Gastrointestinal Disorders Associated with Common Variable Immune Deficiency (CVID) and Chronic Granulomatous Disease (CGD)

Paucity of gastrointestinal plasma cells in common variable immunodeficiency

PURPOSE OF REVIEW

Common variable immunodeficiency enteropathy (CVID-E) is a noninfectious complication of CVID caused by chronic inflammation of the gastrointestinal (GI) tract. Based on literature, a paucity or lack of plasma cells, although not obligatory for diagnosis, is a pathognomonic feature of CVID and more frequent in CVID-E. However, there is no consensus on standardized histopathological analysis of this feature in biopsies. In this systematic review, we highlight methods of reproducible plasma cell quantification of biopsies in CVID and describe the plasma cell counts and classes as presented in the literature.

RECENT FINDINGS

Reduced plasma cell counts are commonly found over the entire GI tract, except for in the oesophagus. Immunoglobulin A+ (IgA+) plasma cells appear to be the most commonly reduced plasma cell class in CVID, yet there is scarce literature on the predictive value of low IgA+ plasma cell counts in CVID-E.

SUMMARY

We propose two optimized methodologies of quantification using a cut-of value of <10 plasma cells per HPF at 40× magnification, or a proportion of ≥1-5% of total mononuclear cells, recorded over ≥3 sections, and in ≥2 biopsies, as the most conservative agreeable definitions for a paucity of plasma cells to be used in diagnostics and further research.

Dissecting Secondary Immunodeficiency: Identification of Primary Immunodeficiency within B-Cell Lymphoproliferative Disorders

Distinguishing between primary (PID) and secondary (SID) immunodeficiencies, particularly in relation to hematological B-cell lymphoproliferative disorders (B-CLPD), poses a major clinical challenge. We aimed to analyze and define the clinical and laboratory variables in SID patients associated with B-CLPD, identifying overlaps with late-onset PIDs, which could potentially improve diagnostic precision and prognostic assessment. We studied 37 clinical/laboratory variables in 151 SID patients with B-CLPD. Patients were classified as "Suspected PID Group" when having recurrent-severe infections prior to the B-CLPD and/or hypogammaglobulinemia according to key ESID criteria for PID. Bivariate association analyses showed significant statistical differences between "Suspected PID"- and "SID"-groups in 10 out of 37 variables analyzed, with "Suspected PID" showing higher frequencies of childhood recurrent-severe infections, family history of B-CLPD, significantly lower serum Free Light Chain (sFLC), immunoglobulin concentrations, lower total leukocyte, and switch-memory B-cell counts at baseline. Rpart machine learning algorithm was performed to potentially create a model to differentiate both groups. The model developed a decision tree with two major variables in order of relevance: sum κ + λ and history of severe-recurrent infections in childhood, with high sensitivity 89.5%, specificity 100%, and accuracy 91.8% for PID prediction. Identifying significant clinical and immunological variables can aid in the difficult task of recognizing late-onset PIDs among SID patients, emphasizing the value of a comprehensive immunological evaluation. The differences between "Suspected PID" and SID groups, highlight the need of early, tailored diagnostic and treatment strategies for personalized patient management and follow up.

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.

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

Background

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

Methods

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

Results

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

Conclusions

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

[Pulmonary complications of Chronic Granulomatous Disease]

Chronic Granulomatosis Disease (CGD) is an inherited immune deficiency due to a mutation in the genes coding for the subunits of the NADPH oxidase enzyme that affects the oxidative capacity of phagocytic cells. It is characterized by increased susceptibility to bacterial and fungal infections, particularly Aspergillus, as well as complications associated with hyperinflammation and granulomatous tissue infiltration. There exist two types of frequently encountered pulmonary manifestations: (1) due to their being initially pauci-symptomatic, possibly life-threatening infectious complications are often discovered at a late stage. Though their incidence has decreased through systematic anti-bacterial and anti-fungal prophylaxis, they remain a major cause of morbidity and mortality; (2) inflammatory complications consist in persistent granulomatous mass or interstitial pneumoniae, eventually requiring immunosuppressive treatment. Pulmonary complications recurring since infancy generate parenchymal and bronchial sequelae that impact functional prognosis. Hematopoietic stem cell allograft is a curative treatment; it is arguably life-sustaining and may limit the morbidity of the disease. As a result of improved pediatric management, life expectancy has increased dramatically. That said, new challenges have appeared with regard to adults: difficulties of compliance, increased inflammatory manifestations, acquired resistance to anti-infectious therapies. These different developments underscore the importance of the transition period and the need for multidisciplinary management.

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

Background

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

Methods

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

Results

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

Conclusions

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

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.

CVID-Associated Intestinal Disorders in the USIDNET Registry: An Analysis of Disease Manifestations, Functional Status, Comorbidities, and Treatment

Common variable immunodeficiency (CVID) has been subdivided into five phenotypes, including one marked by non-infectious enteropathies that lead to significant morbidity and mortality. We examined a large national registry of patients with CVID to better characterize this population and understand how the presence of enteropathy influences nutritional status, patient function, and the risk of additional non-infectious disorders in CVID patients. We also sought to illustrate the range of treatment strategies for CVID-associated enteropathies. We extracted patient data from the United States Immunodeficiency Network (USIDNET) database, which included 1415 patients with CVID, and compared those with and without intestinal disorders. Demographic and genetic profiles, functional status, and treatments targeting intestinal disorders are reported. Intestinal disorders were present in 20% of patients with CVID, including chronic diarrhea, inflammatory bowel disease, malabsorption, and others. Compared to those without enteropathies, this patient subset exhibited significantly lower Karnofsky-Lansky functional scores, greater reliance on nutritional support, higher rates of vitamin deficiencies, and increased prevalence of hematologic disorders, liver disease, pulmonary disease, granulomatous disease, and lymphoma. Genetic data were reported for only 5% of the cohort. No mutations segregated significantly to patients with or without intestinal disease. Corticosteroids were most frequently used for treatment. Patients with CVID-associated intestinal disorders exhibit higher rates of autoimmune and inflammatory comorbidities, lymphoma, malnutrition, and debility. We review recent studies implicating specific pathways underlying this immune dysregulation. Further studies are needed to evaluate the role of targeted immunomodulatory therapies for CVID-associated intestinal disorders.

