Relation between macrophage and T helper-2 lymphocyte functions in human neoplasms: neopterin, interleukin-10 and interleukin-6 blood levels in early or advanced solid tumors.

At present, it is known that there are two main mechanisms responsible for cancer-related immunosuppression, mediated by macrophages and by TH2 lymphocytes. The relation existing between macrophage- and TH2-mediated immunosuppression still remains to be understood. The present study was performed in an attempt to establish which is the correlation existing in cancer patients between IL-10 and neopterin levels, which reflect TH2- and macrophage-mediated suppressive events, respectively. The study included 40 solid tumor patients and 60 healthy subjects as controls. Serum concentrations of neopterin and IL-10 were measured by the RIA method and by an immuno-enzymetric assay, respectively. Because of its possible production both by TH2 and macrophages, serum levels of IL-6 were also determined. Neopterin, IL-10 IL-6 mean concentrations were significantly higher in cancer patients than in controls. Mean values of both neopterin and IL-6 were significantly higher in metastatic patients than in those with locally limited disease. IL-10 mean levels were also significantly higher in patients with metastatic disease. IL-6 levels were significantly correlated with those of neopterin, whereas no correlation was found between neopterin and IL-10 values. This preliminary study would suggest that macrophage- and TH2-mediated immunosuppression may occur independently in solid tumors, and that it becomes more evident with disease progression.