The Epidemiology and Clinical Manifestations of Autoimmunity in Selective IgA Deficiency

Adult-Onset Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Cervical Adenitis Syndrome on the Basis of Selective IgA Deficiency

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis syndrome (PFAPA) is an autoinflammatory disease that is thought to occur with the contribution of genetic and environmental factors, but its etiology has not been clearly elucidated. It is characterized by recurrent attacks with fever, pharyngitis, oral aphthous lesions, and cervical lymphadenopathy, and an increase in the level of serum acute phase reactants is observed during the attacks. Although PFAPA usually begins in childhood, adult-onset cases are also reported in the literature. In the pathogenesis of PFAPA, an increase in the expression of various inflammatory cytokines, especially interleukin-1β (IL-1β), is observed as a result of the increase in inflammasome activity. Selective IgA deficiency (SIgAD) is the most prevalent primary immunodeficiency. Although most SIgAD cases remain asymptomatic and remain undiagnosed, it is known that the risk of mucosal infection is generally increased in SIgAD cases. In addition, the frequency of autoinflammatory diseases is increased in SIgAD cases compared with the general population. We aim to present a case of adult-onset PFAPA and SIgAD coexistence.

Predominantly antibody deficiency and the association with celiac disease in Sweden: A nationwide case-control study

BACKGROUND

Predominantly antibody deficiency (PAD) is associated with noninfectious inflammatory gastrointestinal disease. Population estimates of celiac disease (CeD) risk in those with PAD are limited.

OBJECTIVE

To estimate population risk of PAD in individuals with CeD.

METHODS

We conducted a nationwide case-control study in Swedish individuals who received a diagnosis of CeD between 1997 and 2017 (n = 34,980), matched to population comparators by age, sex, calendar year, and county. The CeD was confirmed through the Epidemiology Strengthened by histopathology Reports in Sweden study, which provided information on biopsy specimens from each of Sweden's pathology departments. PAD was identified using International Classification of Diseases, 10th Revision coding and categorized according to the International Union of Immunologic Societies. Logistic regression was used to calculate adjusted odds ratios (aORs) and 95% CIs.

RESULTS

PAD was more prevalent in CeD than in population controls (n = 105 [0.3%] vs n = 57 [0.033%], respectively). This translated to an aOR of 8.23 (95% CI 5.95-11.48). The association was strongest with common variable immunodeficiency (aOR 17.25; 95% CI 6.86-52.40), and slightly lower in other PAD (aOR 8.39; 95% CI 5.79-12.32). The risk of CeD remained increased at least 5 years after diagnosis of PAD (aOR 4.79; 95% CI 2.89-7.97, P-heterogeneity ≤ 0.001).

CONCLUSION

PAD was associated with an increased risk of CeD. A particularly strong association was seen in those with CVID, although this should be interpreted cautiously given the limited understanding of the mechanisms of histopathologic changes in these patients.

Celiac Disease-Related Conditions: Who to Test?

Celiac disease (CeD) is a chronic immune-mediated condition triggered by gluten consumption in genetically predisposed individuals. Approximately 1% of the general population is affected by the disorder. Disease presentation is heterogeneous and, despite growing awareness among physicians and the public, it continues to be underestimated. The most effective strategy for identifying undiagnosed CeD is proactive case finding through serologic testing in high-risk groups. We reviewed the most recent evidence on the association between CeD and more than 20 conditions. In light of this review, CeD screening is recommended in individuals with (1) autoimmune disease and accompanying symptoms suggestive of CeD; (2) diseases that may mimic CeD (eg, irritable bowel syndrome [IBS], inflammatory bowel disease [IBD], and microscopic colitis); and (3) among patients with conditions with a high CeD prevalence: first-degree relatives, idiopathic pancreatitis, unexplained liver enzyme abnormalities, autoimmune hepatitis, primary biliary cholangitis, hyposplenism or functional asplenia with severe bacterial infection, type 1 diabetes mellitus, Hashimoto's thyroiditis and Graves' disease, Sjögren's syndrome, dermatitis herpetiformis, recurrent aphthous syndrome and enamel defects, unexplained ataxia, peripheral neuropathy, delayed menarche or premature menopause, Down syndrome, Turner syndrome, Williams syndrome, chronic fatigue syndrome, IgA nephropathy, and IgA deficiency. CeD serology should be the initial step in the screening process. However, for patients with any of the aforementioned disorders who are undergoing upper endoscopy, biopsies should be performed to rule out CeD.

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.

Clinical and experimental treatment of primary humoral immunodeficiencies

Selective IgA deficiency (sIgAD), common variable immunodeficiency (CVID), and transient hypogammaglobulinemia of infancy (THI) are the most frequent forms of primary antibody deficiencies. Difficulties in initial diagnosis, especially in the early childhood, the familiar occurrence of these diseases, as well as the possibility of progression to each other suggest common cellular and molecular patomechanism and a similar genetic background. In this review, we discuss both similarities and differences of these three humoral immunodeficiencies, focusing on current and novel therapeutic approaches. We summarize immunoglobulin substitution, antibiotic prophylaxis, treatment of autoimmune diseases, and other common complications, i.e. cytopenias, gastrointestinal complications, and granulomatous disease. We discuss novel therapeutic approaches such as allogenic stem cell transplantation and therapies targeting-specific proteins, dependent on the patient's genetic defect. The diversity of possible therapeutics models results from a great heterogeneity of the disease variants, implying the need of personalized medicine approach as a future of primary humoral immunodeficiencies treatment.

Nonallergic Diseases Associated With Foods

Clinicians are faced with evaluating real and alleged reactions to foods that may be allergic or nonallergic. Pathogenesis, diagnosis, and treatment of various non-IgE-mediated diseases are discussed in this review. These food-related conditions range from mild to severe. Referral for an allergy workup may be pursued despite the lack of IgE-mediated symptoms. Diagnostic testing is available for defined non-IgE-mediated food diseases that are either immunologic or nonimmunologic. These include celiac disease and related disorders, carbohydrate maldigestion, pancreatic insufficiency, and histamine intolerance. In contrast, there is a paucity of definitive studies to prove food intolerance diseases. There are no definitive diagnostic criteria or testing for nonceliac gluten sensitivity. Functional gastrointestinal disorders, such as irritable bowel syndrome, are better stratified diagnostically but still lack reliable testing. Both nonceliac gluten sensitivity and irritable bowel syndrome are linked to dietary triggers including fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Therefore, dietary alteration alone may be diagnostic and therapeutic when all other conditions are ruled out. These conditions are important considerations when evaluating a patient with history of a food reaction. There is little evidence that foods are causative in other ailments such as acne, migraines, and nasal congestion and hypersecretion.

