Objective: To investigate the role of CD4(+)CD25(+) regulatory T cells (Tr cells) in the pathogenesis of asthma in children.
Methods: Peripheral blood samples were collected from 20 pediatric patients with asthma, 10 male and 10 female, aged 7 (3-12), and 20 healthy children, 10 male and 10 female, aged 6.5 (2-11). Lymphocytes were isolated. Flow cytometry was used to examine the percentages of CD4(+)CD25(+) regulatory T cells, IL-10 secreting CD4(+)CD25(+) regulatory T cells (CD4(+)CD25(+)-IL-10), and transforming growth factor (TGF)-beta secreting CD4(+)CD25(+) regulatory T cells (CD4(+)CD25(+)-TGF-beta). RT-PCR and real-time PCR were used to detect the mRNA expression of suppressor of cytokine signal 1 (SOSC1) and Foxp3.
Results: The percentages of CD4(+)CD25(+) regulatory T cells of the asthma children was 6.51% +/- 1.94%, significantly lower than that of the healthy children (11.96% +/- 2.30%, P < 0.01); the percentage of CD4(+)CD25(+)-IL-10 of the asthma children was 1.46% +/- 0.35%, significantly lower than that of the healthy children (5.65% +/- 1.70%, P < 0.01); and the percentage of CD4(+)CD25(+)-TGF-beta of the asthma children was 1.24% +/- 0.21%, significantly lower than that t of the healthy children (4.23% +/- 1.65%, P < 0.01). The Foxp3 mRNA expression of the asthma children was 0.12 +/- 0.05, significantly lower than that of the healthy children (1.71 +/- 0.58, P < 0.01); and the SOCS1 mRNA expression of the asthma children was 0.38 +/- 0.19, significantly lower than that of the healthy children (1.51 +/- 0.41, P < 0.01).
Conclusion: The decrease of CD4(+)CD25(+) regulatory T cells may be involved in the pathogenesis of asthma. The decreased mRNA expression of Foxp3 and SOCS1 may be associated with the aberrant development of CD4(+)CD25(+) regulatory T cells.