Interleukin-12 was not involved in promotion of T helper cell differentiation induced by theophylline

To investigate the effect of theophylline on the naive T cell differentiation and the probable role of interleukin-12 (IL-12).

Naive cord blood T cells were treated with theophylline 10 mg/L for 3 d after stimulation with PHA 100 mg/L. Differentiation of T cells was analyzed by flow cytometry. Theophylline 10 mg/L and IL-12-mAb 0.025 mg/L were added in cord blood mononuclear cell (CBMC) cultures primed with LPS 1 mg/L to detect the levels of IL-12 and IL-12P40. The whole blood cultures were obtained from twelve health volunteers with or without administration of theophylline (200 mg). Cytokines were measured by enzyme linked immuno-sorbent assay.

Theophylline promoted T helper 1 (Th1) cells differentiation from naive T cells (21.9 %+/-10.3 % vs 9.4 %+/-5.6 %, P<0.05), but had no significant effect on Th2 deviation. But theophylline inhibited the production of IL-12 and IL-12P40 by CBMC in vitro (28+/-6 ng/L vs 57+/-14 ng/L and 88+/-34 ng/L vs 214+/-82 ng/L, P<0.01) and reduced IL-12 and IL-12P40 levels in whole blood cultures from healthy subjects (19+/-11 ng/L vs 31+/-15 ng/L and 92+/-13 ng/L vs 196+/-49 ng/L, P<0.01).

Theophylline promoted the differentiation of Th1 cells. IL-12 seemed not to be involved in this process.