Total serum IgA levels and HLA-DQB1*02:01 allelic status

Immunoglobulin A Deficiency (IgAD) is the most common primary immunodeficiency and is significantly associated with Celiac Disease (CD), which recognizes a specific background of human leukocyte antigens (HLA) predisposition (including HLA-DQB1*02:01 allele). A number of studies investigated the role of HLA in IgAD etiopathogenesis: HLA-DQB1*02 alleles are included in the main haplotypes linked to this primary immunodeficiency. In this preliminary study, we investigated the potential impact of HLA-DQB1*02:01 allelic status on total serum IgA levels: 108 serum samples from the bone marrow donors' registry were analyzed for total IgA concentration with respect to the HLA-DQB1*02:01 status. Although total serum IgA levels between HLA-DQB1*02:01 carriers and HLA-DQB1*02:01 negative donors were not different, we observed a statistically significant difference (p=0.0118) in total serum IgA levels among donors with low IgA concentration (<80mg/dL) in the sub-analysis between HLA-DQB1*02:01 positive group (including both homozygous and heterozygous carriers) compared to HLA-DQB1*02:01 negative donors. Our results might suggest a role of HLA-DQB1*02:01 allelic variant in the determination of total serum IgA levels, at least in patients affected with IgA deficiency and/or otherwise predisposed to it; however, larger and more standardized studies are needed to confirm this speculation.

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.

Mucosal IgA immune complex induces immunomodulatory responses in allergic airway and intestinal TH2 disease

BACKGROUND

IgA is the most abundant immunoglobulin at the mucosal surface and although its role in regulating mucosal immunity is not fully understood, its presence is associated with protection from developing allergic disease.

OBJECTIVE

We sought to determine the role of IgA immune complexes for therapeutic application to mucosal allergic responses.

METHODS

Trinitrophenol (TNP)-specific IgA immune complexes were applied, using TNP-coupled ovalbumin (OVA), to airway and gut mucosal surfaces in systemically sensitized allergic animals to regulate allergen challenge responses. Animals were assessed for both pathologic and immune-mediated responses in the lung and gut, respectively, using established mouse models.

RESULTS

The mucosal application of IgA immune complexes in the lung and gut with TNP-OVA regulated TH2-driven allergic response in the lung and gut, reducing TH2 cytokines and mucus (lung) as well as diarrhea and temperature loss (gut), but increasing IL-10 and the number of regulatory T cells. The IgA-OVA immune complex did not alter peanut-induced anaphylaxis, indicating antigen specificity. Using OVA-specific DO.11-green fluorescent protein IL-4 reporter mouse-derived TH2-skewed cells in a transfer model demonstrated that mucosal IgA immune complex treatment reduced TH2-cell expansion and increased the number of regulatory T cells. To address a potential mechanism of action, TGF-β and IL-10 were induced in bone marrow-derived dendritic cells when they were exposed to IgA immune complex, suggesting a regulatory phenotype induced in dendritic cells that also led to an altered primary T-cell-mediated response in in vitro OVA-specific assays.

CONCLUSIONS

These studies highlight one possible mechanism of how allergen-specific IgA may provide a regulatory signal to reduce the development of allergic responses in the lung and gut.

Allergy and autoimmunity in children: non-mutually exclusive diseases. A narrative review

In last decades a simultaneous increase in the prevalence of atopic and autoimmune disorders in pediatric population has been observed. Despite the Th1-Th2 paradigm, supporting the polarization of the immune system with Th1 response involved in autoimmune diseases and Th2 response leading to hypersensitivity reactions, recent evidence suggests a possible coexistence of common pathogenic pathways as result of shared immune dysregulation. Similar genes and other mechanisms such as epithelial barrier damage, gut microbiota dysbiosis and reduced number of T regs and IL-10 contribute to the onset of allergy and autoimmunity. IgA deficiency is also hypothesized to be the crosslink between celiac disease and allergy by lowering gut mucous membrane protection from antigens and allergens. The present narrative review aims to give an overview of the co-occurrence of allergic and autoimmune disorders (celiac disease, inflammatory bowel diseases, type 1 diabetes mellitus, thyroid disease, juvenile idiopathic arthritis) in pediatric population, based on the available evidence. We also highlighted the common pathogenic pathways that may underpin both. Our findings confirm that allergic and autoimmune diseases are commonly associated, and clinicians should therefore be aware of the possible coexistence of these conditions in order to ameliorate disease management and patient care. Particular attention should be paid to the association between atopic dermatitis or asthma and celiac disease or type 1 diabetes and vice versa, for therapeutic interventions. Further studies are needed to better clarify mechanisms involved in the pathogenesis and eventually identify new therapeutic strategies.

Study of the immune response in celiac patients with selective IgA deficiency who start a gluten-free diet

Studies are scarce regarding IgG anti-tissue transglutaminase 2 (tTG) normalization in selective IgA deficient (SIgAD) celiac disease (CD) patients after beginning a gluten free diet (GFD). The aim of this study is to analyse the decreasing dynamics of IgG anti-tTG in patients diagnosed with CD who start a GFD. To achieve this objective, IgG and IgA anti-tTG levels at diagnosis and during follow-up in 11 SIgAD CD patients and in 20 IgA competent CD patients were retrospectively evaluated. At diagnosis, statistical differences were not found when comparing IgA anti-tTG levels of IgA competent subjects with IgG anti-tTG levels of SIgAD subjects. Regarding the decreasing dynamics, even though no statistical differences were found (p = 0.06), normalization rates were slower for SIgAD CD patients. After 1 and 2 years on GFD, respectively, only 18.2% and 36.3% of the SIgAD CD patients normalized IgG anti-tTG levels; otherwise, IgA anti-tTG reached values under the reference values in 30% and 80% of the IgA competent patients in the same time-points. Although IgG anti-tTG has demonstrated a high diagnostic efficiency in SIgAD CD pediatric patients, this test does not appear to be as precise for long-term GFD response monitoring as IgA anti-tTG levels in IgA sufficient patients.

Clinical manifestation for immunoglobulin A deficiency: a systematic review and meta-analysis

OBJECTIVES

Immunoglobulin A deficiency (IgAD) is a common disease with an unknown genetic defect, characterized by the decreased or absent IgA with other isotypes normal, normal subclasses, and specific antibodies. Patients with this disorder represent a spectrum of clinical manifestations including infections, autoimmune disorders, malignancy, and allergic diseases. The current study aimed to evaluate their prevalence and categorized them.

METHODS

We searched PubMed, Web of Science, and Scopus databases to find eligible studies from the earliest available date to January 2022 with standard keywords. Pooled estimates of clinical manifestations prevalence and the corresponding 95% confidence intervals were calculated using random-effects models.

RESULTS

The most prevalent clinical manifestations belonged to infection (64.8%) followed by allergic diseases (26.16%) and autoimmunity (22.0%), respectively. In selective IgA deficiency patients as the largest group of IgAD in current study, celiac disease (6.57%), Inflammatory bowel disease (4.01%), and rheumatoid arthritis (3.80%) were the most prevalent autoimmunity. Meanwhile, the most frequent infection was respiratory tract infection, fungal infection, and gastrointestinal infection at 50.74%, 18.48%, and 15.79%, respectively. In addition, the pooled prevalence of asthma, allergic rhinitis, and allergic conjunctivitis were 19.06%, 15.46%, and 11.68%, respectively which were reported as the most widespread allergic diseases.

