HLA-DR antigen expression on melanoma metastases and the course of the disease.

Melanoma cells freshly isolated from regional lymph node metastases of 59 stage II malignant melanoma patients were analyzed by indirect immunofluorescence staining with monoclonal antibody TAL 1B5, detecting the HLA-DR alpha chain. The expression of HLA-A,B,C antigens, using antibody W6/32, was also investigated in 45 of these cases. There were no substantial differences in the course of the disease with respect to the percentage of positive cells. In 13 malignant melanoma patients two to four simultaneous and/or successive metastases (both locoregional and distant-subcutaneous) were analysed for HLA-DR. With simultaneous metastases (7 cases) the percentage of HLA-DR-positive cells was mostly very similar, and in no case was there more than 25% variation. As to successive metastases (9 cases) the percentage of HLA-DR-positive cells remained practically unchanged or decreased during the course of the disease.