Common variable immune deficiency: Dissection of the variable

Immunological biomarkers associated with survival in a cohort of Argentinian patients with common variable immunodeficiency

Background

Common variable immunodeficiency (CVID) is the most common symptomatic syndrome among inborn errors of immunity. Although several aspects of CVID immunopathology have been elucidated, predictive factors for mortality are incompletely defined. A genetic cause can be identified only in approximately 30% of patients.

Objective

We sought to develop a mortality predictive score on the basis of the immunophenotypes and genotypes of patients with CVID.

Methods

Twenty-one patients diagnosed with CVID in Córdoba, Argentina, were analyzed for clinical and laboratory data. Immunophenotyping was done by flow cytometry. CVID-associated mutations were identified by whole-exome sequencing.

Results

Alive (15) and deceased (6) patients were compared. Univariate analysis showed significant differences in CD4+ T cells (P = .002), natural killer (NK) cells (P = .001), and memory switched B cells (P = .001) between groups. Logistic regression analysis showed a negative correlation between CD4+, NK, and memory switched B-cell counts and probability of survival over a 10-year period (CD4+ T cells: odds ratio [OR], 1.01; 95% CI, 1.001-1.020; NK cells: OR, 1.07; 95% CI, 1.02-1.17; and memory switched B cells: OR, 26.23; 95% CI, 2.06-2651.96). Receiver-operating characteristic curve analysis identified a survival cutoff point for each parameter (CD4+ T cells: 546 cells/mL; AUC, 0.87; sensitivity, 60%; specificity, 100%; memory switched B cells: 0.84 cells/mL; AUC, 0.92; sensitivity, 100%; specificity, 85%; and NK cells: 45 cells/mL; AUC, 0.92; sensitivity, 83%; specificity, 100%). Genetic analysis on 14 (9 female and 5 male) patients from the cohort revealed mutations associated with inborn errors of immunity in 6 patients.

Conclusions

A score to predict mortality is proposed on the basis of CD4+ T, NK, and memory switched B-cell counts in patients with CVID.

Cellular and molecular basis of proximal small intestine disorders

The proximal part of the small intestine, including duodenum and jejunum, is not only dedicated to nutrient digestion and absorption but is also a highly regulated immune site exposed to environmental factors. Host-protective responses against pathogens and tolerance to food antigens are essential functions in the small intestine. The cellular ecology and molecular pathways to maintain those functions are complex. Maladaptation is highlighted by common immune-mediated diseases such as coeliac disease, environmental enteric dysfunction or duodenal Crohn's disease. An expanding spectrum of more than 100 rare monogenic disorders inform on causative molecular mechanisms of nutrient absorption, epithelial homeostasis and barrier function, as well as inflammatory immune responses and immune regulation. Here, after summarizing the architectural and cellular traits that underlie the functions of the proximal intestine, we discuss how the integration of tissue immunopathology and molecular mechanisms can contribute towards our understanding of disease and guide diagnosis. We propose an integrated mechanism-based taxonomy and discuss the latest experimental approaches to gain new mechanistic insight into these disorders with large disease burden worldwide as well as implications for therapeutic interventions.

Increased risk of gastric cancer in relation with pernicious anaemia in patients with primary antibody deficiency: A nationwide case control study

BACKGROUND/AIM

We aimed to assess gastrointestinal cancers risks in a large cohort of individuals with primary antibody deficiency (PAD) and their association with risk of autoimmune and inflammatory gastrointestinal diseases.

METHODS

Investigating a French national database of inpatient admissions between 2010 and 2018, we identified 12,748 patients with PAD and 38,244 control non-exposed individuals. We performed multiple exposed-non-exposed studies using conditional logistic regression.

RESULTS

In comparison with non-exposed patients, PAD patients had increased risk of in situ gastric carcinoma (Odds Ratio (OR) =10.5 [95 % CI 2.2; 50.5]), malignant gastric tumor (OR=3.2 [95 % CI 2.2; 4.4]) and colorectal cancer (OR=1.2 [95 % CI 1; 1.5]). PAD patients had also increased risk of pernicious anaemia (OR=8 |95 % CI 5.6; 11.5]), Crohn's disease (OR= 4.4 [95 % CI 3.5; 5.6]), ulcerative colitis (OR=2.9 [95 % CI 2.4; 3.6]) and coeliac disease (OR=13.3 [95 % CI 9.1; 19.5]). Within patients with gastric cancer, those with PAD had increased risk of pernicious anaemia (OR=8.4 [95 % CI 1.5; 215]; p = 0.01) but not of H. pylori infection.

CONCLUSIONS

Risk of gastric cancer is particularly high in PAD patients and notably risk of in situ gastric carcinoma in association with pernicious anaemia. It supports indication of early endoscopic screening in these patients.

A case report navigating CVID and sarcoidosis overlaps in pediatric nephritis

Common variable immunodeficiency (CVID) can be complicated by granulomatous disease, often granulomatous lymphocytic interstitial lung disease (GLILD). Granulomatous interstitial nephritis represents an atypical presentation in pediatrics. Our patient is a previously healthy 13-year-old white male with a recent diagnosis of CVID. He presented with a rash and laboratory findings included pancytopenia (white blood cells 2.6 cells × 103/μl, hemoglobin 11.8 g/dl, platelets 60 × 103/μl), hypercalcemia (14.9 mg/dl), elevated Vit D 1,25 OH level (>200 pg/ml), hyperuricemia (8.8 mg/dl), and acute kidney injury (AKI) (serum creatinine 1.1 mg/dl; baseline 0.64 mg/dl). A broad infectious workup was unremarkable. The rash improved with empiric doxycycline. Hypercalcemia and hyperuricemia were managed with fluid resuscitation, calcitonin, and zoledronic acid. Evaluation for malignancy including a positron emission tomography scan, revealed multiple mediastinal hypermetabolic lymph nodes and pulmonary ground glass opacities, later reported as small pulmonary nodules by computed tomography (CT). Splenomegaly was confirmed by ultrasound and CT. Peripheral smear, bone marrow biopsy, and genetic testing were non-revealing. His angiotensin-converting enzyme level was elevated (359 U/L), raising concerns for sarcoidosis. Given Stage 1 AKI, a renal biopsy was pursued and identified non-caseating granulomatous interstitial nephritis. Treatment with 60 mg of prednisone began for presumed sarcoidosis for 4 months, causing steroid-induced hypertension and mood changes. Zoledronic acid minimally reduced serum creatinine. Pneumocystis jirovecii pneumonia prophylaxis was initiated due to T-cell cytopenia. Chest CT findings showed a suboptimal response to steroids. A bronchoalveolar lavage demonstrated >50% lymphocytes (normal <10%) and the lung biopsy exhibited non-caseating granulomas, indicating GLILD. Rubella was identified by staining. Following a fever, he was found to have elevated liver enzymes and confirmed hepatitis with portal hypertension on CT. A liver biopsy revealed epithelioid non-caseating granuloma and HHV6 was detected by PCR. He was treated with four cycles of rituximab and granulocyte-colony stimulating factor for persistent neutropenia. Subsequent treatment with mycophenolate led to the resolution of the granulomatous lesions and cytopenias. The rare complication of granulomatous interstitial nephritis in CVID illustrates the intricate nature of diagnosis. This case underscores the necessity for a holistic view of the patient's clinical and immune phenotype, including distinctive radiological presentations, for precise diagnoses and tailored management of CVID.

