Detection of CD5 in B-cell chronic lymphoproliferative diseases by flow cytometry: a strong expression in B-cell chronic lymphocytic leukemia.

PURPOSE CD5 is a T cell marker, aberrantly express in B cell chronic lymphocytic leukemia (B-CLL) and mantle cell lymphoma (MCL). Other chronic B cell malignancies including hairy cell leukemia (HCL) and B cell prolymphocytic leukemia (B-PLL) are CD5 negative or express this antigen in a weak way. In this study, CD5 expression was investigated in leukemic cells from 42 patients with chronic B cell lymphoproliferative disease. METHODS We studied the CD5 expression in leukemic cells from 42 patients with chronic B-cell malignancies by flow cytometry. Demographic features such as age, sex and clinical date were also analyzed. RESULTS There were 22 males and 20 females. The immunophenotyping showed that 35 cases were B-CLL, 3 B-PLL and HCL and one patient was MCL. CD5 expression was present in all B-CLL and MCL. Low expression of CD5 was observed in one patient with B-PLL and negative in all cases of HCL. CONCLUSION Our date demonstrated that CD5 expression can help distinguish among B-CLL from HCL and B-PLL, but is similar expressed in MCL.