Selective IgA deficiency in autoimmune diseases

Epigenome-wide Association Study Shows Differential DNA Methylation of MDC1, KLF9, and CUTA in Autoimmune Thyroid Disease

CONTEXT

Autoimmune thyroid disease (AITD) includes Graves disease (GD) and Hashimoto disease (HD), which often run in the same family. AITD etiology is incompletely understood: Genetic factors may account for up to 75% of phenotypic variance, whereas epigenetic effects (including DNA methylation [DNAm]) may contribute to the remaining variance (eg, why some individuals develop GD and others HD).

OBJECTIVE

This work aimed to identify differentially methylated positions (DMPs) and differentially methylated regions (DMRs) comparing GD to HD.

METHODS

Whole-blood DNAm was measured across the genome using the Infinium MethylationEPIC array in 32 Australian patients with GD and 30 with HD (discovery cohort) and 32 Danish patients with GD and 32 with HD (replication cohort). Linear mixed models were used to test for differences in quantile-normalized β values of DNAm between GD and HD and data were later meta-analyzed. Comb-p software was used to identify DMRs.

RESULTS

We identified epigenome-wide significant differences (P < 9E-8) and replicated (P < .05) 2 DMPs between GD and HD (cg06315208 within MDC1 and cg00049440 within KLF9). We identified and replicated a DMR within CUTA (5 CpGs at 6p21.32). We also identified 64 DMPs and 137 DMRs in the meta-analysis.

CONCLUSION

Our study reveals differences in DNAm between GD and HD, which may help explain why some people develop GD and others HD and provide a link to environmental risk factors. Additional research is needed to advance understanding of the role of DNAm in AITD and investigate its prognostic and therapeutic potential.

Defective autophagy and autophagy activators in myasthenia gravis: a rare entity and unusual scenario

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction (NMJ) that results from autoantibodies against nicotinic acetylcholine receptors (nAchRs) at NMJs. These autoantibodies are mainly originated from autoreactive B cells that bind and destroy nAchRs at NMJs preventing nerve impulses from activating the end-plates of skeletal muscle. Indeed, immune dysregulation plays a crucial role in the pathogenesis of MG. Autoreactive B cells are increased in MG due to the defect in the central and peripheral tolerance mechanisms. As well, autoreactive T cells are augmented in MG due to the diversion of regulatory T (Treg) cells or a defect in thymic anergy leading to T cell-mediated autoimmunity. Furthermore, macroautophagy/autophagy, which is a conserved cellular catabolic process, plays a critical role in autoimmune diseases by regulating antigen presentation, survival of immune cells and cytokine-mediated inflammation. Abnormal autophagic flux is associated with different autoimmune disorders. Autophagy regulates the connection between innate and adaptive immune responses by controlling the production of cytokines and survival of Tregs. As autophagy is involved in autoimmune disorders, it may play a major role in the pathogenesis of MG. Therefore, this mini-review demonstrates the potential role of autophagy and autophagy activators in MG.Abbreviations: Ach, acetylcholine; Breg, regulatory B; IgG, immunoglobulin G; MG, myasthenia gravis; NMJ, neuromuscular junction; ROS, reactive oxygen species; Treg, regulatory T; Ubl, ubiquitin-like.

A Distinct Anti-EBV DNase Profile in Patients with Undifferentiated Nasopharyngeal Carcinoma Compared to Classical Antigens

Nasopharyngeal cancer (NPC) is a prevalent type of cancer that often takes the form of undifferentiated carcinoma in the Maghreb region. It affects people of all ages. NPC diagnosis, mainly based on detecting Epstein-Barr virus (EBV), has not been well evaluated in North Africa. We compared the classical EBV serological tests using indirect immunofluorescence to the detection of EBV DNase antibodies by immunoblot in Algerian NPC patients. Significant variations were observed among different age groups of patients regarding the presence of VCA-IgA antibodies (0-14 and ≥30 years old, p < 0.0001; 15-19 and ≥30 years old, p < 0.01) and EA-IgA (0-14 and ≥30 years old, p < 0.01; 15-29 and ≥30 years old, p < 0.05). Differences were also noted in the titers of IgA anti-VCA and anti-EA antibodies across the three age groups. Some patients under the age of 30 with detectable IgG anti-VCA antibodies had undetectable IgA anti-VCA antibodies. These patients had a strong anti-DNase IgA response. However, older individuals had a higher level of anti-DNase IgG. Before treatment, children had strong DNase reactivity as indicated by specific IgA antibodies. Young adults had high IgA anti-DNase response, but the elderly (90.9%) had a lower response for these antibodies. Following therapy, the children retained high levels of IgA anti-DNase antibodies, and 66% of the young adults demonstrated robust antibody reactivity against DNase. In contrast, IgG responses to anti-DNase were low in children. This study demonstrated the utility of anti-DNase responses in the diagnosis and prognosis of NPC.

Insights from a 30-year journey: function, regulation and therapeutic modulation of PD1

PD1 was originally discovered in 1992 as a molecule associated with activation-induced cell death in T cells. Over the past 30 years, it was found that PD1 has a critical role in avoiding overactivation-induced cell death and autoimmunity, whereas its inhibition unleashes anticancer immunity. Here, we outline the journey from the discovery of PD1 to its role as a breakthrough target in cancer immunotherapy. We describe its regulation and function and examine how a mechanistic understanding of PD1 signalling suggests a central function in setting the T cell activation threshold, thereby controlling T cell proliferation, differentiation, exhaustion and metabolic status. This threshold theory, in combination with new insights into T cell metabolism and a better understanding of immune cell modulation by the microbiota, can provide guidance for the development of efficient combination therapies. Moreover, we discuss the mechanisms underlying immune-related adverse events after PD1-targeted therapy and their possible treatment.

