Autoimmunity in common variable immunodeficiency

Diverse phenotypic manifestations of small intestinal mucosa in non-infectious common variable immunodeficiency bowel disease: A case report

BACKGROUND

Common variable immunodeficiency (CVID) is a primary antibody immunodeficiency disorder characterized by diminished IgG levels. Despite ongoing research, the precise pathogenesis of CVID remains unclear. Genetic factors account for only 10%-20% of cases, with an estimated incidence of 1 in 10000 to 1 in 100000, affecting individuals across all age groups.

CASE SUMMARY

We report the case of a 32-year-old man with CVID who presented with a chief complaint of “recurrent diarrhea and significant weight loss over the past 2 years”. Laboratory tests on admission showed fat droplets in stool, while other parameters were within normal ranges. Gastroscopy revealed a smooth gastric mucosa without bile retention or signs of Helicobacter pylori infection; however, the mucosa of the descending segment of the duodenum appeared rough. Further evaluation of the small intestine using computed tomography indicated no abnormalities. Finally, the whole-small bowel double-balloon enteroscopy (DBE) was performed, which revealed various phenotypic changes in the small intestinal mucosa. The patient was diagnosed with CVID, which improved after immunoglobulin therapy, with favorable follow-up outcomes.

CONCLUSION

Non-infectious enteropathy in CVID is rare. Therefore, DBE is essential for diagnosing small intestinal involvement in such cases.

Navigating the Complexities of Common Variable Immunodeficiency Enteropathy: From Established Therapies to Emerging Interventions

Common Variable Immunodeficiency (CVID) is a prevalent primary immunodeficiency in adults, marked by low immunoglobulin levels and recurrent infections. This review examines the gastrointestinal complications of CVID, including both infectious and non-infectious manifestations. It highlights therapeutic strategies, from antimicrobials to novel biologics, and the role of immune modulation. The review also explores the impact of gut microbiota dysbiosis on CVID pathogenesis and emphasizes the need for personalized treatment approaches and routine cancer screening due to the elevated risk of gastrointestinal malignancy in CVID patients.

Reappraisal of IgG subclass deficiencies: a retrospective comparative cohort study

Objective

The aim of the present study was to investigate the clinical spectrum of IgG subclass deficiencies (IgGSDs) and assess the relative clinical significance of diagnosing each specific IgGSD disorder as compared to the common variable immunodeficiency (CVID).

Methods

The clinical spectrum and immunological findings from 96 patients, diagnosed with diverse IgGSDs, were retrospectively evaluated. Specific IgGSDs were compared with each other and a cohort of 270 patients with CVID.

Results

In comparison to CVID, recurrent lower respiratory tract infections (LRTIs) and bronchiectasis were rarer in IgGSDs, while recurrent mucocutaneous herpes simplex virus reactivations were more common. With respect to autoimmunity, IgGSDs were associated with arthritis, while autoimmune cytopenias were less frequently observed than in CVID. Among IgGSDs, herpes zoster was more common in IgG3SD. Arthritis was more prevalent in IgG1 + 3SD. Given its association with LRTI, splenomegaly, immune thrombocytopenic purpura, and the lower class-switched memory B-cell counts, IgG2 + 4SD is the IgGSD that rather resembles CVID.

Conclusions

Comparative evaluation of phenotypes and treatments of patients with IgGSDs and CVID reveals distinct features, suggesting the differential clinical significance of diagnosing IgGSDs. The differential clinical expressions of IgGSDs highlight the need for studying each IgGSD separately in order to optimize disorder-specific follow-up procedures and prophylactic anti-infective measures.

If and When to Consider Prophylactic Immunoglobulin Replacement Therapy in Secondary Hypogammaglobulinemia

Secondary hypogammaglobulinemia (SHG), or decreased IgG levels due to reduced production or increased loss caused by medications or underlying conditions, can be associated with increased infection risk. Although immunoglobulin replacement therapy (IgRT) is generally accepted as a strategy to help prevent recurrent bacterial infections in SHG, controversy exists as to whether it should be initiated to prevent the first occurrence of infection. This question has been raised particularly in the setting of anti-CD20 therapy, solid organ transplant, and B-cell malignancies and their treatments once IgG levels fall below 300 to 400 mg/dL. This article reviews the evidence for and against initiating IgRT in these settings, as well as associated considerations for evaluation and monitoring. Although it is relatively clear that infection risk increases with decreasing IgG levels, the exact contribution of SHG to overall infection risk and the protective benefit of IgRT in the absence of infections remain unclear. In the absence of clear consensus, shared decision-making is often needed to determine if and when to initiate IgRT.

Common variable immunodeficiency: autoimmune cytopenias and advances in molecular diagnosis

Common variable immunodeficiency (CVID) is one of the most common groups of human inborn errors of immunity. In addition to infections resulting from insufficient levels of immunoglobulins and antibodies, a significant proportion of patients develop autoimmune cytopenias, especially immune thrombocytopenia, hemolytic anemia, or neutropenia. They may be the initial manifestation of CVID in a patient who has not had significant infections, and similar episodes may recur at intervals over time. Treatment of these hematologic complications includes the use of corticosteroids or other medications, often including rituximab; splenectomy is discouraged. Here we outline the overall occurrence of these blood cytopenias in a cohort of 408 patients, as well as the clinical and genetic associations noted in these individuals.

High occurrence of autoimmune and lymphoproliferative manifestations in adults with common variable immunodeficiency in southern Taiwan

There are no reported case series of common variable immunodeficiency (CVID) from southern Taiwan. A 20-year review was performed in adult CVID from a southern Taiwan medical center. Patients with ages of 18 years or older were enrolled from May, 2003 to April, 2023. Twelve patients were identified, 8 females/4 males aged 23 to 68 (38.9 ± 13.4) with one to 11 years (5.0 ± 3.3) delay of diagnosis after disease onset. There were concomitant autoimmune disorders in 7 (58 %), splenomegaly in 10 (83 %), lymphadenopathy in 4 (25 %) and B-cell lymphoma in 2 (17 %). All received intravenous immunoglobulin (IVIg) infusion with improved autoimmune-mediated arthritis in 2. Patients with higher IgG trough levels (above 500 mg/dL) had a better survival than those with lower IgG trough levels. Adult CVID in southern Taiwan has a high occurrence of autoimmune and lymphoproliferative manifestations. Early diagnosis with IVIg infusion might improve the presentations.

