RESUMO
BACKGROUND: Selective IgA deficiency (SIgAD) is the most prevalent inborn errors of immunity with almost unknown etiology. This study aimed to investigate the clinical diagnostic and prognostic values of lymphocyte subsets and function in symptomatic SIgAD patients. METHODS: A total of 30 available SIgAD patients from the Iranian registry and 30 age-sex-matched healthy controls were included in the present study. We analyzed B and T cell peripheral subsets and T cell proliferation assay by flow cytometry in SIgAD patients with mild and severe clinical phenotypes. RESULTS: Our results indicated a significant increase in naïve and transitional B cells and a strong decrease in marginal zone-like and switched memory B-cells in SIgAD patients. We found that naïve and central memory CD4+ T cell subsets, as well as Th1, Th2 and regulatory T cells, have significantly decreased. On the other hand, there was a significant reduction in central and effector memory CD8+ T cell subsets, whereas proportions of both (CD4+ and CD8+) terminally differentiated effector memory T cells (TEMRA) were significantly elevated in our patients. Although some T cell subsets in severe SIgAD were similar, a decrease in marginal-zone and switched memory B cells and an increase in CD21low B cell of severe SIgAD patients were slightly prominent. Moreover, the proliferation activity of CD4+ T cells was strongly impaired in SIgAD patients with a severe phenotype. CONCLUSION: SIgAD patients have varied cellular and humoral deficiencies. Therefore, T cell and B cell assessment might help in better understanding the heterogeneous pathogenesis and prognosis estimation of the disease.
RESUMO
Background: Selective IgA deficiency is the most prevalent form of primary immunodeficiencies. The pathogenesis of the disease is still unknown. Several studies have suggested a defect in B cell responses to IL-10; however, the main reason for this defect has not been reported. Elucidating IL-10 signaling defects and their correlation with clinical manifestations could be helpful for better understanding and treatment of the disease. Methods: In this study, 15 SIgAD patients and 15 age- and sex-matched healthy controls were included. Surface expression of transforming growth factor ß receptor II (TGF-ß RII), IL-10R and IgA was assessed by flow cytometry in human purified B cells before and after stimulation by IL-10. Protein expression of STAT3, p-STAT3 and SOCS3 was measured by Western blotting analysis. TGF-ß and IgA secretion was evaluated by ELISA. Finally, the measurement of B cell apoptosis was performed by flow cytometry. Results: The TGF-ßRII expression level was decreased after stimulation with IL-10 in patients compared with controls. Notably, the TGF-ß level were higher after stimulation with mCD40L and IL-10 in the control group as compared to stimulation with mCD40L alone. The IgA+ B cell percentage and IgA secretion levels were significantly increased in controls as compared with SIgAD patients. The relative concentration of the total STAT3 was decreased as compared with controls. Conclusion: The defect in IgA production in SIgAD patients could be due to inadequate B cell responses to IL-10 stimulation that probably originate from defective regulation of IL-10-mediated TGF-b 'symbol' production TGF-ß response by IL-10. Furthermore, it is suggested that the absence of STAT3 protein baseline expression could impair cytokine-mediated signaling such as thatinduced by IL-!0 and IL-21.