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.

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.

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.

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.

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.

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.

IgA in human health and diseases: Potential regulator of commensal microbiota

Gut microbiota has extensive and tremendous impacts on human physiology and pathology. The regulation of microbiota is therefore a cardinal problem for the mutualistic relationship, as both microbial overgrowth and excessive immune reactions toward them could potentially be detrimental to host homeostasis. Growing evidence suggests that IgA, the most dominant secretory immunoglobulin in the intestine, regulates the colonization of commensal microbiota, and consequently, the microbiota-mediated intestinal and extra-intestinal diseases. In this review, we discuss the interactions between IgA and gut microbiota particularly relevant to human pathophysiology. We review current knowledge about how IgA regulates gut microbiota in humans and about the molecular mechanisms behind this interaction. We further discuss the potential role of IgA in regulating human diseases by extrapolating experimental findings, suggesting that IgA can be a future therapeutic strategy that functionally modulates gut microbiota.

IgA rheumatoid factor in rheumatoid arthritis

OBJECTIVES

Rheumatoid factor (RF) is a well-established marker for the diagnosis and classification of rheumatoid arthritis (RA). Most studies evaluated IgM RF or isotype-nonspecific total RF assays. We evaluated the added value of IgA RF in this context.

METHODS

An international sample cohort consisting of samples from 398 RA patients and 1073 controls was tested for IgA RF with 3 commercial assays. For all RA patients and 100 controls essential clinical and serological data for ACR/EULAR classification were available.

RESULTS

The sensitivity of IgA RF for diagnosing RA was lower than the sensitivity of IgM RF. Differences in numerical values between IgA RF assays were observed. With all assays, the highest IgA RF values were found in patients with primary Sjögren's syndrome. Double positivity for IgM RF and IgA RF had a higher specificity for RA than either IgM RF or IgA RF. The sensitivity of double positivity was lower than the sensitivity of either IgA RF or IgM RF. Single positivity for IgA RF was at least as prevalent in controls than in RA patients. Adding IgA RF to IgM RF and anti-citrullinated protein antibodies (ACPA) did not affect RA classification. However, combined positivity for IgA RF, IgM RF and IgG ACPA had a higher specificity and lower sensitivity for RA classification than positivity for either of the antibodies.

CONCLUSIONS

IgA RF showed a lower sensitivity than IgM RF. Combining IgA RF with IgM RF and ACPA did not improve sensitivity of RA classification. Combined positivity (IgA-RF/IgM-RF/ACPA) increased specificity.

Autoimmunity in Primary Immunodeficiencies (PID)

Primary immunodeficiency (PID) may impact any component of the immune system. The number of PID and immune dysregulation disorders is growing steadily with advancing genetic detection methods. These expansive recognition methods have changed the way we characterize PID. While PID were once characterized by their susceptibility to infection, the increase in genetic analysis has elucidated the intertwined relationship between PID and non-infectious manifestations including autoimmunity. The defects permitting opportunistic infections to take hold may also lead the way to the development of autoimmune disease. In some cases, it is the non-infectious complications that may be the presenting sign of PID autoimmune diseases, such as autoimmune cytopenia, enteropathy, endocrinopathies, and arthritis among others, have been reported in PID. While autoimmunity may occur with any PID, this review will look at certain immunodeficiencies most often associated with autoimmunity, as well as their diagnosis and management strategies.

STXBP6 and B3GNT6 Genes are Associated With Selective IgA Deficiency

Immunoglobulin A Deficiency (IgAD) is a polygenic primary immune deficiency, with a strong genetic association to the human leukocyte antigen (HLA) region. Previous genome-wide association studies (GWAS) have identified five non-HLA risk loci (IFIH1, PVT1, ATG13-AMBRA1, AHI1 and CLEC16A). In this study, we investigated the genetic interactions between different HLA susceptibility haplotypes and non-MHC genes in IgAD. To do this, we stratified IgAD subjects and healthy controls based on HLA haplotypes (N = 10,993), and then performed GWAS to identify novel genetic regions contributing to IgAD susceptibility. After replicating previously published HLA risk haplotypes, we compared individuals carrying at least one HLA risk allele (HLA-B*08:01-DRB1*03:01-DQB1*02:01 or HLA-DRB1*07:01-DQB1*02:02 or HLA-DRB1*01-DQB1*05:01) with individuals lacking an HLA risk allele. Subsequently, we stratified subjects based on the susceptibility alleles/haplotypes and performed gene-based association analysis using 572,856 SNPs and 24,125 genes. A significant genome-wide association in STXBP6 (rs4097492; p = 7.63 × 10^-9) was observed in the cohort carrying at least one MHC risk allele. We also identified a significant gene-based association for B3GNT6 (P _Gene = 2.1 × 10^-6) in patients not carrying known HLA susceptibility alleles. Our findings indicate that the etiology of IgAD differs depending on the genetic background of HLA susceptibility haplotypes.

Serum complements and immunoglobulin profiles in systemic lupus erythematosus patients: An observational study at a teaching hospital

Context:

Serum complement proteins and autoantibodies play an important role in the pathogenesis and diagnosis of systemic lupus erythematosus (SLE). Abnormalities in various immunoglobulin levels are described in patients of SLE.

Aims:

To study the spectrum of clinical manifestations and measure the serum levels of complement C3, complement C4, autoantibodies and immunoglobulin G (IgG) in patients of SLE and compare with healthy controls.

Settings and Design:

The present study is a prospective hospital-based observational study conducted between May 2014 and December 2018.

Statistical Analysis Used:

Unpaired t-test was used to compare the mean values between the SLE patients and healthy controls.

