important role. In this paper, we review the main immunodeficiencies associated with autoimmunity, focusing on the pathogenic mechanisms responsible for autoimmunity in each condition and on the therapeutic strategies. Moreover, we provide a diagnostic algorithm for the diagnosis of PIDs in patients with autoimmunity.

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.

Common Variable Immunodeficiency and Autoimmune Diseases: A Retrospective Study of 95 Adult Patients in a Single Tertiary Care Center

Common variable immunodeficiency (CVID) is the most common clinically significant primary immunodeficiency in adulthood, which presents a broad spectrum of clinical manifestations, often including non-infectious complications in addition to heightened susceptibility to infections. These protean manifestations may significantly complicate the differential diagnosis resulting in diagnostic delay and under-treatment with increased mortality and morbidity. Autoimmunity occurs in up to 30% of CVID patients, and it is an emerging cause of morbidity and mortality in this type of patients. 95 patients (42 males and 53 females) diagnosed with CVID, basing on ESID diagnostic criteria, were enrolled in this retrospective cohort study. Clinical phenotypes were established according to Chapel 2012: i) no other disease-related complications, ii) cytopenias (thrombocytopenia/autoimmune hemolytic anemia/neutropenia), iii) polyclonal lymphoproliferation (granuloma/lymphoid interstitial pneumonitis/persistent unexplained lymphadenopathy), and iv) unexplained persistent enteropathy. Clinical items in the analysis were age, gender, and clinical features. Laboratory data included immunoglobulin (Ig)G, IgM and IgA levels at diagnosis, flow-cytometric analysis of peripheral lymphocytes (CD3+, CD3+CD4+, CD3+CD8+, CD19+, CD4+CD25highCD127low, CD19hiCD21loCD38lo, and follicular T helper cell counts). Comparisons of continuous variables between groups were performed with unpaired t-test, when applicable. 39 patients (41%) showed autoimmune complications. Among them, there were 21 females (53.8%) and 18 males (46.2%). The most prevalent autoimmune manifestations were cytopenias (17.8%), followed by arthritis (11.5%), psoriasis (9.4%), and vitiligo (6.3%). The most common cytopenia was immune thrombocytopenia, reported in 10 out of 95 patients (10.5%), followed by autoimmune hemolytic anemia (n=3, 3.1%) and autoimmune neutropenia (n=3, 3.1%). Other autoimmune complications included thyroiditis, coeliac disease, erythema nodosum, Raynaud’s phenomenon, alopecia, recurring oral ulcers, autoimmune gastritis, and primary biliary cholangitis. There were no statistically significant differences comparing immunoglobulin levels between CVID patients with or without autoimmune manifestations. There was no statistical difference in CD3+, CD8+, CD4+CD25highCD127low T, CD19, CD19hiCD21loCD38lo, and follicular T helper cell counts in CVID patients with or without autoimmune disorders. In conclusion, autoimmune manifestations often affect patients with CVID. Early recognition and tailored treatment of these conditions are pivotal to ensure a better quality of life and the reduction of CVID associated complications.

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.

Dysregulatory processes of the cellular link of the immune system in the dynamics of common variable immunodeficiency

Common variable immunodeficiency (CVID) is a variant of primary immunodeficiency in which inhibition of antibody production is formed due to disorders of intercellular interaction affecting cellular elements of both innate and adaptive immune responses. A feature of CVID is the late start and variability of clinical minifestation. These arguments determine the purpose of the study: to identify the dynamics of changes in the cellular parameters of the adaptive and innate immune response depending on the duration and severity of the infectious manifestation of CVID. In this regard, a retrospective analysis of medical histories and dynamic observation of fifteen patients with CVID were carried out. Selection of specific parameters of cellular indices of factors of innate resistance and adaptive immunity was carried out on the basis of systemic-functional approach of immunodiagnostics. It is shown that in patients with CVID -mediated hypogammaglobulinemia and infectious phenotype of clinical manifestation, enhancement of quantitative and functional potentials of T-link effector cells of adaptive immunity is recorded against the background of reduction of number of regulatory T-helpers. With a more severe clinical course of the disease, the number of CD3+HLA DR + limphocytes is lower than with a more favorable version, there is a tendency to decrease the number of these cells, as well as the number of peripheral Treg with an increase in the length of the disease. Cellular components of innate immunity are characterized by a decrease in neutrophil activity, inhibition of antigen-presenting monocyte activity, the number and cytotoxicity of natural killers. At the same time, the tendency to decrease the cytolytic potential of NK with an increase in the length of illness and statistically significant differences depending on the severity of the manifestation of the infectious phenotype of CVID was recorded. The obtained results determine the importance of evaluating the cellular link of the immune system in patients with CVID, including as a prognostic criterion for the severity of the course.