CONCLUSIONS

Our results showed that apart from undiagnosed IgAD patients, IgAD patients represent a wide range of clinical manifestations. Infection, allergy, and autoimmunity are the most common clinical manifestations. The concurrent presence of IgA and IgG subtypes deficiency could be associated with increased susceptibility to infection. Considering the probability of developing new clinical complications during follow-up, periodic assessments of IgAD patients should be inspected.

Serum immunoglobulin A (IgA) levels in children affected with Juvenile Idiopathic Arthritis

Background and objective

Immunoglobulin A (IgA) is the most abundant antibody isotype in the human body, considering its presence on the mucosal surfaces, in addition to the amount circulating in the bloodstream. Serum IgA levels can be variably altered in several pathological settings. However, very few studies specifically investigated serum IgA in Juvenile Idiopathic Arthritis (JIA). In the present study, we specifically assessed serum IgA levels in our cohort of patients affected with JIA.

Methods

In this cross-sectional study, serum IgA levels were measured in patients with JIA (and age-matched controls) and analyzed according to age class. The correlation of serum IgA levels with hematological, inflammatory, and disease activity parameters was assessed.

Results

No significant difference in the frequency of low IgA levels (according to the definition of complete and partial IgA deficiency) was observed between JIA patients and controls, overall. This pediatric study population showed a progressive increase of total serum IgA concentrations with age, as expected; however, in JIA patients aged 10-17 years, total IgA serum levels resulted to be significantly higher than in age-matched control subjects. No clear correlation between IgA levels and the examined inflammatory, hematological, and disease activity parameters was observed in JIA patients, except for the erythrocyte sedimentation rate (ESR) in oligoarticular JIA patients: here, serum IgA levels showed a positive and moderate covariation with ESR, which was also observed for disease activity (JADAS-10) in selected oJIA patients without biological therapy.

Conclusions

In our cohort of JIA patients, total serum IgA levels were not reduced and were actually increased in adolescents compared to controls. Larger studies are needed to confirm this finding, which cannot be certainly explained based on the available data in this study, even though JIA disease control and/or chronic inflammation may be implicated to some extent.

Primary Immunodeficiencies in Children Initially Admitted with Gastrointestinal/Liver Manifestations

Purpose

The gastrointestinal system is the most commonly affected organ, followed by the lungs, in patients with primary immunodeficiency disease (PID). Hence, it is common for children with PIDs to present with gastrointestinal symptoms. We aimed to analyze the clinical and histopathological findings of patients who were initially admitted to pediatric gastroenterology/hepatology clinics and subsequently diagnosed with PIDs to identify the clinical clues for PIDs.

Methods

The demographic, laboratory, and histopathological findings, treatment modality, and outcomes of patients initially admitted to the pediatric gastroenterology/hepatology unit and subsequently diagnosed with PIDs were recorded.

Results

The study included 24 patients (58.3% male; median age [range]: 29 [0.5-204] months). Common clinical presentations included chronic diarrhea (n=8), colitis (n=6), acute hepatitis (n=4), and acute liver failure (n=2). The association of autoimmune diseases, development of malignant diseases, and severe progression of viral diseases was observed in 20.8%, 8.3%, and 16.6% of the patients, respectively. Antibody deficiency was predominantly diagnosed in 29.2% of patients, combined immunodeficiency in 20.8%, immune dysregulation in 12.5%, defects in intrinsic and innate immunity in 4.2%, autoinflammatory disorders in 8.3%, and congenital defects of phagocytes in 4.2%. Five patients remained unclassified (20.8%).

Conclusion

Patients with PIDs may initially experience gastrointestinal or liver problems. It is recommended that the association of autoimmune or malignant diseases or severe progression of viral diseases provide pediatric gastroenterologists some suspicion of PIDs. After screening using basic laboratory tests, genetic analysis is mandatory for a definitive diagnosis.

Proposal to Screen for Zinc and Selenium in Patients with IgA Deficiency

The increase in life expectancy can be a consequence of the world's socioeconomic, sanitary and nutritional conditions. Some studies have demonstrated that individuals with a satisfactory diet variety score present a lower risk of malnutrition and better health status. Zinc and selenium are important micronutrients that play a role in many biochemical and physiological processes of the immune system. Deficient individuals can present both innate and adaptive immunity abnormalities and increased susceptibility to infections. Primary immunodeficiency diseases, also known as inborn errors of immunity, are genetic disorders classically characterized by an increased susceptibility to infection and/or dysregulation of a specific immunologic pathway. IgA deficiency (IgAD) is the most common primary antibody deficiency. This disease is defined as serum IgA levels lower than 7 mg/dL and normal IgG and IgM levels in individuals older than four years. Although many patients are asymptomatic, selected patients suffer from different clinical complications, such as pulmonary infections, allergies, autoimmune diseases, gastrointestinal disorders and malignancy. Knowing the nutritional status as well as the risk of zinc and selenium deficiency could be helpful for the management of IgAD patients.

OBJECTIVES

to investigate the anthropometric, biochemical, and nutritional profiles and the status of zinc and selenium in patients with IgAD.

METHODS

in this descriptive study, we screened 16 IgAD patients for anthropometric and dietary data, biochemical evaluation and determination of plasma and erythrocyte levels of zinc and selenium.

RESULTS

dietary intake of zinc and selenium was adequate in 75% and 86% of the patients, respectively. These results were consistent with the plasma levels (adequate levels of zinc in all patients and selenium in 50% of children, 25% of adolescents and 100% of adults). However, erythrocyte levels were low for both micronutrients (deficiency for both in 100% of children, 75% of adolescents and 25% of adults).

CONCLUSION

our results highlight the elevated prevalence of erythrocyte zinc and selenium deficiency in patients with IgAD, and the need for investigation of these micronutrients in their follow-up.

Type 1 diabetes and inborn errors of immunity: Complete strangers or 2 sides of the same coin?

Type 1 diabetes (T1D) is a polygenic disease and does not follow a mendelian pattern. Inborn errors of immunity (IEIs), on the other hand, are caused by damaging germline variants, suggesting that T1D and IEIs have nothing in common. Some IEIs, resulting from mutations in genes regulating regulatory T-cell homeostasis, are associated with elevated incidence of T1D. The genetic spectrum of IEIs is gradually being unraveled; consequently, molecular pathways underlying human monogenic autoimmunity are being identified. There is an appreciable overlap between some of these pathways and the genetic variants that determine T1D susceptibility, suggesting that after all, IEI and T1D are 2 sides of the same coin. The study of monogenic IEIs with a variable incidence of T1D has the potential to provide crucial insights into the mechanisms leading to T1D. These insights contribute to the definition of T1D endotypes and explain disease heterogeneity. In this review, we discuss the interconnected pathogenic pathways of autoimmunity, β-cell function, and primary immunodeficiency. We also examine the role of environmental factors in disease penetrance as well as the circumstantial evidence of IEI drugs in preventing and curing T1D in individuals with IEIs, suggesting the repositioning of these drugs also for T1D therapy.