Material and Methods:

A total of 100 cases of SLE and 100 healthy controls were included in the study. The clinical data were retrieved. Serum antinuclear antibody, anti-ds DNA antibody, and anti-Smith antibody levels, and complements C3, C4 and IgG were measured.

Results:

Arthritis (89%) and anaemia (65%) were two common clinical presentations. The low complement C3 levels and C4 were detected in 64 and 62% of the SLE patients. Serum IgG was increased in 41% of the patients. A reduced level of IgG was detected in 6% of the patients.

Conclusion:

Primary care physicians should be aware of the clinical and serological manifestations of SLE as early detection will reduce end-organ damage. Autoantibody testing and complement testing should be done in all suspected cases. This study showed a significantly reduced C3 and C4 and elevated IgG in many cases of SLE as compared to control. Hypogammaglobulinemia was also present in a minority of the cases.

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.

Intestinal CD11b+ B Cells Ameliorate Colitis by Secreting Immunoglobulin A

The intestinal mucosal immune environment requires multiple immune cells to maintain homeostasis. Although intestinal B cells are among the most important immune cells, little is known about the mechanism that they employ to regulate immune homeostasis. In this study, we found that CD11b⁺ B cells significantly accumulated in the gut lamina propria and Peyer's patches in dextran sulfate sodium-induced colitis mouse models and patients with ulcerative colitis. Adoptive transfer of CD11b⁺ B cells, but not CD11b^-/- B cells, effectively ameliorated colitis and exhibited therapeutic effects. Furthermore, CD11b⁺ B cells were found to produce higher levels of IgA than CD11b^- B cells. CD11b deficiency in B cells dampened IgA production, resulting in the loss of their ability to ameliorate colitis. Mechanistically, CD11b⁺ B cells expressed abundant TGF-β and TGF-β receptor II, as well as highly activate phosphorylated Smad2/3 signaling pathway, consequently promoting the class switch to IgA. Collectively, our findings demonstrate that CD11b⁺ B cells are essential intestinal suppressive immune cells and the primary source of intestinal IgA, which plays an indispensable role in maintaining intestinal homeostasis.

Risk of autoimmune diseases in patients with RASopathies: systematic study of humoral and cellular immunity

BACKGROUND

Abnormalities of the immune system are rarely reported in patients affected by RASopathies. Aim of the current study was to investigate the prevalence of immune system dysfunction in a cohort of patients affected by RASopathies.

STUDY DESIGN

A group of 69 patients was enrolled: 60 at the Federico II University, Naples, 7 at University Magna Graecia of Catanzaro, 2 at "Scuola Medica Salernitana", Salerno. An age- and sex-matched control group was also enrolled. Autoimmune disorders were investigated according to international consensus criteria. Immune framework was also evaluated by immunoglobulin levels, CD3, CD4, CD8, CD19, CD56 lymphocyte subpopulations, autoantibodies levels and panel of inflammatory molecules, in both patients and controls.

RESULTS

Frequent upper respiratory tract infections were recorded in 2 patients; pneumonia, psoriasis and alopecia in single patients. Low IgA levels were detected in 8/44 patients (18.18%), low CD8 T cells in 13/35 patients (37.14%). Anti-tg and anti-TPO antibodies were detected in 3/24 patients (12.5%), anti r-TSH in 2 cases (8.33%), all in euthyroidism. Serum IgA and CD8 levels were significantly lower in patients than in controls (p 0.00685; p 0.000656 respectively). All tested patients showed increased inflammatory molecules compared to controls. These findings may anticipate the detection of overt autoimmune disease.

CONCLUSIONS

Patients affected by RASopathies are at risk to develop autoimmune disorders. Routine screening for autoimmunity is recommended in patients with RASopathy.

Subcutaneous immunoglobulin replacement therapy in a patient with 18q deletion syndrome, primary immune deficiency, and type 1 diabetes

18q deletion syndrome (OMIM #601808) results from a deletion of a part of a long arm of 18 chromosome and is characterized by mental retardation and congenital malformations. We present an exceptional case of a 12-year-old girl with severe phenotype of 18q deletion syndrome, frequent infections, type 1 diabetes, autoimmune thyroiditis, and vitiligo. At first, the patient was diagnosed with selective immunoglobulin A (sIgAD) which explained her susceptibility to both infections and autoimmunity. With time, sIgAD progressed to common variable immune deficiency-like (CVID-like) disorder. She had a minimum of 12 infections per year, approximately twice as many courses of different antibiotics and up to three hospitalizations annually, making the treatment of diabetes difficult. Due to safety issues (increased risk of adverse reaction to blood products) and patient’s convenience, subcutaneous IgG (SCIG) replacement therapy was initiated. We noticed a substantial decrease in the number of infections and improvement of metabolic control of diabetes.

Clinical heterogeneity among pediatric patients with autoimmune type 1 diabetes stratified by immunoglobulin deficiency

BACKGROUND

Type 1 diabetes (T1D) may coexist with primary immunodeficiencies, indicating a shared genetic background.

OBJECTIVE

To evaluate the prevalence and clinical characteristics of immunoglobulin deficiency (IgD) among children with T1D.

METHODS

Serum samples and medical history questionnaires were obtained during routine visits from T1D patients aged 4-18 years. IgG, IgA, IgM, and IgE were measured by nephelometry and enzyme-linked immunosorbent assay (ELISA). IgG and IgM deficiency (IgGD, IgMD) were defined as IgG/IgM >2 standard deviations (SD) below age-adjusted mean. IgE deficiency was defined as IgE <2 kIU/L. IgA deficiency (IgAD) was defined as IgA >2 SD below age-adjusted mean irrespective of other immunoglobulin classes (absolute if <0.07 g/L, partial otherwise) and as selective IgAD when IgA >2 SD below age-adjusted mean with normal IgG and IgM (absolute if <0.07 g/L, partial otherwise).

