Phenotype of chronic lymphocytic leukemia (CLL) B-Cells

Summary In the present report we studied the phenotype of peripheral blood mononuclear cells (PBMC) from 25 patients with B-cell chronic lymphocytic leukemia (CLL). Cells from all the cases expressed monoclonal surface immunoglobulins (SmIg), formed rosettes with mouse erythrocytes (MRFC) and were positive with OKB2 and OKIa monoclonal antibodies. In addition, CCB1 monoclonal antibody was positive in 17 out of 20, Leu-1 in 18 out of 21 and Leu-8 in 23 out of 25 cases. Double labelling experiments confirmed that the Leu-8 antigen was co-expressed on Leu-1+, CCB2+, HLA-DR+ B-CLL cells. Thus, B-CLL cells generally express the SmIg+, MRFC+, Leu-1+, OKB2+, Leu-8+ phenotype. Since it is known that normal peripheral blood B cells may be divided into two subpopulations according to Leu-8 expression, our data indicate that B-CLL cells originate from the more immature Leu-8+ B-cell subset which will respond to anti-IgM, whereas it reacts poorly to pokeweed mitogen.