The Importance of Considering Common Variable Immunodeficiency in Patients With Chronic Diarrhea

Chronic diarrhea poses a diagnostic challenge due to its diverse etiology, encompassing various gastrointestinal disorders. This case report emphasizes the clinical significance of considering common variable immunodeficiency (CVID) as a potential underlying cause in a patient presenting with chronic diarrhea. In this case study, we describe a 36-year-old female with a 9-year history of chronic diarrhea, recurrent sinopulmonary infections, and weight loss for 3 years, where previous evaluations failed to yield a diagnosis. This case underscores the diagnostic hurdles faced by healthcare professionals, often causing a delay in identifying fewer common conditions like immunodeficiency syndromes. Early recognition of CVID is crucial, enabling timely intervention with immunoglobulin replacement therapy, markedly enhancing patients' quality of life and averting complications. This report highlights the necessity for a comprehensive evaluation of non-responsive chronic diarrhea cases and raises awareness about CVID as an essential consideration, facilitating precise diagnoses and tailored treatments.

Management of liver disease and portal hypertension in common variable immunodeficiency (CVID)

Patients with common variable immunodeficiency (CVID) frequently develop liver disease and associated complications, which represent an increasingly prevalent unmet medical need. The main hepatic manifestation of CVID is nodular regenerative hyperplasia (NRH), resulting in non-cirrhotic portal hypertension (NCPH). Liver disease is often underdiagnosed, leading to poor outcomes and decreased survival. The increasing numbers of patients with CVID who are diagnosed late with progressive liver disease underscores the importance of appropriate clinical management and treatment of liver complications. At the same time, specific guidelines for the clinical management of CVID-related liver disease are still lacking. Here, we review the epidemiology of CVID-related liver disease, reveal new insights into NRH and NCPH biology and highlight recently uncovered opportunities for NCPH diagnostics in CVID. Finally, we focus on current management of liver disease, portal hypertension and its complications - the key challenge in patients with CVID. Specifically, we review recent data regarding the role of transjugular intrahepatic portosystemic shunt and liver transplantation in clinical management. The role for anticoagulants and immunosuppressants targeting the pathogenesis of NRH will also be discussed. We propose an updated algorithm for the diagnostic work-up and treatment of NCPH in CVID. Finally, we consider future needs and therapeutic opportunities for CVID-related liver 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.

Dysbiosis and primary B-cell immunodeficiencies: current knowledge and future perspective

According to Elie Metchnikoff, an originator of modern immunology, several pivotal functions for disease and health are provided by indigenous microbiota. Nonetheless, important mechanistic insights have been elucidated more recently, owing to the growing availability of DNA sequencing technology. There are 10 to 100 trillion symbiotic microbes (such as viruses, bacteria, and yeast) in each human gut microbiota. Both locally and systemically, the gut microbiota has been demonstrated to impact immune homeostasis. Primary B-cell immunodeficiencies (PBIDs) are a group of primary immunodeficiency diseases (PIDs) referring to the dysregulated antibody production due to either intrinsic genetic defects or failures in functions of B cells. Recent studies have found that PBIDs cause disruptions in the gut's typical homeostatic systems, resulting in inadequate immune surveillance in the gastrointestinal (GI) tract, which is linked to increased dysbiosis, which is characterized by a disruption in the microbial homeostasis. This study aimed to review the published articles in this field to provide a comprehensive view of the existing knowledge about the crosstalk between the gut microbiome and PBID, the factors shaping the gut microbiota in PBID, as well as the potential clinical approaches for restoring a normal microbial community.

The paradox of autoimmunity and autoinflammation in inherited neutrophil disorders - in search of common patterns

Congenital defects of neutrophil number or function are associated with a severe infectious phenotype that may require intensive medical attention and interventions to be controlled. While the infectious complications in inherited neutrophil disorders are easily understood much less clear and explained are autoimmune and autoinflammatory phenomena. We survey the clinical burden of autoimmunity/autoinflammation in this setting, search for common patterns, discuss potential mechanisms and emerging treatments.

Predominant Antibody Deficiency and Risk of Microscopic Colitis: a Nationwide Case-Control Study in Sweden

PURPOSE : Predominant antibody deficiency (PAD) disorders, including common variable immunodeficiency (CVID), have been linked to increased risk of gastrointestinal infections and inflammatory bowel diseases. However, there are limited data on the relationship between PAD, specifically CVID, and risk of microscopic colitis (MC).

METHODS

We performed a nationwide case-control study of Swedish adults with MC diagnosed between 1997 and 2017 (n = 13,651). Data on biopsy-verified MC were retrieved from all of Sweden's pathology departments through the Epidemiology Strengthened by histoPathology Reports in Sweden (ESPRESSO) study. We defined predominant antibody deficiency using International Union of Immunologic Societies (IUIS) phenotypic classification. Individuals with MC were matched to population controls by age, sex, calendar year, and county. We used logistic regression to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULTS

The prevalence of PAD in MC was 0.4% as compared to 0.05% in controls. After adjustment for potential confounders, this corresponded to an aOR of 7.29 (95%CI 4.64-11.63). The magnitude of the association was higher for CVID (aOR 21.01, 95% 5.48-137.44) compared to other antibody deficiencies (aOR 6.16, 95% CI 3.79-10.14). In exploratory analyses, the association between PAD and MC was particularly strong among males (aOR 31.73, 95% CI 10.82-135.04).