Granulomatous Lymphocytic Interstitial Lung Disease (GLILD) in Common Variable Immunodeficiency (CVID): A Multicenter Retrospective Study of Patients From Italian PID Referral Centers

Background: Granulomatous and Lymphocytic Interstitial Lung Diseases (GLILD) is a severe non-infectious complication of Common Variable Immunodeficiency (CVID), often associated with extrapulmonary involvement. Due to a poorly understood pathogenesis, GLILD diagnosis and management criteria still lack consensus. Accordingly, it is a relevant cause of long-term loss of respiratory function and is closely associated with a markedly reduced survival. The aim of this study was to describe clinical, immunological, laboratory and functional features of GLILD, whose combination in a predictive model might allow a timely diagnosis. Methods: In a multicenter retrospective cross-sectional study we enrolled 73 CVID patients with radiologic features of interstitial lung disease (ILD) associated to CVID (CVID-ILD) and 125 CVID patients without ILD (controls). Of the 73 CVID-ILD patients, 47 received a definite GLILD diagnosis while 26 received a clinical-radiologic diagnosis of CVID related ILD defined as uILD. Results: In GLILD group we found a higher prevalence of splenomegaly (84.8 vs. 39.2%), autoimmune cytopenia (59.6 vs. 6.4%) and bronchiectasis (72.3 vs. 28%), and lower IgA and IgG serum levels at CVID diagnosis. GLILD patients presented lower percentage of switched-memory B cells and marginal zone B cells, and a marked increase in the percentage of circulating CD21lo B cells (14.2 vs. 2.9%). GLILD patients also showed lower total lung capacity (TLC 87.5 vs. 5.0%) and gas transfer (DLCO 61.5 vs. 5.0%) percent of predicted. By univariate logistic regression analysis, we found IgG and IgA levels at CVID diagnosis, presence of splenomegaly and autoimmune cytopenia, CD21lo B cells percentage, TLC and DCLO percent of predicted to be associated to GLILD. The joint analysis of four variables (CD21lo B cells percentage, autoimmune cytopenia, splenomegaly and DLCO percent of predicted), together in a multiple logistic regression model, yielded an area under the ROC curve (AUC) of 0.98 (95% CI: 0.95-1.0). The AUC was only slightly modified when pooling together GLILD and uILD patients (0.92, 95% CI: 0.87-0.97). Conclusions: we propose the combination of two clinical parameters (splenomegaly and autoimmune cytopenia), one lung function index (DLCO%) and one immunologic variable (CD21lo%) as a promising tool for early identification of CVID patients with interstitial lung disease, limiting the use of aggressive diagnostic procedures.

Granulomatous Lymphocytic Interstitial Lung Disease (GLILD) in Common Variable Immunodeficiency (CVID): A Multicenter Retrospective Study of Patients From Italian PID Referral Centers

Background: Granulomatous and Lymphocytic Interstitial Lung Diseases (GLILD) is a severe non-infectious complication of Common Variable Immunodeficiency (CVID), often associated with extrapulmonary involvement. Due to a poorly understood pathogenesis, GLILD diagnosis and management criteria still lack consensus. Accordingly, it is a relevant cause of long-term loss of respiratory function and is closely associated with a markedly reduced survival. The aim of this study was to describe clinical, immunological, laboratory and functional features of GLILD, whose combination in a predictive model might allow a timely diagnosis. Methods: In a multicenter retrospective cross-sectional study we enrolled 73 CVID patients with radiologic features of interstitial lung disease (ILD) associated to CVID (CVID-ILD) and 125 CVID patients without ILD (controls). Of the 73 CVID-ILD patients, 47 received a definite GLILD diagnosis while 26 received a clinical-radiologic diagnosis of CVID related ILD defined as uILD. Results: In GLILD group we found a higher prevalence of splenomegaly (84.8 vs. 39.2%), autoimmune cytopenia (59.6 vs. 6.4%) and bronchiectasis (72.3 vs. 28%), and lower IgA and IgG serum levels at CVID diagnosis. GLILD patients presented lower percentage of switched-memory B cells and marginal zone B cells, and a marked increase in the percentage of circulating CD21lo B cells (14.2 vs. 2.9%). GLILD patients also showed lower total lung capacity (TLC 87.5 vs. 5.0%) and gas transfer (DLCO 61.5 vs. 5.0%) percent of predicted. By univariate logistic regression analysis, we found IgG and IgA levels at CVID diagnosis, presence of splenomegaly and autoimmune cytopenia, CD21lo B cells percentage, TLC and DCLO percent of predicted to be associated to GLILD. The joint analysis of four variables (CD21lo B cells percentage, autoimmune cytopenia, splenomegaly and DLCO percent of predicted), together in a multiple logistic regression model, yielded an area under the ROC curve (AUC) of 0.98 (95% CI: 0.95-1.0). The AUC was only slightly modified when pooling together GLILD and uILD patients (0.92, 95% CI: 0.87-0.97). Conclusions: we propose the combination of two clinical parameters (splenomegaly and autoimmune cytopenia), one lung function index (DLCO%) and one immunologic variable (CD21lo%) as a promising tool for early identification of CVID patients with interstitial lung disease, limiting the use of aggressive diagnostic procedures.

Bronchiectasis severity correlates with outcome in patients with primary antibody deficiency

Bronchiectasis is a well-recognised complication of primary antibody deficiency (PAD) syndromes. Previous data suggest that mortality in common variable immune deficiency (CVID) is not associated with isolated bronchiectasis. A retrospective analysis of patients with CVID and specific antibody deficiency in two tertiary referral centres with lung disease was conducted. Severity of bronchiectasis at presentation was associated with mortality. Lower FEV₁, colonisation with Pseudomonas aeruginosa and a diagnosis of COPD were also associated with mortality. Bronchiectasis is an important driver of mortality in patients with PAD syndromes.

