Comparative analysis of normal and malignant CD5+ B lymphocytes.

The T-cell related CD5 molecule is expressed by the major B cell population which forms primary follicles in fetal lymph nodes and spleen and circulates in cord blood but decreases to a numerically minor proportion (5-10% of all B cells) in adults [1, 3-5, 8, 9, 12, 14, 16]. The CD5 molecule is also expressed by the monoclonal B cells of B-chronic lymphocytic leukemia (B-CLL: reviewed in [5]). Even if there is no proof that CD5+ B cells are the target of the transforming events which lead to B-CLL, they are regarded as the normal counterpart of B-CLL. Therefore, the aim of the present work was the analysis of the phenotype, the cell cycle control and the cytoskeleton organization of normal CD5+ B lymphocytes in comparison with the data obtained on malignant CD5+ cells from B-CLL patients.