A Novel Heterozygous NFKB2 Variant in a Multiplex Family with Common Variable Immune Deficiency and Autoantibodies Against Type I IFNs

We studied a family with three male individuals across two generations affected by common variable immune deficiency (CVID). We identified a novel missense heterozygous variant (c.2602T>A:p.Y868N) of NFKB2 in all patients and not in healthy relatives. Functional studies of the mutant allele in an overexpression system and of the patients' cells confirmed the deleteriousness of the NFKB2 variant and genotype, respectively, on the activation of the non-canonical NF-κB signaling pathway. Impaired processing of p100 into p52 underlies p100 accumulation, which results in gain-of-function (GOF) of IκBδ inhibitory activity and loss-of-function (LOF) of p52 transcriptional activity. The three patients' plasma contained autoantibodies that neutralized IFN-α2 and/or IFN-ω, accounting for the severe or recurrent viral diseases of the patients, including influenza pneumonia in one sibling, and severe COVID-19 and recurrent herpes labialis in another. Our results confirm that NFKB2 alleles that are IκBδ GOF and p52 LOF can underlie CVID and drive the production of autoantibodies neutralizing type I IFNs, thereby predisposing to severe viral diseases.

Equine common variable immunodeficiency: lessons from 100 clinical cases

The clinical manifestation of recurrent fevers and infections alerts the clinician to the possibility of an underlying immunodeficiency. Common variable immunodeficiency (CVID) in the horse is a rare late-onset, non-familial immunologic disorder of B cell depletion and/or dysfunction with resultant inadequate antibody production. The most common clinical presentations in horses with CVID are recurrent upper and/or lower respiratory infections, meningitis and/or ataxia, cholangiohepatitis, infectious colitis, infectious dermatitis, and severe gastrointestinal parasitism. Immune-mediated and lymphoproliferative conditions are additional clinical features. The diagnosis of CVID in horses is based on persistent hypogammaglobulinemia primarily caused by a serum IgG concentration below 10.00 g/L in at least 2 different measurements, often accompanied by a serum IgM concentration below 0.50 g/L. Most horses with CVID show a persistent peripheral blood B cell distribution below 6% of total circulating lymphocytes, indicating severe B cell paucity or depletion, but the B cell distribution can be within the normal reference interval. Post-mortem findings add diagnostic information about the distribution of B and T cells in lymphoid tissues. Clinical management of horses with immunodeficiency is intense and expensive, and these factors weigh on the difficult decision of elective euthanasia. To date, no genetic mutation has been identified in horse patients with CVID, and the large number of breeds of single-affected individuals in a same herd or immediate lineage from various parts of the U.S. and the world do not point at an obvious inheritable mechanism of disease or environmental risk factors. This article describes the clinical and immunological findings in 100 cases, and comparisons with the disease in human patients.

38.3 Primary Immunodeficiencies: When is it not just "JIA"

Juvenile Idiopathic Arthritis (JIA) is sometimes considered a diagnosis of exclusion as the name signifies that no cause is evident for this form of arthritis. Despite this JIA has some classical clinical features and many categories are defined based on the phenotype. Since there is no diagnostic test for JIA, diseases that can mimic JIA, including Primary Immunodeficiencies (PID) can sometimes be misdiagnosed as JIA. The clues to suspecting PIDs are early age of onset, presence of family history, increased susceptibility to infections, unusual features like urticaria, interstitial lung disease, sensorineural hearing loss and poor response to conventional therapy, amongst others. This review will highlight the basics of PIDs and will discuss PIDs that can present with arthritis and hence can be confused with JIA.

Oral Diseases as a Manifestation of Inborn Errors of Immunity

Oral findings such as inflammation, ulcerations, or lesions can indicate serious systemic diseases and should prompt suspicion of acquired chronic conditions or inborn errors of immunity (IEIs). Currently, there are approximately 500 disease entities classified as IEIs, with the list expanding annually. The awareness of the existence of such conditions is of paramount importance, as patients with these disorders frequently necessitate the utilization of enhanced diagnostic techniques. This is exemplified by patients with impaired antibody production, in whom conventional serological methods may prove to be undiagnostic. Patients with IEI may require distinct therapeutic approaches or antimicrobial prophylaxis throughout their lives. An accurate diagnosis and, more importantly, early identification of patients with immune deficiencies is crucial to ensure the quality and longevity of their lives. It is important to note that the failure to establish a proper diagnosis or to provide adequate treatment could also have legal implications for medical professionals. The article presents IEIs, which may manifest in the oral cavity, and their diagnosis alongside therapeutic procedures.

The Horse with Recurrent Fevers and Infections: Approach to Common Variable Immunodeficiency

Equine common variable immunodeficiency (CVID) is a rare, late-onset, nonfamilial humoral deficiency characterized by B-cell depletion and/or dysfunction resulting in inadequate antibody production and predisposition to recurrent infections. Serum immunoglobulin concentration and peripheral blood lymphocyte immunophenotyping are required to diagnose and characterize CVID in horses. Early recognition of the disease by the equine practitioner is paramount to managing the quality of life for these patients, for whom specific treatment is not yet available and long-term prognosis remains poor. An approach to the diagnosis, identification of complicating factors, and management of horses with CVID are discussed.

Autoimmunity in patients with inborn errors of immunity: A case series

OBJECTIVE

To assess the prevalence of systemic and organ-specific autoimmunity among individuals with human inborn errors of immunity (IEI).

METHODS

Retrospective study. We recorded demographic variables, type of immunodeficiency, and systemic and organ specific autoimmunity.

RESULTS

We included 48 patients (54.1% men) with mean age of 32.1 years. The most common IEIs included combined immunodeficiency with syndromic features (31.2%) and predominantly antibody deficiency (20.1%). We observed autoimmunity in 15 patients (31.2%): 12 organ-specific autoimmunity and 5 systemic autoimmunity, not mutually exclusive groups. Organ-specific autoimmunity preceded the onset of IEI in 5 patients, was concurrent in one patient, and developed after the diagnosis of IEI in 6 cases. From the systemic autoimmunity group, we observed polyarteritis nodosa (n = 2), antiphospholipid syndrome (APS) (n = 2), and overlap of limited systemic sclerosis/APS/Sjögren's syndrome (n = 1), and in all cases, this occurred after the IEI diagnosis.