RESULTS

Among 395 patients (53.4% boys) with the median age of 11.2 (8.4-13.7) and diabetes duration 3.6 (1.1-6.0) years, 90 (22.8%) were found to have hypogammaglobulinemia. The IgGD and IgAD were the most common each in 40/395 (10.1%). Complex IgD was found in seven patients. Increased odds of infection-related hospitalization (compared to children without any IgD) was related to having any kind of IgD and IgAD; OR (95%CI) = 2.1 (1.2-3.7) and 3.7 (1.8-7.5), respectively. Furthermore, IgAD was associated with having a first-degree relative with T1D OR (95%CI) = 3.3 (1.4-7.6) and suffering from non-autoimmune comorbidities 3.3 (1.4-7.6), especially neurological disorders 3.5 (1.2-10.5).

CONCLUSIONS

IgDs frequently coexist with T1D and may be associated with several autoimmune and nonimmune related disorders suggesting their common genetic background.

Low-Risk Human Leukocyte Antigen Genes and Mild Villous Atrophy Typify Celiac Disease With Immunoglobulin A Deficiency

OBJECTIVES

We aimed to establish if in celiac disease (CD) with immunoglobulin A deficiency (IgAD) duodenal histopathology is influenced by human leukocyte antigen (HLA)-DQB1∗02 alleles dosage. Clinical differences between patients with CD and patients with CD and IgAD (CD-IgAD) were also evaluated.

METHODS

Five hundred and sixteen CD and 16 patients with CD-IgAD, enrolled over the time of 8 years, took part in this study. The severity of duodenal histopathology and frequency of CD at-risk HLA class II genes were compared in patients with CD versus patients with CD-IgAD. HLA class II genotypes were subdivided into two categories of genetic risk: high: HLA-DR3/DR7, -DR3/DR3, -DR4/DR4 -DR3/DR4 and low: HLA-DR5/DR7, -DR3/X, -DR4/X and X/X, where X means neither -DR3 nor -DR4. Then, they were compared with two types of duodenal histopathology: 0, 1, 2 and 3a of mild villous atrophy (MVA) and 3b and 3c of severe villous atrophy (SVA) according to the Marsh-Oberhuber classification. Clinical data concerning gender, number of esophagogastroduodenoscopies (EGDs) and association with other autoimmune diseases were obtained from medical records.

RESULTS

In comparison with CD, CD-IgAD showed an increased frequency of MVA (P < 0.0001). Furthermore, CD-IgAD with MVA showed an increase of HLA low-risk genotypes (P = 0.036) and half HLA-DQ2 heterodimers (P = 0.0443). Interestingly, CD-IgAD demanded an increased number of EGDs to reach the diagnosis of CD (P = 0.0104) and autoimmune liver diseases were more frequent compared to CD (P = 0.0049).

CONCLUSIONS

CD-IgAD is associated with MVA, low-risk HLA class II genes, an increased number of EGDs and autoimmune liver diseases.

Innate Mechanisms in Selective IgA Deficiency

Selective IgA deficiency (SIgAD), characterized by a serum IgA level below 0.07 mg/ml, while displaying normal serum levels of IgM and IgG antibodies, is the most frequently occurring primary immunodeficiency that reveals itself after the first four years after birth. These individuals with SIgAD are for the majority healthy and even when they are identified they are usually not investigated further or followed up. However, recent studies show that newborns and young infants already display clinical manifestations of this condition due to aberrancies in their immune defense. Interestingly, there is a huge heterogeneity in the clinical symptoms of the affected individuals. More than 50% of the affected individuals do not have clinical symptoms, while the individuals that do show clinical symptoms can suffer from mild to severe infections, allergies and autoimmune diseases. However, the reason for this heterogeneity in the manifestation of clinical symptoms of the individuals with SIgAD is unknown. Therefore, this review focusses on the characteristics of innate immune system driving T-cell independent IgA production and providing a mechanism underlying the development of SIgAD. Thereby, we focus on some important genes, including TNFRSF13B (encoding TACI), associated with SIgAD and the involvement of epigenetics, which will cover the methylation degree of TNFRSF13B, and environmental factors, including the gut microbiota, in the development of SIgAD. Currently, no specific treatment for SIgAD exists and novel therapeutic strategies could be developed based on the discussed information.

Imaging Features of Primary Immunodeficiency Disorders

Primary immunodeficiency disorders (PIDs), which are humoral, combined, and innate defects of the immune system, are relatively uncommon and may go undiagnosed in patients experiencing recurrent infections, resulting in increased morbidity and mortality. PIDs are clinically characterized by a broad spectrum of disorders, including repeated infections, autoimmune disorders, lymphoproliferative diseases, congenital anomalies, and increased risk of malignancy. Cardiothoracic imaging plays a crucial role in the diagnosis of PIDs owing to the high rates of repeated respiratory infections leading to bronchiectasis and other forms of chronic lung disease. Although PIDs as a group may seem similar in terms of radiologic features and clinical manifestations, there are specific entities that are pertinent to each PID on an individual level. For example, patients with common variable immunodeficiency may develop a unique granulomatous lymphocytic interstitial lung disease, and Good syndrome is associated with thymoma. Familiarity with the imaging characteristics of these disorders may expedite diagnosis and prognostication, and better direct therapy. Reviewing the thoracic manifestations of all PIDs is beyond the scope of this article; thus, the focus herein is on discussing the thoracic manifestations of the most common PIDs and their imaging features. © RSNA, 2021An earlier incorrect version appeared online. This article was corrected on March 25, 2021.

