LITTLE EXPRESSION OF CYTOKINE MESSENGER-RNA BY FRESH TUMOR-INFILTRATING MONONUCLEAR LEUKOCYTES FROM GLIOMA AND LUNG ADENOCARCINOMA

We investigated whether cytokine genes were activated in human tumour-infiltrating mononuclear leukocytes (TIML) obtained from six lung adenocarcinomas and seven glioblastomas, TIML were extracted by mechanical disruption and isolated by double density gradient of Ficoll, We performed mRNA reverse transcription-polymerase chain reaction (RT-PCR) on these fresh (noncultured) TIML and autologous peripheral blood mononuclear leukocytes (PERIL) using primers for the cytokines IL-1 beta, IL-6, IL-2, IL-4, GM-CSF, IFN-gamma and TNF-beta. In addition, we compared patients' TIML and PERIL populations with healthy normal and alpha-CD3 activated PBML as an optimally activated reference population, Gel bands of RT-PCR products were quantitated in relative units (RU) as a function of their size and intensity by computerized image-analysis. Lung and brain patients' TIML showed IL-1 beta and IL-6 cytokine mRNA expressed in the average of 2-log RU but not significantly different from autologous and normal healthy PERIL, IL-2, IFN-gamma and TNF-beta also did not appear expressed in the TIML at higher levels than in autologous or healthy normal PERIL, However in two thirds of patients, lung TIML could be distinguished from autologous PBML by specific expression of GM-CSF and from healthy normal PERIL by expression of IL-4, Similarly, most brain TIML expressed mRNA significantly above healthy normal PERIL for GM-CSF and IL-4, In comparison with alpha-CD3 activated healthy PERIL, our results suggest that lung and brain TIML had detectable cytokine mRNA, but they seemed poorly activated in total number of genes and amount of cytokine mRNA, Absence, insufficient amounts or deficient combinations of cytokine production by TIML may be factors that prevented an optimal activation of the immune response in these tumours. (C) 1995 Academic Press Limited