Bronchoalveolar Lavage Fluid Reflects a TH1-CD21low B-Cell Interaction in CVID-Related Interstitial Lung Disease

Background

About 20% of patients with common variable immunodeficiency (CVID) suffer from interstitial lung disease (ILD) as part of a systemic immune dysregulation. Current understanding suggests a role of B cells in the pathogenesis based on histology and increased levels of BAFF and IgM associated with active disease corroborated by several reports which demonstrate the successful use of rituximab in CVID-ILD. It is debated whether histological confirmation by biopsy or even video-assisted thoracoscopy is required and currently not investigated whether less invasive methods like a bronchoalveolar lavage (BAL) might provide an informative diagnostic tool.

Objective

To gain insight into potential immune mechanisms underlying granulomatous and lymphocytic interstitial lung disease (GLILD) and to define biomarkers for progressive ILD by characterizing the phenotype of B- and T-cell populations and cytokine profiles in BAL fluid (BALF) of CVID-ILD compared to sarcoidosis patients and healthy donors (HD).

Methods

Sixty-four CVID, six sarcoidosis, and 25 HD BALF samples were analyzed by flow cytometric profiling of B- and T-cells and for cytokines by ELISA and Multiplexing LASER Bead technology.

Results

Both sarcoidosis and CVID-ILD are characterized by a predominantly T-cell mediated lymphocytosis in the BALF. There is an increase in T follicular helper (TFH)-like memory and decrease of regulatory T cells in CVID-ILD BALF. This TFH-like cell subset is clearly skewed toward TH1 cells in CVID-ILD. In contrast to sarcoidosis, CVID-ILD BALF contains a higher percentage of B cells comprising mostly CD21low B cells, but less class-switched memory B cells. BALF analysis showed increased levels of APRIL, CXCL10, and IL-17.

Conclusion

Unlike in sarcoidosis, B cells are expanded in BALF of CVID-ILD patients. This is associated with an expansion of TFH- and TPH-like cells and an increase in APRIL potentially supporting B-cell survival and differentiation and proinflammatory cytokines reflecting not only the previously described TH1 profile seen in CVID patients with secondary immune dysregulation. Thus, the analysis of BALF might be of diagnostic value not only in the diagnosis of CVID-ILD, but also in the evaluation of the activity of the disease and in determining potential treatment targets confirming the prominent role of B-cell targeted strategies.

Histology of Interstitial Lung Disease in Common Variable Immune Deficiency

Interstitial lung disease (ILD) is an important non-infectious complication in several primary immune deficiencies. In common variable immune deficiency (CVID) it is associated with complex clinical phenotypes and adverse outcomes. The histology of ILD in CVID is heterogeneous and mixed patterns are frequently observed within a single biopsy, including non-necrotising granulomatous inflammation, lymphoid interstitial pneumonitis, lymphoid hyperplasia, follicular bronchiolitis, organizing pneumonia, and interstitial fibrosis; ILD has to be differentiated from lymphoma. The term granulomatous-lymphocytic interstitial lung disease (GLILD), coined to describe the histopathological findings within the lungs of patients with CVID with or without multisystem granulomata, is somewhat controversial as pulmonary granulomata are not always present on histology and the nature of infiltrating lymphocytes is variable. In this mini review we summarize the literature on the histology of CVID-related ILD and discuss some of the factors that may contribute to the inter- and intra- patient variability in the histological patterns reported. Finally, we highlight areas for future development. In particular, there is a need for standardization of histological assessments and reporting, together with a better understanding of the immunopathogenesis of CVID-related ILD to resolve the apparent heterogeneity of ILD in this setting and guide the selection of rational targeted therapies in different patients.

Analysis of Granulomatous Lymphocytic Interstitial Lung Disease Using Two Scoring Systems for Computed Tomography Scans-A Retrospective Cohort Study

Background

Granulomatous lymphocytic interstitial lung disease (GLILD) is present in about 20% of patients with common variable immunodeficiency disorders (CVID). GLILD is characterized by nodules, reticulation, and ground-glass opacities on CT scans. To date, large cohort studies that include sensitive CT outcome measures are lacking, and severity of structural lung disease remains unknown. The aim of this study was to introduce and compare two scoring methods to phenotype CT scans of GLILD patients.

Methods

Patients were enrolled in the “Study of Interstitial Lung Disease in Primary Antibody Deficiency” (STILPAD) international cohort. Inclusion criteria were diagnosis of both CVID and GLILD, as defined by the treating immunologist and radiologist. Retrospectively collected CT scans were scored systematically with the Baumann and Hartmann methods.

Results

In total, 356 CT scans from 138 patients were included. Cross-sectionally, 95% of patients met a radiological definition of GLILD using both methods. Bronchiectasis was present in 82% of patients. Inter-observer reproducibility (intraclass correlation coefficients) of GLILD and airway disease were 0.84 and 0.69 for the Hartmann method and 0.74 and 0.42 for the Baumann method.

Conclusions

In both the Hartmann and Baumann scoring method, the composite score GLILD was reproducible and therefore might be a valuable outcome measure in future studies. Overall, the reproducibility of the Hartmann method appears to be slightly better than that of the Baumann method. With a systematic analysis, we showed that GLILD patients suffer from extensive lung disease, including airway disease. Further validation of these scoring methods should be performed in a prospective cohort study involving routine collection of standardized CT scans.

Clinical Trial Registration

https://www.drks.de, identifier DRKS00000799.

Serum Free Immunoglobulins Light Chains: A Common Feature of Common Variable Immunodeficiency?

