Canadian Health&Care; Mall

This study has demonstrated that the frequencies of IL-10-producing CD4+ and CD8+ T cells were higher in atopic asthmatics than in healthy controls. In atopic nonasthmatics, the frequency of IL-10-producing CD4+, but not CD8+, T cells was higher than in healthy controls. Furthermore, stimulation with PMA and ionomycin increased the frequencies of IL-10-producing CD4+ and CD8+ T cells in healthy controls and atopic nonasthmatics, but not in asthmatics. The time course study using healthy control samples showed that the stimulation with PMA and ionomycin increased the frequencies of IL-10-producing CD4+ and CD8+ T cells after 4 h of stimulation. Their frequencies reached a maximum after 24 h of stimulation. A previous study demonstrated that IL-10 mRNA from Th1- and Th2-like clones was first detected after 8 h of stimulation with anti-CD3 mAb plus phorbol acetate and reached a maximum after 24 h . The production of IL-10 protein, detected by ELISA, appeared after 12 h of stimulation and continued to increase thereafter. The earlier appearance of IL-10-producing cells in the current study seems inconsistent with the previous study. A small accumulation of IL-10 protein in the supernatant of cultured T cells at the earlier time points may not be detected by ELISA due to its limitation of sensitivity. Cytokine flow cytometry is expected to determine more detailed kinetics of IL-10 production, particularly in the early phase of activation in each subset of T cells.