Myelo-monocytoid immunophenotypes of B-cell chronic lymphocytic leukemia cells

Leukemia cells from ten patients with B-cell chronic lymphocytic leukemia (B-CLL) and one with B-CLL of mixed cell type (B-CLL/PL) were analyzed to delineate the cellular characteristics, especially the myelomonocytic nature. Most of the surface phenotypes were consistent with the previous reports. However, the frequency of positivity for CD22 and CD25 was much higher in the examined cases of B-CLL than in Western reports. B-CLL cells frequently possessed antigens which are mainly expressed in myelomonocytic cells: 8/10 for CD11b and 4/10 for CD11c, although the presence of CD14 was not apparent (0/10). In addition, colony stimulating factor-1 receptors (CSF-1R) were expressed in 6 of the 10 B-CLL cases. The reactivity with antigens such as CD14, CD11c, and CSF-R was markedly enhanced by in vitro incubation. Alterations in antigen expression and in in vitro survival by growth factors for myelomonocytic lineage were observed in certain cases. These data imply that not only are B-CLL cells phenotypically closely related to myelomonocytic lineage but that they may also be influenced by growth factors for that lineage.