The effects of interleukin-10 or TGF-beta on anti-CD3/CD28 induced activation of CD8+CD28- and CD8+CD28+ T cells in allergic asthma.

The CD8+CD28- and CD8+CD28+ T cells play a primordial role in peripheral tolerance, but little is known about their implication in allergic asthma. This study was designed to determine the changes in a proportion of human circulatory CD8+ subsets before and after short term culture in the presence of anti-CD3/CD28 and IL-10 or TGF-beta. Flow cytometry analysis revealed increased percentage of CD8+CD28- T cells but decreased percentage of CD8+CD28+ T cells enriched from peripheral blood of adult allergic asthma individuals compared to controls (baseline). In comparison to the baseline, co-stimulation with anti-CD3/CD28 and IL-10 decreased the proportion of CD8+CD28- T cells in severe allergic asthma subjects, whereas it increased this value in mild to moderate asthmatic subjects and controls. Adding TGF-beta decreased the proportion of CD8+CD28- T cells from allergic asthma subjects, whereas it has opposite effects on this subset from controls. IL-10 and TGF-beta had some plethoric effects on FoxP3 expression in anti-CD3/CD28 activated CD8+CD28- T cells. Thus, these findings indicate that a control mechanism involving IL-10 and TGF-beta might be defective in allergic asthma subjects.