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Journal of Gastrointestinal and Liver... Dec 2023Celiac disease is a common gastroenterological illness. Current diagnostics of the disease are based on serological markers and histology of duodenal biopsies. Hitherto,... (Review)
Review
Celiac disease is a common gastroenterological illness. Current diagnostics of the disease are based on serological markers and histology of duodenal biopsies. Hitherto, a strict gluten-free diet is the only effective treatment and is necessary for good control of the disease. Serological tests in current use have very high specificity and sensitivity for diagnostics, but in follow-up they have some limitations. Their levels do not accurately reflect mucosal healing, and they are unable to detect minimal transgressions in the diet. This problem is significant in patients with IgA deficiency, and there exist no robust follow-up tools for monitoring these patients' adherence to treatment. For their follow-up, we currently use IgG-based tests, and these antibodies persist for a long time even when a patient has stopped consuming gluten. More accurate and specific biomarkers are definitely needed. Adherence to a gluten-free diet is essential not only for intestinal mucosa healing and alleviation of symptoms but also for preventing complications associated with celiac disease. Here, we summarize current evidence regarding noninvasive biomarkers potentially useful for follow-up not only of patients with IgA deficiency but for all patients with celiac disease. We describe several very promising biomarkers with potential to be part of clinical practice in the near future.
Topics: Humans; Celiac Disease; Follow-Up Studies; IgA Deficiency; Glutens; Diet, Gluten-Free; Biomarkers; Immunoglobulin A
PubMed: 38147608
DOI: 10.15403/jgld-4926 -
The Journal of Allergy and Clinical... Sep 2023Secretory IgA interacts with commensal bacteria, but its impact on human mycobiota ecology has not been widely explored. In particular, whether human IgA-deficiency is...
BACKGROUND
Secretory IgA interacts with commensal bacteria, but its impact on human mycobiota ecology has not been widely explored. In particular, whether human IgA-deficiency is associated with gut fungal dysbiosis remains unknown.
OBJECTIVES
Our goal was to study the impact of IgA on gut mycobiota ecology.
METHODS
The Fungi-Flow method was used to characterize fecal, systemic, and maternal IgA, IgM, and IgG responses against 14 representative fungal strains (yeast/spores or hyphae forms) in healthy donors (HDs) (n = 34, 31, and 20, respectively) and to also compare gut mycobiota opsonization by secretory antibodies in HDs (n = 28) and patients with selective IgA deficiency (SIgAd) (n = 12). Stool mycobiota composition was determined by internal transcribed spacer gene sequencing in HDs (n = 23) and patients with SIgAd (n = 17). Circulating CD4 T-cell cytokine secretion profiles were determined by intracellular staining. The impact of secretory IgA, purified from breast milk (n = 9), on Candidaalbicans growth and intestinal Caco-2 cell invasion was tested in vitro.
RESULTS
Homeostatic IgA binds commensal fungi with a body fluid-selective pattern of recognition. In patients with SIgAd, fungal gut ecology is preserved by compensatory IgM binding to commensal fungi. Gut Calbicans overgrowth nevertheless occurs in this condition but only in clinically symptomatic patients with decreased T17/T22 T-cell responses. Indeed, secretory IgA can reduce in vitro budding and invasion of intestinal cells by Calbicans and therefore exert control on this pathobiont.
CONCLUSION
IgA has a selective impact on Calbicans ecology to preserve fungal-host mutualism.
Topics: Female; Humans; Candida albicans; Caco-2 Cells; IgA Deficiency; Immunoglobulin A; Immunoglobulin A, Secretory; Immunoglobulin M
PubMed: 37169153
DOI: 10.1016/j.jaci.2023.03.033 -
Journal of Clinical Immunology Dec 2023Inherited deficiencies of CD40 and CD40 ligand (CD40L) reflect the crucial immunological functions of CD40-CD40L interaction/signaling. Although numerous studies have...
PURPOSE
Inherited deficiencies of CD40 and CD40 ligand (CD40L) reflect the crucial immunological functions of CD40-CD40L interaction/signaling. Although numerous studies have provided a detailed description of CD40L deficiency, reports of CD40 deficiency are scarce. Herein, we describe the characteristics of all reported patients with CD40 deficiency.
