Semiquantitative analysis of Th1 and Th2 cytokine expression in CD3+, CD4+, and CD8+ renal-cell-carcinoma-infiltrating lymphocytes

The mRNA expression of Th1 and Th2 cytokines was compared in freshly isolated CD3(+) tumor-infiltrating lymphocytes (CD3(+) TIL) and in autologous CD3(+) peripheral blood lymphocytes (CD3(+) PBL) obtained simultaneously from 20 patients with renal cell carcinomas (RCC). In addition cytokine expression was compared in CD4(+) TIL and CD8(+) TIL from another group of 20 patients with RCC. TIL were isolated from mechanically disaggregated tumor material and PBL from peripheral blood by gradient centrifugation and subsequent selection with anti-CD3, anti-CD4 or anti-CD8 magnetic beads. In these pure lymphocyte preparations the constitutive expression of interleukin-l (IL-1), IL-2, IL-10, interferon gamma (IFN gamma), and tumor necrosis factor alpha (TNF alpha) was determined by using a polymerase-chain-reaction-assisted mRNA amplification assay. In the CD3(+) TIL, levels of mRNA for IFN gamma, IL-10, IL-1 and TNF alpha were significantly higher than in the autologous CD3(+) PBL whereas IL-2 expression was rather low and did not differ in the two populations. Comparison of cytokine mRNA expression in CD4(+) TIL and simultaneously obtained CD8(+) TIL revealed a significantly higher expression of IFN gamma in CD8(+) cells. These data reflect an in vivo activation of RCC-infiltrating lymphocytes at the mRNA level with respect to the Th1 as well as the Th2 immune response. Th1 activation seems to be most evident in the CD8(+) TIL.