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Interaction between TL1A and death receptor 3 (DR3) co-stimulates T cells, induces production of several pro-inflammatory cytokines and has been linked to pathogenesis of inflammatory bowel disease (IBD). This study aimed to establish a link between expression of TL1A and selected TL1A-induced pro-inflammatory cytokines involved in IBD pathogenesis (IL-4, IL-13, IL-17A and IFN-c) and to investigate a connection between serum concentration of TL1A in patients with IBD and activation of peripheral blood T cells. Elevated levels of IL-4 (2.91-fold) and IL-13 (4.05-fold) mRNA were detected in the inflamed colon mucosa of patients with ulcerative colitis (UC), IFN-c mRNA was upregulated (3.23-fold) in the inflamed colon mucosa of patients with Crohn's disease (CD), whereas upregulation of IL-17A and TL1A mRNA was present in the inflamed colon mucosa of patients with both CD and UC (IL-17A: 4.48-fold and 2.74-fold, TL1A: 3.19-fold and 3.22-fold, respectively) vs. control subjects. We did not detect any changes in DR3 mRNA expression in the investigated groups of patients. TL1A mRNA level in colon mucosa of patients with IBD correlated only with the level of IL-17A mRNA but no other investigated cytokines. In colon mucosa, expression of TL1A and DR3 was localized to enterocytes and lamina propria mononuclear cells. We did not find any correlation between serum concentrations of TL1A and IL-17A or changes of CD4(+) or CD8(+) lymphocytes phenotype in patients with IBD. Therefore, our data indicate that TL1A may contribute to pathogenesis of IBD via local but not systemic induction of IL-17A but not IL-4, IL-13 or IFN-c.

Almost all cases of hyperthyroidism in children result from Graves' disease (GD). Recent studies have confirmed a significant role of T regulatory cells (Tregs) in the development of autoimmune diseases. However, the interactions between T cell responses and Treg proliferation in GD are still poorly understood. The aim of this study was to assess the proliferation of Treg cells (Tregs) and CD3+ T lymphocytes isolated from 50 children with GD before and after treatment with the thyreostatic drug methimazole (MMI). The proliferation rates, measured by methyl-3H-thymidyne incorporation, of CD3+ cells and Tregs stimulated with mitogen phorbol 12-myristate 13-acetate (PMA) were compared with those of unstimulated cells. The proliferation rates of both PMA-stimulated and unstimulated CD3+ cells prior to treatment with MMI were significantly higher than after treatment. Simultaneously, the proliferation rates of both PMA-stimulated and unstimulated Tregs were significantly lower before MMI treatment. Moreover, we observed higher cell proliferation rates of unstimulated and PMA-stimulated Tregs before the initiation of MMI therapy and after treatment in patients who had no relapse of hyperthyroidism. There was a positive correlation between the CD3+ cells proliferation rate before MMI treatment and fT3, as well as fT4 concentration in peripheral blood. The proliferation rates of CD3+ T cells before and after MMI treatment positively correlated with the TSI index. Thus, children suffering from Graves' disease presented lower Tregs proliferative potential compared with CD3+ T cells. Cocultures of CD3+ T cells and Tregs showed that Tregs were not capable of efficiently inhibiting the proliferation of CD3+ T cells in GD patients. Conclusions. MMI treatment reduced the proliferative activity of CD3+ T cells in pediatric GD patients and increased the proliferation rate of Tregs. We suggest that Treg cells that are partly dysfunctional in GD disease are probably suppressed by CD3+ T cells and that methimazole exerts some immunomodulatory effects.

In comparison to healthy volunteers, untreated children with IBD have higher percentage of DR3(+) PBMCs than adults with IBD undergoing anti-inflammatory treatment. In most of the investigated PBMCs populations, the frequency of DR3(+) cells is correlated with the level of CRP. We suggest anti-inflammatory treatment may lead to reduction in the frequency of DR3(+) PBMCs. © 2016 International Clinical Cytometry Society.