A comprehensive overview of juvenile idiopathic arthritis: From pathophysiology to management

Rheumatoid Arthritis (RA) is a progressive autoimmune disease. It is among the most widespread chronic illnesses in children, with an annual incidence of 1.6 to 23 new instances per 100,000 adolescents. About 1 child in every 1000 develops Juvenile Idiopathic Arthritis (JIA) type of chronic arthritis. The cause of JIA is not well known but what known is that it involves inflammation of the synovium and destruction of tissues in joints which can cause early-onset of oligo articular JIA. It is challenging to diagnose the condition in some children who initially complain of pain and joint swelling as there is no blood test discovered that can confirm the diagnoses of JIA. As JIA patients are immunosuppressed due to the use of drugs, making them vulnerable to catch infections like COVID 19 which can lead to cardiovascular diseases having high rate of morbidity and mortality. The comorbidity like Diabetes has higher incidence in these patients resulting in synergistic effect on inflammation. Currently, the connection of genetics in JIA provides evidence that HLA Class I and II alleles have a role in the pathophysiology of various subtypes of JIA which includes inflammation in the axial skeletal. The primary objective of therapy in juvenile idiopathic arthritis is the suppression of clinical symptoms. The pharmacological approach includes use of medications like DMARDs, NSAIDs etc. and non-pharmacological approach includes physiotherapy, which helps in restoring normal joint function and herbs as adjuvants which has the benefit of no side effects.

Making sense of plasma cell heterogeneity

Plasma cells (PCs) are essential for the quality and longevity of protective immunity. The canonical humoral response to vaccination involves induction of germinal centers in lymph nodes followed by maintenance by bone marrow-resident PCs, although there are many variations of this theme. Recent studies have highlighted the importance of PCs in nonlymphoid organs, including the gut, central nervous system, and skin. These sites harbor PCs with distinct isotypes and possible immunoglobulin-independent functions. Indeed, bone marrow now appears unique in housing PCs derived from multiple other organs. The mechanisms through which the bone marrow maintains PC survival long-term and the impact of their diverse origins on this process remain very active areas of research.

Immune tolerance breakdown in inborn errors of immunity: Paving the way to novel therapeutic approaches

Up to 25% of the patients with inborn errors of immunity (IEI) also exhibit immunodysregulatory features. The association of immune dysregulation and immunodeficiency may be explained by different mechanisms. The understanding of mechanisms underlying immune dysregulation in IEI has paved the way for the development of targeted treatments. In this review article, we will summarize the mechanisms of immune tolerance breakdown and the targeted therapeutic approaches to immune dysregulation in IEI.

Establishment of New Immunostatistical Equations for Diagnosis and Follow-Up of Gluten-Free Diet in Patients with Celiac Disease

<b>Background and Objective:</b> Celiac disease (CD) is an autoimmune condition characterized by immune responses to gluten. The reported prevalence of CD has increased globally due to improved screening and diagnostic techniques, however, there is significant global variation in methods of diagnosis and follow-up. A new immunostatistical equation that determines the values of two types of antibodies using the total IgA test. <b>Materials and Methods:</b> Only 70 blood samples were taken from people who had celiac disease or were suspected of having it, with ages ranging from 5 to 40 years and they were separated into two groups. The first group contained 40 people of both sexes who had previously been diagnosed with celiac disease, while the second group included 30 individuals of both sexes, with ages ranging from 5 to 35 years, who were suspected of having celiac disease due to the appearance of some clinical symptoms. The control group also included 30 blood samples from healthy individuals of both sexes, with ages ranging from 5 to 40 years. Total IgA antibody tTG/IgA and DGP/IgA levels were estimated for all study samples. <b>Results:</b> By using a regression coefficient test the results showed the percentage of the effect of total IgA on tTG/IgA, DGP/IgA amounted to 11 and 25%, respectively, as shown by the value of the coefficient of clarifications (R²) in patients with CD. On the other hand, The percentage of the effect of total IgA on tTG/IgA and DGP/IgA amounted to 11, 14%, respectively, as shown by the value of the coefficient of clarifications (R²) in patients with suspected CD in p<u><</u>0.05. The results of the study were revealed and through the regression coefficient, four new immunostatistical equations were mathematically derived that give the value of tTG/IgA and DGP/IgA based solely on the total IgA test in the laboratory. <b>Conclusion:</b> By adopting one laboratory test which determines total IgA, the study concluded four new immunostatistical equations that will help academic researchers and attending physicians to diagnose celiac disease in addition to following up on patient's adherence to a gluten-free diet.

Crohn's Disease-Like Features in a Patient With IgE and Selective IgG1 and IgG3 Deficiency

We report a 19-year-old male with congenital, combined deficiency of immunoglobulin (Ig) E and 2/4 subclasses of IgG (G1, G3) and chronic diarrhea. He presented at six years of age with chronic recurrent diarrhea responsive to immunoglobulin treatment. Initially, it was considered of infectious origin. However, at the age of 14 years, ileocolonoscopy and magnetic resonance enterography (MRE) were performed, and they showed a mild, limited, non-specific, terminal ileitis with increased eosinophil count on histology. A diagnosis of possible eosinophilic gastroenteritis was made, and budesonide was administered with temporary relief. However, at the age of 19 years, repeat ileocolonoscopy showed multiple ulcers in the terminal ileum and aphthous ulcers in the cecum, and repeat MRE demonstrated extensive ileal involvement. Esophagogastroduodenoscopy demonstrated the involvement of the upper GI tract with aphthous ulcers. Subsequently, gastric, ileal, and colonic biopsies revealed Ziehl-Neelsen-negative, non-caseating granulomas. We hereby report the first case of IgE and selective IgG1 and IgG3 deficiency complicated with Crohn's disease-like extensive GI involvement.

Liver immunity, autoimmunity, and inborn errors of immunity

The liver is the front line organ of the immune system. The liver contains the largest collection of phagocytic cells in the body that detect both pathogens that enter through the gut and endogenously produced antigens. This is possible by the highly developed differentiation capacity of the liver immune system between self-antigens or non-self-antigens, such as food antigens or pathogens. As an immune active organ, the liver functions as a gatekeeping barrier from the outside world, and it can create a rapid and strong immune response, under unfavorable conditions. However, the liver's assumed immune status is anti-inflammatory or immuno-tolerant. Dynamic interactions between the numerous populations of immune cells in the liver are key for maintaining the delicate balance between immune screening and immune tolerance. The anatomical structure of the liver can facilitate the preparation of lymphocytes, modulate the immune response against hepatotropic pathogens, and contribute to some of its unique immunological properties, particularly its capacity to induce antigen-specific tolerance. Since liver sinusoidal endothelial cell is fenestrated and lacks a basement membrane, circulating lymphocytes can closely contact with antigens, displayed by endothelial cells, Kupffer cells, and dendritic cells while passing through the sinusoids. Loss of immune tolerance, leading to an autoaggressive immune response in the liver, if not controlled, can lead to the induction of autoimmune or autoinflammatory diseases. This review mentions the unique features of liver immunity, and dysregulated immune responses in patients with autoimmune liver diseases who have a close association with inborn errors of immunity have also been the emphases.