Limitations in the clinical utility of vaccine challenge responses in the evaluation of primary antibody deficiency including Common Variable Immunodeficiency Disorders

Vaccine challenge responses are an integral component in the diagnostic evaluation of patients with primary antibody deficiency, including Common Variable Immunodeficiency Disorders (CVID). There are no studies of vaccine challenge responses in primary hypogammaglobulinemia patients not accepted for subcutaneous/intravenous immunoglobulin (SCIG/IVIG) replacement compared to those accepted for such treatment. Vaccine challenge responses in patients enrolled in two long-term prospective cohorts, the New Zealand Hypogammaglobulinemia Study (NZHS) and the New Zealand CVID study (NZCS), were compared in this analysis. Almost all patients in the more severely affected SCIG/IVIG treatment group achieved protective antibody levels to tetanus toxoid and H. influenzae type B (HIB). Although there was a highly significant statistical difference in vaccine responses to HIB, tetanus and diphtheria toxoids, there was substantial overlap in both groups. In contrast, there was no significant difference in Pneumococcal Polysaccharide antibody responses to Pneumovax® (PPV23). This analysis illustrates the limitations of evaluating vaccine challenge responses in patients with primary hypogammaglobulinemia to establish the diagnosis of CVID and in making decisions to treat with SCIG/IVIG. The conclusion from this study is that patients with symptoms attributable to primary hypogammaglobulinemia with reduced IgG should not be denied SCIG/IVIG if they have normal vaccine responses.

Exploring gastric cancer genetics: A turning point in common variable immunodeficiency

Background

Gastric cancer (GC) stands as a prominent cause of cancer-related mortality and ranks second among the most frequently diagnosed malignancies in individuals with common variable immunodeficiency (CVID).

Objective

We sought to conduct a comprehensive, large-scale genetic analysis to explore the CVID-associated germline variant landscape within gastric adenocarcinoma samples and to seek to delineate the transcriptomic similarities between GC and CVID.

Methods

We investigated the presence of CVID-associated germline variants in 1591 GC samples and assessed their impact on tumor mutational load. The progression of GC was evaluated in patients with and without these variants. Transcriptomic similarities were explored by matching differentially expressed genes in GC to healthy gastric tissue with a CVID transcriptomic signature.

Results

CVID-associated germline variants were found in 60% of GC samples. Our analysis revealed a significant association between the presence of CVID-related genetic variants and higher tumor mutational load in GC (P < .0001); high GC mutational load seems to be linked to immunotherapy response and worse prognosis. Transcriptomic similarities unveiled key genes and pathways implicated in innate immune responses and tumorigenesis. We identified upregulated genes related to oncogene drivers, inflammation, tumor suppression, DNA repair, and downregulated immunomodulatory genes shared between GC and CVID.

Conclusions

Our findings contribute to a deeper understanding of potential molecular modulators of GC and shed light on the intricate interplay between immunodeficiency and cancer. This study underscores the clinical relevance of CVID-related variants in influencing GC progression and opens avenues for further exploration into novel therapeutic approaches.

Is there a role for microbiome-based approach in common variable immunodeficiency?

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by low levels of serum immunoglobulins and increased susceptibility to infections, autoimmune disorders and cancer. CVID embraces a plethora of heterogeneous manifestations linked to complex immune dysregulation. While CVID is thought to be due to genetic defects, the exact cause of this immune disorder is unknown in the large majority of cases. Compelling evidences support a linkage between the gut microbiome and the CVID pathogenesis, therefore a potential for microbiome-based treatments to be a therapeutic pathway for this disorder. Here we discuss the potential of treating CVID patients by developing a gut microbiome-based personalized approach, including diet, prebiotics, probiotics, postbiotics and fecal microbiota transplantation. We also highlight the need for a better understanding of microbiota-host interactions in CVID patients to prime the development of improved preventive strategies and specific therapeutic targets.

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.

Chronic Diarrhea with Villous Blunting of the Small Intestine Under Capsule Endoscopy in Common Variable Immunodeficiency and X-Linked Agammaglobulinemia: A Case Series

Introduction

Primary immunodeficiencies (PIDs) are a heterogeneous group of disorders, common variable immunodeficiency disorder (CVID) and X-linked agammaglobulinemia (XLA) are PIDs related to B-cell defect, characterized by reduced levels of immunoglobulins and immune dysregulation. Infections are the most common clinical manifestations, while underlying autoimmune and inflammatory conditions are present in some patients with CVID and XLA, leading to clinical misdiagnosis and diagnostic delay. Chronic diarrhea in patients with CVID and XLA, particularly complicated malabsorption and protein-energy malnutrition, is responsible for poor prognostic outcomes.

Methods

In this study, we described three PID adult patients (two with CVID and one with XLA) who presented with varying degrees of chronic diarrhea, weight loss, and protein-energy malnutrition. We suggest that villous blunting of the small intestine under capsule endoscopy may be an endoscopic feature of PID-related enteropathy, thus highlighting the application of capsule endoscopy in patients with CVID and XLA presenting with chronic diarrhea.

Conclusion

We also summarize regular Ig supplementation is the basic treatment for CVID and XLA patients, proper enteral nutrition and probiotic therapy can be explored to use to alter gut microbiota and modulate intestinal immune response. However, vedolizumab is not helpful to PID-related enteropathy therapy, as it exacerbates the inflammatory response in extra-intestinal organs and ultimately causes poor clinical outcomes.

Interleukin-9 rescues class switching of Memory B cells derived from Common variable immunodeficiency patients

Impaired class switch memory (CSM) B cell formation is the hallmark of common variable immunodeficiency (CVID). Various T cell abnormalities have been observed in CVID patients indicating inadequate T-cell help to B cells. A major setback in understanding its pathogenesis is due to diverse clinical presentation. Therefore, we performed extensive immunological investigation in a cohort of CVID patients with similar clinical findings in order to unravel the T cell dysfunction and its influence on the defective humoral immune response. All recruited CVID patients exhibited B cells in the normal range, but reduced CSM B cells. However, patients showed reduced T cell proliferation, reduced level of serum Interleukin-9 (IL-9) and frequency of IL-9 expressing CD4 (Th-9) cells. IL-9 supplementation along with CD40 engagement was effective in inducing in vitro CSM B cells formation in CVID patients. Thus, IL-9 supplementation has the potential to restore impaired CSM B cell formation in CVID.