METHODS
The PubMed, Embase and Web of Science databases were searched for relevant literature published till 7th August 2023. Study deduplication and identification of relevant reports was performed using the online PICO Portal. The data were extracted using a pre-designed data extraction form and the SPSS software was used for analysis.
RESULTS
Systematic literature review revealed 40 unique patients with CD40 deficiency. Respiratory tract and gastrointestinal infections were the predominant clinical manifestations (observed in 93% and 57% patients, respectively). Sclerosing cholangitis has been reported in nearly one-third of patients. Cryptosporidium sp. (29%) and Pneumocystis jirovecii (21%) were the most common microbes identified. Very low to undetectable IgG levels and severely reduced/absent switch memory B cells were observed in all patients tested/reported. Elevated IgM levels were observed in 69% patients. Overall, splice-site and missense variants were the most common (36% and 32%, respectively) molecular defects identified. All patients were managed with immunoglobulin replacement therapy and antimicrobial prophylaxis was utilized in a subset. Hematopoietic stem cell transplantation (HSCT) has been performed in 45% patients (curative outcome observed in 73% of these patients). Overall, a fatal outcome was reported in 21% patients.
CONCLUSIONS
We provide a comprehensive description of all important aspects of CD40 deficiency. HSCT is a promising curative treatment option for CD40 deficiency.
Topics: Humans; CD40 Ligand; Cryptosporidiosis; Cryptosporidium; Hyper-IgM Immunodeficiency Syndrome; Immunologic Deficiency Syndromes; CD40 Antigens; Immunoglobulin M; Lymphopenia
PubMed: 38129705
DOI: 10.1007/s10875-023-01633-1 -
Clinical Immunology (Orlando, Fla.) Aug 2023X-Linked Hyper-IgM Syndrome is caused by pathogenic variants in CD40LG. Three patients with atypical clinical and immunological features were identified with variants in...
X-Linked Hyper-IgM Syndrome is caused by pathogenic variants in CD40LG. Three patients with atypical clinical and immunological features were identified with variants in CD40LG requiring further characterization. Flow cytometry was used to evaluate CD40L protein expression and binding capacity to a surrogate receptor, CD40-muIg. Though functional anomalies were observed, there was still a lack of clarity regarding the underlying mechanism. We developed structural models for wild-type and the three variants of CD40L protein observed in these patients (p. Lys143Asn, Leu225Ser and Met36Arg) to evaluate structural alterations by molecular mechanic calculations, and assess protein movement by molecular dynamic simulations. These studies demonstrate that functional analysis of variants of unknown significance in CD40LG can be supplemented by advanced computational analysis in atypical clinical contexts. These studies in combination identify the deleterious effects of these variants and potential mechanisms for protein dysfunction.
Topics: Humans; CD40 Antigens; CD40 Ligand; Hyper-IgM Immunodeficiency Syndrome; Hyper-IgM Immunodeficiency Syndrome, Type 1; Immunoglobulin M; Mutation
PubMed: 37433422
DOI: 10.1016/j.clim.2023.109692 -
The Lancet. Gastroenterology &... Nov 2023Whether coeliac disease in adults can be diagnosed with serology alone remains controversial. We aimed to evaluate the accuracy of serum anti-tissue transglutaminase IgA...
Serum anti-tissue transglutaminase IgA and prediction of duodenal villous atrophy in adults with suspected coeliac disease without IgA deficiency (Bi.A.CeD): a multicentre, prospective cohort study.
BACKGROUND
Whether coeliac disease in adults can be diagnosed with serology alone remains controversial. We aimed to evaluate the accuracy of serum anti-tissue transglutaminase IgA (tTG-IgA) in the diagnosis of coeliac disease.
