Infiltrating lymphocytes and antigen expression in uveal melanoma

Monoclonal antibodies and flow cytometry were used to study lymphocyte, monocyte and tumor cell antigen expression in uveal melanoma. Forty-one melanomas were studied after various forms of treatment. An antimelanoma antibody, 13A3E, stained 81.7% of the cells. Tumors treated with helium ions or 125I plaques had 13A3E staining reduced to 62.5%, p = 0.011. HLA-A,B,C stained 85.4%, and HLA-DR stained 7.0% of the cells. T cells (CD3 positive) comprised 4.5% (range 0.1-29.2%) of total cell population. Natural killer (NK) cells, B cells and macrophages were present in small numbers (mean less than 2.5% in each case). Tumors with numerous T cells (greater than 5%), were used for T cell subtype studies. The mean helper/inducer (CD4) to cytotoxic/suppressor (CD8) ratio was 1.00 (range 0.11-3.15). CD8 decreased, and CD4 increased with age in unirradiated tumors (p less than 0.02).