Adipokines from adipose tissue and common variable immunodeficiency: Is there any association?

Adiponectin and leptin are adipokines, secreted by white adipose tissue (WAT), which play an important role in energy homeostasis. Some evidence has shown that adipokine-producing adipose cells present in the bone marrow (BM) appear to exert an influence on hematopoiesis and B cell development. Common variable immunodeficiency (CVID) is one of the most common inborn errors of immunity in humans. In CVID, numerical and/or functional defects of B cells and their precursors result in hypogammaglobulinemia, usually Immunoglobulin (Ig) A and IgG. Manifestations of CVID include immunodeficiency, autoimmunity, inflammation and lymphoproliferation, resulting in a wide range of phenotypes. How adipokines interact and influence the pathophysiology of CVID is still unclear. In this review, we seek to summarize the aspects known so far concerning the interface between adipokines, B cells and CVID. More research is needed to fully understand these interactions; this knowledge is a potential avenue for the discovery of useful biomarkers and may provide new therapeutic targets for the treatment of patients with CVID and related diseases.

Chronic Aichi Virus Infection As a Cause of Long-Lasting Multiorgan Involvement in Patients With Primary Immune Deficiencies

BACKGROUND

Metagenomic next-generation sequencing (mNGS) was used to assess patients with primary or secondary immune deficiencies (PIDs and SIDs) who presented with immunopathological conditions related to immunodysregulation.

METHODS

Thirty patients with PIDs or SIDs who presented with symptoms related to immunodysregulation and 59 asymptomatic patients with similar PIDs or SIDs were enrolled. mNGS was performed on organ biopsy. Specific Aichi virus (AiV) reverse-transcription polymerase chain reaction (RT-PCR) was used to confirm AiV infection and screen the other patients. In situ hybridization (ISH) assay was done on AiV-infected organs to identify infected cells. Virus genotype was determined by phylogenetic analysis.

RESULTS

AiV sequences were detected using mNGS in tissue samples of 5 patients and by RT-PCR in peripheral samples of another patient, all of whom presented with PID and long-lasting multiorgan involvement, including hepatitis, splenomegaly, and nephritis in 4 patients. CD8+ T-cell infiltration was a hallmark of the disease. RT-PCR detected intermittent low viral loads in urine and plasma from infected patients but not from uninfected patients. Viral detection stopped after immune reconstitution obtained by hematopoietic stem cell transplantation. ISH demonstrated the presence of AiV RNA in hepatocytes (n = 1) and spleen tissue (n = 2). AiV belonged to genotype A (n = 2) or B (n = 3).

CONCLUSIONS

The similarity of the clinical presentation, the detection of AiV in a subgroup of patients suffering from immunodysregulation, the absence of AiV in asymptomatic patients, the detection of viral genome in infected organs by ISH, and the reversibility of symptoms after treatment argue for AiV causality.

Clinical manifestations and approach to the management of patients with common variable immunodeficiency and liver disease

Purpose

The clinical spectrum of common variable immunodeficiency (CVID) includes predisposition to infections, autoimmune/inflammatory complications and malignancy. Liver disease is developed by a proportion of patients with CVID, but limited evidence is available about its prevalence, pathogenesis and prognostic outcome. This lack of evidence leads to the absence of guidelines in clinical practice. In this study, we aimed at defining the characteristics, course and management of this CVID complication in Spain.

Methods

Spanish reference centers were invited to complete a cross-sectional survey. Thirty-eight patients with CVID-related liver disease from different hospitals were evaluated by a retrospective clinical course review.

Results

In this cohort, abnormal liver function and thrombocytopenia were found in most of the patients (95% and 79% respectively), in keeping with the higher incidence of abnormal liver imaging and splenomegaly. The most common histological findings included nodular regenerative hyperplasia (NRH) and lymphocytic infiltration, which have been associated with portal hypertension (PHTN) leading to a poorer prognosis. Autoimmune/inflammatory complications occurred in 82% of the CVID patients that developed liver disease and 52% of the patients treated with immunomodulators showed a reduction in the liver function tests' abnormalities during treatment. Among the experts that conducted the survey, there was 80% or more consensus that the workup of CVID-related liver disease requires liver profile, abdominal ultrasound and transient elastography. The majority agreed that liver biopsy should be essential for diagnosis. There was 94% consensus that endoscopic studies should be performed in the presence of PHTN. However, there was 89% consensus that there is insufficient evidence on the management of these patients.

Conclusion

Liver disease varies in severity and may contribute substantially to morbidity and mortality in patients with CVID. Hence the importance of close follow-up and screening of this CVID complication to prompt early targeted intervention. Further research is needed to evaluate the pathophysiology of liver disease in patients with CVID to identify personalized treatment options. This study emphasizes the urgent need to develop international guidelines for the diagnosis and management of this CVID complication.

Long-term follow-up in common variable immunodeficiency: the pediatric-onset and adult-onset landscape

Introduction

The primary aim of this study is to investigate the evolution of the clinical and laboratory characteristics during the time in a longitudinal cohort of pediatric-onset and adult-onset Common Variable Immunodeficiency (CVID) patients in order to identify early predictive features of the disease and immune dysregulation complications.

Methods

This is a retrospective-prospective monocentric longitudinal study spanning from 1984 to the end of 2021. The data of pediatric-onset vs. adult-onset patients have been compared for immunological features and for infectious and non-infectious complications assessed at diagnosis and follow-up.

Results

Seventy-three CVID patients have been enrolled, with a mean of 10.0 years (SD ± 8.17) of prospective follow-up. At diagnosis, infections were observed in 89.0% of patients and immune dysregulation in 42.5% of patients. At diagnosis, 38.6% of pediatric-onset and 20.7% of adult-onset patients presented with only infections. Polyclonal lymphoid proliferation (62.1%) and autoimmunity (51.7%) were more prevalent in the adult-onset than in the pediatric-onset group (polyclonal lymphoid proliferation 52.3% and autoimmunity 31.8%, respectively). Enteropathy was present in 9.1% of pediatric-onset and 17.2% of adult-onset patients. The prevalence of polyclonal lymphoid proliferation increased during follow-up more in pediatric-onset patients (diagnosis 52.3%-follow-up 72.7%) than in adult-onset patients (diagnosis 62.1%-follow-up 72.7%). The cumulative risk to develop immune dysregulation increases according to the time of disease and the time of diagnostic delay. At the same age, pediatric-onset patients have roughly double the risk of having a complication due to immune dysregulation than adult-onset patients, and it increases with diagnostic delay. The analysis of lymphocyte subsets in the pediatric-onset group showed that CD21 low B cells at diagnosis may be a reliable prognostic marker for the development of immune dysregulation during follow-up, as the ROC curve analysis showed (AUC = 0.796). In the adult-onset group, the percentage of transitional B cells measured at diagnosis showed a significant accuracy (ROC AUC = 0.625) in identifying patients at risk of developing immune dysregulation.