When secretion turns into excretion - the different roles of IgA

IgA deficiency is the commonest immunodeficiency affecting up to 1 in 700 individuals. The effects of IgA deficiency are difficult to see in many individuals, are mild in many fewer and severe in fewer still. While monovalent IgA is found in serum, dimeric IgA is secreted through mucosal surfaces where it helps to maintain epithelial homeostasis. Studies with knockout mice have taught us that there are subtle inflammatory consequences of removing secretory IgA (sIgA), and the best explanation for these changes can be related by the loss of the 'excretory' immune system. The excretion of antigens is a logical process in regulating the immune system, given the long half-life of complement fixing antibodies. But the function of IgA as an immune or inflammation regulator may go beyond antigen removal.

A Comprehensive Review of the Neurological Manifestations of Celiac Disease and Its Treatment

Celiac disease (CD) is a common chronic inflammatory disorder occurring in genetically predisposed individuals secondary to gluten ingestion. CD usually presents with gastrointestinal symptoms such as pain, bloating, flatulence, and constipation or diarrhea. However, individuals can present in a nonclassical manner with only extraintestinal symptoms. The neurological manifestations of CD include ataxia, cognitive impairment, epilepsy, headache, and neuropathy. A lifelong gluten-free diet is the current recommended treatment for CD. This review discusses the relevant neurological manifestations associated with CD and the novel therapeutics. Further research is required to get a better understanding of the underlying pathophysiology of the neurological manifestations associated with CD. Clinicians should keep CD in the differential diagnosis in individuals presenting with neurological dysfunction of unknown cause.

Selective immunoglobulin A deficiency in children with diabetes mellitus: Data from a medical center in Ukraine

The aim of this study was to estimate the prevalence of selective immunoglobulin A deficiency (SIgAD) among children with type 1 diabetes mellitus (DM) in Ternopil region (western Ukraine). Serum IgA levels were measured in 240 patients aged 4-17 years with DM and in 324 children of a control group of the same age. Normal IgA level was observed in 210 (87.5%) patients, increased-in 18 (7.5%), decreased (lower than the age reference value)-in 12 (5.0%) patients with DM. The mean IgA level in patients with DM was 152.11±73.78 mg/dL. SIgAD criteria were met by 7 (2.9%) children with DM, but none of the children of the control group met the SIgAD criteria. Female / male ratio among the patients with SIgAD was 1/6. There was no history of recurrent infections in these patients. No correlation between IgA and HbA1c levels was detected. Autoimmune thyroiditis was observed in 42.9% of patients with DM and SIgAD, and in 3.5% of patients with DM and normal or increased IgA levels. Thus, the prevalence of selective IgA deficiency in children with DM in Ternopil region (Ukraine) is 2.9% (1:34). This study shows that patients with low IgA levels need further re-examination of IgA levels to exclude SIgAD. Children with SIgAD and DM should be monitored for autoimmune manifestations that may affect the course and consequences of the disease.

Promoting intestinal IgA production in mice by oral administration with anthocyanins

While recent years have witnessed ever-growing evidence on the prebiotic attributes of anthocyanins for treatment of microbiota-associated diseases, the complex interplay between anthocyanin uptake, the gut microbiota, and the intestinal mucosal immune system remains poorly understood. Here, we investigate the effects of bilberry anthocyanins on the gut microbiota composition and metabolism, and the intestinal mucosal immune system of mice. We observed an increased proportion of IgA-producing plasma cells in the mesenteric lymph nodes (MLNs) and an enhanced secretion of secretory immunoglobulin A (sIgA) and antimicrobial peptides in the small intestine. Small intestine transcriptome analysis further suggested that anthocyanins influenced IgA production. We found that oral administration of anthocyanins altered the gut microbiota through maintaining the anaerobic intestinal environment, promoting the secretion of sIgA and antimicrobial peptides, and downregulating cell motility and mobile genetic elements of commensal bacteria. These observations suggest that the oral administration of anthocyanins helps in maintaining intestinal homeostasis and thus it may find applications in immunotherapy and related fields.

Autoimmune hemolytic anemia: causes and consequences

INTRODUCTION

Autoimmune hemolytic anemia (AIHA) is classified according to the direct antiglobulin test (DAT) and thermal characteristics of the autoantibody into warm and cold forms, and in primary versus secondary depending on the presence of associated conditions.

AREAS COVERED

AIHA displays a multifactorial pathogenesis, including genetic (association with congenital conditions and certain mutations), environmental (drugs, infections, including SARS-CoV-2, pollution, etc.), and miscellaneous factors (solid/hematologic neoplasms, systemic autoimmune diseases, etc.) contributing to tolerance breakdown. Several mechanisms, such as autoantibody production, complement activation, monocyte/macrophage phagocytosis, and bone marrow compensation are implicated in extra-/intravascular hemolysis. Treatment should be differentiated and sequenced according to AIHA type (i.e. steroids followed by rituximab for warm, rituximab alone or in association with bendamustine or fludarabine for cold forms). Several new drugs targeting B-cells/plasma cells, complement, and phagocytosis are in clinical trials. Finally, thrombosis and infections may complicate disease course burdening quality of life and increasing mortality.

EXPERT OPINION

Beyond warm and cold AIHA, a gray-zone still exists including mixed and DAT negative forms representing an unmet need. AIHA management is rapidly changing through an increasing knowledge of the pathogenic mechanisms, the refinement of diagnostic tools, and the development of novel targeted and combination therapies.

In Search for the Missing Link in APECED-like Conditions: Analysis of the AIRE Gene in a Series of 48 Patients

Autoimmune diseases are a heterogeneous group of disorders of the immune system. They can cluster in the same individual, revealing various preferential associations for polyendocrine autoimmune syndromes. Clinical observation, together with advances in genetics and the understanding of pathophysiological processes, has further highlighted that autoimmunity can be associated with immunodeficiency; autoimmunity may even be the first primary immunodeficiency manifestation. Analysis of susceptibility genes for the development of these complex phenotypes is a fundamental issue. In this manuscript, we revised the clinical and immunologic features and the presence of AIRE gene variations in a cohort of 48 patients affected by high polyautoimmunity complexity, i.e., APECED-like conditions, also including patients affected by primary immunodeficiency. Our results evidenced a significant association of the S278R polymorphism of the AIRE gene with APECED-like conditions, including both patients affected by autoimmunity and immunodeficiency and patients with polyautoimmunity compared to healthy controls. A trend of association was also observed with the IVS9+6 G>A polymorphism. The results of this genetic analysis emphasize the need to look for additional genetic determinants playing in concert with AIRE polymorphisms. This will help to improve the diagnostic workup and ensure a precision medicine approach to targeted therapies in APECED-like patients.

IgA deficiency and autoimmune comorbidities in Juvenile Idiopathic Arthritis

OBJECTIVES

(1) To describe the prevalence of IgA deficiency (IgAD), uveitis, coeliac disease (CD) and thyroid disorders in a multicentric cohort of patients diagnosed with JIA and, (2) to evaluate whether patients with JIA and IgAD present other autoimmune diseases more frequently than patients with normal serum levels of IgA.

METHODS

Retrospective chart review of a cohort of patients diagnosed with JIA followed at the paediatric rheumatology units of two hospitals in Madrid, Spain.