CONCLUSION

Our findings confirm the coexistence of autoimmunity and IEI. This overlap may be attributed to B and T cell disorders, as well as potential alterations in the microbiota in these patients.

Flow cytometry-based diagnostic approach for inborn errors of immunity: experience from Algeria

Purpose

In this study, we retrospectively reviewed the use of flow cytometry (FCM) in the diagnosis of inborn errors of immunity (IEIs) at a single center in Algeria. Sharing insights into our practical experience, we present FCM based diagnostic approaches adapted to different clinical scenarios.

Methods

Between May 2017 and February 2024, pediatric and adult patients presenting with clinical features suggestive of immunodeficiency were subjected to FCM evaluation, including lymphocyte subset analysis, detection of specific surface or intracellular proteins, and functional analysis of immune cells.

Results

Over a nearly seven-year period, our laboratory diagnosed a total of 670 patients (372 (55.5%) males and 298 (44.5%) females), distributed into 70 different IEIs belonging to 9 different categories of the International Union of Immunological Societies classification. FCM was used to diagnose and categorize IEI in 514 patients (76.7%). It provided direct diagnostic insights for IEIs such as severe combined immunodeficiency, Omenn syndrome, MHC class II deficiency, familial hemophagocytic lymphohistiocytosis, and CD55 deficiency. For certain IEIs, including hyper-IgE syndrome, STAT1-gain of function, autoimmune lymphoproliferative syndrome, and activated PI3K delta syndrome, FCM offered suggestive evidence, necessitating subsequent genetic testing for confirmation. Protein expression and functional assays played a crucial role in establishing definitive diagnoses for various disorders. To setup such diagnostic assays at high and reproducible quality, high level of expertise is required; in house reference values need to be determined and the parallel testing of healthy controls is highly recommended.

Conclusion

Flow cytometry has emerged as a highly valuable and cost-effective tool for diagnosing and studying most IEIs, particularly in low-income countries where access to genetic testing can be limited. FCM analysis could provide direct diagnostic insights for most common IEIs, offer clues to the underlying genetic defects, and/or aid in narrowing the list of putative genes to be analyzed.

CVID With Unusual Peripheral Mononeuropathy and Associated IL-7 Receptor Mutation

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency. It is characterized by hypogammaglobulinemia and can present with a broad range of symptoms including recurrent bacterial infections, autoimmunity, and malignancy. Rarely, it has been implicated with peripheral neuropathy. We present a case of CVID with peripheral neuropathy and a pathogenic heterozygous variant of IL-7 receptor gene. The patient is a 38-year-old female with a history of recurrent infections since childhood including pneumonia and sinus infections status post tonsillectomy and sinus surgery. She subsequently developed severe left leg and lower back pain that progressed to left foot drop and decreased sensation over the left leg. She was found to have severe hypogammaglobulinemia and poor polysaccharide and protein response, thus meeting criteria for CVID. Mononeuropathy is a rare finding in CVID. Genetic panel was performed and was significant for a single pathogenic variant in IL-7 receptor. Disruptions in the IL-7 and IL-7 receptor signaling pathway have been associated with autoimmunity such as rheumatoid arthritis and multiple sclerosis. Further investigation is indicated to determine the clinical significance of this variant.

Gene Signature of Regulatory T Cells Isolated from Children with Selective IgA Deficiency and Common Variable Immunodeficiency

Selective IgA deficiency (SIgAD) is the most common form and common variable immunodeficiency (CVID) is the most symptomatic form of predominant antibody deficiency. Despite differences in the clinical picture, a similar genetic background is suggested. A common feature of both disorders is the occurrence of autoimmune conditions. Regulatory T cells (Tregs) are the major immune cell type that maintains autoimmune tolerance. As the different types of abnormalities of Treg cells have been associated with autoimmune disorders in primary immunodeficiency (PID) patients, in our study we aimed to analyze the gene expression profiles of Treg cells in CVID and SIgAD patients compared to age-matched healthy controls. The transcriptome-wide gene profiling was performed by microarray technology. As a result, we analyzed and visualized gene expression patterns of isolated population of Treg cells. We showed the differences at the gene level between patients with and without autoimmunizations. Our findings suggest that the gene signatures of Treg cells isolated from SIgAD and CVID patients differ from age-matched healthy controls and from each other, presenting transcriptional profiles enriched in innate immune or Th response, respectively. The occurrence of autoimmunity in both types of PID is associated with down-regulation of class I IFNs signaling pathways. In summary, our findings improve our understanding of Treg dysfunctions in patients with common PIDs and associated autoimmunity.

Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is the most common primary immune deficiency characterized by impaired production of specific immunoglobulin. The clinical manifestations are heterogeneous including acquisition of recurrent bacterial infections after a period of wellness, lymphoproliferation, autoimmunity, pulmonary disease, liver disease, enteropathy, granulomas, and an increased risk of malignancy. The etiology of CVID is largely unknown, with a considerable number of patients having an underlying genetic defect causing immune dysregulation. The antibody deficiency found in CVID is treated with lifelong immunoglobulin therapy, which is preventative of the majority of infections when given regularly.

Clinical and immunological characterisation of patients with common variable immunodeficiency related immune thrombocytopenia

Primary Immune thrombocytopenia (ITP) is an autoimmune disease. Secondary ITP occurs in patients with underlying diseases such as common variable immunodeficiency (CVID). CVID is one of the most common symptomatic primary immunodeficiencies in adults, characterised by infectious and non-infectious symptoms. Amongst CVID patients, ITP is the most frequent autoimmune manifestation. In this single-centre study, we performed a clinical and immunological characterisation of 20 patients with CVID-related ITP and 20 ITP patients without CVID to compare severity and remission rates. We found that patients with CVID-related ITP had a higher WHO Bleeding Scale at initial diagnosis yet showed higher remission rates and required less treatment. Patients with ITP needed up to seven therapy options and were often treated with second-line drug therapy, whilst only one CVID-related ITP patient required second-line drug therapy. Therefore, we show that the course of thrombocytopenia in patients with CVID-related ITP is milder. Furthermore, we show that soluble interleukin-2 receptor (sIL-2R, CD25) was higher in CVID-related ITP compared to ITP patients and could accurately classify patient cohorts with an Area Under the Receiver Operating Characteristic of 0.92. Whilst none of the ITP patients had a history of immunodeficiency, we found immunological abnormalities in 12 out of 18 patients. Therefore, we recommend screening ITP patients for CVID and other immunodeficiencies to detect immune abnormalities early, as we found patients with reduced immunoglobulin levels as well as severe lymphocytopenia in our ITP cohort.