Serum free light chain (sFLC) is a recently proposed biomarker for CVID diagnosis. Most CVID patients present low or undetectable sFLC up to 10-fold lower compared to other primary antibody deficiencies. Given that κ and λ light chains are normally secreted in excess with respect to immunoglobulins, this finding points to an intrinsic defect of B cell differentiation in CVID. sFLC levels were prospectively evaluated in a cohort of 100 primary immunodeficiency (PID) patients and in 49 patients with secondary immunodeficiency to haematological malignancy (SID). CVID patients had significantly lower κ and/or λ values (mean: κ: 1.39 ± 1.7 mg/L and λ: 1.97 ± 2.24 mg/L) compared to "other PIDs" (κ: 13.97 ± 5.88 mg/L and λ: 12.92 ± 7.4 mg/L, respectively, p < 0.001 both), and SID (κ 20.9 ± 22.8 mg/L and λ 12.8 ± 8.7 mg/L, respectively, p < 0.001 both). The sum of kappa and lambda (sum κ + λ) in CVID patients (7.25 ± 7.90 mg/L) was significantly lower respect to other PIDs (26.44 ± 13.25 mg/L, p < 0.0001), and to SID patients (28.25 ± 26.24 mg/L, p = 0.0002). ROC analysis of the sum κ + λ disclosed an area under the curve (AUC) of 0.894 for CVID diagnosis (SD 0.031; 95% CI: 0.83-0.95, p < 0.0001), with optimal cut-off of 16.7 mg/L, giving the highest combination of sensitivity (92%), specificity (75%) and NPV (98%). The Relative Risk (RR) for patients presenting a sum κ + λ below 16.7 mg/L was 20.35-fold higher (95%, CI: 5.630-75.93) for CVID than below this threshold. A similar behavior of the sFLC in our CVID cohort with respect to previously published studies was observed. We propose a cut-off of sum κ + λ 16.7 with diagnostic application in CVID patients, and discuss potential specific defects converging in low or undetectable sFLC.

Rheumatologic and autoimmune manifestations in primary immune deficiency

PURPOSE OF REVIEW

Here we review the rheumatologic and autoimmune features of primary immune deficiencies with a focus on recently recognized genetic diseases, the spectrum of autoimmunity in PID, and targeted therapies.

RECENT FINDINGS

Primary immune deficiencies (PIDs) were initially described as genetic diseases of the immune system leading to susceptibility to infection. It is now well recognized that immune dysfunction and dysregulation also cause noninfectious complications including autoimmunity. The increased application of molecular testing for PID has revealed the diversity of clinical disease. Recent discoveries of diseases with prominent autoimmunity include activated phosphoinositide 3-kinase δ syndrome and PIDs caused by gain-of-function in STAT1 and STAT3. Similarly, identification of larger cohorts of patients with molecular diagnoses in more common PIDs, such as common variable immune deficiency (CVID), has led to increased understanding of the range of autoimmunity in PIDs. Understanding the molecular basis of these PIDs has the potential to lead to targeted therapy to treat associated autoimmunity.

SUMMARY

Autoimmunity and rheumatologic disease can be presenting symptoms and/or complicating features of primary immunodeficiencies. Evaluation for PIDs in patients who have early-onset, multiple, and/or atypical autoimmunity can enhance diagnosis and therapeutic options.

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.

Incidence of malignancy in patients with common variable immunodeficiency according to therapeutic delay: an Italian retrospective, monocentric cohort study

Background

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency and has a broad spectrum of clinical manifestations. Among non-infectious complications, an increased incidence of malignancies may have a special relevance for survival, but little is known about treatment efficacy on malignant complications.

Methods

This was a monocenter retrospective study on CVID patients, designed to provide preliminary data for the investigation of the possible link between therapeutic delay and tumor incidence.

Results

A total of 67 CVID subjects were included. The median diagnostic delay was 7.5 years (range: 0–63 years), and the median therapeutic delay was 8.5 years (range: 0–67 years). Malignancies were diagnosed in 18 (27%) patients. Eight out of 18 (44%) patients with a malignancy had lymphoma. Patients who developed a malignancy showed a longer therapeutic delay in comparison to patients with no malignancy, although no statistical significance was achieved (11 years vs 8 years, respectively, p = 0.424). We observed a lower frequency of malignancy in CVID patients with reduced therapeutic delay compared with patients with therapeutic delay ≥ 10 years. With a therapeutic delay of > 1 year, 74% had no tumor, and 25% had a tumor; with a therapeutic delay of > 10 years, 65% had no tumor and 35% had a malignancy. Among patients who had no malignancy, 64% had a therapeutic delay of < 10 years, and 36% had a therapeutic delay of ≥ 10 years. Among patients with malignancy, 47% of subjects had a therapeutic delay < 10 years, and 53% a therapeutic delay ≥ 10 years.

Conclusions

The observation of clinical characteristics of our patients with CVID may suggest that an early institution of IgG replacement therapy could be of benefit for the prevention of malignant complications.