Immunoglobulin levels in systemic lupus erythematosus: A narrative review

Immunoglobulins play a fundamental role in the protection of the human body against internal and external threats. They also contribute to the immune system homeostasis and maintenance of self-tolerance. Hypogammaglobulinemia is occasionally encountered in routine clinical practice by rheumatologists. Low levels of immunoglobulins can occur as primary or secondary issues and may predispose patients to various forms of infection. However, the impact of the low immunoglobulin level abnormality varies with the underlying condition. In this narrative review, we shed light on the overall types and functions of immunoglobulins for clinicians. We discuss important principles of immunoglobulin measurements. We then consider the primary and secondary causes of low immunoglobulins with a special focus on hypogammaglobulinemia in patients with systemic lupus erythematosus (SLE).

Antithyroid Drug-Induced Lupus Erythematosus and Immunoglobulin A Deficiency

Patient: Male, 32-year-old

Final Diagnosis: Drug induced lupus erythematosus

Symptoms: Lymphadenopathy • proteinuria • rash

Medication: —

Clinical Procedure: Renal biopsy

Specialty: Endocrinology and Metabolic • Immunology • General and Internal Medicine

The Epidemiology and Clinical Manifestations of Autoimmunity in Selective IgA Deficiency

Selective immunoglobulin A deficiency (SIgAD) is the most common primary immunodeficiency, defined as an isolated deficiency of IgA (less than 0.07 g/L). Although the majority of people born with IgA deficiency lead normal lives without significant pathology, there is nonetheless a significant association of IgA deficiency with mucosal infection, increased risks of atopic disease, and a higher prevalence of autoimmune disease. To explain these phenomena, we have performed an extensive literature review to define the geoepidemiology of IgA deficiency and particularly the relative risks for developing systemic lupus erythematosus, hyperthyroidism, hypothyroidism, type 1 diabetes mellitus, Crohn's disease, ulcerative colitis, rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, and vitiligo; these diseases have strong data to support an association. We also note weaker associations with scleroderma, celiac disease, autoimmune hepatitis, immune thrombocytopenic purpura, and autoimmune hemolytic anemia. Minimal if any associations are noted with myasthenia gravis, lichen planus, and multiple sclerosis. Finally, more recent data provide clues on the possible immunologic mechanisms that lead to the association of IgA deficiency and autoimmunity; these lessons are important for understanding the etiology of autoimmune disease.

B Cell Disorders in Children: Part II

PURPOSE OF REVIEW

B cell disorders result in decreased levels or function of immunoglobulins in an individual. Genetic mutations have been reported in a variety of B cell disorders. This review, in follow-up to a previous review, describes some rare B cell disorders as well as their known underlying genetic etiologies.

RECENT FINDINGS

Genetic studies identify and permit precise classification of an increasing number of B cell disorders, leading to a greater understanding of B cell development and function. The B cell disorders are rare diseases. While clinicians are most familiar with X-linked agammaglobulinemia and so-called common variable immunodeficiency (CVID), there are many causes of hypogammaglobulinemia. Genetic testing provides a specific diagnosis, offers useful information for genetic counseling, and can identify previously unrecognized B cell disorders.

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.

Vaccine therapy for dysbiosis-related diseases

Progress in genomic analysis has resulted in the proposal that the intestinal microbiota is a crucial environmental factor in the development of multifactorial diseases, such as obesity, diabetes, rheumatoid arthritis, and inflammatory bowel diseases represented by Crohn’s disease and ulcerative colitis. Dysregulated gut microbiome contributes to the pathogenesis of such disorders; however, there are few effective treatments for controlling only disease-mediating bacteria. Here, we review current knowledge about the intestinal microbiome in health and disease, and discuss a regulatory strategy using a parenteral vaccine with emulsified curdlan and CpG oligodeoxynucleotides, which we have recently developed. Unlike other conventional injectable immunizations, our vaccine contributes to the induction of antigen-specific systemic and mucosal immunity. This vaccine strategy can prevent infectious diseases such as Streptococcus pneumoniae infection, and control metabolic symptoms mediated by intestinal bacteria (e.g. Clostridium ramosum) by induction of high titers of antigen-specific IgA at target mucosal sites. In the future, our vaccination approach could be an effective therapy for common infectious diseases and dysbiosis-related disorders that have been difficult to control so far.

Defective formation of IgA memory B cells, Th1 and Th17 cells in symptomatic patients with selective IgA deficiency

Objective

Selective IgA deficiency (sIgAD) is the most common primary immunodeficiency in Western countries. Patients can suffer from recurrent infections and autoimmune diseases because of a largely unknown aetiology. To increase insights into the pathophysiology of the disease, we studied memory B and T cells and cytokine concentrations in peripheral blood.

Methods

We analysed 30 sIgAD patients (12 children, 18 adults) through detailed phenotyping of peripheral B‐cell, CD8⁺ T‐cell and CD4⁺ T‐cell subsets, sequence analysis of IGA and IGG transcripts, in vitro B‐cell activation and blood cytokine measurements.

Results

All patients had significantly decreased numbers of T‐cell‐dependent (TD; CD27⁺) and T‐cell‐independent (TI; CD27⁻) IgA memory B cells and increased CD21^low B‐cell numbers. IgM⁺IgD⁻ memory B cells were decreased in children and normal in adult patients. IGA and IGG transcripts contained normal SHM levels. In sIgAD children, IGA transcripts more frequently used IGA2 than controls (58.5% vs. 25.1%), but not in adult patients. B‐cell activation after in vitro stimulation was normal. However, adult sIgAD patients exhibited increased blood levels of TGF‐β1, BAFF and APRIL, whereas they had decreased Th1 and Th17 cell numbers.