Common variable immunodeficiency-an independent risk factor for atherosclerotic cardiovascular diseases

Atherosclerosis, a disease of chronic inflammation of the arterial wall, is the main cause of most cardiovascular diseases (CVDs). Common variable immunodeficiency (CVID), a group of diseases characterized by frequent infections due to defective antibody production and lack of human immunoglobulins, plays a role in immune activation and inflammation. Thus, it can be hypothesized that CVID increases the risk for atherosclerotic CVDs. On the other hand, it is also possible that CVID patients are protected from atherosclerotic CVDs based on their life-long immunoglobulin therapy. Here, we examined whether patients with CVID have an increased risk for atherosclerotic CVDs or whether they are protected from these diseases. Using an electronic patient database registry search of a population of 83 CVID patients and their age- and sex-matched, tenfold larger control population we demonstrate that CVID patients have a statistically significantly higher risk for coronary heart disease (OR 2.4, p = 0.015) and peripheral vascular disease (OR 12.5, p < 0.001). Regarding cerebrovascular disease, there was a trend towards CVID patients having more strokes or ischemic attacks, but the difference was not statistically significant (OR 2.0, p = 0.133). The combined OR for CVID patients for atherosclerotic CVDs was 2.6 (p = 0.001). CVID population had more hypertension, but smoking was more seldom. There were no statistically significant differences in the incidence of diabetes or levels of serum total, HDL or LDL cholesterol, or glycosylated hemoglobin A1c between CVID patients and their controls. CVID patients had infections more frequently and the OR for autoimmune diseases was 3.8 (p < 0.001). Finally, a multivariate logistic analysis showed that CVID is an independent risk factor for atherosclerotic CVDs (p = 0.002). The present study demonstrates for the first time that CVID is an independent risk factor for atherosclerotic CVDs. Further studies are required to fully understand the exact mechanisms behind this.

Screening for Antibody Deficiencies in Adults by Serum Electrophoresis and Calculated Globin

PURPOSE

This study aimed to investigate the correlation between calculated globulin (CG, total protein level minus albumin level) and the gamma globulin fraction (Gamma), obtained from serum protein electrophoresis with serum IgG levels in adults (≥ 18 years).

METHODS

Using linear regression models, analyses of CG and Gamma levels correlation with IgG levels in adults were performed. Receiver-operator curves were created to determine cutoff values and the respective sensitivity and specificity measures.

RESULTS

A total of 886 samples were analyzed. CG and Gamma were positively and statistically correlated with IgG levels (r2 = 0.4628 for CG, and = 0.7941 for Gamma, p < 0.0001 for both analyses). For the detection of hypogammaglobulinemia, i.e., IgG level below the reference value (6 g/L), a CG cutoff value of 24 g/L showed a sensitivity of 86.2% (95% CI 69.4-94.5) and a specificity of 92% (90.0-93.6). A Gamma cutoff value of 7.15 g/L yielded a sensitivity of 100% (88.3-100) and a specificity of 96.8 (95.3-97.8).

CONCLUSION

Both CG and Gamma levels determined by protein electrophoresis analysis may be used to screen for antibody deficiencies in adults, enabling earlier diagnosis of antibody deficiencies in a routine clinical setting.

Intravenous immunoglobulin treatment improves multiple neuropsychiatric outcomes in patients with pediatric acute-onset neuropsychiatric syndrome

Pediatric Acute-Onset Neuropsychiatric Syndrome (PANS) is defined by acute onset of diverse neuropsychiatric manifestations, presumably in the setting of underlying immune dysfunction. We used standardized neuropsychological testing to assess how intravenous immunoglobulins (IVIG) impact neurological and cognitive functions in PANS patients by comparing pretreatment with post-treatment scores. A 5-year retrospective study was undertaken in Children's Postinfectious Autoimmune Encephalopathy Center at University of Arizona. We identified 12 children diagnosed with PANS and treated with immunomodulatory IVIG doses, who also completed neuropsychological testing before and after treatment. We tracked multiple patient characteristics, type/timeline of testing, and number of IVIG courses. Score change of 1 standard deviation in any tested domain/subdomain was considered improvement. We further reviewed records for laboratory signs of triggering infection and immune dysfunction. Improvement occurred in 11/12 patients, in one or multiple domains/subdomains, independently of time between disease onset and IVIG initiation (0-7 years). Participants received 1-7 IVIG courses. Improvement was primarily seen in memory (58%), sensory-motor (37%) and visual-motor integration (30%). In 5/12 patients we detected hypogammaglobulinemia requiring ongoing IVIG replacement, one patient had isolated low IgA. Only one patient had to discontinue IVIG therapy due to severe adverse effects. Standardized neuropsychological testing represents an important tool to objectively measure improvement in PANS patients. IVIG was tolerated well and showed efficacy in the vast majority of participants, independently from timelapse since disease onset, emphasizing impact of immunomodulation in PANS. Significant presence of baseline hypogammaglobulinemia in children with PANS emphasizes the presumed role of immune dysfunction in disease pathogenesis.

[Autoimmunity and Freiburg classification in common variable immunodeficiency]

Introduction

Up to 25% of patients with common variable immunodeficiency (CVID) debut with autoimmunity, which is related to the Freiburg classification, which is based on flow cytometry.

Objective

to determine the frequency and type of autoimmune diseases and their association with the Freiburg classification in adults with CVID.

Methods

A cross-sectional, analytical and observational study was carried out with 33 patients belonging to the Primary Immunodeficiency Clinic of a third level hospital, with a diagnosis of CVID. They were divided into 3 phenotypes according to the Freiburg classification.

