Higher percentage of in vitro apoptotic cells at time of diagnosis in patients with chronic lymphocytic leukemia indicate earlier treatment requirement: Ten years follow up

Abstract

Chronic lymphocytic leukemia (CLL) has an extremely variable clinical course. Biological reasons for that wide variation in clinical course and survival rates in CLL patients are not fully understood. The aim of the study was to evaluate the value of spontaneous apoptosis of CLL cells in vitro determined at presentation of disease, in prediction of treatment requirements and evolution of the CLL. Malignant B cells were isolated from the whole blood of 30 newly diagnosed CLL patients and cultured for 24 hours in RPMI-1640 medium supplemented with 10% of serum obtained from the same CLL patient. Cells were later fixed and processed for embedding in Epon, or cell smears were prepared and stained with TUNEL technique. Ten-year follow-up revealed that patients with lower percentage of cells in apoptosis at presentation of disease had significant longer time treatment initiation (log rank test p < 0.05). On the contrary, apoptosis of CLL cells was not shown to have significant impact on survival of patients (Kaplan Meier log rank test p > 0.05). The results of this study emphasize the importance of apoptosis of CLL cells at the time of the initial diagnosis in pathobiology of this disease.