Cytokines are powerful modulators of immune responses, the local produ
ction of which could be relevant to the interaction between tumour and
immune system. This study investigated the transcription of genes enc
oding interleukin (IL) 2, IL-4, IL-10 and interferon (IFN) gamma in ly
mphocyte-infiltrated renal cell carcinoma biopsies from ten patients u
sing the reverse polymerase chain reaction technique. Autologous perip
heral blood mononuclear cells and healthy renal parenchyma tissue were
tested in parallel. The beta-actin gene, used as a positive control,
was transcribed in all samples. In contrast, transcription of cytokine
genes was confined to tumour biopsies: IL-2 gene transcripts were det
ectable in five biopsies and IL-10 transcripts in seven. IL-4 and IFN-
gamma gene transcripts were detectable in one biopsy each. In two pati
ents no cytokine gene transcription could be identified. These data un
derline that heterogeneous patterns of cytokine gene transcription can
be observed in renal cell carcinoma biopsies. Although transcription
of an immunostimulatory lymphokine such as IL-2 was observed in 50 per
cent of biopsies, the most frequently transcribed cytokine gene coded
for an inhibitory factor, IL-10.