Immunohistochemical findings in jejunal specimens from patients with IgA deficiency

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.

Microbial ecology perturbation in human IgA deficiency

Paradoxically, loss of immunoglobulin A (IgA), one of the most abundant antibodies, does not irrevocably lead to severe infections in humans but rather is associated with relatively mild respiratory infections, atopy, and autoimmunity. IgA might therefore also play covert roles, not uniquely associated with control of pathogens. We show that human IgA deficiency is not associated with massive quantitative perturbations of gut microbial ecology. Metagenomic analysis highlights an expected pathobiont expansion but a less expected depletion in some typically beneficial symbionts. Gut colonization by species usually present in the oropharynx is also reminiscent of spatial microbiota disorganization. IgM only partially rescues IgA deficiency because not all typical IgA targets are efficiently bound by IgM in the intestinal lumen. Together, IgA appears to play a nonredundant role at the forefront of the immune/microbial interface, away from the intestinal barrier, ranging from pathobiont control and regulation of systemic inflammation to preservation of commensal diversity and community networks.

Detection of celiac disease and lymphocytic enteropathy by parallel serology and histopathology in a population-based study

BACKGROUND & AIMS

Although serologic analysis is used in diagnosis of celiac disease, histopathology is considered most reliable. We performed a prospective study to determine the clinical, pathologic, and serologic spectrum of celiac disease in a general population (Kalixanda study).

METHODS

A random sample of an adult general population (n = 1000) was analyzed by upper endoscopy, duodenal biopsy, and serologic analysis of tissue transglutaminase (tTg) levels; endomysial antibody (EMA) levels were analyzed in samples that were tTg+. The cut off values for diagnosis of celiac disease were villous atrophy with 40 intraepithelial lymphocytes (IELs)/100 enterocytes (ECs).

RESULTS

Samples from 33 subjects were tTg+, and 16 were EMA+. Histologic analysis identified 7 of 1000 subjects (0.7%) with celiac disease; all were tTg+, and 6 of 7 were EMA+. Another 26 subjects were tTg+ (7/26 EMA+). This was addressed by a second quantitative pathology study (nested case control design) using a threshold of 25 IELS/100 ECs. In this analysis, all 13 samples that were tTg+ and EMA+ had > or =25 IELs/100 ECs. In total, 16 subjects (1.6%) had serologic and histologic evidence of gluten-sensitive enteropathy. IELs were quantified in duodenal biopsy samples from seronegative individuals (n = 500); 19 (3.8%) had >25 IELs and lymphocytic duodenosis.

CONCLUSIONS

Measurement of > or =25 IELs/100 ECs correlated with serologic indicators of celiac disease; a higher IEL threshold could miss 50% of cases. Quantification of tTg is a sensitive test for celiac disease; diagnosis can be confirmed by observation of > or =25 IELs/100ECs in duodenal biopsy specimens. Lymphocytic enteropathy (celiac disease and lymphocytic duodenosis) is common in the population (5.4%).

High density of intraepithelial gammadelta lymphocytes and deposits of immunoglobulin (Ig)M anti-tissue transglutaminase antibodies in the jejunum of coeliac patients with IgA deficiency

The diagnosis of coeliac disease (CD) represents a special challenge in selective immunoglobulin (Ig)A deficiency (IgAD). A high density of T cell receptor (TCR)gammadelta(+) intraepithelial lymphocytes (IELs) and intestinal IgA anti-tissue transglutaminase 2 (anti-TG2) antibody deposits are suggestive of CD. We analysed the density of TCRgammadelta(+) IELs and the deposition of IgM anti-TG2 antibodies in the jejunal mucosa of IgAD patients with and without CD. Immunohistochemical analyses for the number of CD3+ and TCRgammadelta(+) IELs and double immunofluorescence assay for IgM anti-TG2 antibody deposits were performed in biopsies from 25 children with IgAD (nine untreated CD, seven potential CD and nine without CD). Sixteen immunologically intact children without CD represented the controls. IgAD without CD had a higher number of CD3+ and TCRgammadelta(+) IELs than controls (P < 0.05), but lower than IgAD with CD (P < 0.01). No significant differences were noted between IgAD subjects without CD and those with potential CD. Furthermore, IgAD patients without CD showed a higher TCRgammadelta(+)/CD3+ ratio than the control group (P < 0.05), while the ratio was similar to subjects with CD and potential CD. Intestinal IgM anti-TG2 antibody deposits were present in six of seven of the IgAD patients with untreated CD, one of seven with potential CD and none of those without CD. Most of the patients with IgAD show immune activation in the jejunal mucosa. IgM anti-TG2 antibody deposits are present only in CD. Intestinal IgM anti-TG2 and immunohistochemical markers do not discriminate between IgAD and potential CD with IgAD. Therefore, the serum IgG CD-associated autoantibodies remains very important for the diagnosis of CD in IgAD.