METHODS
In this multicentre, prospective cohort study, adult participants (aged ≥18 years) with suspected coeliac disease without IgA deficiency who were not on a gluten-free diet and who had a local serum tTG-IgA measurement, were enrolled from Feb 27, 2018, to Dec 24, 2020, by 14 tertiary referral centres (ten from Europe, two from Asia, one from Oceania, and one from South America) to undergo local endoscopic duodenal biopsy. Local serum tTG-IgA was measured with 14 different test brands and concentration expressed as a multiple of each test's upper limit of normal (ULN), and defined as positive when greater than 1 times the ULN. The main study outcome was the reliability of serum tests for the diagnosis of coeliac disease, as defined by duodenal villous atrophy (Marsh type 3 or Corazza-Villanacci grade B). Histology was evaluated by the local pathologist, with discordant cases (positive tTG-IgA without duodenal villous atrophy or negative tTG-IgA with duodenal villous atrophy) re-evaluated by a central pathologist. The reliability of serum tests for the prediction of duodenal villous atrophy was evaluated according to sensitivity, specificity, positive predictive value, negative predictive value, and the area under the receiver operating characteristic curve (AUC) for categorical and continuous data.
FINDINGS
We enrolled 436 participants with complete local data on serum tTG-IgA and duodenal histology (296 [68%] women and 140 [32%] men; mean age 40 years [SD 15]). Positive serum tTG-IgA was detected in 363 (83%) participants and negative serum tTG-IgA in 73 (17%). Of the 363 participants with positive serum tTG-IgA, 341 had positive histology (true positives) and 22 had negative histology (false positives) after local review. Of the 73 participants with negative serum tTG-IgA, seven had positive histology (false negatives) and 66 had negative histology (true negatives) after local review. The positive predictive value was 93·9% (95% CI 89·2-98·6), the negative predictive value was 90·4% (85·5-95·3), sensitivity was 98·0% (95·3-100·0), and specificity was 75·0% (66·6-83·4). After central re-evaluation of duodenal histology in 29 discordant cases, there were 348 true positive cases, 15 false positive cases, 66 true negative cases, and seven false negative cases, resulting in a positive predictive value of 95·9% (92·0-99·8), a negative predictive value of 90·4% (85·5-95·3), a sensitivity of 98·0% (95·3-100·0), and a specificity of 81·5% (73·9-89·1). Either using the local or central definition of duodenal histology, the positive predictive value of local serum tTG-IgA increased when the serological threshold was defined at increasing multiples of the ULN (p<0·0001). The AUC for serum tTG-IgA for the prediction of duodenal villous atrophy was 0·87 (95% CI 0·81-0·92) when applying the categorical definition of serum tTG-IgA (positive [>1 × ULN] vs negative [≤1 × ULN]), and 0·93 (0·89-0·96) when applying the numerical definition of serum tTG-IgA (multiples of the ULN). Additional endoscopic findings included peptic gastritis (nine patients), autoimmune atrophic gastritis (three), reflux oesophagitis (31), gastric or duodenal ulcer (three), and Barrett's oesophagus (one). In the 1-year follow-up, a midgut ileum lymphoma was diagnosed in a woman on a gluten-free diet.
INTERPRETATION
Our data showed that biopsy could be reasonably avoided in the diagnosis of coeliac disease in adults with reliable suspicion of coeliac disease and high serum tTG-IgA.
FUNDING
None.
Topics: Adolescent; Adult; Female; Humans; Male; Atrophy; Autoantibodies; Celiac Disease; IgA Deficiency; Immunoglobulin A; Prospective Studies; Reproducibility of Results; Sensitivity and Specificity; Transglutaminases
PubMed: 37696284
DOI: 10.1016/S2468-1253(23)00205-4 -
Frontiers in Immunology 2023Primary antibody deficiencies (PAD) are inborn defects of the immune system that result in increased susceptibility to infections. Despite the reduced response to...
INTRODUCTION
Primary antibody deficiencies (PAD) are inborn defects of the immune system that result in increased susceptibility to infections. Despite the reduced response to vaccination, PAD patients still benefit from it by reducing the risk of severe infections and complications. SARS-CoV-2 vaccines are recommended in PAD patients, but their immune effects are poorly studied. Here, we analyze virus-specific T-cell responses in PAD patients after booster vaccination against SARS-CoV-2.
PATIENTS AND METHODS
The study included 57 adult PAD patients on long-term immunoglobulin replacement therapy (IgRT) diagnosed with X-linked agammaglobulinemia (XLA; n = 4), common variable immunodeficiency (CVID; n = 33), isotype defects or IgG subclass deficiency (n = 6), and unclassified IgG deficiency (n = 14). Of those, 49 patients (86%) received vaccination against SARS-CoV-2 using mRNA vaccine (Pfizer-BioNTech). T-cell responses were assessed at a median of 21 (13 - 30) weeks after the booster dose (mainly the third dose) using commercially available interferon-gamma release assay (IGRA) with recombinant SARS-CoV-2 spike S1 protein.
