DECREASED EXPRESSION OF HLA CLASS-I ON OCULAR MELANOMA-CELLS FOLLOWING IN-VITRO PHOTODYNAMIC THERAPY

Our objective was to investigate whether photodynamic therapy (PDT) in fluences the expression of HLA Class I and beta 2-microglobulin molecu les on cultured uveal melanoma cells. Uveal melanoma cells were incuba ted with hematoporphyrin esters (HPE) and illuminated using red light. HLA expression on cells was determined by flowcytometry. PDT treatmen t induced an immediate reduction in expression of HLA Class I and beta 2-microglobulin, followed by a transient increase in expression after 2 h. Normalization occurred after 6 h. Treatment of ocular melanoma c ells with PDT temporally alters the expression of HLA Class I and beta 2-microglobulin, which may affect anti-tumor-immune responses. (C) 19 97 Elsevier Science Ireland Ltd.