Chronic enteropathy and feeding in children: an update

Enteropathy defines abnormalities of the small intestinal mucosa of various etiologies in which nutrition has a causal or a therapeutic role. Breast milk is the gold-standard feeding during infancy for optimal nutrition in health and the majority of diseases. Therapeutic formulae have decreased the need for enteral or parenteral support. Gastrointestinal infections are worldwide the most frequent cause of enteropathy by increasing mucosal permeability, local expression of costimulatory molecules allowing antigen penetration in the mucosa, and T-cell activation leading sometimes to disruption of oral tolerance. Concomitant malnutrition impairs not only the immunologic response but also the recovery of damaged mucosa with secondary intestinal and pancreatic enzymatic reductions. Optimal nutritional rehabilitation is the cornerstone of the management of persisting diarrhea. Celiac disease and cow's milk protein allergy are examples of chronic enteropathy. Multiple food allergies, even during breast-feeding, are increasingly reported due to an impaired development of oral tolerance. The dietary approach to allergic disease is currently evolving from passive allergen avoidance to active modulation of the immune system to (re)establish tolerance. The gastrointestinal flora provides maturational signals for the lymphoid tissue, improves balance of inflammatory cytokines, reduces bacterial invasiveness and dietary antigen load, and normalizes gut permeability. The clinical effects of nucleotides and zinc merit further clinical evaluation. Major attention has recently focused on the immune effects of dietary lipids in terms of possible prevention of allergic sensitization by downregulating inflammatory response and protecting the epithelial barrier and host-microbe interactions modifying the adherence of microbes to the mucosa.

Increased cell turnover, but no signs of increased T-cell infiltration or inflammatory cytokines in the duodenum of pediatric patients after allogeneic stem cell transplantation

Intestinal immunopathology was studied after allogeneic stem cell transplantation (SCT) in a common clinical setup in 20 children with malignant (n=17) or nonmalignant diseases (n=3) receiving grafts from siblings (7) and unrelated donors (13). In all, 19 had total body irradiation. Duodenal biopsies at 6 and 12 weeks post transplant were evaluated by histology, immunohistochemistry, and ISEL for the detection of T-lymphocytes, inflammatory cytokines, proliferation, and apoptosis. The controls were 12 healthy children and three patients with proven intestinal graft-versus-host disease. An increased rate of apoptosis and proliferation with upregulated expression of HLA-DR antigen was detected up to 3 months post transplant in the SCT patients, even in those with a histologically normal small intestine. A low level of IFNgamma and TNFalpha was observed in the lamina propria. The initial low density of gammadelta-positive T cells had recovered to normal by the time of the second endoscopy at 12 weeks post transplant. We conclude that inflammatory activity and T cell infiltration detected by immunohistochemistry may not belong to the 'normal' recovery of the small intestine after SCT. Increased cell turnover in the intestinal crypts continues until 3 months after SCT, suggesting either an unexpectedly long-lasting effect of transplant-related toxicity or, preferably, an ongoing subclinical alloreactive process, also present in the patients without intestinal symptoms.

Immunologic activity in the small intestinal mucosa of pediatric patients with type 1 diabetes

Involvement of gut immune system has been implicated in the pathogenesis of type 1 diabetes. However, few studies have been performed on the gut mucosa from patients with type 1 diabetes. Thus, we characterized the stage of immune activation in jejunal biopsy samples from 31 children with type 1 diabetes by immunohistochemistry, in situ hybridization, and RT-PCR. We found enhanced expressions of HLA-DR, HLA-DP, and intercellular adhesion molecule-1 by immunohistochemistry even on structurally normal intestine of patients with type 1 diabetes and no signs of celiac disease. In addition, the densities of IL-1 alpha- and IL-4-positive cells detected by immunohistochemistry and IL-4 mRNA-expressing cells evaluated by in situ hybridization were increased in the lamina propria in patients with type 1 diabetes and normal mucosa. Instead, the densities of IL-2, gamma-interferon (IFN-gamma), and tumor necrosis factor alpha-positive cells, the density of IFN-gamma mRNA positive cells, and the amounts of IFN-gamma mRNA detected by RT-PCR correlated with the degree of celiac disease in patients with type 1 diabetes. Our study supports the hypothesis that a link exists between the gut immune system and type 1 diabetes.

