Defective expression and modulation of B7-2/CD86 on B cells in B cell chronic lymphocytic leukemia.

Malignant monoclonal B cells of chronic B cell lymphocytic leukemia (B-CLL) usually fail to be cleared, which indicates important costimulatory molecules may be lacking. Among those costimulatory signals, B7-1/CD80 and B7-2/CD86 caused utmost attention. In this study, B7-1 and B7-2 expression on B cells in chronic B cell lymphocytic leukemia patients were detected. Data showed that B7-2 expression in chronic B cell lymphocytic leukemia patients is significantly lower than in normal people, which suggests defective B7-2 expression may be one of the pathogenic mechanisms of chronic B cell lymphocytic leukemia. Further, we confirmed interferon-gamma could induce B7-2 expression slightly and promote T-cell response against chronic B cell lymphocytic leukemia cells, indicating interferon-gamma has clinical value in chronic leukemia immunotherapy based on modulating B7-2 expression.