Expressions of helper T cells and regulatory T cells in peripheral blood of children with dust mite allergic asthma and their clinical significance

Objective To analyze the expressions of helper T cells (Th) and regulatory T cells (Treg) in peripheral blood of children with dust mite allergic asthma and their clinical significance. Methods Thirty asthmatic children with dust mite positive were included in the study as asthmatic group. Thirty healthy subjects, age and sex matched, were included as healthy control group. Peripheral blood mononuclear cells (PBMC) were isolated by density-gradient centrifugation over Ficoll-Hypaque cushions. The expressions of interferon-γ (IFN-γ), interleukin-4(IL-4) and Foxp3 in CD4+ T cells with or without dust mite stimulation were assessed by intracellular staining and flow cyto-metry (FCM). The anti-inducible costimulatory molecule (ICOS), anti-CD28 or anti-cytotoxic T-lymphocyte antigen-4(CTLA-4) antibodies were added to PBMC and co-cultured for 3 days after dust mite stimulation. The expressions of Th1 (CD4+IFN-γ+T cells), Th2 (CD4+IL-4+T cells) and Treg(CD4+CD25+Foxp3+T cells) were analyzed. The data were analyzed by using statistical software. Results Compared with the healthy control group, in dust mite positive asthma group, the percentage of Th1 cells was remarkably increased (P 0.05). Compared with non-stimulated PBMC of asthma group, the percentages of Th1 and Treg had no significant variation (all P>0.05), while that of Th2 cells was notably increased (P 0.05), while expressions of Th2 cells were significantly decreased (all P 0.05). Conclusions There is a constructive, allergen independent Th1 activation and Treg deficiency as well as allergen inductivity, ICOS- and CD28-dependent Th2 activation in the peripheral blood of children with dust mite allergic asthma. Key words: Dust mite; Allergic asthma; Helper T cell; Regulatory T cell