Results

Of the 33 patients studied, 66.6% presented autoimmune diseases, 19 of them (86.3%) had cytopenia; 42.1% belonged to Freiburg group Ia, 36.8% to Ib and 21% to phenotype II. In 36.6% of the patients, autoimmune cytopenia were the first manifestation of CVID; and up to 70% of them belong to the Freiburg phenotype Ia (p = 0.086). Patients with autoimmune cytopenia had a lower percentage of isotype-switched memory B cells (p = 0.018), no higher percentage of CD21low B cells (p = 0.226).

Conclusions

Classification by CVID phenotypes allows the identification of the patient's profile according to the percentage of memory B cells with isotype change, which is useful to intentionally search for non-infectious complications of the disease.

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.

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.

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

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

Management of a patient with common variable immunodeficiency and hepatopathy

BACKGROUND

Common variable Immunodeficiency (CVID) is a primary immunodeficiency disorder and the most common form of severe antibody deficiency. Both children and adults are affected and clinical manifestations vary widely. Often, CVID manifests with infections, autoimmune phenomena or chronic lung disease, but it also frequently affects the liver. The differential diagnoses of hepatopathies in CVID patients are diverse and the characteristics of CVID patients often make it difficult to determine the correct diagnosis.

CASE PRESENTATION

We present the case of a 39-year-old patient with CVID and elevated liver enzymes, nausea and unintended weight loss, who was referred to our clinic with the suspected diagnose of autoimmune hepatitis or immunoglobulin-induced hepatopathy. Prior, the patient had undergone an extensive diagnostic work-up including liver biopsy but viral hepatitides had only been investigated serologically - with negative antibody results. We searched for viral nucleic acid by polymerase chain reaction and detected hepatitis E virus-RNA. Antiviral therapy was started and the patient recovered quickly.

CONCLUSION

Hepatopathies in CVID patients are common with a broad spectrum of possible causes. While treating CVID patients, the distinct diagnostic and therapeutic requirements of the CVID patients should be closely considered and diagnosed by the appropriate measures.

Inborn Errors of Immunity and Autoimmune Disease

Autoimmunity may be a manifestation of inborn errors of immunity, specifically as part of the subgroup of primary immunodeficiency known as primary immune regulatory disorders. However, although making a single gene diagnosis can have important implications for prognosis and management, picking patients to screen can be difficult, against a background of a high prevalence of autoimmune disease in the population. This review compares the genetics of common polygenic and rare monogenic autoimmunity, and explores the molecular mechanisms, phenotypes, and inheritance of autoimmunity associated with primary immune regulatory disorders, highlighting the emerging importance of gain-of-function and non-germline somatic mutations. A novel framework for identifying rare monogenic cases of common diseases in children is presented, highlighting important clinical and immunologic features that favor single gene disease and guides clinicians in selecting appropriate patients for genomic screening. In addition, there will be a review of autoimmunity in non-genetically defined primary immunodeficiency such as common variable immunodeficiency, and of instances where primary autoimmunity can result in clinical phenocopies of inborn errors of immunity.

Development of a primary care screening algorithm for the early detection of patients at risk of primary antibody deficiency

BACKGROUND

Primary antibody deficiencies (PAD) are characterized by a heterogeneous clinical presentation and low prevalence, contributing to a median diagnostic delay of 3-10 years. This increases the risk of morbidity and mortality from undiagnosed PAD, which may be prevented with adequate therapy. To reduce the diagnostic delay of PAD, we developed a screening algorithm using primary care electronic health record (EHR) data to identify patients at risk of PAD. This screening algorithm can be used as an aid to notify general practitioners when further laboratory evaluation of immunoglobulins should be considered, thereby facilitating a timely diagnosis of PAD.

METHODS

Candidate components for the algorithm were based on a broad range of presenting signs and symptoms of PAD that are available in primary care EHRs. The decision on inclusion and weight of the components in the algorithm was based on the prevalence of these components among PAD patients and control groups, as well as clinical rationale.

RESULTS

We analyzed the primary care EHRs of 30 PAD patients, 26 primary care immunodeficiency patients and 58,223 control patients. The median diagnostic delay of PAD patients was 9.5 years. Several candidate components showed a clear difference in prevalence between PAD patients and controls, most notably the mean number of antibiotic prescriptions in the 4 years prior to diagnosis (5.14 vs. 0.48). The final algorithm included antibiotic prescriptions, diagnostic codes for respiratory tract and other infections, gastro-intestinal complaints, auto-immune symptoms, malignancies and lymphoproliferative symptoms, as well as laboratory values and visits to the general practitioner.

CONCLUSIONS

In this study, we developed a screening algorithm based on a broad range of presenting signs and symptoms of PAD, which is suitable to implement in primary care. It has the potential to considerably reduce diagnostic delay in PAD, and will be validated in a prospective study. Trial registration The consecutive prospective study is registered at clinicaltrials.gov under NCT05310604.

Assessment of low immunoglobulin levels and clinical manifestations in patients with mastocytosis

Background

Patients with a low IgG level alone or with low IgA or IgM levels have been reported to be susceptible to respiratory tract infections and recurrent sinusitis. Patients diagnosed with CVID have a higher prevalence of autoimmune diseases and lymphoid malignancies. Mastocytosis is a myeloproliferative disease, not typically associated with autoimmune disease or frequent infections.

Objective

We sought to determine the distribution of immunoglobulins in children and adults with mastocytosis. Evaluate the impact of low immunoglobulins on the clinical management of patients with mastocytosis.

Methods

We performed a 10-year retrospective analysis on 320 adult and pediatric patients with mastocytosis for immunoglobulins using an electronic medical query. We identified 25 adults and 9 children with one or more low immunoglobulins. Patient records were examined for a history of infections and autoimmune disorders.

Results

Serum immunoglobulins in children and adults with mastocytosis fell within a normal range. Among patients with low IgG levels alone or with low IgM and /or IgA, 20% had a history of infections and 20% of adults had autoimmune disorders. The most common infection was recurrent otitis media (OM).

Conclusion

Patients with mastocytosis typically have normal immunoglobulins. With few exceptions, those with low immunoglobulins did not have frequent infections or autoimmune diseases. This data supports the conclusion that routine determination of immunoglobulins in patients with mastocytosis is not required and reserved for patients with clinical conditions, which might be related to an immunoglobulin deficiency.

