engleski

Regulatory T cells in children undergoing immunotherapy

Regulatory T (Treg) cells have the capacity to inhibit potentially harmful immune responses in different human diseases. Many distinct types of Treg cells have been described according to their surface phenotype or by their ability to secrete immunoregulatory cytokines, such as interleukin 10 (IL-10) and transforming growth factor beta (TGF-b). So-called natural CD4+ CD25high Treg cells are CD45RO+, HLA-DRlow and intracellular CTLA-4+. Although these cells express CD25, which is usually considered as an activation marker, they lack the expression of other activation markers such as CD69. The aim of this study was to detect Treg cells in peripheral blood obtained from healthy adult volunteers (n=5) and children allergic to Dermatophagoides pteronyssinus undergoing specific immunotherapy (n=3). For that purpose, we first identified natural Treg cells using four-color flow cytometry. In healthy adults, 2, 6  1, 5 % of CD4+CD25high natural Treg cells among all CD4+ cells were detected. As observed earlier, CD4+CD25high were CD69-HLA-DRlow CD45RO+CTLA-4+. The phenotype and percentages of CD4+CD25+Treg from allergic children before immunotherapy was similar to the phenotype observed in adult healthy volunteers. Although no difference was observed in the percentage of CD4+CD25+ Tregs, a proportion of CTLA+ Tregs was increased after 3 months of immunotherapy. In addition, we established a method for detection of IL-10 and TGF-b in T cells. Peripheral blood mononuclear cells were cultured alone or in the presence of phorbol esther and ionomycin for 6 to 72 hours. Maximal percentage of IL-10 and TGF-b positive T cells was observed after 24 hours of culture. The percentage of IL-10 and TGF-b secreting cells increased during immunotherapy. These results indicate that analysis of CTLA-4 in Tregs as well as intracellular IL-10 and TGF-b cytokine analysis by flow cytometry could be useful markers to monitor the effect of specific immunotherapy in allergic individuals.

regulatory T cells; IL-10; TGF beta; immunotherapy

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