Discussion

The longitudinal evaluation of lymphocyte subsets combined with clinical phenotype can improve the prediction of lymphoid proliferation and allow experts to achieve early detection and better management of such complex disorder.

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.

Microbiome and Its Dysbiosis in Inborn Errors of Immunity

Inborn errors of immunity (IEI) can present with infections, autoimmunity, lymphoproliferation, granulomas, and malignancy. IEIs are due to genetic abnormalities that disrupt normal host-immune response or immune regulation. The microbiome appears essential for maintaining host immunity, especially in patients with a defective immune system. Altered gut microbiota in patients with IEI can lead to clinical symptoms. Microbial dysbiosis is the consequence of an increase in pro-inflammatory bacteria or a reduction in anti-inflammatory bacteria. However, functional and compositional differences in microbiota are also involved. Dysbiosis and a reduced alpha-diversity are well documented, particularly in conditions like common variable immunodeficiency. Deranged microbiota is also seen in Wiskott–Aldrich syndrome, severe combined immunodeficiency, chronic granulomatous disease, selective immunoglobulin-A deficiency, Hyper IgE syndrome (HIGES), X-linked lymphoproliferative disease-2, immunodysregulation, polyendocrinopathy, enteropathy, x-linked syndrome, and defects of IL10 signalling. Distinct gastrointestinal, respiratory, and cutaneous symptoms linked to dysbiosis are seen in several IEIs, emphasizing the importance of microbiome identification. In this study, we discuss the processes that maintain immunological homeostasis between commensals and the host and the disruptions thereof in patients with IEIs. As the connection between microbiota, host immunity, and infectious illnesses is better understood, microbiota manipulation as a treatment strategy or infection prevention method would be more readily employed. Therefore, optimal prebiotics, probiotics, postbiotics, and fecal microbial transplantation can be promising strategies to restore the microbiota and decrease disease pathology in patients with IEIs.

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.

Severe Ascites in Common Variable Immunodeficiency

Liver disease is one of the possible clinical manifestations of common variable immunodeficiency and can range from mild hepatomegaly and persistent elevation of liver enzymes to cirrhosis, portal hypertension, and nodular regenerative hyperplasia. The last one is the most common histologic presentation of liver involvement by common variable immunodeficiency and its clinical spectrum can range from asymptomatic to cholestasis, liver cirrhosis, or idiopathic non-cirrhotic portal hypertension, with the severe manifestations being less recognised. We present a case of a 48-year-old woman who was referred for an internal medicine consultation for evaluation of rapidly progressing (span of three months) large-volume ascites and marked asthenia. The patient had a past medical history of common variable immunodeficiency and a recent episode of severe haemolytic anaemia. Peritoneal fluid analyses identified portal hypertension as the cause of the ascites. Abdominal Doppler ultrasound and contrasted abdominal computed tomography confirmed the presence of permeable hepatic and portal veins. Liver biopsy revealed regenerative nodular hyperplasia without cirrhosis. A diagnosis of idiopathic non-cirrhotic portal hypertension secondary to common variable immunodeficiency was made. Treatment was adjusted with considerable improvement in ascites. In conclusion, idiopathic non-cirrhotic portal hypertension is a possible and often overlooked complication in patients with common variable immunodeficiency and is an exclusion diagnosis that requires a high level of suspicion, especially in patients with ascites.

B- and T-Cell Subset Abnormalities in Monogenic Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is a heterogeneous group of inborn errors of immunity characterized by reduced serum concentrations of different immunoglobulin isotypes. CVID is the most prevalent symptomatic antibody deficiency with a broad range of infectious and non-infectious clinical manifestations. Various genetic and immunological defects are known to be involved in the pathogenesis of CVID. Monogenic defects account for the pathogenesis of about 20-50% of CVID patients, while a variety of cases do not have a defined genetic background. Deficiencies in molecules of B cell receptor signaling or other pathways involving B-cell development, activation, and proliferation could be associated with monogenetic defects of CVID. Genetic defects damping different B cell developmental stages can alter B- and even other lymphocytes’ differentiation and might be involved in the clinical and immunologic presentations of the disorder. Reports concerning T and B cell abnormalities have been published in CVID patients, but such comprehensive data on monogenic CVID patients is few and no review article exists to describe the abrogation of lymphocyte subsets in these disorders. Hence, we aimed to review the role of altered B- and T-cell differentiation in the pathogenesis of CVID patients with monogenic defects.

Malabsorption Syndromes and Food Intolerance

Feeding intolerance is ubiquitous in neonatal intensive care units with as many signs and symptoms as possible diagnoses. Optimizing nutrition is paramount in both preterm and term infants. Determining the cause of feeding intolerance and adjusting nutrition interventions is an important part of the daily care of newborns. This review discusses the role of malabsorption and food intolerance as possible causes of nutrition difficulties in the newborn.

Targeted next-generation sequencing revealed a novel homozygous mutation in the LRBA gene causes severe haemolysis associated with Inborn Errors of Immunity in an Indian family

OBJECTIVES

LPS-responsive beige-like anchor protein (LRBA) deficiency abolishes LRBA protein expression due to biallelic mutations in the LRBA gene that lead to autoimmune manifestations, inflammatory bowel disease, hypogammaglobulinemia in early stages, and variable clinical manifestations.

MATERIALS AND METHODS

Mutational analysis of the LRBA gene was performed in Indian patients using targeted Next Generation Sequencing (t-NGS) and confirmed by Sanger sequencing using specific primers of exons 53. Then, bioinformatics analysis and protein modeling for the novel founded mutations were also performed. The genotype, phenotype correlation was done according to the molecular findings and clinical features.

RESULTS

We report an unusual case of a female patient born of a consanguineous marriage, presented with severe anaemia and jaundice with a history of multiple blood transfusions of unknown cause up to the age of 5 yrs. She had hepatosplenomegaly with recurrent viral and bacterial infections. Tests for hemoglobinopathies, enzymopathies, and hereditary spherocytosis were within the normal limits. The t-NGS revealed a novel homozygous missense variation in exon 53 of the LRBA gene (chr4:151231464C > T; c.7799G > A) (p.C2600Y), and the parents were heterozygous. The further immunological analysis is suggestive of hypogammaglobulinaemia and autoimmune haemolytic anaemia. The bioinformatics tools are suggestive of deleterious and disease-causing variants.

CONCLUSION

This study concludes the importance of a timely decision of targeted exome sequencing for the molecular diagnostic tool of unexplained haemolytic anaemia with heterogeneous clinical phenotypes.

