Cytokine-mediated interactions among inflammatory cells may contribute to pathogenesis of allergic asthma. To understand the role of soluble interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) on the disease activity and regulation in asthma, changes in serum concentrations of IL-10 and TGF-beta elaborated by activated T-lymphocyte before and after prednisolone therapy with clinical improvement were determined. Circulating levels of IL-10 and TGF-beta in sera from 16 normal control subjects and in sera from 22 allergic asthmatic children with acute exacerbation and in stable condition were respectively detected by commercially available enzyme-linked immunosorbent assay kits. The mean concentrations of serum IL-10 in asthmatics with acute exacerbation (6.77 +/- 4.08 pg/mL) and during stable condition (5.14 +/- 1.17 pg/mL) were lower than that in control subjects (7.15 +/- 4.72 pg/mL). However, the difference was not statistically significant among these three study groups. The mean concentration of serum TGF-beta in stable asthmatics (40.73 +/- 15.95 pg/mL) was significantly higher than that in asthmatics with acute exacerbation (27.64 +/- 3.66 pg/mL; p < 0.05) and that in healthy control group (28.77 +/- 8.35 pg/mL; p < 0.05), while there was no statistical difference between the latter two groups. This study provides further evidence that serum TGF-beta, rather than IL-10, may play a role in regulation of disease activity and serve as an indicator for clinical control of allergic asthmatics.