RESULTS
Vaccinated PAD patients showed an increased (3.8-fold, p = 0.004) release of IFN-γ upon S1 stimulation. In this group, we also documented higher serum levels of anti-SARS-CoV-2 IgG (4.1-fold, p = 0.01), although they were not associated with IGRA results. Further subgroup analysis revealed very similar IGRA responses in CVID and unclassified IgG deficiencies that were 2.4-fold increased compared to XLA and 5.4-fold increased compared to patients with isotype defects or IgG subclass deficiencies (e.g., vs. CVID: p = 0.016). As expected, CVID and XLA patients showed decreased serum titers of anti-SARS-CoV-2 antibodies compared to other studied groups (e.g., CVID vs. unclassified IgG deficiency: 4.4-fold, p = 0.006). The results did not depend directly on IgRT mode or dose, number of vaccine doses and time from the last booster dose, and clinical manifestations of PAD. Interestingly, anti-SARS-CoV-2 titers were positively correlated with serum immunoglobulin levels before IgRT (e.g., for IgA: r = 0.45, p<0.001; for IgG: r = 0.34, p = 0.009) and the percentage of peripheral blood NK cells (r = 0.48, p<0.001).
CONCLUSIONS
Our results documented satisfactory cellular immune response in PAD patients after booster SARS-CoV-2 vaccination. Therefore, even patients with agammaglobulinemia should benefit from vaccination due to the apparent induction of cell-mediated immunity, which, together with IgRT, grants comprehensive protection against the pathogen.
Topics: Adult; Humans; COVID-19 Vaccines; SARS-CoV-2; IgG Deficiency; COVID-19; Immunity, Cellular; Common Variable Immunodeficiency; Antibodies, Viral; Immunoglobulin G; Primary Immunodeficiency Diseases
PubMed: 37901210
DOI: 10.3389/fimmu.2023.1275892 -
Frontiers in Cellular and Infection... 2023Patients with Human Hyper IgM syndromes (HIGM) developed pulmonary and gastrointestinal infections since infancy and most patients have mutations in the CD40 ligand...
Elevated levels of enteric IgA in an unimmunised mouse model of Hyper IgM syndrome derived from gut-associated secondary lymph organs even in the absence of germinal centres.
INTRODUCTION
Patients with Human Hyper IgM syndromes (HIGM) developed pulmonary and gastrointestinal infections since infancy and most patients have mutations in the CD40 ligand (CD40L) gene. Most HIGM patients compared to healthy subjects have higher/similar IgM and lower IgG, and IgA serum concentrations but gut antibody concentrations are unknown. CD40L on activated T-cells interacts with CD40 on B-cells, essential for the formation of germinal centres (GCs) inside secondary lymphoid organs (SLOs), where high-affinity antibodies, long-lived antibody-secreting plasma cells, and memory B-cells, are produced. C57BL6-CD40 ligand deficient mice (C57BL6- ), are a model of HIGM, because serum immunoglobulin concentrations parallel levels observed in HIGM patients and have higher faecal IgA concentrations. In mice, TGFβ and other cytokines induce IgA production.
AIMS
To compare and evaluate B-cell populations and IgA-producing plasma cells in peritoneal lavage, non-gut-associated SLOs, spleen/inguinal lymph nodes (ILN), and gut-associated SLOs, mesenteric lymph nodes (MLN)/Peyer´s patches (PP) of unimmunised C57BL6- and C57BL6-wild-type (WT) mice.
MATERIAL AND METHODS
Peritoneal lavages, spleens, ILN, MLN, and PP from 8-10 weeks old C57BL6- and WT mice, were obtained. Organ cryosections were analysed by immunofluorescence and B-cell populations and IgA-positive plasma cell suspensions by flow cytometry.
