Chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL), the most frequent form of leukemia in Western countries, is characterized by the clonal proliferation and accumulation of neoplastic B lymphocytes in the blood, bone marrow, lymph nodes, and spleen. The median age of patients at diagnosis is 65 years, with only 10 to 15 percent under 50 years of age. In most series, more men than women are affected. The course of the disease is variable. Whereas some patients with CLL have a normal life span, others die within five years after diagnosis. During the past few years, important advances have been made in the . . .