In vitro assessment of immunocompetence in patients with malignant melanoma.

Ninety-four patients with malignant melanoma and 96 healthy controls were tested for lymphocyte proliferative capacity in a microblastogenesis assay. Each lymphocyte sample was assayed for incorporation of (3H)thymidine after stimulation with PHA, PWM, Con A (two doses), PPD, and allogeneic lymphocytes (MLC). MLC was the only assay that revealed a substantial and significant difference between the melanoma patients and controls. Almost all assays showed lower values in patients with more advanced disease. However, it was not possible to accurately predict clinical outcome from data obtained from in vitro immunocompetence tests. These results indicate the relatively limited clinical usefulness of assays of lymphocyte proliferative capacity in melanoma patients.