[Analysis of infiltrating lymphocytes in choroidal melanoma]

We performed immunohistochemistry on tumor infiltrating lymphocytes (TILs) in a 78-year-old man with choroidal malignant melanoma. Cell suspensions of TILs from fresh specimens and peripheral blood lymphocytes (PBLs) were stained with anti-CD3, anti-CD4, anti-CD8, anti-CD29, anti-CD45RA, and anti-human leukocyte antigen (HLA)-DR monoclonal antibodies and analyzed using three-color flow cytometry. In light microscopy, the number of infiltrating lymphocytes around the tumor was very small. Immunohistochemically, T lymphocytes were more numerous than B lymphocytes. Flow cytometric analysis showed that CD8+ cells were more numerous than CD4+ cells in CD3+ cells in TILs, and most of these cells also expressed HLA-DR antigen. CD29+ (memory) cells were increased and CD45RA+ (naive) cells were decreased in CD4+ cells in TILs as compared with PBLs. We concluded that the increase in the percentage of activated memory T lymphocytes and the decrease of naive T lymphocytes may reflect a localized antigen-specific immunological response in choroidal malignant melanoma.