HLA antigen frequencies in malignant melanoma patients. A second study

Two groups of malignant melanoma (MM) patients were considered: the group of 140 patients previously published and a new one of 58, both typed for HLA-A, -B and -C antigens at the Istituto Nazionale Tumori of Milan. The control group consisted of healthy blood donors not related to the patients. Only the HLA-Bw35 antigen frequency was significantly decreased in both groups of patients. To investigate the HLA-A and -B blanks, 62 MM patients and 90 healthy controls, who showed non-homozygotic blanks when they were firstly HLA typed, volunteered to repeat the HLA typing three or more times in a 2-year period. A significant increase in both HLA-A and -B blanks in the patients as compared to controls was noticed (p = 3 X 10(-4) and 3 X 10(-5), respectively). In the future, attempts should be made to correlate the HLA antigen and blank frequencies with the evolution of the disease and, also, to verify the hypothesis that the HLA-Bw35 antigen may be an associated resistance factor against the tumor.