Usefulness of CD45 density in the diagnosis of B-cell chronic lymphoproliferative disorders

Background: Although many B-cell chronic lymphoproliferative disorders (BCLPDs) including B-cell chronic lymphocytic leukemia (B-CLL) have characteristic clinical and biological features, the overlapping morphologic and immunophenotypic profiles of various BCLPDs, is still the main problem. Aim: Our aim was to evaluate the usefulness of CD45 expression in the immunological classification of BCLPDs. Setting and design: A prospective study was set in a university hospital to investigate the CD45 intensity, particularly in B-CLL. Materials and Methods: The expression of CD45 in 37 patients with BCLPD including typical B-CLL (Group I), atypical B-CLL and CLL/PLL (II), and hairy cell leukemia (HCL), B-prolymphocytic leukemia (B-PLL), and B-non Hodgkin′s lymphoma (B-NHL) as non-CLL BCLPDs (III) and in eight healthy age matched controls (IV) was quantitatively compared by flow cytometric CD45/RALS gating strategy. Statistical analysis: The mean, median, and peak channel scores of CD45 obtained for the four groups were compared using one-way analysis of variance test. A P value < 0.05 was to be considered statistically significant. Results: Lower CD45 density is associated highly with typical CLL and differences between typical CLL and other groups were significant (P>0.001, 0.001, and 0.001). Non-CLL cases had significantly brighter CD45 expression than atypical CLL (P=0.014). No differences were found between normal lymphocytes and non-CLL BCLPD cases. Conclusions: CD45 is a useful marker, to discriminate the typical CLL from the non-CLL BCLPD and from atypical CLL.