Name of the registry: Comitato Etico Regionale delle Marche. Trial registration number: 1505. Date of registration: 27/10/2016, Retrospectively registered URL of trial registry record: http://www.ospedaliriuniti.marche.it/portale/archivio13_cerm-ancona_0_446_1.html. The trial was not registered before the first participant was enrolled

Serum Free Light Chains in Common Variable Immunodeficiency Disorders: Role in Differential Diagnosis and Association With Clinical Phenotype

We report on an observational, multicenter study of 345 adult CVID patients, designed to assess the diagnostic value and the clinical association of serum free light chain (sFLC) pattern in Common Variable Immunodeficiency disorders (CVID). Sixty CVID patients were tested twice in order to assess intraindividual variability of sFLC. As control groups we included 138 patients affected by undefined primary antibody defects (UAD), lymphoproliferative diseases (LPDs), and secondary antibody deficiencies not related to hematological malignancies (SID). CVID patients presented lower κ and λ chain concentration compared to controls, showing low intraindividual sFLC variability. On the basis of the sFLC pattern, patients were classified into four groups: κ-λ+, κ+λ-, κ-λ-, κ+λ+. The most common pattern in CVID patients was κ-λ- (51%), followed by κ-λ+, (25%), κ+λ+ (22%), and κ+λ- (3%). In UAD, LPD, and SID groups κ+λ+ was the most common pattern observed. By analyzing the possible association between sFLC patterns and disease-related complications of CVID, we observed that patients belonging to the κ-λ- group presented more commonly unexplained enteropathy compared to the κ+λ+ group and showed higher frequency of bronchiectasis and splenomegaly compared to both the κ-λ+ and κ+λ+ patients. When compared to the other groups, κ-λ- had also lower serum IgG, IgA, and IgM concentrations at diagnosis, lower frequency of CD27+IgD-IgM- switched memory B cells, and higher frequency of CD21^low B cells, receiving earlier CVID diagnosis. Thus, lower levels of sFLC might be an epiphenomenon of impairment in B cell differentiation, possibly leading κ-λ- patients to a higher risk for bacterial infections and chronic lung damage. Based on these results, we suggest adding sFLC assay to the diagnostic work-up of hypogammaglobulinemia and during follow-up. The assay may be useful to differentiate CVID from other causes of hypogammaglobulinemia and to early detect monoclonal lymphoproliferation occurring over years. Moreover, since the sFLC pattern seems to be related to disease phenotypes and clinical manifestations of CVID and after confirmation by further studies, sFLC assay might be considered a promising prognostic tool for identifying patients at higher risk of developing enteropathy and chronic lung damage or splenomegaly. This will allow designing a tailored follow-up for CVID patients.

Serum Free Light Chains in Common Variable Immunodeficiency Disorders: Role in Differential Diagnosis and Association With Clinical Phenotype

We report on an observational, multicenter study of 345 adult CVID patients, designed to assess the diagnostic value and the clinical association of serum free light chain (sFLC) pattern in Common Variable Immunodeficiency disorders (CVID). Sixty CVID patients were tested twice in order to assess intraindividual variability of sFLC. As control groups we included 138 patients affected by undefined primary antibody defects (UAD), lymphoproliferative diseases (LPDs), and secondary antibody deficiencies not related to hematological malignancies (SID). CVID patients presented lower κ and λ chain concentration compared to controls, showing low intraindividual sFLC variability. On the basis of the sFLC pattern, patients were classified into four groups: κ−λ+, κ+λ−, κ−λ−, κ+λ+. The most common pattern in CVID patients was κ−λ− (51%), followed by κ−λ+, (25%), κ+λ+ (22%), and κ+λ− (3%). In UAD, LPD, and SID groups κ+λ+ was the most common pattern observed. By analyzing the possible association between sFLC patterns and disease-related complications of CVID, we observed that patients belonging to the κ−λ− group presented more commonly unexplained enteropathy compared to the κ+λ+ group and showed higher frequency of bronchiectasis and splenomegaly compared to both the κ−λ+ and κ+λ+ patients. When compared to the other groups, κ−λ− had also lower serum IgG, IgA, and IgM concentrations at diagnosis, lower frequency of CD27+IgD–IgM– switched memory B cells, and higher frequency of CD21^low B cells, receiving earlier CVID diagnosis. Thus, lower levels of sFLC might be an epiphenomenon of impairment in B cell differentiation, possibly leading κ−λ− patients to a higher risk for bacterial infections and chronic lung damage. Based on these results, we suggest adding sFLC assay to the diagnostic work-up of hypogammaglobulinemia and during follow-up. The assay may be useful to differentiate CVID from other causes of hypogammaglobulinemia and to early detect monoclonal lymphoproliferation occurring over years. Moreover, since the sFLC pattern seems to be related to disease phenotypes and clinical manifestations of CVID and after confirmation by further studies, sFLC assay might be considered a promising prognostic tool for identifying patients at higher risk of developing enteropathy and chronic lung damage or splenomegaly. This will allow designing a tailored follow-up for CVID patients.

The Usefulness of Scintigraphic Studies in the Assessment of Asymptomatic Bowel Disease in Patients with Primary Antibody Diseases

Enteropathy may be the first presentation of immunodeficiency or it may occur during the course of the disease and in association with malabsorption in patients affected by primary antibody diseases. For these patients, immunoglobulin G (IgG) replacement therapy prevents infectious and non-infectious complications. Nonetheless some patients cannot achieve optimal IgG trough levels, even when treated with high Ig doses in absence of protein-losing syndromes. We investigated seven patients affected by common variable immunodeficiencies (CVIDs) and treated with high Ig doses (600–800 mg/kg/month) showing low IgG trough level. Patients underwent abdominal scintigraphy with human polyclonal immunoglobulin G labeled with 99mTc and with white blood cells labeled by 111 Indium-oxinate to investigate asymptomatic bowel inflammation. A concentration of labeled leukocytes in abdominal segments greater than that observed with human polyclonal immunoglobulin G was evident only in one patient. In five patients a slight concentration of both radiopharmaceuticals was reported, due to mild intestinal inflammatory response. These data might be related to mild increase of capillary permeability in the absence of inflammation leukocyte mediated. This study discloses a new cause of IgG-accelerated catabolism due to inflammatory bowel conditions without diarrhea in CVID patients.