Evaluation of malnutrition risk and nutrition status in adult patients with common variable immunodeficiency

BACKGROUND

The aim of this study is to determine the prevalence of malnutrition in outpatients with common variable immunodeficiency (CVID) and the utility of nutrition screening tools to detect malnutrition in these patients.

METHODS

Fifty outpatients with CVID were included in the study. Nutrition risk for each patient was evaluated using four nutrition screening tools: Malnutrition Screening Tool (MST), Malnutrition Universal Screening Tool (MUST), Short Nutritional Assessment Questionnaire (SNAQ), and Nutritional Risk Screening 2002 (NRS-2002).

RESULTS

According to MUST, MST, SNAQ, and NRS-2002, malnutrition risk was determined to be 48% (n = 24), 26% (n = 13), 20% (n = 10), and 20% (n = 10), respectively. Malnutrition was detected in 54% (n = 27) of the patients. It was found that MUST showed a better correlation in detecting malnutrition in outpatients with CVID (κ = 0.482, P = 0.001). MUST has a higher positive and negative predictive value than other nutrition screening tools (79% and 70%, respectively). In the multivariate logistic regression analysis, it was found that low serum immunoglobulin A (IgA) levels at diagnosis increased the risk of malnutrition by ∼15 times, and low CD19⁺ B-cell counts increased the risk by approximately eight times.

CONCLUSION

The prevalence of malnutrition in patients with CVID was found to be quite high, and there was a strong correlation between malnutrition and low CD19⁺ B-cell counts and low serum IgA levels. Given the high rate of malnutrition in patients with CVID, nutrition assessment is recommended rather than starting with nutrition screening.

Treatment of Autoimmune Diseases with Therapeutic Antibodies: Lessons Learned from PID Patients Allow for Stratification of the Infection Risk

Over the years, a wide variety of therapeutic antibodies has been successfully introduced in the autoimmunology clinic and many more are on the edge to follow. Many of these treatments address either a pathogenic circulating molecule or a cell-bound molecule. Whereas the former target results in neutralization of the soluble factor, the latter target either inhibits cellular function or induces selective cell death. If this targeted molecule or cell is part of the immune system, this therapy evokes a state of immunodeficiency. Knowing the exact function of the respective components enables the risk stratification for possible infectious complications in patients treated with biologics. Much of the understanding of the function of immune cells and their associated molecules, in relation to redundancy in the immune system, is derived from studies in knockout mice. However, as mice are not men in terms of their life-expectancy, their infection exposure, or the composition of their immune system, the most useful knowledge for estimating the consequence of therapeutic intervention on immune competence comes from monitoring patients. In the current chapter, we focus on patients with a primary immunodeficiency (PID) because they provide us with a unique perspective to estimate the redundancy of a certain genetic defect for overall immune competence. These patients have inborn errors of the immune system that, in general, are due to single gene defects. Depending on the immunological pathway that is defective, patients can present with different types of (opportunistic) infectious diseases, as well as other clinical manifestations. Based on selected examples, we focus in this chapter on finding parallels in the infectious risk of autoimmune patients treated with biologics and PID patients with a defect in the immunological pathway that is affected by the respective biologic. The goal is to learn from the (dis)similarities between both patient populations in terms of safety profiles of biologic treatments.

Immunogenicity of Anti-SARS-CoV-2 Vaccines in Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is characterized by hypogammaglobulinemia and/or a defective antibody response to T-dependent and T-independent antigens. CVID response to immunization depends on the antigen type, the vaccine mechanism, and the specific patient immune defect. In CVID patients, humoral and cellular responses to the currently used COVID-19 vaccines remain unexplored. Eighteen CVID subjects receiving 2-dose anti-SARS-CoV-2 vaccines were prospectively studied. S1-antibodies and S1-specific IFN-γ T cell response were determined by ELISA and FluoroSpot, respectively. The immune response was measured before the administration and after each dose of the vaccine, and it was compared to the response of 50 healthy controls (HC). The development of humoral and cellular responses was slower in CVID patients compared with HC. After completing vaccination, 83% of CVID patients had S1-specific antibodies and 83% had S1-specific T cells compared with 100% and 98% of HC (p = 0.014 and p = 0.062, respectively), but neutralizing antibodies were detected only in 50% of the patients. The strength of both humoral and cellular responses was significantly lower in CVID compared with HC, after the first and second doses of the vaccine. Absent or discordant humoral and cellular responses were associated with previous history of autoimmunity and/or lymphoproliferation. Among the three patients lacking humoral response, two had received recent therapy with anti-B cell antibodies. Further studies are needed to understand if the response to COVID-19 vaccination in CVID patients is protective enough. The 2-dose vaccine schedule and possibly a third dose might be especially necessary to achieve full immune response in these patients.

Biochemically deleterious human NFKB1 variants underlie an autosomal dominant form of common variable immunodeficiency

Autosomal dominant (AD) NFKB1 deficiency is thought to be the most common genetic etiology of common variable immunodeficiency (CVID). However, the causal link between NFKB1 variants and CVID has not been demonstrated experimentally and genetically, as there has been insufficient biochemical characterization and enrichment analysis. We show that the cotransfection of NFKB1-deficient HEK293T cells (lacking both p105 and its cleaved form p50) with a κB reporter, NFKB1/p105, and a homodimerization-defective RELA/p65 mutant results in p50:p65 heterodimer–dependent and p65:p65 homodimer–independent transcriptional activation. We found that 59 of the 90 variants in patients with CVID or related conditions were loss of function or hypomorphic. By contrast, 258 of 260 variants in the general population or patients with unrelated conditions were neutral. None of the deleterious variants displayed negative dominance. The enrichment in deleterious NFKB1 variants of patients with CVID was selective and highly significant (P = 2.78 × 10⁻¹⁵). NFKB1 variants disrupting NFKB1/p50 transcriptional activity thus underlie AD CVID by haploinsufficiency, whereas neutral variants in this assay should not be considered causal.

Intestinal immunoregulation: lessons from human mendelian diseases

The mechanisms that maintain intestinal homeostasis despite constant exposure of the gut surface to multiple environmental antigens and to billions of microbes have been scrutinized over the past 20 years with the goals to gain basic knowledge, but also to elucidate the pathogenesis of inflammatory bowel diseases (IBD) and to identify therapeutic targets for these severe diseases. Considerable insight has been obtained from studies based on gene inactivation in mice as well as from genome wide screens for genetic variants predisposing to human IBD. These studies are, however, not sufficient to delineate which pathways play key nonredundant role in the human intestinal barrier and to hierarchize their respective contribution. Here, we intend to illustrate how such insight can be derived from the study of human Mendelian diseases, in which severe intestinal pathology results from single gene defects that impair epithelial and or hematopoietic immune cell functions. We suggest that these diseases offer the unique opportunity to study in depth the pathogenic mechanisms leading to perturbation of intestinal homeostasis in humans. Furthermore, molecular dissection of monogenic intestinal diseases highlights key pathways that might be druggable and therapeutically targeted in common forms of IBD.

