[CD5-positive B-cell prolymphocytic leukemia]

CD5 is a T-cell marker that is expressed in mature B cell malignancies and other B cell chronic lymphoproliferative disorders, but the biologic function of CD5 is unknown. We report a 68-year-old woman with B-cell prolymphocytic leukemia (B-PLL) expressing CD5 antigen. On admission, jaundice and hepatosplenomegaly were noted. Hematological examination demonstrated a platelet count of 2.8 x 10(4)/microl and a white blood cell count of 19,900/microl with 69% PLL cells. Surface marker analysis of the PLL cells was positive for CD5, CD19, CD20, sIgM, and was negative for CD23, and cyclin D1 was negative in immunostaining.