Interferon-Driven Immune Dysregulation in Common Variable Immunodeficiency-Associated Villous Atrophy and Norovirus Infection

PURPOSE

About 15% of patients with common variable immunodeficiency (CVID) develop a small intestinal enteropathy, which resembles celiac disease with regard to histopathology but evolves from a distinct, poorly defined pathogenesis that has been linked in some cases to chronic norovirus (NV) infection. Interferon-driven inflammation is a prominent feature of CVID enteropathy, but it remains unknown how NV infection may contribute.

METHODS

Duodenal biopsies of CVID patients, stratified according to the presence of villous atrophy (VA), IgA plasma cells (PCs), and chronic NV infection, were investigated by flow cytometry, multi-epitope-ligand cartography, bulk RNA-sequencing, and RT-qPCR of genes of interest.

RESULTS

VA development was connected to the lack of intestinal (IgA+) PC, a T helper 1/T helper 17 cell imbalance, and increased recruitment of granzyme+CD8+ T cells and pro-inflammatory macrophages to the affected site. A mixed interferon type I/III and II signature occurred already in the absence of histopathological changes and increased with the severity of the disease and in the absence of (IgA+) PCs. Chronic NV infection exacerbated this signature when compared to stage-matched NV-negative samples.

CONCLUSIONS

Our study suggests that increased IFN signaling and T-cell cytotoxicity are present already in mild and are aggravated in severe stages (VA) of CVID enteropathy. NV infection preempts local high IFN-driven inflammation, usually only seen in VA, at milder disease stages. Thus, revealing the impact of different drivers of the pathological mixed IFN type I/III and II signature may allow for more targeted treatment strategies in CVID enteropathy and supports the goal of viral elimination.

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.

Primary antibody deficiency-associated arthritis shares features with spondyloarthritis and enteropathic arthritis

OBJECTIVE

The clinical spectrum of primary antibody deficiencies (PADs) and especially common variable immunodeficiency (CVID) includes various autoimmune disorders. We studied the prevalence and the features of articular rheumatic disease in a cohort of patient with PADs.

METHODS

In this retrospective cohort study, complete clinical data of 268 patients with PADs, mainly consisting of patients with CVID, visiting the immunology outpatient clinic of a German tertiary hospital between 2018 and 2021 were collected. Those included case history, physical examination, laboratory as well as radiological findings.

RESULTS

Inflammatory arthritis was diagnosed in 16.4% of studied patients and was significantly more common among patients with PAD-associated enteropathy (OR 13.39, p=0.0001), splenomegaly (OR 6.09, p=0.0001) or atopic diseases (OR 3.31, p=0.021). Given HLA-B27 status, the involvement of the axial skeleton and the presence of features, such as anterior uveitis, inflammatory bowel disease, psoriasis and/or dactylitis, 75% of studied patients fulfilled the Assessment of Spondyloarthritis International Society classification criteria.

CONCLUSION

PAD-associated arthritis frequently shares features with spondyloarthritis (SpA) and enteropathic arthritis. The latter may suggest the interconnected pathomechanisms of inflammatory arthritis in SpA and PADs.

Immunosuppression in Patients With Primary Immunodeficiency-Walking the Line

Individuals with primary immunodeficiency (PIDD) experience not only infectious complications but also immune dysregulation leading to autoimmunity, inflammation, and lymphoproliferative manifestations. Management of these complications often requires treatment with additional immunosuppressive medications, which pose an additional risk of infectious complications. Immunosuppression in individuals with PIDD therefore requires careful assessment and consideration of risks and benefits. Medications should be closely monitored, and strategies for risk mitigation of adverse events considered, such as exposure reduction, appropriate vaccination, use of antibiotics/antivirals, and optimization of immunoglobulin replacement therapy. In a subset of individuals who are not tolerating immune modulation or experiencing disease progression despite appropriate interventions, hematopoietic stem-cell transplantation is a management option.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

An Expert Opinion/Approach: Clinical Presentations, Diagnostic Considerations, and Therapeutic Options for Gastrointestinal Manifestations of Common Variable Immune Deficiency

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency. It is characterized by impaired B-cell differentiation. Although patients can be diagnosed with CVID anytime during their lifetime, most patients have symptoms for 5-9 years before their diagnosis. The diagnosis of CVID starts with a detailed history focusing on the infectious and noninfectious manifestations of the disease. In patients who are suspected to experience CVID, quantitative immunoglobulins (Ig) should be checked to confirm the diagnosis. IgG should be at least 2 times less than the age-specific SD along with either a low IgA or IgM and with evidence of impaired vaccine response. CVID is usually associated with infectious and/or noninfectious conditions, the latter of which can be inflammatory, autoimmune, lymphoproliferative, or malignant, among other manifestations. Ig therapy has positively affected the disease course of patients with infectious complications but has limited effect on the noninfectious manifestations because the noninfectious complications are related to immune dysregulation involving B cells and T cells rather than primarily due to antibody deficiency. When the gastrointestinal (GI) system is involved, patients with CVID may display signs and symptoms that mimic several GI conditions such as celiac disease, pernicious anemia, or inflammatory bowel diseases. The inflammatory bowel disease-like condition is usually treated with steroids, 5-aminosalicylates, thiopurines, or biologic agents to control the inflammation. In this review, the clinical presentations, diagnostic considerations, and therapeutic options for GI manifestations of CVID will be discussed to facilitate the individualized management of these often-complex patients.

Seronegative autoimmune diseases: A challenging diagnosis

Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

CVID patients developing autoimmune cytopenias display characteristic immune phenotypic features.

Gastrointestinal involvement of common variable immunodeficiency: A diagnostic challenge to the physician

A 35-year-old male presented with fatigue for 1 month and was found to have megaloblastic anaemia. Further evaluation showed low globulin levels and pan hypogammaglobulinemia. Past history was significant for chronic small bowel diarrhoea and bilateral genu valgum deformity from childhood. Hence, a malabsorption syndrome with a probable antibody deficiency was suspected. An upper gastrointestinal (GI) endoscopy was done, which revealed chronic atrophic gastritis with Helicobacter pylori infection, dysplasia and subtotal villous atrophy with a paucity of plasma cells, which was suggestive of common variable immunodeficiency (CVID)-related enteropathy. CVID can present with predominantly autoimmune GI manifestations without any history of recurrent infections. The risk of gastric dysplasia and malignancy is high in CVID and needs close monitoring.