Pulmonary Hypertension in Patients with Common Variable Immunodeficiency

PURPOSE

Common variable immunodeficiency (CVID) is known to cause infectious, inflammatory, and autoimmune manifestations. Pulmonary hypertension (PH) is an unusual complication of CVID with largely unknown characteristics and mechanisms.

METHODS

We report the clinical, functional, hemodynamics, radiologic and histologic characteristics, and outcomes of CVID-associated PH patients from the French PH Network.

RESULTS

Ten patients were identified. The median (range) age at CVID diagnosis was 36.5 (4-49) years and the median delay between CVID and PH diagnosis was 12 (0-30) years. CVID-associated PH affected predominantly women (female-to-male ratio 9:1). Most patients were New York Heart Association functional class III with a severe hemodynamic profile and frequent portal hypertension (n = 6). Pulmonary function tests were almost normal in 70% of patients and showed a mild restrictive syndrome in 30% of patients while the diffusing capacity for carbon monoxide was decreased in all but one patient. High-resolution computed tomography found enlarged mediastinal nodes, mild interstitial infiltration with reticulations and nodules. Two patients had a CIVD-interstitial lung disease, and one presented with bronchiectasis. Pathologic assessment of lymph nodes performed in 5 patients revealed the presence of granulomas (n = 5) and follicular lymphoid hyperplasia (n = 3). At last follow-up (median 24.5 months), 9 patients were alive, and one patient died of Hodgkin disease.

CONCLUSION

PH is a possible complication of CVID whose pathophysiological mechanisms, while still unclear, would be due to the inflammatory nature of CVID. CVID-associated PH presents as precapillary PH with multiple possible causes, acting in concert in some patients: a portal hypertension, a pulmonary vascular remodeling, sometimes a pulmonary parenchymal involvement and occasionally an extrinsic compression by mediastinal lymphadenopathies, which would be consistent with its classification in group 5 of the current PH classification.

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.

Non-Infectious Granulomatous Lung Disease: Imaging Findings with Pathologic Correlation

Non-infectious granulomatous lung disease represents a diverse group of disorders characterized by pulmonary opacities associated with granulomatous inflammation, a relatively nonspecific finding commonly encountered by pathologists. Some lesions may present a diagnostic challenge because of nonspecific imaging features; however, recognition of the various imaging manifestations of these disorders in conjunction with patients' clinical history, such as age, symptom onset and duration, immune status, and presence of asthma or cutaneous lesions, is imperative for narrowing the differential diagnosis and determining appropriate management of this rare group of disorders. In this pictorial review, we describe the pathologic findings of various non-infectious granulomatous lung diseases as well as the radiologic features and high-resolution computed tomography imaging features.

A Pathogenic Missense Variant in NFKB1 Causes Common Variable Immunodeficiency Due to Detrimental Protein Damage

In common variable immunodeficiency (CVID), heterozygous damaging NFKB1 variants represent the most frequent monogenic cause. NFKB1 encodes the precursor p105, which undergoes proteasomal processing to generate the mature NF-κB transcription factor subunit p50. The majority of NFKB1 sequence changes comprises missense variants of uncertain significance (VUS), each requiring functional evaluation to assess causality, particularly in families with multiple affected members presenting with different phenotypes. In four affected members of a German family, all diagnosed with CVID, we identified a previously uncharacterized heterozygous NFKB1 missense variant (c.1049A>G; p.Tyr350Cys). The clinical phenotypes varied markedly regarding onset, frequency and severity of infections. Consistent immunologic findings were hypogammaglobulinemia with normal specific antibody response to protein- and polysaccharide-based vaccinations, reduced switched memory B cells and decreased lymphocyte proliferation upon stimulation with the B cell mitogen SAC. To assess the pathogenicity of the NFKB1 missense variant, we employed immunophenotyping and functional analyses in a routine in vitro cell culture model. Following site-directed mutagenesis to introduce the variant into overexpression vectors encoding EGFP-fused p105 or p50, we analyzed transiently transfected HEK293T cells by confocal imaging and Western blotting. The cytoplasmic p105-Tyr350Cys precursor gained only weak expression levels indicating accelerated decay. The missense change disabled processing of the precursor to prevent the generation of mutant p50. Unlike the wildtype p50, the overexpressed mutant p50-Tyr350Cys was also not sustainable and showed a conspicuous subnuclear mislocalization with accumulation in dense aggregates instead of a homogenous distribution. Electrophoretic mobility shift assays, fluorescence-based reporter gene analyses and co-transfection experiments however demonstrated, that the DNA-binding activity of p50-Tyr350Cys and the interaction with RelA(p65), IκBα and wildtype p50 were preserved. Mutation carriers had reduced p105 and p50 levels, indicating insufficient protein amounts as the most likely primary defect. In conclusion, the missense variant c.1049A>G caused a detrimental defect, preventing the persistent expression of both, the p105-Tyr350Cys precursor and the mature p50-Tyr350Cys. The variable clinical phenotypes among affected family members sharing an identical pathogenic NFKB1 variant support a disease mechanism provoked by a p105/p50 (haplo)insufficient condition.

Interstitial Lung Disease in Common Variable Immunodeficiency

Interstitial lung disease (ILD) is a common complication in patients with common variable immunodeficiency (CVID) and often associated with other features, such as bronchiectasis and autoimmunity. As the ILD term encompasses different acute and chronic pulmonary conditions, the diagnosis is commonly made based on imaging features; histopathology is less frequently available. From a cohort of 637 patients with CVID followed at our center over 4 decades, we reviewed the data for 46 subjects (30 females, 16 males) who had lung biopsies with proven ILD. They had a median age at CVID diagnosis of 26 years old, with a median IgG level at diagnosis of 285.0 mg/dL with average isotype switched memory B cells of 0.5%. Lung biopsy pathology revealed granulomas in 25 patients (54.4%), lymphoid interstitial pneumonia in 13 patients (28.3%), lymphoid hyperplasia not otherwise specified in 7 patients (15.2%), cryptogenic organizing pneumonia in 7 patients (15.2%), follicular bronchitis in 4 patients (8.7%), and predominance of pulmonary fibrosis in 4 patients (8.7%). Autoimmune manifestations were common and were present in 28 (60.9%) patients. Nine patients (19.6%) died, with a median age at death of 49-years-old. Lung transplant was done in 3 of these patients (6.5%) who are no longer alive. These analyses reveal the high burden of this complication, with almost one-fifth of the group deceased in this period. Further understanding of the causes of the development and progression of ILD in CVID patients is required to define the best management for this patient population.

