Leukocyte Labeling With ⁵¹Chromium. IV. The Kinetics of Chronic Lymphocytic Leukemic Lymphocytes

The kinetics of radiochromate-labeled autologous blood lymphocytes were studied in ten cases of chronic lymphocytic leukemia (CLL). The labeled cells equilibrated with an enlarged recirculating lymphocyte pool (RLP) distributed between the blood, the spleen, and the bone marrow. The size of the RLP, estimated from dilution of the labeled cells, was better correlated with the degree of splenomegaly and marrow infiltration than was the blood lymphocyte count. The marrow fraction of the RLP turned over more slowly than the splenic pool. The half-life of the labeled cells in the RLP varied in individual cases from one to 11 days. Lymphocyte life span was not related either to the blood lymphocyte count or to the size of the RLP. The mean half-life of 3.8 days was significantly shorter than the normal lymphocyte half-life of 18 days. We conclude that CLL is characterized by overproduction of a strain of abnormally short-lived lymphocytes.