Heterogeneity of clonal lymphocytes with regard to bcl-2 protein concentration and cell size

The existence of subpopulations of clonal lymphocytes in patients with low grade lymphoproliferative disorders, with regard to both cell size and bcl-2 protein concentration is reported. Flow cytometric analysis showed that the lymphocytes with higher levels of bcl-2 corresponded to a subset of larger lymphocytes. Statistical analysis suggested that the increased concentration of bcl-2 was not accounted for by the increase in cell size and it is possible that these cells form a functionally distinct component of the clonal proliferation. One patient, analysed in greater detail during treatment with a purine analogue, showed the subpopulations to exhibit a differential sensitivity to chemotherapy.