RESULTS

A total of 193 patients were included. Of them, 123 were females (64%). Median age at disease onset was 5.6 years (IQR 2.5-9.7) and the median time of follow-up was 5.1 years (IQR 2.2-8.1). The three most common ILAR categories were oligoarticular (53%), polyarticular RF negative (20%) and enthesitis related arthritis (10%). Serum IgA levels were available in 172/193 (89%); 25/172 (15%) had selective (<7mg/dl, n=8) or partial (7-69mg/dl, n=17) IgAD. All the patients had periodic eye exams. Eighteen children (9%) had anterior uveitis, 15/18 chronic and 3/18 acute. Serum anti transglutaminase IgA, or IgG in IgAD were obtained in 135/193 (70%). Four children (3%) were diagnosed with CD either by intestinal biopsy (n=3) or by the combination of characteristic clinical, serological and genetic features (n=1); two of them had IgAD (p=0.12; OR=6.4; 95% CI 0.9-47.6). Only 1/153 (0.7%) patient had hyperthyrotropinemia with positive anti-thyroid antibodies and required replacement therapy.

CONCLUSION

Patients with JIA frequently present autoimmune comorbidities. IgAD does not seem to increase their prevalence, with the possible exception of CD.

Bruton's Tyrosine Kinase Supports Gut Mucosal Immunity and Commensal Microbiome Recognition in Autoimmune Arthritis

Bruton's tyrosine kinase (Btk) deficiency preferentially eliminates autoreactive B cells while sparing normal humoral responses, but has not been studied in mucosal immunity. Commensal microbes and intact BTK signaling have been independently shown to be essential for arthritis development in K/BxN mice. Here, we examine how BTK-mediated signaling interfaces with the gut microbiome. Btk-deficient K/BxN mice were found to have small Peyer's Patches with reduced germinal center and IgA class-switched B cells. IgA-switched plasma cells in small intestines were reduced, especially in villi of Btk-deficient mice. IgH CDR3 sequencing showed similar V gene diversity and somatic hypermutation frequency despite Btk deficiency but showed reduced CDR3 amino acid polarity, suggesting potential qualitative differences in the gut plasma cell repertoire. Small intestinal IgA was low and IgA coating of commensal bacteria was reduced. IgA-seq showed a shift in small intestinal microbes that are normally IgA-coated into the uncoated fraction in Btk-deficient mice. Overall, this study shows that BTK supports normal intestinal IgA development in response to commensals. This manuscript was previously published as a preprint at: https://www.biorxiv.org/content/10.1101/2021.03.10.434762v2.

Immunoglobulin A-specific deficiency induces spontaneous inflammation specifically in the ileum

OBJECTIVE

Although immunoglobulin A (IgA) is abundantly expressed in the gut and known to be an important component of mucosal barriers against luminal pathogens, its precise function remains unclear. Therefore, we tried to elucidate the effect of IgA on gut homeostasis maintenance and its mechanism.

DESIGN

We generated various IgA mutant mouse lines using the CRISPR/Cas9 genome editing system. Then, we evaluated the effect on the small intestinal homeostasis, pathology, intestinal microbiota, cytokine production, and immune cell activation using intravital imaging.

RESULTS

We obtained two lines, with one that contained a <50 base pair deletion in the cytoplasmic region of the IgA allele (IgA tail-mutant; IgA^tm/tm) and the other that lacked the most constant region of the IgH α chain, which resulted in the deficiency of IgA production (IgA^-/-). IgA^-/- exhibited spontaneous inflammation in the ileum but not the other parts of the gastrointestinal tract. Associated with this, there were significantly increased lamina propria CD4⁺ T cells, elevated productions of IFN-γ and IL-17, increased ileal segmented filamentous bacteria and skewed intestinal microflora composition. Intravital imaging using Ca²⁺ biosensor showed that IgA^-/- had elevated Ca²⁺ signalling in Peyer's patch B cells. On the other hand, IgA^tm/tm seemed to be normal, suggesting that the IgA cytoplasmic tail is dispensable for the prevention of the intestinal disorder.

CONCLUSION

IgA plays an important role in the mucosal homeostasis associated with the regulation of intestinal microbiota and protection against mucosal inflammation especially in the ileum.

Evaluation of Specific Antibody Responses in Patients with Selective IgA Deficiency and Ataxia Telangiectasia

BACKGROUND

Specific Antibody Deficiency (SAD) is a primary immunodeficiency disease (PID) characterized by the occurrence of recurrent infections and inadequate antibody response to polysaccharide new antigens.

OBJECTIVE

This study aims to determine the titer of specific antibodies against unconjugated 23-valent pneumococcal polysaccharide vaccine (PPSV-23), the presence of SAD, and its association with clinical and laboratory findings in Ataxia-telangiectasia (A-T) and selective immunoglobulin A deficiency (SIgAD) patients.

METHODS

32 A-T patients and 43 SIgAD patients were included in the study. Samples of the patients were obtained before and three weeks after vaccination with PPSV-23. Specific immunoglobulin G (IgG) directed towards pneumococcal capsular antigen and specific antibodies against whole pneumococcal antigens was measured.

RESULTS

Comparison of the response to vaccination revealed that 81.3% of A-T patients and 18.6% of the SIgAD patients had an inadequate response to PPSV-23 (p<0.001). The prevalence of recurrent infection (p=0.034) and pneumonia (p=0.003) in SIgAD patients was significantly higher in non-responders than responders. Likewise, the number of marginal zone B cells (p=0.037), transitional B cells (p=0.019), plasmablasts (p=0.019), CD8+ naïve T cells (p=0.036), and percentage of CD8+ T cells (p=0.047), switched memory B cells (SMB) (p=0.026) and immunoglobulin M (IgM) memory B cells (p=0.022) in SIgAD patients were significantly lower in non-responder group than responder group. In contrast, the percentage of CD4 T+ cells in A-T patients was lower in the non-responder group than responders (p=0.035).

CONCLUSION

SAD is more frequent in A-T patients than SIgAD patients. The role of SMB and T cells should not be underestimated in SAD.

Selective IgA Deficiency and Allergy: A Fresh Look to an Old Story

Selective IgA deficiency (SIgAD) is the most common human primary immune deficiency (PID). It is classified as a humoral PID characterized by isolated deficiency of IgA (less than 7 mg/dL but normal serum IgG and IgM) in subjects greater than 4 years of age. Intrinsic defects in the maturation of B cells and a perturbation of Th cells and/or cytokine signals have been hypothesized to contribute to SIgAD pathogenesis. The genetic basis of IgA deficiency remains to be clarified. Patients with SIgAD can be either asymptomatic or symptomatic with clinical manifestations including allergy, autoimmunity and recurrent infections mainly of the respiratory and gastrointestinal tract. Studies analyzing allergy on SIgAD patients showed prevalence up to 84%, supporting in most cases the relationship between sIgAD and allergic disease. However, the prevalence of allergic disorders may be influenced by various factors. Thus, the question of whether allergy is more common in SIgAD patients compared to healthy subjects remains to be defined. Different hypotheses support an increased susceptibility to allergy in subjects with SIgAD. Recurrent infections due to loss of secretory IgA might have a role in the pathogenesis of allergy, and vice versa. Perturbation of microbiota also plays a role. The aim of this review is to examine the association between SIgAD and atopic disease and to update readers on advances over time at this important interface between allergy and SIgAD.

