Quantitative analysis of cytokine mRNA expression in peripheral blood mononuclear cells following treatment with interleukin-2

After activation with interleukin-2 (IL-2), peripheral blood mononuclear cells (PBMC) have been reported to induce the expression of mRNA coding various cytokines, including interleukin(IL)-1 alpha, -1 beta and tumor necrosis factor alpha (TNF alpha). We examined the cytokine mRNA expression of PBMC following treatment with IL-2 in vitro and in vivo by a quantitative method using the reverse transcription/polymerase chain reaction (RT-PCR). After stimulating PBMC with IL-2 in vitro, peak levels of IL-1 alpha mRNA were reached between 3 h and 12 h, and thereafter declined. The IL-1 beta expression increased, with levels peaking at 1-6 h and, had decreased by 96 h. The expression of TNF alpha was elevated both 1-3 h and 24-48 h after stimulation. The peak levels of IL-1 alpha and -1 beta mRNA and the early elevation of TNF alpha mRNA mainly accounted for the cytokine mRNA expression in adherent cells; however, the late induction of TNF alpha mRNA was observed in nonadherent cells. In patients with advanced carcinoma, the IL-1 alpha and -1 beta mRNA expression were elevated after IL-2 treatment for 5 consecutive days, while the expression of TNF alpha mRNA also increased. These results indicate that the quantitative RT-PCR method appears to be useful for analyzing the cytokine mRNA expression of PBMC after treatment with IL-2.