CONCLUSION

In this population-based study, predominant antibody deficiency was associated with increased risk of MC, particularly among males. Clinicians who encounter these patients should consider a detailed infectious history and screening for antibody deficiency.

CVID-associated intestinal disorders in the USIDNET registry: An analysis of disease manifestations, functional status, comorbidities, and treatment

Common variable immunodeficiency (CVID) has been subdivided into five phenotypes, including one marked by non-infectious enteropathies that lead to significant morbidity and mortality. We examined a large national registry of patients with CVID to better characterize this population and understand how the presence of enteropathy influences nutritional status, patient function, and the risk of additional non-infectious disorders in CVID patients. We also sought to illustrate the range of treatment strategies for CVID-associated enteropathies. We extracted patient data from the United States Immunodeficiency Network (USIDNET) database, which included 1415 patients with CVID, and compared those with and without intestinal disorders. Demographic and genetic profiles, functional status, and treatments targeting intestinal disorders are reported. Intestinal disorders were present in 20% of patients with CVID, including chronic diarrhea, inflammatory bowel disease, malabsorption, and others. Compared to those without enteropathies, this patient subset exhibited significantly lower Karnofsky-Lansky functional scores, greater reliance on nutritional support, higher rates of vitamin deficiencies, and increased prevalence of hematologic disorders, liver disease, pulmonary disease, granulomatous disease, and lymphoma. Genetic data were reported for only 5% of the cohort. No mutations segregated significantly to patients with or without intestinal disease. Corticosteroids were most frequently used for treatment. Patients with CVID-associated intestinal disorders exhibit higher rates of autoimmune and inflammatory comorbidities, lymphoma, malnutrition, and debility. We review recent studies implicating specific pathways underlying this immune dysregulation. Further studies are needed to evaluate the role of targeted immunomodulatory therapies for CVID-associated intestinal disorders.

[Management of hypogammaglobulinemia]

Hypogammaglobulinemia (hypoγ) is defined as a serum IgG level < 7 g/L. It is most often detected on serum protein electrophoresis. Given the existence of transient hypoγ, its persistence should be checked at distance, preferably by requesting a blood test for IgG, IgA and IgM, which will be needed to characterize a possible primary immune deficiency (PID). In the case of association with a monoclonal component, the first step is to look for a cryoglobulin causing a false hypoγ. Otherwise, the etiological investigation is dictated by the clinical examination. For example, the notion of chronic diarrhea should lead to a search for an enteropathy causing a digestive loss of gammaglobulins (an ambiguous situation because some DIP can be complicated by an enteropathy). In the absence of an obvious explanation, a secondary cause must first be ruled out (secondary immune deficiencies are 30 times more common than PID). The first simple test to perform is 24-hour proteinuria, coupled with urinary protein electrophoresis, to rule out 2 diagnoses: nephrotic syndrome and light chain myeloma. Subsequently, blood immunophenotyping looking for a circulating B clone is recommended, allowing the investigations to be directed towards a lymphoid hemopathy. Drug-induced hypoγ may also be suspected if certain drugs such as corticosteroids, anti-epileptics or immunosuppressive agents (especially anti-CD20) are taken. The profile of a drug-induced hypoγ is different from that of a DIP: it is rarely profound, the IgA level is preserved and there is no deficit in switched memory B lymphocytes. Finally, a thoracoabdominal CT-scan will help to rule out a thymoma and identify a deep tumor syndrome. If all these tests are normal, a PID is suspected, the leader of which in adults remains the common variable immunodeficiency, which is the most frequent symptomatic PID in adults.

Gastrointestinal Involvement in Primary Antibody Deficiencies

Primary antibody deficiencies (PADs) are the most frequent group of inborn errors of immunity. Impaired B-cell development, reduced production of immunoglobulins (mainly IgG and IgA), and specific antibodies resulting in recurrent infections are their hallmarks. Infections typically affect the respiratory tract; however, gastrointestinal involvement is also common. These include infection with Helicobacter pylori, Salmonella, Campylobacter species, Giardia, and noroviruses. Impaired IgA production also contributes to dysbiosis and thereby an increase in abundance of species with proinflammatory properties, resulting in immune system dysregulation. Dysregulation of the immune system results in a broad spectrum of non-infectious manifestations, including autoimmune, lymphoproliferative, and granulomatous complications. Additionally, it increases the risk of malignancy, which may be present in more than half of patients with PADs. Higher prevalence is often seen in monogenic causes, and gastrointestinal involvement may clinically mimic various conditions including inflammatory bowel diseases and celiac disease but possess different immunological features and response to standard treatment, which make diagnosis and therapy challenging. The spectrum of malignancies includes gastric cancer and lymphoma. Thus, non-infectious manifestations significantly affect mortality and morbidity. In this overview, we provide a comprehensive insight into the epidemiology, genetic background, pathophysiology, and clinical manifestations of infectious and non-infectious complications.

The Importance of Endoscopy with Biopsy: Real-World Evidence of Gastrointestinal Involvement in Primary Immunodeficiency in Two Main Northern Italian Centres

INTRODUCTION

Inborn errors of immunity (IEI) represent a heterogeneous group of diseases in which the true prevalence of GI involvement is not well-known. This study evaluates the prevalence of lower GI manifestations in patients with common variable immunodeficiency (CVID), analysing the histologic findings in colonic samples and assessing any correlations with biochemical abnormalities.

