CORRELATION BETWEEN PRETREATMENT SERUM LEVELS OF NEOPTERIN AND RESPONSE TO INTERLEUKIN-2 IMMUNOTHERAPY IN CANCER-PATIENTS

IL-6 levels have been proven to correlate with resistance to IL-2 immu notherapy. Since IL-6 may be produced by both macrophages and TH2 lymp hocytes, it is not possible to establish whether the negative prognost ic significance of IL-6 levels may primarily depend on an enhanced mac rophage or TH2 activation Macrophage activation may be documented by t he increase in its specific marker neopterin. In an attempt to establi sh whether the negative significance of IL-6 high levels prior to IL-2 immunotherapy may reflect an enhanced macrophage activation, we have investigated the relation existing between pretreatment concentrations of neopterin and response to IL-2 immunotherapy in cancer patients. T he study included 20 metastatic venal cell cancer patients, who weve t reated with IL-2 subcutaneously at 6 million IU/day for 5 days/week fo r 6 weeks. Before the onset of IL-2 therapy, abnormally high serum lev els of neopterin were seen in 11/20 patients. Moreover, neopterin conc entrations were significantly correlated with those of IL-6. Tumor reg ression rate was significantly higher in patients with normal than in those with elevated levels of neopterin prior to therapy (5/9 vs 1/11, P < 0.05), as well as the percent of the survival at 1 year (9/9 vs 4 /11, P < 0.01). This preliminary study would suggest that pretreatment values of the macrophage marker neopterin correlate with resistance t o IL-2 cancer immunotherapy.