Conclusion

Impaired IgA memory formation in sIgAD patients is not due to a B‐cell activation defect. Instead, decreased Th1 and Th17 cell numbers and high blood levels of BAFF, APRIL and TGF‐β1 might reflect disturbed regulation of IgA responses in vivo.

These insights into B‐cell extrinsic immune defects suggest the need for a broader immunological focus on genomics and functional analyses to unravel the pathogenesis of sIgAD.

Development of prime-boost-type next-generation mucosal vaccines

Our bodies are constantly exposed to a wide variety of pathogenic micro-organisms through mucosal sites. Therefore, effective vaccines that can protect at the mucosa are vital; however, only a few clinically established mucosal vaccines are available. Although conventional injectable vaccines can induce antigen-specific serum immunoglobulin G (IgG) and prevent severe infection, it is difficult to efficiently inhibit the invasion of pathogens at mucosal surfaces because of the inadequate ability to induce antigen-specific IgA. Recently, we have developed a parenteral vaccine with emulsified curdlan and CpG oligodeoxynucleotides and reported its application. Unlike other conventional injectable vaccines, this immunization contributes to the induction of antigen-specific mucosal and systemic immune responses. Even if antigen-specific IgA at the mucosa disappears, this immunization can induce high-titer IgA after boosting with a small amount of antigen on the target mucosal surface. Indeed, vaccination with Streptococcus pneumoniae antigen effectively prevented lung infection induced by this bacterium. In addition, vaccination with Clostridium ramosum, which is a representative pathobiont associated with obesity and diabetes in humans, reduced obesity in mice colonized with this microorganism. This immunization approach might be an effective treatment for intestinal bacteria-mediated diseases that have been difficult to regulate so far, as well as common infectious diseases.

The Potential Role of Genomic Medicine in the Therapeutic Management of Rheumatoid Arthritis

During the last decade, important advances have occurred regarding understanding of the pathogenesis and treatment of rheumatoid arthritis (RA). Nevertheless, response to treatment is not universal, and choosing among different therapies is currently based on a trial and error approach. The specific patient’s genetic background influences the response to therapy for many drugs: In this sense, genomic studies on RA have produced promising insights that could help us find an effective therapy for each patient. On the other hand, despite the great knowledge generated regarding the genetics of RA, most of the investigations performed to date have focused on identifying common variants associated with RA, which cannot explain the complete heritability of the disease. In this regard, rare variants could also contribute to this missing heritability as well as act as biomarkers that help in choosing the right therapy. In the present article, different aspects of genetics in the pathogenesis and treatment of RA are reviewed, from large-scale genomic studies to specific rare variant analyses. We also discuss the shared genetic architecture existing among autoimmune diseases and its implications for RA therapy, such as drug repositioning.

Metabolism at the centre of the host-microbe relationship

Maintaining homoeostatic host–microbe interactions is vital for host immune function. The gut microbiota shapes the host immune system and the immune system reciprocally shapes and modifies the gut microbiota. However, our understanding of how these microbes are tolerated and how individual, or communities of, gut microbes influence host function is limited. This review will focus on metabolites as key mediators of this complex host–microbe relationship. It will look at the central role of epithelial metabolism in shaping the gut microbiota, how microbial metabolites influence the epithelium and the mucosal and peripheral immune system, and how the immune system shapes microbial composition and metabolism. Finally, this review will look at how metabolites are involved in cross‐talk between different members of the microbiota and their role during infections.

Immunoglobulin A Dysgammaglobulinemia Is Associated with Pediatric-Onset Obsessive-Compulsive Disorder

Background: Inflammation and immune dysregulation have been implicated in the pathogenesis of pediatric-onset obsessive-compulsive disorder (OCD) and tic disorders such as Tourette syndrome (TS). Though few replicated studies have identified markers of immune dysfunction in this population, preliminary studies suggest that serum immunoglobulin A (IgA) concentrations may be abnormal in these children with these disorders. Methods: This observational retrospective cohort study, conducted using electronic health records (EHRs), identified 206 children with pediatric-onset OCD and 1024 adults diagnosed with OCD who also had testing for serum levels of IgA. IgA deficiency and serum IgA levels in pediatric OCD were compared with IgA levels from children diagnosed with autism spectrum disorders (ASD; n = 524), tic disorders (n = 157), attention-deficit/hyperactivity disorder (ADHD; n = 534), anxiety disorders (n = 1206), and celiac disease, a condition associated with IgA deficiency (n = 624). Results: Compared with ASD and anxiety disorder cohorts, the pediatric OCD cohort displayed a significantly higher likelihood of IgA deficiency (OR = 1.93; 95% CI = 1.18-3.16, and OR = 1.98; 95% CI = 1.28-3.06, respectively), though no difference was observed between pediatric OCD and TS cohorts. Furthermore, the pediatric OCD cohort displayed similar rates of IgA deficiency and serum IgA levels when compared with the celiac disease cohort. The pediatric OCD cohort also displayed the highest percentage of IgA deficiency (15%,) when compared with TS (14%), celiac disease (14%), ADHD (13%), ASD (8%), and anxiety disorder (8%) cohorts. When segregated by sex, boys with OCD displayed a significantly higher likelihood of IgA deficiency when compared with all comparison cohorts except for celiac disease and tic disorders; no significant difference in IgA deficiency was observed between female cohorts. Pediatric OCD subjects also displayed significantly lower adjusted serum IgA levels than the ASD and anxiety disorder cohorts. Adults with OCD were also significantly less likely than children with OCD to display IgA deficiency (OR = 2.71; 95% CI = 1.71-4.28). When compared with children with celiac disease, no significant difference in IgA levels or rates of IgA deficiency were observed in the pediatric OCD cohort. Conclusions: We provide further evidence of IgA abnormalities in pediatric-onset OCD. These results require further investigation to determine if these abnormalities impact the clinical course of OCD in children.