Beyond Infections: New Warning Signs for Inborn Errors of Immunity in Children

Patients with inborn errors of immunity (IEI) are susceptible to developing a severe infection-related clinical phenotype, but the clinical consequences of immune dysregulation, expressed with autoimmunity, atopy, and lymphoproliferation could represent the first sign in a significant percentage of patients. Therefore, during the diagnostic work-up patients with IEI are frequently addressed to different specialists, including endocrinologists, rheumatologists, and allergologists, often resulting in a delayed diagnosis. In this paper, the most relevant non-infectious manifestations of IEI are discussed. Particularly, we will focus on the potential presentation of IEI with autoimmune cytopenia, non-malignant lymphoproliferation, severe eczema or erythroderma, autoimmune endocrinopathy, enteropathy, and rheumatologic manifestations, including vasculitis and systemic lupus erythematosus. This paper aims to identify new warning signs to suspect IEI and help in the identification of patients presenting with atypical/non-infectious manifestations.

The Role of HLA in the Association between IgA Deficiency and Celiac Disease

Selective IgA deficiency (SIgAD) is the most frequent primary immune defect. Since SIgAD is not characterized by relevant infectious issues in most cases, it is often diagnosed during the diagnostic work up of several and different autoimmune disorders, which are associated with this primary immune defect. The genetic background of SIgAD is complex and three HLA haplotypes resulted to be more frequently associated with it; in detail, two of them include HLA-DQB1^∗02 allelic variants, which are essential predisposing factors to develop Celiac Disease (CD). Here, we discuss the evidence regarding the role of HLA in the etiopathogenesis of SIgAD and its association with CD. Actually, the HLA region seems to play a modest role in the genetic predisposition to SIgAD and we may speculate that the association with the HLA-DQB1^∗02 alleles (or haplotypes including them) could derive from its link with CD. Indeed, SIgAD and some related immunological alterations are likely to predispose to several autoimmune diseases (with and despite different HLA backgrounds), including CD, which is relatively common and directly associated with the HLA-DQB1^∗02 allelic variants coding the DQ2 heterodimer. Further and specific studies are needed to make final conclusions in this regard.

Selective IgA Deficiency a Probable Risk of Recurrent Chest Infections in Asthmatics

BACKGROUND

Selective immunoglobulin A (IgA) deficiency is characterized by a high incidence of both recurrent infections and atopic diseases. Asthma is one of the most common lung diseases affecting around 300 million people worldwide and is associated with risk of serious pneumococcal disease and microbial infections. Multiple studies have attributed this to impaired innate and adaptive immunity in asthmatics. An additional probable hypothesis is the existence of an underlying primary immunodeficiency (PID), such as selective IgA deficiency (sIgAD).

AIM

To assess the prevalence of selective IgA deficiency and its correlation to recurrent infections in asthmatic patients.

METHODS

A case-control study was conducted on 80 subjects who were divided into 3 groups: 20 Asthmatic patients with recurrent chest infections (Group A), 20 asthmatic patients without recurrent chest infections (Group B) and 40 healthy controls (Group C).

RESULTS

On comparing the 3 studied groups, there was a statistically significant difference between the three groups (p = ˂0.001) concerning serum IgA. The mean serum IgA was statistically significantly lower in Group A&B than in Group C. Furthermore, it was significantly lower in Group A than in Group B and C (p1,2 <0.002 and <0.001*, respectively). The percentage of selective IgA deficiency or partial IgA deficiency in asthmatic patients was 56% (26 patients). Group A showed a statistically significant higher percentage of selective/partial IgA deficiency.

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

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

Diagnosing and Monitoring Celiac Patients with Selective IgA Deficiency: Still an Open Issue

Although, the association between celiac disease (CD) and selective immunoglobulin A deficiency (SIgAD) has been known for more than fifty years, the procedures for diagnosing and monitoring patients with both conditions are still far from definitive. When serological markers were introduced as pre-bioptic investigations, it was immediately clear that searching for specific IgA antibodies without checking total serum IgA could lead to a failure in diagnosing IgA-deficient CD patients, while specific IgG antibodies could be useful as additional tests, because they are frequently found in the serum of affected patients. Nonetheless, until recently the diagnosis of CD in IgA-deficient patients was based on the few, fragmentary and often contradictory data available in literature. The introduction of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidelines in 2012 provided the current criteria for diagnosing CD in IgA-deficient patients, although some issues remained open, such as the selection of patients who should undergo specific IgG antibody testing and the choice of the most reliable IgG-based test for both diagnosis and follow-up. A real-life study recently assessed the impact of the 2012 ESPGHAN guidelines in diagnosing and monitoring CD in SIgAD patients, highlighting several pitfalls that can lead to operational uncertainties and difficulties in patient management. In the present report, the evolution of diagnostic tools and criteria for CD in SIgAD patients has been critically assessed, both strengths and open issues have been highlighted, and future perspectives for improving the current diagnostic protocols have been suggested.

Relationship between selective IgA deficiency and COVID-19 prognosis

The prevalence and mortality rates of coronavirus disease 2019 (COVID-19) vary widely among populations. Mucosal immunity is the first barrier to pathogens' entry into the body. Immunoglobulin A (IgA) is the main antibody of mucosal immunity. We explored the relationship between selective immunoglobulin A deficiency (SIgAD) and the severity of COVID-19. We included 424 patients (203 females) with COVID-19. Eleven patients had SIgAD. Laboratory data on patients with SIgAD and normal IgA levels were compared. The relationship between SIgAD and severe COVID-19 infection was explored by logistic regression analysis. In univariate logistic regression analysis, the risk of severe disease in COVID-19 patients with SIgAD was approximately 7.7-fold higher than in the other patients (odds ratio [OR], 7.789; 95% confidence interval [CI], 1.665-36.690, p = 0.008), while it was 4-fold (OR, 4.053; 95% CI, 1.182-13.903, p = 0.026) higher in multivariate logistic regression analysis. Serum IgA levels were positively correlated with total lymphocyte counts, and negatively correlated with C-reactive protein (CRP) levels, which were found as a risk factor for severe COVID-19.In SIgAD patients, the number of SARS-CoV-2 viruses that pass through mucosal membranes may be increased, leading to complications such as cytokine storm syndrome and acute respiratory distress syndrome.

The Epidemiology and Clinical Presentations of Atopic Diseases in Selective IgA Deficiency

Selective IgA deficiency (sIgAD) is the most common primary immunodeficiency disease (PID), with an estimated occurrence from about 1:3000 to even 1:150, depending on population. sIgAD is diagnosed in adults and children after the 4th year of age, with immunoglobulin A level below 0.07 g/L and normal levels of IgM and IgG. Usually, the disease remains undiagnosed throughout the patient's life, due to its frequent asymptomatic course. If symptomatic, sIgAD is connected to more frequent viral and bacterial infections of upper respiratory, urinary, and gastrointestinal tracts, as well as autoimmune and allergic diseases. Interestingly, it may also be associated with other PIDs, such as IgG subclasses deficiency or specific antibodies deficiency. Rarely sIgAD can evolve to common variable immunodeficiency disease (CVID). It should also be remembered that IgA deficiency may occur in the course of other conditions or result from their treatment. It is hypothesized that allergic diseases (e.g., eczema, rhinitis, asthma) are more common in patients diagnosed with this particular PID. Selective IgA deficiency, although usually mildly symptomatic, can be difficult for clinicians. The aim of the study is to summarize the connection between selective IgA deficiency and atopic diseases.