MATERIALS AND METHODS

A retrospective study was performed by collecting the data of IEI adult patients followed up at two main Northern Italian centres. Demographic and clinical data, and blood tests were collected. A colonoscopy with multiple biopsies in standard sites, in addition to a biopsy for any macroscopic lesion, was performed. The gastrointestinal Symptom Rating Scale for Irritable Bowel Syndrome (GSRS-IBS) and the short Inflammatory Bowel Disease Questionnaire (sIBDQ) were used to assess GI symptoms.

RESULTS

141 patients were included: 121 (86.5%) with CVID, 17 (12.1%) with IgG subclass deficiency, and 2 (1.4%) with X-linked agammaglobulinemia. Of the patients, 72 (51%) complained of GI symptoms. No differences were seen between patients receiving or not IgRT. GI infections were found in 9 patients (6.4%). No significant correlations were found between gut infections and symptoms or leukocyte infiltrates. Colonoscopy alterations were present in 79 patients (56%), and the most common were colon polyps (42%). Microscopical abnormalities were seen in 60 histologic samples (42.5%) and the most frequent was nodular lymphoid hyperplasia (40%). A leukocyte infiltrate was present in 67 samples (47.5%), and the most common was a lymphocyte infiltrate (33%). No correlation was found between GI symptoms and macroscopic alterations, whereas a positive correlation between symptoms and microscopic alterations was detected.

CONCLUSIONS

GI symptoms and microscopic alterations in colon samples are closely related; hence, it is important to carry out serial colonic biopsies in every CVID patient, even in the absence of macroscopic lesions.

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.

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.

When malignancy hits twice – synchronous gastric carcinoma and non-Hodgkin-B-cell lymphoma in a patient with common variable immunodeficiency

Patients with common variable immunodeficiency (CVID) generally bear a higher risk of non Hodgkin B-cell lymphomas and solid tumors, in particular gastric adenocarcinoma.

Here we report a case of a 58-year-old male CVID patient who developed both malignancies within a very short period, as documented by two subsequent esophagogastroduodenoscopies performed within 4 months. While the first upper gastrointestinal endoscopy for routine surveillance purposes was uneventful, the second one after developing unexplained weight loss revealed two new neoplastic lesions in the stomach. The histological evaluation revealed a poorly differentiated adenocarcinoma infiltrating the muscularis propria forcing gastrectomy as well as a high-grade B-non-Hodgkin-lymphoma with detection of a MYC- and BCL6-translocation, necessitating chemotherapy with R-CHOP.

This case emphasizes the necessity of high awareness for gastric neoplasia in patients with CVID and highlights the need of a standardized yet not established endoscopic surveillance protocol for this vulnerable group.

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.

Protein-losing Enteropathy as a Complication and/or Differential Diagnosis of Common Variable Immunodeficiency

As protein-losing enteropathy (PLE) can lead to hypogammaglobulinemia and lymphopenia, and since common variable immunodeficiency (CVID) is associated with digestive complications, we wondered if (1) PLE could occur during CVID and (2) specific features could help determine whether a patient with antibody deficiency has CVID, PLE, or both. Eligible patients were thus classified in 3 groups: CVID + PLE (n = 8), CVID-only (= 19), and PLE-only (n = 13). PLE was diagnosed using fecal clearance of α1-antitrypsin or 111In-labeled albumin. Immunoglobulin (Ig) A, G, and M, naive/memory B and T cell subsets were compared between each group. CVID + PLE patients had multiple causes of PLE: duodenal villous atrophy (5/8), nodular follicular hyperplasia (4/8), inflammatory bowel disease-like (4/8), portal hypertension (4/8), giardiasis (3/8), and pernicious anemia (1/8). Compared to the CVID-only group, CVID + PLE patients had similar serum Ig levels, B cell subset counts, but lower naive T cell proportion and IgG replacement efficiency index. Compared to the CVID-only group, PLE-only patients did not develop infections but had higher serum levels of IgG (p = 0.03), IgA (p < 0.0001), and switched memory B cells (p = 0.001); and decreased naive T cells (CD4⁺: p = 0.005; CD8⁺: p < 0.0001). Compared to the PLE-only group, CVID + PLE patients had higher infection rates (p = 0.0003), and lower serum Ig (especially IgA: p < 0.001) and switched memory B cells levels. In conclusion, PLE can occur during CVID and requires higher IgG replacement therapy dosage. PLE can also mimic CVID and is associated with milder immunological abnormalities, notably mildly decreased to normal serum IgA and switched memory B cell levels.

Are we forgetting to carry out serum protein electrophoresis as part of diagnosis workup?

Background

Common variable immunodeficiency (CVID) is a rare disease that affects children and adults and is often difficult to diagnose. Despite being one of the most frequent causes of immunodeficiency, involving gastrointestinal (GI), respiratory, and hematological systems, the disease onset can have heterogeneous and intermittent symptoms, frequently leading to diagnostic delay. GI symptoms are common and can include diarrhea, but the asymptomatic periods lead to overlooking the recurrent pattern. The same can occur with respiratory infections, thus delaying CVID suspicion. The starting point for CVID diagnosis is the decreased gamma globulin levels in serum protein electrophoresis (SPE), also observed through direct immunoglobulin’s dosage.

Case presentation

The patient is a 38 years-old man who had intermittent diarrhea and recurrent airway infections for 19 years, but the CVID diagnosis was achieved only after SPE was carried out. At that time, he was already malnourished, and developed other complications related to CVID in a short period.

Conclusions

SPE is readily available and inexpensive, but is not part of the laboratory approach in diarrhea. According to the case presented herein, it can be useful for patients with recurrent infections or other clues of the disease.

