STUDY OF IL-2 RECEPTOR EXPRESSION AFTER CHEMOIMMUNOTHERAPY IN PATIENTS TREATED FOR METASTATIC MALIGNANT-MELANOMA

Using flow cytometry, cellular IL-2 receptors were studied before and following chemoimmunotherapy combination in 20 patients with metastati c malignant melanoma (MMM). Patients received cisplatin (100 mg/m(2)) at days 1 and 28, recombinant IL-2 by continuous infusion from days 3 to 6, 17 to 21, 31 to 34, and 45 to 49. Interferon-alpha (IFN-alpha) w as given subcutaneously three times weekly. In terms of clinical respo nse, we observed 55% objective response (complete: 15%). When pretreat ment blood samples were compared with those of healthy donors, we did not observe any change in low (alpha chain) and high affinity receptor (alpha+beta) expression. In contrast, intermediate affinity p75 (beta chain) expression was decreased significantly (P less than or equal t o 0.0001) in MMM patients. During treatment, we found a dramatic incre ase of beta chain as well as high affinity (alpha+beta) expression in responding patients, as soon as IL-2 therapy began. Furthermore, the i ncrease of beta chain expression was limited to natural killer (NK) ce lls (CD56(+)). In non-responding patients, on the other hand, increase of both receptors was seen only at day 31. These data suggest the inv olvement of beta chain expression in the mechanism of cell activation after chemoimmunotherapy. Moreover, this early beta chain expression i s correlated with the clinical response to chemoimmunotherapy.