RESULTS
In unimmunised WT mice, GCs were only observed in the gut-associated SLOs, but GCs were absent in all C57BL6- SLOs. PP and MLN of C57BL6- mice exhibited a significantly higher number of IgA-producing cells than WT mice. In the spleen and ILN of C57BL6- mice IgA-producing cells significantly decreased, while IgM-positive plasma cells increased. C57BL6- B-1 cells were more abundant in all analysed SLOs, whereas in WT mice most B-1 cells were contained within the peritoneal cavity. C57BL6- B-cells in MLN expressed a higher TGFβ receptor-1 than WT mice. Mouse strains small intestine microvilli (MV), have a similar frequency of IgA-positive cells.
DISCUSSION
Together our results confirm the role of PP and MLN as gut inductive sites, whose characteristic features are to initiate an IgA preferential immune response production in these anatomical sites even in the absence of GCs. IgA antibodies play a pivotal role in neutralising, eliminating, and regulating potential pathogens and microorganisms in the gut.
Topics: Humans; Mice; Animals; CD40 Ligand; Hyper-IgM Immunodeficiency Syndrome; Germinal Center; Intestine, Small; Immunoglobulin A; Immunoglobulin M; Transforming Growth Factor beta
PubMed: 37457961
DOI: 10.3389/fcimb.2023.1172021 -
Nature Communications Dec 2023Immunoglobulin A (IgA) is acknowledged to play a role in the defence of the mucosal barrier by coating microorganisms. Surprisingly, IgA-deficient humans exhibit few...
Immunoglobulin A (IgA) is acknowledged to play a role in the defence of the mucosal barrier by coating microorganisms. Surprisingly, IgA-deficient humans exhibit few infection-related complications, raising the question if the more specific IgG may help IgM in compensating for the lack of IgA. Here we employ a cohort of IgA-deficient humans, each paired with IgA-sufficient household members, to investigate multi-Ig bacterial coating. In IgA-deficient humans, IgM alone, and together with IgG, recapitulate coating of most bacterial families, despite an overall 3.6-fold lower Ig-coating. Bacterial IgG coating is dominated by IgG1 and IgG4. Single-IgG2 bacterial coating is sparse and linked to enhanced Escherichia coli load and TNF-α. Although single-IgG2 coating is 1.6-fold more prevalent in IgA deficiency than in healthy controls, it is 2-fold less prevalent than in inflammatory bowel disease. Altogether we demonstrate that IgG assists IgM in coating of most bacterial families in the absence of IgA and identify single-IgG2 bacterial coating as an inflammatory marker.
Topics: Humans; Bacteria; Escherichia coli; IgA Deficiency; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M
PubMed: 38065985
DOI: 10.1038/s41467-023-44007-2 -
Allergy and Asthma Proceedings Sep 2023There are no published epidemiologic studies with regard to the prevalence of neurologic diseases among subjects with selective immunoglobulin A (IgA) deficiency...
There are no published epidemiologic studies with regard to the prevalence of neurologic diseases among subjects with selective immunoglobulin A (IgA) deficiency (sIgAD). To investigate the prevalence of neurologic diseases among the Israeli population with sIgAD. A population-based case-control study among members of a large nationwide health maintenance organization in Israel providing services to > 700,000 members. The sIgAD group included individuals ≥4 years of age with a serum IgA level of <0.07 g/L and with a diagnosis of sIgAD. The control group was randomly sampled from the entire study population with a case-control ratio of five controls for each case (1:5), with exact matching for age, gender, ethnic group, and socioeconomic status category. A total of 796 subjects ages 20.58 ± 15.46 years; 391 female subjects (49.1%) were identified as having sIgAD. The control group was constituted of 3980 matched subjects. The sIgAD group was characterized by a higher prevalence of autism spectrum disorder and tic disorders. Migraine was less prevalent in the sIgAD group (19 [2.39%]) than in the control group (168 [4.22%]), odds ratio (OR) 0.55 (95% confidence interval {CI}, 0.34-0.90); p = 0.016]. More cases of subjects with epilepsy were observed in the sIgAD group (14 [1.76%]) than in the control group (31 [0.80%]), OR 2.28 (95% CI, 1.12 - 4.44; p = 0.015). Our observation raises the question of the role of IgA in noninfectious diseases of the central nervous system. Further basic studies are needed to explain our observation.
Topics: Humans; Female; IgA Deficiency; Prevalence; Autism Spectrum Disorder; Case-Control Studies; Immunoglobulin A
PubMed: 37641224
DOI: 10.2500/aap.2023.44.230036