Functions of Tfh Cells in Common Variable Immunodeficiency

Common variable immunodeficiency is the most common clinical primary immunodeficiency in adults. Its hallmarks are hypogammaglobulinemia and compromised B-cell differentiation into memory or antibody-secreting cells leading to recurrent infections. This disease is heterogeneous, with some patients harboring multiple complications such as lymphoproliferative disorders, autoimmune manifestations, or granulomatous inflammation. The mechanisms leading to these complications remain elusive despite numerous associations found in the literature. For instance, although described as a B cell intrinsic disease, numerous abnormalities have been reported in other immune cell compartments. Here, we tuned our attention to follicular helper T cells, a CD4⁺ T cell population specialized in B cell help, considering the recent publications showing an involvement of these cells in CVID pathogenesis.

Current Understanding and Recent Developments in Common Variable Immunodeficiency Associated Autoimmunity

Common variable immunodeficiency (CVID) is the most prevalent symptomatic primary immunodeficiency and comprises a group of disorders with similar antibody deficiency but a myriad of different etiologies, most of which remain undefined. The variable aspect of CVID refers to the approximately half of patients who develop non-infectious complications in addition to heightened susceptibility to infection. The pathogenesis of these complications is poorly understood and somewhat counterintuitive because these patients that are defined by their immune futility simultaneously have elevated propensity for autoimmune disease. There are numerous aspects of immune dysregulation associated with autoimmunity in CVID that have only begun to be studied. These findings include elevations of T helper type 1 and follicular helper T cells and B cells expressing low levels of CD21 as well as reciprocal decreases in regulatory T cells and isotype-switched memory B cells. Recently, advances in genomics have furthered our understanding of the fundamental biology underlying autoimmunity in CVID and led to precision therapeutic approaches. However, these genetic etiologies are also associated with clinical heterogeneity and incomplete penetrance, highlighting the fact that continued research efforts remain necessary to optimize treatment. Additional factors, such as commensal microbial dysbiosis, remain to be better elucidated. Thus, while recent advances in our understanding of CVID-associated autoimmunity have been exciting and substantial, these current scientific advances must now serve as building blocks for the next stages of discovery.

Predominantly Antibody-Deficient Patients With Non-infectious Complications Have Reduced Naive B, Treg, Th17, and Tfh17 Cells

Background: Patients with predominantly antibody deficiency (PAD) suffer from severe and recurrent infections that require lifelong immunoglobulin replacement and prophylactic antibiotic treatment. Disease incidence is estimated to be 1:25,000 worldwide, and up to 68% of patients develop non-infectious complications (NIC) including autoimmunity, which are difficult to treat, causing high morbidity, and early mortality. Currently, the etiology of NIC is unknown, and there are no diagnostic and prognostic markers to identify patients at risk.

Objectives: To identify immune cell markers that associate with NIC in PAD patients.

Methods: We developed a standardized 11-color flow cytometry panel that was utilized for in-depth analysis of B and T cells in 62 adult PAD patients and 59 age-matched controls.

Results: Nine males had mutations in Bruton's tyrosine kinase (BTK) and were defined as having X-linked agammaglobulinemia. The remaining 53 patients were not genetically defined and were clinically diagnosed with agammaglobulinemia (n = 1), common variable immunodeficiency (CVID) (n = 32), hypogammaglobulinemia (n = 13), IgG subclass deficiency (n = 1), and specific polysaccharide antibody deficiency (n = 6). Of the 53, 30 (57%) had one or more NICs, 24 patients had reduced B-cell numbers, and 17 had reduced T-cell numbers. Both PAD–NIC and PAD+NIC groups had significantly reduced Ig class-switched memory B cells and naive CD4 and CD8 T-cell numbers. Naive and IgM memory B cells, Treg, Th17, and Tfh17 cells were specifically reduced in the PAD+NIC group. CD21^lo B cells and Tfh cells were increased in frequencies, but not in absolute numbers in PAD+NIC.

Conclusion: The previously reported increased frequencies of CD21^lo B cells and Tfh cells are the indirect result of reduced naive B-cell and T-cell numbers. Hence, correct interpretation of immunophenotyping of immunodeficiencies is critically dependent on absolute cell counts. Finally, the defects in naive B- and T-cell numbers suggest a mild combined immunodeficiency in PAD patients with NIC. Together with the reductions in Th17, Treg, and Tfh17 numbers, these key differences could be utilized as biomarkers to support definitive diagnosis and to predict for disease progression.

Liver stiffness assessment by transient elastography suggests high prevalence of liver involvement in common variable immunodeficiency

BACKGROUND

Up to 50% of patients with common variable immunodeficiency (CVID) present persistently increased serum levels of liver enzymes and/or mild hepatomegaly. Ultrasound-based transient elastography (TE) is largely used for early detection of the progression of chronic liver diseases, but has never been employed in CVID. We performed a cross-sectional study to evaluate TE values in a cohort of adult CVID-patients.

