MESSENGER-RNA EXPRESSION OF THE IMMUNOSUPPRESSIVE CYTOKINE IL-10 IN HUMAN GLIOMAS

Interleukin 10 (IL-10) was initially discovered on the basis of its ab ility to suppress cytokine synthesis, Additionally, it can exert immun osuppressive effects on a variety of cell types. Because patients with malignant gliomas present with a general impairment of the immune sys tem, we investigated IL-10 expression in the glioma tissue, Because ex pression of IL-10 and IL-6 is associated in hematopoietic cells and IL -6 can act as an autocrine growth stimulatory for glioblastoma cell li nes, we looked in addition for a relationship between IL-10 and IL-6 e xpression Using a quantitative reverse transcriptase polymerase chain reaction, IL-10 and IL-6 mRNA levels were determined in 37 glial tumor s of different grades including 2 recurrencies, 3 specimens from norma l brain tissue, and 3 glioblastoma cell lines. Expression of IL-10 mRN A was demonstrable in all tumors as well as in normal brain. High grad e tumors and recurrent cases expressed significantly higher amounts of IL-10-specific mRNA compared with low grade tumors, whereas 2 of 3 ce ll lines shouted only weak constitutive expression, mRNA for IL-6 was found in 86.5% of all gliomas with a com elation concerning the expres sion levels for both cytokines in 69% of gliomas. We suggest that IL-1 0 may contribute to the progression of astrocytomas by suppressing the patient's immune response, whereas IL-6 provides an additional growth advantage.