A Case of Common Variable Immunodeficiency with CREBP Gene Mutation without Rubinstein Taybi Syndrome Features

Hypogammaglobulinemias, based on inborn errors of immunity, are primary immunodeficiencies (PIDs) that can also be diagnosed for the first time in adulthood. Common variable immunodeficiency (CVID) is a multifactorial disease often symptomatic due to antibody deficiency. In addition, some PIDs are classified into the category of immunodeficiencies with syndromic features due to their accompanying clinical findings unrelated to immunity. In this article, a patient with CVID who was diagnosed in adulthood and who was revealed to have a mutation specific to Rubinstein–Taybi syndrome and clinical features reminiscent of this syndrome only after molecular tests was presented.

A Case Report on Bovine Colostrum as a Potential Therapeutic Agent Alternative to Treat Gastrointestinal Complications of Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) or acquired hypogammaglobulinemia is one of the common forms of primary immunodeficiency, which primarily affects the respiratory tract, but is often associated with gastrointestinal complications. The pathophysiology is not fully understood, making a diagnosis of CVID difficult. The low levels of IgG and IgA and defective B cells make intravenous immunoglobulin (IVIG) therapy the mainstay of management. The present article describes the journey of a 41-year-old male suffering from CVID and severe recurrent uncontrollable gastrointestinal infections requiring Intravenous immunoglobulin therapy, which was successfully substituted with an alternative oral Hyperimmune Bovine Colostrum and Zinc combination for long term gastrointestinal disease control in a more affordable manner.

Keywords: Common variable immunodeficiency, Hypogammaglobulinemia, Primary Immunodeficiency, Gastrointestinal infection, Intravenous Immunoglobulin Therapy, Bovine Colostrum.

Druggable monogenic immune defects hidden in diverse medical specialties: Focus on overlap syndromes

In the last two decades two new paradigms changed our way of perceiving primary immunodeficiencies: An increasing number of immune defects are more associated with inflammatory or autoimmune features rather than with infections. Some primary immune defects are due to hyperactive pathways that can be targeted by specific inhibitors, providing innovative precision treatments that can change the natural history of diseases. In this article we review some of these “druggable” inborn errors of immunity and describe how they can be suspected and diagnosed in diverse pediatric and adult medicine specialties. Since the availability of precision treatments can dramatically impact the course of these diseases, preventing the development of organ damage, it is crucial to widen the awareness of these conditions and to provide practical hints for a prompt detection and cure.

Primary Hypogammaglobulinaemia with Inflammatory Bowel Disease-Like Features: An ECCO CONFER Multicentre Case Series

BACKGROUND

Hypogammaglobulinaemia is a disorder characterized by low serum immunoglobulin levels and a high prevalence of gastrointestinal manifestations. In some cases, clinical and endoscopic features are indistinguishable from those of inflammatory bowel disease [IBD].

METHODS

This was a multicentre case series performed as a part of the European Crohn's and Colitis Organisation [ECCO] Collaborative Network of Exceptionally Rare case reports [CONFER] project.

RESULTS

This report includes 27 patients with primary hypogammaglobulinaemia and IBD-like features: 20 males and seven females, median age 45.6 years (interquartile range [IQR] 35.2-59). Crohn's disease-like features were noted in 23 patients, and four patients had ulcerative colitis-like features. The diagnosis of hypogammaglobulinaemia preceded a diagnosis of IBD-like features in 20 patients [median of 7 years prior, IQR 2.6-20.6 years], and followed the appearance of IBD-like features in seven cases [median of 1 year after, IQR 0.45-5.6 years]. Hypogammaglobulinaemia aetiologies were common variable immunodeficiency [66.6%], agammaglobulinaemia [7.4%], selective IgA-deficiency [11.1%], Good's syndrome [7.4%], IgG subclass deficiency with IgA deficiency [3.7%] and hyper-IgM [3.7%]. In addition to antibiotics and intravenous immunoglobulin [IVIG] for hypogammaglobulinaemia, 12 patients received IBD-related treatment including 5-aminosalicylate agents [two patients], corticosteroids [one patient], thiopurines [three patients], anti-tumour necrosis factor [four patients] and vedolizumab [two patients]. By the end of the follow-up (44.5 months [IQR 18-81]), 21/27 [77%] patients were in clinical remission.

CONCLUSION

This case series describes IBD-like features in patients with hypogammaglobulinaemia. The diagnosis of IBD-like features mainly occurred after that of hypogammaglobulinaemia, with successful recovery in the majority of cases after appropriate treatment.

Defective humoral immunity disrupts bile acid homeostasis which promotes inflammatory disease of the small bowel

Mucosal antibodies maintain gut homeostasis by promoting spatial segregation between host tissues and luminal microbes. Whether and how mucosal antibody responses influence gut health through modulation of microbiota composition is unclear. Here, we use a CD19^-/- mouse model of antibody-deficiency to demonstrate that a relationship exists between dysbiosis, defects in bile acid homeostasis, and gluten-sensitive enteropathy of the small intestine. The gluten-sensitive small intestine enteropathy that develops in CD19^-/- mice is associated with alterations to luminal bile acid composition in the SI, marked by significant reductions in the abundance of conjugated bile acids. Manipulation of bile acid availability, adoptive transfer of functional B cells, and ablation of bacterial bile salt hydrolase activity all influence the severity of small intestine enteropathy in CD19^-/- mice. Collectively, results from our experiments support a model whereby mucosal humoral immune responses limit inflammatory disease of the small bowel by regulating bacterial BA metabolism.

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.