Immunoglobulin Replacement Therapy is critical and cost-effective in increasing life expectancy and quality of life in patients suffering from Common Variable Immunodeficiency Disorders (CVID): A health-economic assessment

BACKGROUND

Common variable immunodeficiency disorders (CVID), the most common form of primary antibody deficiency, are rare conditions associated with considerable morbidity and mortality. The clinical benefit of immunoglobulin replacement therapy (IgGRT) is substantial: timely treatment with appropriate doses significantly reduces mortality and the incidence of CVID-complications such as major infections and bronchiectasis. Unfortunately, CVID-patients still face a median diagnostic delay of 4 years. Their disease burden, expressed in annual loss of disability-adjusted life years, is 3-fold higher than in the general population. Hurdles to treatment access and reimbursement by healthcare payers may exist because the value of IgGRT is poorly documented. This paper aims to demonstrate cost-effectiveness and cost-utility (on life expectancy and quality) of IgGRT in CVID.

METHODS AND FINDINGS

With input from a literature search, we built a health-economic model for cost-effectiveness and cost-utility assessment of IgGRT in CVID. We compared a mean literature-based dose (≥450mg/kg/4wks) to a zero-or-low dose (0 to ≤100 mg/kg/4wks) in a simulated cohort of adult patients from time of diagnosis until death; we also estimated the economic impact of diagnostic delay in this simulated cohort. Compared to no or minimal treatment, IgGRT showed an incremental benefit of 17 life-years (LYs) and 11 quality-adjusted life-years (QALYs), resulting in an incremental cost-effectiveness ratio (ICER) of €29,296/LY and €46,717/QALY. These results were robust in a sensitivity analysis. Reducing diagnostic delay by 4 years provided an incremental benefit of six LYs and four QALYs compared to simulated patients with delayed IgGRT initiation, resulting in an ICER of €30,374/LY and €47,495/QALY.

CONCLUSIONS

The health-economic model suggests that early initiation of IgGRT compared to no or delayed IgGRT is highly cost-effective. CVID-patients' access to IgGRT should be facilitated, not only because of proven clinical efficacy, but also due to the now demonstrated cost-effectiveness.

B Cell Dysregulation in Common Variable Immunodeficiency Interstitial Lung Disease

Common variable immunodeficiency (CVID) is the most frequently diagnosed primary antibody deficiency. About half of CVID patients develop chronic non-infectious complications thought to be due to intrinsic immune dysregulation, including autoimmunity, gastrointestinal disease, and interstitial lung disease (ILD). Multiple studies have found ILD to be a significant cause of morbidity and mortality in CVID. Yet, the precise mechanisms underlying this complication in CVID are poorly understood. CVID ILD is marked by profound pulmonary infiltration of both T and B cells as well as granulomatous inflammation in many cases. B cell depletive therapy, whether done as a monotherapy or in combination with another immunosuppressive agent, has become a standard of therapy for CVID ILD. However, CVID is a heterogeneous disorder, as is its lung pathology, and the precise patients that would benefit from B cell depletive therapy, when it should administered, and how long it should be repeated all remain gaps in our knowledge. Moreover, some have ILD recurrence after B cell depletive therapy and the relative importance of B cell biology remains incompletely defined. Developmental and functional abnormalities of B cell compartments observed in CVID ILD and related conditions suggest that imbalance of B cell signaling networks may promote lung disease. Included within these potential mechanisms of disease is B cell activating factor (BAFF), a cytokine that is upregulated by the interferon gamma (IFN-γ):STAT1 signaling axis to potently influence B cell activation and survival. B cell responses to BAFF are shaped by the divergent effects and expression patterns of its three receptors: BAFF receptor (BAFF-R), transmembrane activator and CAML interactor (TACI), and B cell maturation antigen (BCMA). Moreover, soluble forms of BAFF-R, TACI, and BCMA exist and may further influence the pathogenesis of ILD. Continued efforts to understand how dysregulated B cell biology promotes ILD development and progression will help close the gap in our understanding of how to best diagnose, define, and manage ILD in CVID.

[Common variable immunodeficiency disorders: Part 2. Updated clinical manifestations and therapeutic management]

Common variable immunodeficiency disorders (CVID) are the most common symptomatic primary antibody deficiency in adults with an estimated prevalence of 1/25,000. The most frequent clinical manifestations are upper respiratory tract infections (including pneumonia, bronchitis, and sinusitis) predominantly with Streptococcus pneumoniae or H. influenzae. However, CVID are complicated in 20 to 30 % of cases of non-infectious manifestations which have been well characterized in recent years. Several complications can be observed including autoimmune, lymphoproliferative, granulomatous or cancerous manifestations involving one or more organs. These complications, mostly antibody-mediated cytopenias, are correlated with a decrease in the number of circulating switched memory B cells. Replacement therapy with polyvalent gammaglobulins has greatly improved the prognosis of these patients but it remains poor in the presence of digestive complications (especially in the case of chronic enteropathy and/or porto-sinusoidal vascular disease), pulmonary complications (bronchiectasis and/or granulomatous lymphocytic interstitial lung disease) and when progression to lymphoma. Much progress is still to be made, in particular on the therapeutic management of non-infectious complications which should benefit in the future from targeted treatments based on knowledge of genetics and immunology.

AA Amyloidosis Secondary to Primary Immune Deficiency: About 40 Cases Including 2 New French Cases and a Systematic Literature Review

BACKGROUND

Primary immune deficiencies (PIDs) are a heterogeneous group of disorders resulting from defects in immune system. They lead to increased susceptibility to infections and immune dysregulation. The resulting chronic inflammation can induce long-term complications, including AA amyloidosis (AAA).

OBJECTIVES

To present the French cases of PID-related AAA and perform a systematic literature review to determine its main features and predisposing factors.

METHODS

A systematic literature review was performed by searching MEDLINE up until 2019. New French cases were identified with the help of the Reference Center for Auto-Inflammatory Diseases and AA Amyloidosis and the Reference Center for Hereditary Immune Deficiencies.

RESULTS

Forty patients were identified including 2 new French cases. PIDs were varied: immunoglobulin deficits (n = 30), chronic granulomatous disease (n = 3), hyper-IgM syndrome (n = 3), hereditary complete C4 deficiency (n = 1), leucocyte adhesion deficiency type 1 (n = 1), hyper-IgE syndrome (n = 1), and Chediak-Higashi syndrome (n = 1). The mean age at PID diagnosis was 22.2 ± 16.02 years. Renal involvement was the most common manifestation of AAA (80%). Infections were extremely heterogeneous; bacterial infection with pulmonary involvement was the most frequent. Bronchiectasis was particularly common (52.5%). The delay between the first symptoms of PID and AAA diagnosis was 16.18 ± 7 years. Thirteen concomitant diagnoses were made. Twenty patients died during follow-up.

