[Major histocompatibility complex class II antigens on renal cell cancer--immunohistochemical study and effect on...

Products of major histocompatibility complex (MHC) play important roles in immune reaction. Class II MHC antigens serve as restriction elements for cells presenting antigens to CD4-positive helper T cells and also as histocompatibility antigens responsible for graft rejection. Furthermore, it was reported that expression of class II antigens on tumor cells increases immunogenicity in the murine system. In an attempt to investigate the relationship between renal cell cancer (RCC) and host's immune responses, we examined the expression of class II MHC antigens on RCC tissues of 30 cases and tumor cell lines. Immunohistochemical study showed that class II antigens were detected on 29 out of 30 RCC tissues to various degrees with an order of positivity DR greater than DP greater than DQ but not normal renal tubular cells. Significant correlation was found between the expression of DQ or DP and the degree of lymphocyte infiltration. Three lines of RCC were examined by flowcytometric analysis, and were found to lack class II antigens. In KRC/Y and ACHN, however, HLA-DR-positive cells and in KRC/Y a smaller number of HLA-DP-positive cells were found when these cells were treated with interferon-gamma but not interferon-alpha. The result suggests that the expression of class II antigens on RCC might be modified by interferon-gamma which is produced by tumor infiltrating lymphocytes or administrated for cancer treatment. Their expression is considered to affect host's immune response to RCC.