Gut Microbiome and Common Variable Immunodeficiency: Few Certainties and Many Outstanding Questions

Common variable immunodeficiency (CVID) is the most common symptomatic primary antibody immunodeficiency, characterized by reduced serum levels of IgG, IgA, and/or IgM. The vast majority of CVID patients have polygenic inheritance. Immune dysfunction in CVID can frequently involve the gastrointestinal tract and lung. Few studies have started to investigate the gut microbiota profile in CVID patients. Overall, the results suggest that in CVID patients there is a reduction of alpha and beta diversity compared to controls. In addition, these patients can exhibit increased plasma levels of lipopolysaccharide (LPS) and markers (sCD14 and sCD25) of systemic immune cell activation. CVID patients with enteropathy exhibit decreased IgA expression in duodenal tissue. Mouse models for CVID unsatisfactorily recapitulate the polygenic causes of human CVID. The molecular pathways by which gut microbiota contribute to systemic inflammation and possibly tumorigenesis in CVID patients remain poorly understood. Several fundamental questions concerning the relationships between gut microbiota and the development of chronic inflammatory conditions, autoimmune disorders or cancer in CVID patients remain unanswered. Moreover, it is unknown whether it is possible to modify the microbiome and the outcome of CVID patients through specific therapeutic interventions.

Inborn Errors of Immunity and Cancer

Simple Summary

Inborn Errors of Immunity (IEI) are a heterogeneous group of disorders characterized by a defect in the function of at least one, and often more, components of the immune system. The overall risk for cancer in children with IEI ranges from 4 to 25%. Several factors, namely, age of the patient, viral infection status and IEI type can influence the development of different cancer types. Immunologists and oncologists should interact to monitor and promptly diagnose the potential development of cancer in known IEI patients, as well as an underlying IEI in newly diagnosed cancers with suggestive medical history or high rate of therapy-related toxicity. The creation of an international registry of IEI cases with detailed information on the occurrence of cancer is fundamental to optimizing the diagnostic process and to evaluating the outcomes of new therapeutic options, with the aim of improving prognosis and reducing comorbidities.

Abstract

Inborn Errors of Immunity (IEI) are a heterogeneous group of disorders characterized by a defect in the function of at least one, and often more, components of the immune system. The aim of this narrative review is to discuss the epidemiology, the pathogenesis and the correct management of tumours in patients with IEI. PubMed was used to search for all of the studies published over the last 20 years using the keywords: “inborn errors of immunity” or “primary immunodeficiency” and “cancer” or “tumour” or “malignancy”. Literature analysis showed that the overall risk for cancer in children with IEI ranges from 4 to 25%. Several factors, namely, age of the patient, viral infection status and IEI type can influence the development of different cancer types. The knowledge of a specific tumour risk in the presence of IEI highlights the importance of a synergistic effort by immunologists and oncologists in tracking down the potential development of cancer in known IEI patients, as well as an underlying IEI in patients with newly diagnosed cancers. In the current genomic era, the creation of an international registry of IEI cases integrated with malignancies occurrence information is fundamental to optimizing the diagnostic process and to evaluating the outcomes of new therapeutic options, with the hope to obtain a better prognosis for these patients.

Seronegative autoimmune enteropathy with duodenal sparing and colonic clues in an adult female

Autoimmune enteropathy (AIE) is a rare immune disorder of the gut seldom found in adults and characterized by uncontrollable diarrhea resulting in malabsorption. While AIE is known to be pan-enteric, virtually all cases have presented with altered duodenal histology following known patterns with or without macroscopic change. We describe a unique case of seronegative AIE lacking typical duodenal manifestations in a 43-year-old female. To our knowledge, this is the first report of AIE lacking usual duodenal histologic changes, which resulted in missed diagnosis for years. Ultimately, crypt epithelial apoptosis, mononuclear inflammation of the lamina propria, and goblet cell loss of intestinal mucosa besides the duodenum clinched the diagnosis of AIE. Colonic histologic abnormalities consistent with AIE in the setting of diarrhea with malnutrition despite duodenal sparing should prompt suspicion for AIE given the pan-enteric nature of this disease.

[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.

Primary Immunodeficiency Diseases and Gastrointestinal Distress: Coping Strategies and Dietary Experiences to Relieve Symptoms

In this article, we focus on adults with primary immunodeficiency disease (PID) and their experiences with gastrointestinal (GI) distress with the aim of exploring how they experience living with their condition and the actions they take to relieve GI distress. Twelve adults with PID and GI distress participated in semi-structured, in-depth interviews. The interviews were analyzed following the steps of thematic analysis (TA). The study revealed the complexity of the psychosocial aspects of living with PID and GI distress. Participants experienced GI distress to be highly challenging in daily life and felt they had to cope with the condition alone, without adequate help from the health care service. Participants used a wide and diverse range of coping strategies, and the search for normalcy was evident. Health care professionals should be more proactive in supporting individuals with PID in their struggle to find solutions to problems arising from GI distress.

Infections in Patients with Chronic Granulomatous Disease Treated with Tumor Necrosis Factor Alpha Blockers for Inflammatory Complications

PURPOSE

Management of inflammatory complications of chronic granulomatous disease (CGD) is challenging. The aim of this study was to assess safety, with a focus on infections, and effectiveness of tumor necrosis factor alpha (TNF-α) blockers in CGD patients.

METHODS

A retrospective, single-center cohort study of CGD patients treated by anti-TNF-α agents at Necker-Enfants Malades University Hospital (Paris, France) and registered at the French National Reference Center for Primary Immunodeficiencies (CEREDIH).