CONCLUSION

AAA is a rare life-threatening complication of PID, especially in cases of long diagnostic and therapeutic delays. Bronchiectasis should be considered as a warning sign of chronic inflammation and increased risk of AAA.

Clinical Outcomes of COVID-19 Patients with Pre-existing, Compromised Immune Systems: A Review of Case Reports

In the ongoing COVID-19 pandemic, all COVID-19 patients are naïve patients as it is the first-time humans have been exposed to the SARS-CoV-2 virus. As with exposure to many viruses, individuals with pre-existing, compromised immune systems may be at increased risk of developing severe symptoms and/or dying because of (SARS-CoV-2) infection. To learn more about such individuals, we conducted a search and review of published reports on the clinical characteristics and outcomes of COVID-19 patients with pre-existing, compromised immune systems. Here we present our review of patients who possess pre-existing primary antibody deficiency (PAD) and those who are organ transplant recipients on maintenance immunosuppressants. Our review indicates different clinical outcomes for the patients with pre-existing PAD, depending on the underlying causes. For organ transplant recipients, drug-induced immune suppression alone does not appear to enhance COVID-19 mortality risk - rather, advanced age, comorbidities, and the development of secondary complications appears required.

Gut Microbiota-Dependent Trimethylamine N-Oxide Associates With Inflammation in Common Variable Immunodeficiency

A substantial proportion of patients with common variable immunodeficiency (CVID) have inflammatory and autoimmune complications of unknown etiology. We have previously shown that systemic inflammation in CVID correlates with their gut microbial dysbiosis. The gut microbiota dependent metabolite trimethylamine N-oxide (TMAO) has been linked to several metabolic and inflammatory disorders, but has hitherto not been investigated in relation to CVID. We hypothesized that TMAO is involved in systemic inflammation in CVID. To explore this, we measured plasma concentrations of TMAO, inflammatory markers, and lipopolysaccharide (LPS) in 104 CVID patients and 30 controls. Gut microbiota profiles and the bacterial genes CutC and CntA, which encode enzymes that can convert dietary metabolites to trimethylamine in the colon, were examined in fecal samples from 40 CVID patients and 86 controls. Furthermore, a food frequency questionnaire and the effect of oral antibiotic rifaximin on plasma TMAO concentrations were explored in these 40 patients. We found CVID patients to have higher plasma concentrations of TMAO than controls (TMAO 5.0 [2.9-8.6] vs. 3.2 [2.2-6.3], p = 0.022, median with IQR). The TMAO concentration correlated positively with tumor necrosis factor (p = 0.008, rho = 0.26), interleukin-12 (p = 0.012, rho = 0.25) and LPS (p = 0.034, rho = 0.21). Dietary intake of meat (p = 0.678), fish (p = 0.715), egg (p = 0.138), dairy products (p = 0.284), and fiber (p = 0.767) did not significantly impact on the TMAO concentrations in plasma, nor did a 2-week course of the oral antibiotic rifaximin (p = 0.975). However, plasma TMAO concentrations correlated positively with gut microbial abundance of Gammaproteobacteria (p = 0.021, rho = 0.36). Bacterial gene CntA was present in significantly more CVID samples (75%) than controls (53%), p = 0.020, potentially related to the increased abundance of Gammaproteobacteria in these samples. The current study demonstrates that elevated TMAO concentrations are associated with systemic inflammation and increased gut microbial abundance of Gammaproteobacteria in CVID patients, suggesting that TMAO could be a link between gut microbial dysbiosis and systemic inflammation. Gut microbiota composition could thus be a potential therapeutic target to reduce systemic inflammation in CVID.

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.

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

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Heterogeneity of Liver Disease in Common Variable Immunodeficiency Disorders

Common variable immunodeficiency (CVID) is the most frequent primary immunodeficiency (PID) in adulthood and is characterized by severe reduction of immunoglobulin serum levels and impaired antibody production in response to vaccines and pathogens. Beyond the susceptibility to infections, CVID encompasses a wide spectrum of clinical manifestations related to a complex immune dysregulation that also affects liver. Although about 50% CVID patients present persistently deranged liver function, burden, and nature of liver involvement have not been systematically investigated in most cohort studies published in the last decades. Therefore, the prevalence of liver disease in CVID widely varies depending on the study design and the sampling criteria. This review seeks to summarize the evidence about the most relevant causes of liver involvement in CVID, including nodular regenerative hyperplasia (NRH), infections and malignancies. We also describe the clinical features of liver disease in some monogenic forms of PID included in the clinical spectrum of CVID as ICOS, NFKB1, NFKB2, CTLA-4, PI3Kδ pathway, ADA2, and IL21-R genetic defects. Finally, we discuss the clinical applications of the various diagnostic tools and the possible therapeutic approaches for the management of liver involvement in the context of CVID.

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.

Primary immunodeficiencies: novel genes and unusual presentations

Recent advances in genomics have greatly expanded the spectrum of primary immune deficiencies (PIDs). Along with the identification of pathogenic variants in novel genes, distinct phenotypes have been associated with different variants in the same gene. Although PIDs have been historically defined based on increased susceptibility to infections, immune dysregulation has emerged as a frequent and in some cases, predominant phenotype. Autoimmune cytopenias with onset in childhood, lasting longer than 12 months, and affecting multiple lineages should raise the suspicion of a possible PID with monogenic origin. Characterization of the various molecular and cellular mechanisms responsible for these unusual manifestations of PIDs, although at times resource intensive, may allow for targeted intervention in many of them.

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.

Impaired HDL Function Amplifies Systemic Inflammation in Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency, characterized by inadequate antibody responses and recurrent bacterial infections. Paradoxically, a majority of CVID patients have non-infectious inflammatory and autoimmune complications, associated with systemic immune activation. Our aim was to explore if HDL, known to have anti-inflammatory properties, had impaired function in CVID patients and thereby contributed to their inflammatory phenotype. We found reduced HDL cholesterol levels in plasma of CVID patients compared to healthy controls, particularly in patients with inflammatory and autoimmune complications, correlating negatively with inflammatory markers CRP and sCD25. Reverse cholesterol transport capacity testing showed reduced serum acceptance capacity for cholesterol in CVID patients with inflammatory and autoimmune complications. They also had reduced cholesterol efflux capacity from macrophages to serum and decreased expression of ATP-binding cassette transporter ABCA1. Human HDL suppressed TLR2-induced TNF release less in blood mononuclear cells from CVID patients, associated with decreased expression of transcriptional factor ATF3. Our data suggest a link between impaired HDL function and systemic inflammation in CVID patients, particularly in those with autoimmune and inflammatory complications. This identifies HDL as a novel therapeutic target in CVID as well as other more common conditions characterized by sterile inflammation or autoimmunity.