METHODS

Full blood count, liver function test, liver and spleen sonogram and ultrasound-based TE were performed in 77 adult CVID patients. Demographic and clinical data were retrospectively collected from medical files.

RESULTS

33.8% (26/77) patients presented increased TE values ranging from moderate fibrosis to cirrhosis. TE values were positively correlated with ALP, γGT, spleen longitudinal diameter and peripheral blood counts (no significant correlation with BMI, AST, ALT, total proteins, albumin, bilirubin and hemoglobin). Moreover, liver stiffness was higher in patients with the clinical phenotypes polyclonal lymphoproliferation and enteropathy, and patients with both these complications had an increased risk (OR: 7.14) of presenting pathologic TE values compared with those without anyone of these.

CONCLUSIONS

Transient elastography is a useful tool to be used alongside clinical and laboratory data to assess liver involvement in CVID.

Focus on Chronic Variable Immunodeficiency for Primary Care Practitioners, the Gatekeepers to Optimal Health Outcomes for Primary Immunodeficiency Syndromes

Purpose of Review

This review sought to assess the extent and causes of suboptimal healthcare outcomes for chronic variable immunodeficiency (CVID).

Recent Findings

Significant improvements in diagnostic technology and treatment protocols over time were found, leading to reduced morbidity and mortality for those accessing therapies. Treatments continue to be largely non-curative with financing (mainly insurance coverage) an obstacle. Symptom recognition by primary care practitioners (PCP) remains a gating factor to treatment and a widespread and persistent barrier to optimal health outcomes.

Summary

CVID is a subtype of primary immunodeficiency (PIDD) associated with under-diagnosis. It has emerged as a health issue more prevalent than historically known. No symptom-recognition framework for early detection of CVID has been generally accepted; those proposed for primary immunodeficiencies have shown low sensitivity, low specificity or both. Positive trends in cases diagnosed have been aided by awareness campaigns and international collaborations. However, treatments for CVID will not realize full potential without effective, accepted frameworks for timely identification in the clinic.

Congenital sideroblastic anemia associated with B cell immunodeficiency, periodic fevers, and developmental delay: A case report and review of mucocutaneous features

This is a 40-year-old woman with sideroblastic anemia with B cell immunodeficiency, periodic fevers, and developmental delay syndrome, who has genital and extragenital lichen sclerosus on the abdomen and the upper back that have become erythematous and painful during febrile episodes. This report summarizes the published cases of sideroblastic anemia with B cell immunodeficiency, periodic fevers, and developmental delay and highlights associated mucocutaneous features.

Appropriate lung management in patients with primary antibody deficiencies

Introduction: Human primary immunodeficiency diseases (PIDs) include a broad spectrum of more than 350 disorders, involving different branches of the immune system and classified as 'rare diseases.' Predominantly antibody deficiencies (PADs) represent more than half of the PIDs diagnosed in Europe and are often diagnosed in the adulthood. Areas covered: Although PAD could first present with autoimmune or neoplastic features, respiratory infections are frequent and respiratory disease represents a relevant cause of morbidity and mortality. Pulmonary complications may be classified as infection-related (acute and chronic), immune-mediated, and neoplastic. Expert opinion: At present, no consensus guidelines are available on how to monitor and manage lung complications in PAD patients. In this review, we will discuss the available diagnostic, prognostic and therapeutic instruments and we will suggest an appropriate and evidence-based approach to lung diseases in primary antibody deficiencies. We will also highlight the possible role of promising new tools and strategies in the management of pulmonary complications. However, future studies are needed to reduce of diagnostic delay of PAD and to better understand lung diseases mechanisms, with the final aim to ameliorate therapeutic options that will have a strong impact on Quality of Life and long-term prognosis of PAD patients.

Interstitial lung disease in patients with common variable immunodeficiency disorders: several different pathologies?

Various reports of disease-related lung pathologies in common variable immunodeficiency disorder (CVID) patients have been published, with differing histological and high-resolution computed tomography (HRCT) findings. Data were extracted from the validated Oxford Primary Immune Deficiencies  Database (PID) database (1986-2016) on adult, sporadic CVID patients with suspected interstitial lung disease (ILD). Histology of lung biopsies was studied in relation to length of follow-up, clinical outcomes, HRCT findings and chest symptoms, to look for evidence for different pathological processes. Twenty-nine CVID patients with lung histology and/or radiological evidence of ILD were followed. After exclusions, lung biopsies from 16 patients were reanalysed for ILD. There were no well-formed granulomata, even though 10 patients had systemic, biopsy-proven granulomata in other organs. Lymphocytic infiltration without recognizable histological pattern was the most common finding, usually with another feature. On immunochemistry (n = 5), lymphocytic infiltration was due to T cells (CD4 or CD8). Only one patient showed B cell follicles with germinal centres. Interstitial inflammation was common; only four of 11 such biopsies also showed interstitial fibrosis. Outcomes were variable and not related to histology, suggesting possible different pathologies. The frequent nodules on HRCT were not correlated with histology, as there were no well-formed granulomata. Five patients were asymptomatic, so it is essential for all patients to undergo HRCT, and to biopsy if abnormal HRCT findings are seen. Internationally standardized pathology and immunochemical data are needed for longitudinal studies to determine the precise pathologies and prognoses in this severe complication of CVIDs, so that appropriate therapies may be found.