Gluten-free diet can ameliorate the symptoms of non-celiac autoimmune diseases

CONTEXT

A gluten-free diet (GFD) is the recommended treatment for gluten-dependent disease. In addition, gluten withdrawal is popular and occasionally is suggested as a treatment for other autoimmune diseases (ADs).

OBJECTIVE

The current systematic review summarizes those entities and discusses the logic behind using a GFD in classical non-gluten-dependentADs.

DATA SOURCES

A search for medical articles in PubMed/MEDLINE, Web of Sciences, LILACS, and Scielo published between 1960 and 2020 was conducted, using the key words for various ADs and GFDs.

DATA EXXTRACTION

Eight-three articles were included in the systematic review (using PRISMA guidelines).

DATA ANALYSIS

Reduction in symptoms of ADs after observance of a GFD was observed in 911 out of 1408 patients (64.7%) and in 66 out of the 83 selected studies (79.5%). The age of the patients ranged from 9 months to 69 years. The duration of the GFD varied from 1 month to 9 years. A GFD can suppress several harmful intraluminal intestinal events. Potential mechanisms and pathways for the action of GFD in the gut - remote organs' axis have been suggested.

CONCLUSION

A GFD might represent a novel nutritional therapeutic strategy for classical non-gluten-dependent autoimmune conditions.

Clinical Features, Immunopathogenesis, and Therapeutic Strategies in Vitiligo

Vitiligo is an autoimmune disease of the skin characterized by epidermal melanocyte loss resulting in white patches, with an approximate prevalence of 0.5-2% worldwide. Several precipitating factors by chemical exposure and skin injury present commonly in patients with vitiligo. Although the diagnosis appears to be straightforward for the distinct clinical phenotype and specific histological features, vitiligo provides many challenges including chronicity, treatment resistance, frequent relapse, associated profound psychosocial effect, and negative impact on quality of life. Multiple mechanisms are involved in melanocyte disappearance, including genetics, environmental factors, and immune-mediated inflammation. Compelling evidence supports the melanocyte intrinsic abnormalities with poor adaptation to stressors leading to instability and release of danger signals, which will activate dendritic cells, natural killer cells, and innate lymphoid cells to initiate innate immunity, ultimately resulting in T-cell mediated adaptive immune response and melanocyte destruction. Importantly, the cross- talk between keratinocytes, melanocytes, and immune cells, such as interferon (IFN)-γ signaling pathway, builds inflammatory loops that give rise to the disease deterioration. Improved understanding of the immune pathogenesis of vitiligo has led to the development of new therapeutic options including Janus kinase (JAK) inhibitors targeting IFN-γ signaling pathways, which can effectively reverse depigmentation. Furthermore, definition of treatment goals and integration of comorbid diseases into vitiligo management have revolutionized the way vitiligo is treated. In this review, we highlight recent developments in vitiligo clinical aspects and immune pathogenesis. Our key objective is to raise awareness of the complexity of this disease, the potential of prospective therapy strategies, and the need for early and comprehensive management.

Human marginal zone B cell development from early T2 progenitors

B cells emerge from the bone marrow as transitional (TS) B cells that differentiate through T1, T2, and T3 stages to become naive B cells. We have identified a bifurcation of human B cell maturation from the T1 stage forming IgMhi and IgMlo developmental trajectories. IgMhi T2 cells have higher expression of α4β7 integrin and lower expression of IL-4 receptor (IL4R) compared with the IgMlo branch and are selectively recruited into gut-associated lymphoid tissue. IgMhi T2 cells also share transcriptomic features with marginal zone B cells (MZBs). Lineage progression from T1 cells to MZBs via an IgMhi trajectory is identified by pseudotime analysis of scRNA-sequencing data. Reduced frequency of IgMhi gut-homing T2 cells is observed in severe SLE and is associated with reduction of MZBs and their putative IgMhi precursors. The collapse of the gut-associated MZB maturational axis in severe SLE affirms its existence in health.

The Prevalence of Selective and Partial Immunoglobulin A Deficiency in Patients with Autoimmune Polyendocrinopathy

Background: Autoimmune disorders are reported as presenting signs in patients with immunoglobulin A (IgA) deficiency. Herein, we aim to evaluate serum IgA among patients with autoimmune polyendocrinopathy.Methods: Patients with two or more autoimmune endocrinopathies were selected and the serum IgA levels were measured. Patients with an isolated low serum IgA (<7 mg/dL) after exclusion of other causes of hypogammaglobulinemia were considered as selective IgA deficiency (SIgAD), while partial IgA deficiency (PIgAD) was defined as IgA levels below lower limits of IgA normal range for age but higher than 7 mg/dL.Results: Fifty-three patients (19 [35.8%] male and 34 [64.2%] female) with autoimmune polyendocrinopathy enrolled in the study. Parental consanguinity and positive family history of autoimmunity were reported in 38.0% and 52.9% of patients, respectively. Overall, IgA deficiency was observed in 5 (9.4%) patients including PIgAD in 3 (5.7%) and SIgAD in 2 (3.8%) patients. Among IgA deficient patients, the first autoimmune disorder was developed at earlier ages (p = .002), and the prevalence of infection (p = .002), lymphoproliferation (p = .021), and overlap between insulin-dependent diabetes mellitus and autoimmune thyroiditis (p = .032) were significantly higher than patients with normal IgA. Also, the number of autoimmune comorbidities was closely correlated with the occurrence of IgA deficiency (p = .008).Conclusion: The prevalence of IgA deficiency in patients with autoimmune polyendocrinopathy is higher than that in the general population. In these patients, immunologic workup may lead to early diagnosis of inborn error of immunity, which can positively impact the evolution of complications and even management of the autoimmune disorders.

Infectious Complications in Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia (AIHA) may be frequently challenged by infectious complications, mainly as a result of immunosuppressive treatments administered. Furthermore, infectious agents are known triggers of AIHA onset and relapse. Although being risk factors for mortality, infections are an underestimated issue in AIHA. This review will collect the available evidence on the frequency and type of infectious complications in AIHA, detailing the risk related to each treatment (i.e., steroids, rituximab, splenectomy, classic immunosuppressive agents, and new target drugs). Moreover, we will briefly discuss the infectious complications in AIHA secondary to other diseases that harbor an intrinsic infectious risk (e.g., primary immunodeficiencies, systemic autoimmune diseases, lymphoproliferative disorders, solid organ and hematopoietic stem cell transplants). Finally, viral and bacterial reactivations during immune suppressive therapies will be discussed, along with suggested screening and prophylactic strategies.