RESULTS

Between 2006 and 2019, 14 (X-linked: n = 10, 71.4%; autosomal-recessive: n = 4, 28.6%) CGD patients with gastrointestinal (n = 12, 85.7%), pulmonary (n = 10, 71.4%), cutaneous (n = 3, 21.4%), and/or genitourinary (n = 2, 14.3%) inflammatory manifestations received one or more doses of infliximab because of steroid-dependent (n = 7, 50%), refractory (n = 4, 28.6%) inflammatory disease or as first-line drug (n = 2, 14.3%; missing data, n = 1). All patients received adequate antimicrobial prophylaxis. Infliximab achieved complete (n = 2, 14.3%) or partial (n = 9, 64.3%) response in 11 (78.6%) patients. Seven (50%) patients were switched to adalimumab. During anti-TNF-α treatment, 11 infections (pneumonia, adenitis, invasive candidiasis, each n = 2; intra-abdominal abscess, bacteremic salmonellosis, Pseudomonas aeruginosa-related folliculitis, cat-scratch disease, proven pulmonary mucormycosis, each n = 1) occurred in 7 (50%) patients. All infectious complications had a favorable outcome. Anti-TNF-α treatment was definitively stopped because of infection in two patients. Nine (64.3%) patients finally underwent hematopoietic stem cell transplantation. No death occurred during follow-up.

CONCLUSIONS

Anti-TNF-α treatment could improve the outcome of severe inflammatory complications in CGD patients, but increases their risk of infections. We suggest that anti-TNF-α treatment might be of short-term benefit in selected CGD patients with severe inflammatory complications awaiting hematopoietic stem cell transplantation.

Consensus of the Italian Primary Immunodeficiency Network on transition management from pediatric to adult care in patients affected with childhood-onset inborn errors of immunity

Medical advances have dramatically improved the long-term prognosis of children and adolescents with inborn errors of immunity (IEIs). Transfer of the medical care of individuals with pediatric IEIs to adult facilities is also a complex task because of the large number of distinct disorders, which requires involvement of patients and both pediatric and adult care providers. To date, there is no consensus on the optimal pathway of the transitional care process and no specific data are available in the literature regarding patients with IEIs. We aimed to develop a consensus statement on the transition process to adult health care services for patients with IEIs. Physicians from major Italian Primary Immunodeficiency Network centers formulated and answered questions after examining the currently published literature on the transition from childhood to adulthood. The authors voted on each recommendation. The most frequent IEIs sharing common main clinical problems requiring full attention during the transitional phase were categorized into different groups of clinically related disorders. For each group of clinically related disorders, physicians from major Italian Primary Immunodeficiency Network institutions focused on selected clinical issues representing the clinical hallmark during early adulthood.

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.

Primary Immunodeficiencies With Defects in Innate Immunity: Focus on Orofacial Manifestations

The field of primary immunodeficiencies (PIDs) is rapidly evolving. Indeed, the number of described diseases is constantly increasing thanks to the rapid identification of novel genetic defects by next-generation sequencing. PIDs are now rather referred to as “inborn errors of immunity” due to the association between a wide range of immune dysregulation-related clinical features and the “prototypic” increased infection susceptibility. The phenotypic spectrum of PIDs is therefore very large and includes several orofacial features. However, the latter are often overshadowed by severe systemic manifestations and remain underdiagnosed. Patients with impaired innate immunity are predisposed to a variety of oral manifestations including oral infections (e.g., candidiasis, herpes gingivostomatitis), aphthous ulcers, and severe periodontal diseases. Although less frequently, they can also show orofacial developmental abnormalities. Oral lesions can even represent the main clinical manifestation of some PIDs or be inaugural, being therefore one of the first features indicating the existence of an underlying immune defect. The aim of this review is to describe the orofacial features associated with the different PIDs of innate immunity based on the new 2019 classification from the International Union of Immunological Societies (IUIS) expert committee. This review highlights the important role played by the dentist, in close collaboration with the multidisciplinary medical team, in the management and the diagnostic of these conditions.

Vedolizumab Induced Clinical, Endoscopic, and Histological Improvement in Common Variable Immunodeficiency Disease-associated Intestinal Enteropathy

After treatment with vedolizumab, a patient with diarrhea and malnutrition secondary to common variable immune deficiency (CVID)–related enteropathy was able to achieve clinical, endoscopic, and histological improvement. Vedolizumab may be a treatment option for patients with CVID-associated enteropathy.

Cytomegalovirus viremia and resistance patterns in immunocompromised children: An 11-year experience

We noted a recent increase in number of immunocompromised children with CMV viremia at our institution. The purpose of this study was to determine the frequency of CMV viremia in this population and evaluate factors associated with drug-resistant mutations. A retrospective review of immunocompromised hosts, 0-21 years of age, who had CMV viremia during 2007-2017. CMV viremia was detected using PCR assays. Genetic mutation assays were performed using PCR sequencing of the phosophotransferase UL 97 gene and the polymerase UL54 gene of CMV using Quest Diagnostics (San Juan Capistrano, CA, USA) or ARUP Labs (Salt Lake City, UT, USA). Thirty-one patients were identified, including 10 (32%) during the last 2 years. Of the 31 patients, 18 had hematopoietic stem cell transplantation (HSCT), 5 had primary immunodeficiency, 4 had malignancies, 3 had heart transplantation and 1 had new Human Immunodeficiency virus (HIV) infection. Antiviral resistance testing was performed on isolates from seven patients: five with persistent viremia (>1 mo), and two prior to starting antiviral therapy. Resistance was identified in three patients' isolates: two with common variable immunodeficiency (CVID) and one with recurrent Hodgkin's lymphoma who had undergone autologous HSCT. The two patients with CVID had chronic diarrhea and malabsorption and had received prolonged oral valganciclovir courses prior to emergence of resistance. The patient with Hodgkin's lymphoma had received a prolonged IV ganciclovir course. All three tested positive for UL97 mutation and two had both UL97 and UL54 gene mutations. Majority of our patients (21/31) with CMV viremia were transplant recipients and ganciclovir resistance developed in 10%. Two had intestinal malabsorption. Treatment with oral valganciclovir should be avoided in patients with poor gut absorption as that may increase the risk of resistance.