Inflammatory cytokines in small intestinal mucosa of patients with potential coeliac disease

T helper cell type 1 (Th1) response to gluten has been implicated in the pathogenesis of coeliac disease (CD). To characterize immunological activation and mild inflammations leading to overt CD in potential coeliac patients, jejunal biopsies were obtained from family members of patients with CD or dermatitis herpetiformis (DH). Nine family members and one latent CD, eight CD patients and eight normal controls furnished jejunal biopsy specimens. Immunohistochemical staining of sections for interleukin-1alpha (IL-1alpha), IL-2, IL-4, interferon-gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), CD3, gammadelta-T cell receptor (gammadelta-TCR), and alphabeta-TCR was carried out with monoclonal antibodies. Further, expression of IL-4 and IFN-gamma messenger RNA was detected by radioactive in situ hybridization in these same samples. In lamina propria, CD patients and potential CD patients had higher densities of IL-2 (P = 0.028, P = 0.043), IL-4 (P = 0.021, P = 0.034) and IFN-gamma positive cells (P = 0.000, P = 0.009) than did controls. Moreover, CD patients showed a higher density of TNF-alpha positive cells (P = 0.012, P = 0.001) than the other two groups, and expression of IFN-gamma mRNA (P = 0.035) was higher in them than in the other two study groups. Additionally, higher densities of TNF-alpha and IFN-gamma positive cells occurred in potential CD patients with high gammadelta-TCR+ intraepithelial lymphocytes (IELs). Our findings support the hypothesis that lamina propria T cells and macrophages, through their secretion of cytokines, play a central role in the pathogenesis of coeliac disease. The inflammatory cytokines found in potential CD specimens strongly suggest that these inflammatory markers can be identified long before visible villous changes have occurred.

Increased frequency of intestinal Escherichia coli carrying genes for S fimbriae and haemolysin in IgA-deficient individuals

Persons with selective IgA deficiency carry an increased risk of coeliac disease, inflammatory bowel disease and perhaps also gastrointestinal malignancies. Inflammatory bowel disease is associated with an increased carriage of adherent and haemolytic Escherichia coli in the intestinal microflora. This study was designed to investigate whether IgA-deficient individuals carry E. coli with virulence-associated properties in their gut flora. The last free-lying colony of E. coli isolates obtained from rectal flora of 25 IgA-deficient and 20 age-matched control individuals was assayed by multiplex PCR for genes for the following adhesins or virulence determinants: P, type 1 and S fimbriae, Dr haemagglutinin, haemolysin, aerobactin and the capsular types K1 and K5. E. coli strains from the intestinal microflora of IgA-deficient individuals more often had the gene for S fimbriae (36% of the strains compared with 0% in control subjects, P=0.003) as well as for haemolysin (40 vs 10% of the strains, P=0.040). IgA-deficient individuals had instead lower frequencies of E. coli carrying genes for type 1 fimbriae in their microflora (68 vs 90%, P=0.14). The results suggest that IgA-deficient individuals carry an increased frequency of E. coli with potentially inflammatogenic properties in their microflora, which may contribute to the development of gastrointestinal disorders such as inflammatory bowel diseases.

Celiac sprue and immunodeficiency states: a 25-year review

Immunoglobulin deficiency, especially deficiency of IgA, has been described in patients with celiac sprue (CS). Our study was performed in an area of high prevalence of CS to determine the prevalence of immunodeficiency states in patients with CS, to examine their clinical characteristics, response to treatment, and HLA phenotypes compared with a group of age- and sex-matched persons with CS but without immunoglobulin deficiency. Fourteen of 604 patients with CS were identified as being selectively deficient in IgA, whereas one had common variable immunodeficiency. At diagnosis, anemia was present in 8 of 14 IgA-deficient patients compared with 10 of 42 controls (p = 0.047), whereas abdominal pain was more common in controls with CS. Autoimmunity and recurrent infection were more prevalent in the IgA-deficient group. Response to gluten-free diet was similar in both groups in terms of histologic structure and recovery of intestinal brush-border enzyme activity. IgA-deficient participants with CS had no increased risk of associated malignancy or lymphoma. HLA phenotypes were similar in both groups. The prevalences of selective IgA deficiency and common variable immunodeficiency in this series of patients with CS are 2.31 in 100 and 0.16 in 100, respectively. Although this group is unique in character, close follow-up coupled with conscientious compliance with a gluten-free diet, remains the mainstay of treatment for these patients.