Specific antibody deficiency: Pearls and pitfalls for diagnosis

OBJECTIVE

Specific antibody deficiency is an immune deficiency defined by the presence of normal quantitative levels of immunoglobulins but impaired antibody responses to polysaccharide antigens in patients presenting with frequent otosinopulmonary infections with pyogenic bacteria. This review summarizes the pitfalls associated with defining exactly what constitutes an "impaired" antibody response to polysaccharide antigens and the importance of documenting actual pyogenic infections before making a diagnosis of an immune deficiency.

DATA SOURCES

PubMed review using the following words: specific antibody deficiency, pneumococcal vaccination, salmonella vaccination, infectious sinusitis Study Selection: This review focused on key studies that have been utilized to define what constitutes a "normal" humoral immune response to pneumococcal and salmonella vaccination in healthy subjects as well as published papers defining current expert opinion.

RESULTS

Published studies demonstrate wide variability in response to pneumococcal vaccination in healthy individuals making it daunting to define what constitutes an abnormal response. These challenges are exacerbated by striking laboratory variability in reporting results.

CONCLUSION

Clinical evaluations in individuals with self-reported recurrent acute sinusitis or lower respiratory infections need to document an infectious etiology with pyogenic bacteria and must rule out an underlying primary airway inflammatory disorder before consideration is made regarding the presence of an immune deficiency. In addition, decision making regarding diagnosis and treatment of patients being evaluated for humoral immunodeficiency should not hinge solely on the strict application of defined cutoffs for "normal" response to a single polysaccharide vaccine, but rather a global assessment of humoral immune function in the context of the clinical presentation.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

Morbidity, Mortality, and Therapeutics in Combined Immunodeficiency: Data From the USIDNET Registry

BACKGROUND

Optimal management of patients with combined immunodeficiency, especially pertaining to hematopoietic stem cell transplantation (HSCT), remains unclear.

OBJECTIVE

To identify factors influencing HSCT and mortality in the population with combined immunodeficiency in North America.

METHODS

We identified 337 participants in the United States Immunodeficiency Network database with diverse forms of combined immunodeficiency and their characteristics, including demographic characteristics, laboratory values, infectious history, comorbidities, and treatment strategies. Univariate analysis was performed using logistic regression, whereas multivariate analysis was performed using multiple Cox proportional hazards.

RESULTS

On univariate analysis, disseminated invasive viral infections and variants in STAT3, GATA2, and, DOCK8 were associated with increased odds of HSCT. Mucocutaneous fungal infections and variants in STAT3 were associated with increased odds of survival, whereas disseminated/invasive fungal infections, disseminated/invasive viral infections, and parasitic infections were associated with decreased odds of survival. On multiple variable Cox proportional hazards analysis, variants in ZAP70, nonspecific bacterial, and disseminated/invasive viral infections were associated with increased hazards of transplantation, whereas variants in multiple genes (RMRP, NEMO, DOCK8, CD40L, and CARD9), disseminated/invasive viral infections, autoimmune disease, and higher absolute lymphocyte count were associated with increased hazards of death. Importantly, demographic characteristics, basic lymphocyte subset counts, and absence of genetic diagnosis were not associated with HSCT or mortality.

CONCLUSIONS

We determined that specific genetic diagnoses and infection burden impacts the decision to undergo HSCT in this cohort. In addition, certain genetic diagnoses and invasive viral infections carry an increased risk of mortality.

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.

Clinical and laboratory parameter analysis in patients with common Variable Immunodeficiency

Introduction: Common Variable Immunodeficiency (CVID) is the most prevalent primary immunodeficiency in adult population. The diagnosis is based on low concentration of at least 2 immunoglobulin classes, mostly IgG, with low IgA and/or IgM. Beside recurrent infections, patients with CVID usually suffer from different respiratory, gastrointestinal, autoimmune and malignant diseases. Leading therapeutic approach to managing CVID is regular intravenous (IVIG) and subcutaneous (SCIG) immunoglobulin replacement therapy. Aim: The aim of the study was to analyze clinical and laboratory parameters in patients with CVID. Material and methods: The present study included 24 patients with CVID who were treated at Clinic of Allergy and Immunology, University Clinical Center of Serbia from 2012 to 2022. Demographic data, clinical and laboratory parameters were obtained from the patients' medical records. The concentrations of IgG, IgM and IgA were measured by nephelometry. Statistical analysis was performed using descriptive methods, Student t test for independent samples and Fisher exact test. Results: Respiratory manifestations were found in 70.8% of patients, gastrointestinal in 45.8%, autoimmune in 29.2% and malignancies in 20.8%. The presence of autoimmune diseases was the most common within the patients aged between 20 to 30 years, and it was statistically significantly higher comparing to other age groups (p = 0.014). Serum IgG concentration of 7.6 ± 2.7 g/l was measured. Statistically significantly higher IgG concentrations were observed in patients receiving SCIG (10.2 ± 1.6), compared to those receiving IVIG (6.7 ± 2.4) (t = -3.3, p = 0.003). Premedication was required in 44.4% of patients receiving IVIG. Conclusion: The most common complication of CVID are chronic lung diseases. Autoimmune diseases are the most frequently diagnosed in patients between the ages of 20 and 30. The use of SCIG is identified as better form of immunoglobulin replacement therapy. Total immunoglobulin serum concentration measuring in patients with recurrent infections and autoimmune diseases can contribute to timely diagnosis.