Serological screening for celiac disease in children with systemic lupus erythematosus

OBJECTIVE

The aim of the present study was to investigate the frequency of celiac disease (CD) in patients with juvenile systemic lupus erythematosus (JSLE) and the potential association of JSLE and CD.

METHODS

This was a cross-sectional study performed from October 2015 to October 2017. A total of 50 patients with JSLE were included in the study. The levels of total IgA and tissue transglutaminase (tTG) IgA antibody were measured in all patients. Subjects with increased tTG were further evaluated for anti-endomysial antibodies (EMAs). Gastroduodenoscopy and intestinal biopsy were performed in those with increased EMA levels to confirm the diagnosis of CD.

RESULTS

The study included 44 (88.0%) female and 6 (12.0%) male patients. Of the 50 patients, 30 (60.0%) received corticosteroids, and only 4 (8.0%) received no therapy at the time of the study. Only 3 (6.0%) patients were positive for tTG IgA. Patients with positive tTG IgA were then tested for EMA IgA antibodies, and none of them had a positive result.

CONCLUSION

We did not find CD in children with systemic lupus erythematosus. Studies with more patients with JSLE are needed to conclude a more precise result.

Cyclical Fevers in a 4-year-old Boy with IgA Deficiency

While immunodeficiencies, such as (Immunoglobulin A) IgA deficiency, may predispose pediatric patients to respiratory illnesses, they are also associated with autoinflammatory conditions. Distinguishing between these possible complications requires an awareness of these uncommon conditions. We report a case of a four-year-old boy with a history of IgA deficiency presenting to his primary care provider with fever of one week’s duration accompanied by abdominal, ear, and throat pain. The patient’s mother reported that he had these symptoms twice a month for the prior ten months during which he occasionally developed oral ulcers. Between episodes, the patient fully recovered without complications. Considering the patient’s history of IgA deficiency, it was originally assumed that the patient had strep throat and coincidental resolution of his symptoms after initiation of antibiotic therapy supported this diagnosis. However, due to the recurrent nature of his symptoms, a preliminary diagnosis of periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) was made. A referral to an otolaryngologist was made, and findings of adenopathy and tonsillitis suggestive of PFAPA were confirmed. The patient was scheduled for adenoidectomy and tonsillectomy, which were performed without complication, leading to the cessation of these episodes.

The microbiome and immunodeficiencies: Lessons from rare diseases. J Autoimmun. 2019;98:132-148. [PMID: 30704941 DOI: 10.1016/j.jaut.2019.01.008]

Primary immunodeficiencies (PIDs) are inherited disorders of the immune system, associated with a considerable increase in susceptibility to infections. PIDs can also predispose to malignancy, inflammation and autoimmunity. There is increasing awareness that some aspects of the immune dysregulation in PIDs may be linked to intestinal microbiota. Indeed, the gut microbiota and its metabolites have been shown to influence immune functions and immune homeostasis both locally and systemically. Recent studies have indicated that genetic defects causing PIDs lead to perturbations in the conventional mechanisms underlying homeostasis in the gut, resulting in poor immune surveillance at the intestinal barrier, which associates with altered intestinal permeability and bacterial translocation. Consistently, a substantial proportion of PID patients presents with clinically challenging IBD-like pathology. Here, we describe the current body of literature reporting on dysbiosis of the gut microbiota in different PIDs and how this can be either the result or cause of immune dysregulation. Further, we report how infections in PIDs enhance pathobionts colonization and speculate how, in turn, pathobionts may be responsible for increased disease susceptibility and secondary infections in these patients. The potential relationship between the microbial composition in the intestine and other sites, such as the oral cavity and skin, is also highlighted. Finally, we provide evidence, in preclinical models of PIDs, for the efficacy of microbiota manipulation to ameliorate disease complications, and suggest that the potential use of dietary intervention to correct dysbiotic flora in PID patients may hold promise.

Follow-up and outcome of symptomatic partial or absolute IgA deficiency in children

Selective IgA deficiency is defined as absolute or partial when serum IgA level is < 7 mg/dl or 2 SD below normal for age, respectively. Few data are available on partial selective IgA deficiency, as probably most children with low serum IgA are seldom referred to a specialist clinic in common pediatric practice. The aim of our study was to better define the profile of both symptomatic forms and their clinical outcome in a pediatric immunology setting. Thus, clinical and immunological data from 103 symptomatic patients with selective IgA deficiency (53 absolute and 50 partial), 4-18 years of age, were collected at diagnosis and 80 patients (44 absolute and 36 partial) were monitored for a mean period of 5 years. Also, the prevalence of TNFRSF13B mutations has been assessed in 56 patients. The most common clinical features were infections (86/103; 83%), allergy (39/103; 38%), and autoimmunity (13/103; 13%). No significative differences were observed between absolute and partial selective IgA deficiency patients. However, a significative difference in the rate of IgA normalization between partial and absolute selective IgA deficiency patients (33 vs 9%, p = 0.01) was detected. Furthermore, a lower incidence of infections was associated to a normalization reversal compared to a final absolute or partial defect status (12 vs 53 and 64% respectively, p < 0.01).Conclusions: Regardless of a diagnosis of absolute or partial defect, monitoring of symptomatic patients with selective IgA deficiency is recommended overtime for prompt identification and treatment of associated diseases. Further, diagnostic workup protocols should be revisited in children with IgA deficiency. What is Known: ● Selective IgA Deficiency is the most common primary immunodeficiency and is usually asymptomatic. ● Symptomatic pediatric patients with selective IgA deficiency mostly suffer with respiratory and gastrointestinal infections. What is New: ● Symptomatic children with partial IgA defect may have similar clinical, immunological, and genetic features than symptomatic children with absolute IgA deficiency. ● Symptomatic children with partial IgA deficiency deserve accurate monitoring for associated diseases as per children with absolute IgA deficiency.

