The relationship of chronic lymphocytic leukemia to normal activated B cells

There is compelling evidence that B-CLL cells are neoplastic counterparts of minor sub-populations of normal B cells. These normal cells include populations of activated B cells. The cell surface phenotype of B-CLL cells, characterized by the lack of several antigens (Ags) present on mature resting B cells and the presence of Ags preferentially expressed on activated B cells supports this hypothesis. Although controversial, B-CLLs are capable of responding in vitro to a variety of growth and differentiation factors which stimulate the proliferation and immunoglobulin secretion of normal activated B cells. These findings coupled with the observations that B-CLL cells produce cytokines which are normally secreted by stimulated B cells provide further evidence for the similarity between normal activated B cells and B-CLL cells.