Immunosuppressive therapy with rituximab in common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary antibody deficiency in adulthood and is characterized by the marked reduction of IgG and IgA serum levels. Thanks to the successful use of polyvalent immunoglobulin replacement therapy to treat and prevent recurrent infections, non-infectious complications, including autoimmunity, polyclonal lymphoproliferation and malignancies, have progressively become the major cause of morbidity and mortality in CVID patients. The management of these complications is particularly challenging, often requiring multiple lines of immunosuppressive treatments. Over the last 5–10 years, the anti-CD20 monoclonal antibody (i.e., rituximab) has been increasingly used for the treatment of both autoimmune and non-malignant lymphoproliferative manifestations associated with CVID. This review illustrates the evidence on the use of rituximab in CVID. For this purpose, first we discuss the mechanisms proposed for the rituximab mediated B-cell depletion; then, we analyze the literature data regarding the CVID-related complications for which rituximab has been used, focusing on autoimmune cytopenias, granulomatous lymphocytic interstitial lung disease (GLILD) and non-malignant lymphoproliferative syndromes. The cumulative data suggest that in the vast majority of the studies, rituximab has proven to be an effective and relatively safe therapeutic option. However, there are currently no data on the long-term efficacy and side effects of rituximab and other second-line therapeutic options. Further randomized controlled trials are needed to optimize the management strategies of non-infectious complications of CVID.

A High Prevalence of Gastrointestinal Manifestations in Common Variable Immunodeficiency

OBJECTIVES

Common variable immunodeficiency (CVID) is associated with a spectrum of autoimmune complications. We studied the prevalence of gastrointestinal (GI) manifestations and infections in patients with CVID.

METHODS

Complete clinical data of 132 Finnish patients with CVID (106 probable and 26 possible CVID) followed up between 2007 and 2016 were collected to a structured database. Data on endoscopies, histology, and laboratory studies were retrieved from patient files.

RESULTS

Most common referral indications were diarrhea and/or weight loss (47%-67%). Patients with probable CVID had higher fecal calprotectin and α1-antitrypsin and lower blood vitamin B12 than patients with possible CVID. Gastroscopy and colonoscopy were done to 71 (67%) and 63 (59%) patients with probable CVID, respectively. Endoscopies showed that 15% of them had chronic active gastritis and 17% atrophic gastritis and 3% had gastric adenocarcinoma. A celiac sprue-like condition was found in 7 patients (10%), of whom 3 responded to a gluten-free diet. Colonoscopies demonstrated unspecific colitis (14%), ulcerative colitis (8%), microscopic colitis (10%), and Crohn's disease (2%). Colonic polyps were noted in 30% of patients, and 3% had lower GI malignancies. Thirty-five patients with CVID had bacterial or parasitic gastroenteritis; chronic norovirus was detected in 4 patients with probable CVID. Patients with GI inflammation had higher levels of fecal calprotectin and blood CD8 T lymphocytes but lower counts of CD19CD27 memory B cells and/or CD19 B cells. Immunophenotype with low B-cell counts was associated with higher fecal calprotectin levels.

DISCUSSION

Patients with CVID had a high prevalence of GI manifestations and infections of the GI tract. GI inflammation was associated with a distinct immunophenotype and elevated fecal calprotectin.

Defects in memory B-cell and plasma cell subsets expressing different immunoglobulin-subclasses in patients with CVID and immunoglobulin subclass deficiencies

BACKGROUND

Predominantly antibody deficiencies (PADs) are the most prevalent primary immunodeficiencies, but their B-cell defects and underlying genetic alterations remain largely unknown.

OBJECTIVE

We investigated patients with PADs for the distribution of 41 blood B-cell and plasma cell (PC) subsets, including subsets defined by expression of distinct immunoglobulin heavy chain subclasses.

METHODS

Blood samples from 139 patients with PADs, 61 patients with common variable immunodeficiency (CVID), 68 patients with selective IgA deficiency (IgAdef), 10 patients with IgG subclass deficiency with IgA deficiency, and 223 age-matched control subjects were studied by using flow cytometry with EuroFlow immunoglobulin isotype staining. Patients were classified according to their B-cell and PC immune profile, and the obtained patient clusters were correlated with clinical manifestations of PADs.

RESULTS

Decreased counts of blood PCs, memory B cells (MBCs), or both expressing distinct IgA and IgG subclasses were identified in all patients with PADs. In patients with IgAdef, B-cell defects were mainly restricted to surface membrane (sm)IgA⁺ PCs and MBCs, with 2 clear subgroups showing strongly decreased numbers of smIgA⁺ PCs with mild versus severe smIgA⁺ MBC defects and higher frequencies of nonrespiratory tract infections, autoimmunity, and affected family members. Patients with IgG subclass deficiency with IgA deficiency and those with CVID showed defects in both smIgA⁺ and smIgG⁺ MBCs and PCs. Reduced numbers of switched PCs were systematically found in patients with CVID (absent in 98%), with 6 different defective MBC (and clinical) profiles: (1) profound decrease in MBC numbers; (2) defective CD27⁺ MBCs with almost normal IgG₃⁺ MBCs; (3) absence of switched MBCs; and (4) presence of both unswitched and switched MBCs without and; (5) with IgG₂⁺ MBCs; and (6) with IgA₁⁺ MBCs.

CONCLUSION

Distinct PAD defective B-cell patterns were identified that are associated with unique clinical profiles.