Establishing the Molecular Diagnoses in a Cohort of 291 Patients With Predominantly Antibody Deficiency by Targeted Next-Generation Sequencing: Experience From a Monocentric Study

Predominantly antibody deficiencies (PAD) are a heterogeneous group of disorders characterized by dysfunctional antibody production, low immunoglobulin levels in serum and impaired vaccine responses. The clinical picture is variable, ranging from mild symptoms to severe complications, which may include autoimmunity, gastrointestinal disease, allergy, and malignancies. If left untreated, PAD patients are at risk of enduring disease progression, irreversible organ damage, and reduced life expectancy. A timely diagnosis has been shown to significantly improve disease prognosis. Here, we report on our experience using targeted gene panel sequencing by employing Agilent's HaloPlex or SureSelect and Illumina's MiSeq technologies in a cohort of 291 individuals who presented with low or absent immunoglobulin levels in combination with or without other clinical features. In total, we have detected over 57 novel or previously reported relevant mutations in ADA, ADA2, BTK, CTLA4, LRBA, NFKB1, NFKB2, PIK3CD, STAT3, and TNFRSF13B. Overall, a genetic diagnosis could be made in 24.7% of the investigated patients. The percentage of coverage for the targeted regions ranged from 90% to 98% in this study. Moreover, functional assays were performed on a defined group of the patients carrying candidate variants in CTLA4, LRBA, NFKB1 and BTK, which confirmed their deleterious effect on protein expression and/or function. This study reiterates that the immunological heterogeneity of predominantly antibody deficiencies may have a diverse genetic origin, although certain clinical features may hint towards a specific group of defects. Employing targeted sequencing panels proves to be a very time- and cost-efficient, yet reliable, method for the establishment of a genetic diagnosis in individuals with PAD. However, in case of negative panel results, or if functional testing reveals inconspicuous observations in patients with a clear indication for genetic testing, further work-up including whole exome or whole genome sequencing should be considered.

The molecular structure and biological functions of RNA methylation, with special emphasis on the roles of RNA methylation in autoimmune diseases

Autoimmune diseases such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and systemic vasculitis are caused by the body's immune response to autoantigens. The pathogenesis of autoimmune diseases is complex. RNA methylation is known to play a key role in disease progression as it regulates almost all aspects of RNA processing, including RNA nuclear export, translation, splicing, and noncoding RNA processing. This review summarizes the mechanisms, molecular structures of RNA methylations and their roles in biological functions. Similar to the roles of RNA methylation in cancers, RNA methylation in RA and SLE involves "writers" that deposit methyl groups to form N6-methyladenosine (m6A) and 5-methylcytosine (m5C), "erasers" that remove these modifications, and "readers" that further affect mRNA splicing, export, translation, and degradation. Recent advances in detection methods have identified N1-methyladenosine (m1A), N6,2-O-dimethyladenosine (m6Am), and 7-methylguanosine (m7G) RNA modifications, and their roles in RA and SLE need to be further studied. The relationship between RNA methylation and other autoimmune diseases has not been reported, and the roles and mechanisms of RNA modifications in these diseases need to be explored in the future.

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.

Mast cell activation disease and immunoglobulin deficiency in patients with hypermobile Ehlers-Danlos syndrome/hypermobility spectrum disorder

Mast cell activation disease (MCAD) includes single organ disease such as asthma, urticaria, and gastroenteritis, as well as multiorgan system involvement such as mast cell activation syndrome and anaphylaxis. Reports link MCAD with hypermobile Ehlers-Danlos syndrome (hEDS), hypermobility spectrum disorder (HSD), and with primary immune deficiencies such as complement and immunoglobulin deficiencies (Ig Def). This study assesses the concurrence of these syndromes. We undertook a cohort analysis of patients seen in a community-based Allergy/Immunology clinic from 2015 to 2019. We searched for diagnostic codes for Ig Def disorders, hypermobility syndrome, hypermobile/Ehlers-Danlos syndrome, and MCADs. Of 974 patients with suspected MCAD, 449 (46%) had a diagnosis of MCAD; 496 (51%) of cases had a combination of at least two of hEDS/HSD, MCAD, and Ig Def. Ig Def was present in 417 (43%) of patients; 188 (19.3%) had hEDS/HSD with an Ig Def with or without MCAD and accounted for 45% of all the cases with Ig Def. Of 974 cases, 101 (10%) had hEDS/HSD and MCAD; 207 (21%) had Ig Def and MCAD; 7 (0.7%) had Ig Def and hEDS/HSD; and 181 (19%) had a combination of all three syndromes. Most patients (74%) with these comorbidities were female. The presence of MCAD and Ig Def should be explored in patients with hEDS/HSD. Identifying underlying contributors to recurrent/chronic inflammation and tissue injury is needed to tailor and personalize therapies. This, in turn, can reduce tissue damage, iatrogenic intervention, and optimize health outcomes.

Granulomatous Lymphocytic Interstitial Lung Disease in a Spectrum of Pediatric Primary Immunodeficiencies

BACKGROUND

Granulomatous lymphocytic interstitial lung disease (GLILD) has been increasingly recognized in children affected with primary immunodeficiencies (PIDs). In this study, we aimed to better characterize the spectrum of pediatric PIDs coexisting with GLILD including clinical and immunological predictors, thoracic imaging findings, and histopathologic features.

METHODS

We respectively reviewed records of six representative cases of children, three of them affected with common variable immunodeficiency (CVID) and three with syndromic immunodeficiencies, in whom a diagnosis of GLILD was established based on clinical, radiological, and histopathologic findings. Clinical and immunological predictors for GLILD were also analyzed in the patients studied.

RESULTS

All the children with GLILD had a history of autoimmune phenomena, organ-specific immunopathology, and immune dysregulation. Defective B-cell maturation and deficiency of memory B cells were found in all the children with GLILD. The radiological and histopathological features consistent with the diagnosis of GLILD, granulomatous disease, and lymphoid hyperplasia, were accompanied by chronic airway disease with bronchiectasis in children with CVID and syndromic PIDs.

CONCLUSIONS

Our study shows that both CVID and syndromic PIDs may be complicated with GLILD. Further studies are required to understand the predictive value of coexisting autoimmunity and immune dysregulation in the recognition of GLILD in children with PIDs.

Autoimmune Hepatitis in a Patient With Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is characterized by defective immunoglobulin synthesis because of impaired B-cell function. Liver abnormalities including autoimmune hepatitis (AIH) have been described in up to 10% of patients. We report a 27-year-old woman with CVID who presented with liver dysfunction secondary to AIH. AIH is both uncommon and challenging diagnostically in patients with CVID because they have low IgG levels and often have low or undetectable autoantibody levels. Liver biopsy and response to therapy play an important role in establishing the diagnosis. Corticosteroids are the mainstay of therapy, with or without immune modulators.

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

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