ABSTRACT
I. INTRODUCTION B-cell chronic lymphocytic leukemia (CLL), which is due to the accumulation of neoplas tic CD5 + B lymphocytes, is the most frequent form of leukemia in the Western hemi sphere, where it accounts for 20% to 40% of all leukemias. CLL predominates in the elderly, with the median age of patients at diagnosis being around 65 years. The course of the disease is heterogeneous. Thus, whereas in some patients survival is not affected by the disease, others die shortly after diagnosis (1-3).
