T and B Lymphocytes in Chronic Lymphocytic Leukemia

To the Editor: Both B-cell and T-cell populations may increase in size and show altered functions during the course of chronic lymphocytic leukemia, but this action does not necessarily indicate that both are neoplastic, as suggested by Davis.¹ T-cell numbers and responses to mitogens, for instance, may vary because of an immune reaction to infectious agents (or perhaps to neoplastic B cells),^2,3 therapy or inhibitors in the serum.⁴ The best evidence that a suspected subpopulation is neoplastic may be its clonal nature, demonstrated immunologically or cytogenetically. This determination is difficult for the B cells in chronic lymphocytic leukemia, although.