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.

Gastrointestinal Disorders Associated with Primary Immunodeficiency Diseases

There are now 354 inborn errors of immunity (primary immunodeficiency diseases (PIDDs)) with 344 distinct molecular etiologies reported according to the International Union of Immunological Sciences (IUIS) (Clin Gastroenterol Hepatol 11: p. 1050-63, 2013, Semin Gastrointest Dis 8: p. 22-32, 1997, J Clin Immunol 38: p. 96-128, 2018). Using the IUIS document as a reference and cross-checking PubMed ( www.ncbi.nlm.nih.pubmed.gov ), we found that approximately one third of the 354 diseases of impaired immunity have a gastrointestinal component [J Clin Immunol 38: p. 96-128, 2018]. Often, the gastrointestinal symptomatology and pathology is the heralding sign of a PIDD; therefore, it is important to recognize patterns of disease which may manifest along the gastrointestinal tract as a more global derangement of immune function. As such, holistic consideration of immunity is warranted in patients with clinically significant gastrointestinal disease. Here, we discuss the manifold presentations and GI-specific complications of PIDDs which could lead patients to seek advice from a variety of clinician specialists. Often, patients with these medical problems will engage general pediatricians, surgeons, gastroenterologists, rheumatologists, and clinical immunologists among others. Following delineation of the presenting concern, accurate and often molecular diagnosis is imperative and a multi-disciplinary approach warranted for optimal management. In this review, we will summarize the current state of understanding of PIDD gastrointestinal disease involvement. We will do so by focusing upon gastrointestinal disease categories (i.e., inflammatory, diarrhea, nodular lymphoid hyperplasia, liver/biliary tract, structural disease, and oncologic disease) with an intent to aid the healthcare provider who may encounter a patient with an as-yet undiagnosed PIDD who presents initially with a gastrointestinal symptom, sign, or problem.

Vedolizumab therapy in common variable immune deficiency associated enteropathy: A case series

A number of gastrointestinal complications occur in common variable immunodeficiency (CVID). Infections are one cause, but various forms of severe non-infectious enteropathy also lead to substantial morbidity. The presence of T cell lymphocytic infiltrates in the mucosa have suggested that vedolizumab, a humanized monoclonal antibody which binds to alpha4 beta7 integrin and inhibits the migration of effector T-lymphocytes into gastrointestinal tissues, would be an effective treatment. A previous report of 3 CVID cases suggested benefit in 2 subjects. In this study 7 CVID patients with severe enteropathy were treated with vedolizumab. Four of the 7 completed vedolizumab induction therapy but 3 subjects had acute decompensation during induction and treatment was stopped. While one subject showed improvement, 6 of the 7 patients were withdrawn from therapy. While vedolizumab may be of use in some CVID subjects, it was not ultimately found helpful in most of these patients.

Gastrointestinal Manifestations and Complications of Primary Immunodeficiency Disorders

Gastrointestinal (GI) involvement can be the presenting disease manifestation in patients with primary immunodeficiency disorders (PIDs). Infections and noninfectious diarrhea are frequent manifestations; however, malignancy and inflammatory and autoimmune-related GI diseases are also described. GI symptoms and disease seen in association with PIDs can mimic other diseases but are often resistant to conventional treatments owing to alternate disease mechanisms. Despite the advances in treatments for these conditions, therapy for immunodeficiency-related GI disease is often empiric.

Gut Antibody Deficiency in a Mouse Model of CVID Results in Spontaneous Development of a Gluten-Sensitive Enteropathy

Primary immunodeficiencies are heritable disorders of immune function. CD19 is a B cell co-receptor important for B cell development, and CD19 deficiency is a known genetic risk factor for a rare form of primary immunodeficiency known as “common variable immunodeficiency” (CVID); an antibody deficiency resulting in low levels of serum IgG and IgA. Enteropathies are commonly observed in CVID patients but the underlying reason for this is undefined. Here, we utilize CD19^−/− mice as a model of CVID to test the hypothesis that antibody deficiency negatively impacts gut physiology under steady-state conditions. As anticipated, immune phenotyping experiments demonstrate that CD19^−/− mice develop a severe B cell deficiency in gut-associated lymphoid tissues that result in significant reductions to antibody concentrations in the gut lumen. Antibody deficiency was associated with defective anti-commensal IgA responses and the outgrowth of anaerobic bacteria in the gut. Expansion of anaerobic bacteria coincides with the development of a chronic inflammatory condition in the gut of CD19^−/− mice that results in an intestinal malabsorption characterized by defects in lipid metabolism and transport. Administration of the antibiotic metronidazole to target anaerobic members of the microbiota rescues mice from disease indicating that intestinal malabsorption is a microbiota-dependent phenomenon. Finally, intestinal malabsorption in CD19^−/− mice is a gluten-sensitive enteropathy as exposure to a gluten-free diet also significantly reduces disease severity in CD19^−/− mice. Collectively, these results support an effect of antibody deficiency on steady-state gut physiology that compliment emerging data from human studies linking IgA deficiency with non-infectious complications associated with CVID. They also demonstrate that CD19^−/− mice are a useful model for studying the role of B cell deficiency and gut dysbiosis on gluten-sensitive enteropathies; a rapidly emerging group of diseases in humans with an unknown etiology.