Humoral and cell-mediated immune response in patients with malignant melanoma. I. In vitro lymphocyte reactivity to PHA and antigens following immunization.

In vitro lymphocyte function was evaluated in 61 patients with different clinical stages of malignant melanoma. Thirty-one of these patients had localized disease, 13 regional metastases, 10 distant lymph node or skin metastases, and 7 visceral metastases. Following immunization, in vitro lymphocyte reactivity to three antigens (diphtheria toxoid, tetanus toxoid and alpha-hemocyanin of Helix pomatia) was studied in the presence of autologous serum, in addition to lymphocyte reactivity to phytohemagglutinin (PHA). The relationship of these tests with the clinical stage and the subsequent course of the disease in a 6 months' observation period was determined. The patients with visceral metastases (7) had a lowered lymphocyte reactivity to PHA compared with controls and the patients with other stages, while they also had a low reactivity to the test antigens (only significantly lowered compared with patients with localized disease). All these patients showed tumor progression or died from metastatic disease. Between the other stages (54 patients) there was no difference in lymphocyte reactivity to the test antigens or PHA. No correlation between lymphocyte reactivity to PHA and the subsequent course of the disease could be demonstrated in these 54 patients. However, lymphocyte reactivity to the test antigens following immunization showed a definite correlation with the subsequent course. Sixty-four percent (9/14) of patients without any lymphocyte reactivity to the three antigens showed tumor recurrence or progression, against 3% (1/40) of patients with positive lymphocyte reactivity to one, two, or three antigens. A suppressive effect of autologous serum on lymphocyte reactivity could be found only in 1 of 20 patients with a low reactivity to PHA or antigens. It is concluded that defects in lymphocyte function are related to subsequent tumor growth in patients with malignant melanoma.