Multiplex Assay for Quantification of Acute Phase Proteins and Immunoglobulin A in Dried Blood Spots

Inflammation is the first line defense mechanism against infection, tissue damage, or cancer development. However, inappropriate inflammatory response may also trigger diseases. The quantification of inflammatory proteins is essential to distinguish between harmful and beneficial immune response. Currently used immunoanalytical assays may suffer specificity issues due to antigen-antibody interaction and possible cross-reactivity of antibody with other protein species. In addition, immunoanalytical assays typically require invasive blood sampling and additional logistics; they are relatively costly and highly challenging to multiplex. We present a multiplex assay based on selected reaction monitoring (SRM) for quantification of seven acute-phase proteins (i.e., SAA1, SAA2-isoform1, SAA4, CRP, A1AT-isoform1, A1AG1, A1AG2) and the adaptive immunity effector IGHA1 in dried blood spots. This type of sample is readily available from all human subjects including newborns. The study utilizes proteotypic isotopically labeled peptides with trypsin-cleavable tag and presents optimized and reproducible workflow and several important practical remarks regarding quantitative SRM assays development. The panel of inflammatory proteins was quantified with sequence specificity capable to differentiate protein isoforms with intra- and interday precision (<16.4% coefficient of variation (CV) and <14.3% CV, respectively). Quantitative results were correlated with immuno-nephelometric assay (typically greater than 0.9 Pearson's R).

Mice Selected for Acute Inflammation Present Altered Immune Response during Pristane-Induced Arthritis Progression

Mouse lines selected for maximal (AIRmax) or minimal acute inflammatory reaction (AIRmin) were used to characterize the immune response and the influence of genetic background during pristane-induced arthritis (PIA). Susceptible AIRmax mice demonstrated exacerbated cellular profiles during PIA, with intense infiltration of lymphocytes, as well as monocytes/macrophages and neutrophils, producing higher levels of IL-1β, IFN-γ, TNF-α, IL-10, total IgG3, and chemokines. Resistant AIRmin mice controlled cell activation more efficiently than the AIRmax during arthritis progression. The weight alterations of the spleen and thymus in the course of PIA were observed. Our data suggest that selected AIRmax cellular and genetic immune mechanisms contribute to cartilage damage and arthritis severity, evidencing many targets for therapeutic actions.

Primary B-cell immunodeficiencies

Primary B-cell immunodeficiencies refer to diseases resulting from impaired antibody production due to either molecular defects intrinsic to B-cells or a failure of interaction between B-cells and T-cells. Patients typically have recurrent infections and can vary with presentation and complications depending upon where the defect has occurred in B-cell development or the degree of functional impairment. In this review, we describe B-cell specific immune defects categorized by presence or absence of peripheral B-cells, immunoglobulins isotypes and evidence of antibody impairment.

Fifteen-minute consultation: The child with an incidental finding of low IgA

Low or absent immunoglobulin A (IgA) levels are frequently found in children in whom immunodeficiency is not suspected. IgA deficiency is the most common primary immunodeficiency disorder in the UK affecting approximately 1 in 600 people. Isolated IgA deficiency is often identified coincidentally when investigating a child for conditions such as coeliac disease. The aim of this article is to provide a structured approach to the history, investigation and management of an isolated IgA deficiency.

Microbiota - an amplifier of autoimmunity

Many studies describe dysbiosis as a change in the microbiota that accompanies autoimmune illnesses, but little is known about whether these changes are a cause or consequence of an altered immune state. The immune system actively shapes the composition of the microbiota, with divergent outcomes in healthy or autoimmune-prone individuals. The gut microbiota in turn acts as an acquired endocrine organ, influencing the physiology of the host via release of nutrients and chemical messengers. Dysbiosis arising from abnormal immune function can initiate or amplify autoimmunity through multiple mechanisms. We examine how the bidirectional relationship between resident microbes and the immune system contributes to autoimmune diseases.

IgA Deficiency and Nephrotic Syndrome in Children

Background: Imunoglobulin A (IgA) deficiency (IgAD) is the most common form of primary immunodeficiency in Western countries. There have been several reports on IgAD complicated by glomerulonephritis in adults, but only very few cases of IgAD with nephropathy have been reported in children. We present two cases of IgAD with relapsing nephrotic syndrome in pediatric age. Case presentation: A 4-year-old boy and a 2-year-old boy presented with bilateral periorbital oedema and weight gain. The results of laboratory tests revealed IgAD (IgA < 7 mg/dL), normal creatinine, hypoprotidaemia, hypoalbuminaemia, and nephrotic proteinuria. A diagnosis of IgAD and idiopathic nephrotic syndrome was made, and steroid treatment (prednisone 60 mg/mq/day) was started. During steroid tapering, the children experienced several relapses and to obtain a positive outcome they required therapy with human monoclonal anti-CD20 antibodies (rituximab in the first child, ofatumumab in the second one). Conclusions: Our cases highlight that IgAD can be observed in nephrotic syndrome and nephropathy in children with IgAD appears to be complicated and difficult to treat with corticosteroids alone. Further research is needed to better describe the clinical manifestations and pathological pictures among subjects with IgAD and nephrotic syndrome to understand whether IgAD has a prognostic value in children with nephrotic syndrome and to let clinical physicians define a more personalized and appropriate approach for the management of these patients.