Chronic lymphocytic leukemia. B-cell chronic lymphocytic leukemia (B-CLL) is the most prevalent leukemia in the Western Hemisphere, accounting for ~25% of all leukemia's. It represents a monoclonal expansion of small, long-lived, apparently slowly dividing CD5+ B cells. Because of the low proliferative index and a presumed uniform proliferative rate of B-CLL cells in vivo (a fact not yet tested or documented), B-CLL appears to be primarily a disease of accumulation rather than proliferation.

Chronic lymphocytic leukemia. B-cell chronic lymphocytic leukemia (B-CLL) is the most prevalent leukemia in the Western Hemisphere, accounting for ~25% of all leukemia's. It represents a monoclonal expansion of small, long-lived, apparently slowly dividing CD5+ B cells. Because of the low proliferative index and a presumed uniform proliferative rate of B-CLL cells in vivo (a fact not yet tested or documented), B-CLL appears to be primarily a disease of accumulation rather than proliferation.

B-CLL remains an incurable illness and there is no survival benefit to early intervention.

Therefore, patients with early stage disease are usually followed closely without initiating treatment. Patients with more extensive disease or progressive cytopenias are eventually treated with cytotoxic agents, with or without prednisone, or with nucleoside analogues that promote apoptosis in the leukemic cells. The clinical outcome of the disease is determined both by the profound dysregulation of the immune system that results in infection and autoimmunity and by leukemic infiltration and destruction of organs. Autoimmune phenomena are common and frequently directed against hematopoietic cells, resulting in autoimmune hemolytic anemia (10-25%) or immune thrombocytopenia.

Inclusion Criteria:

• Must be 18 years of age.
• Must meet the clinical and laboratory criteria for B-CLL (i.e., compatible clinical history and physical exam, presence of lymphocytosis, i.e., >10,000 lymphocytes / mm3, evidence for a monoclonal population of CD5+/CD19+/CD23+ cells in the periphery that have dim surface membrane lg with L chain isotype restriction).
• All patients will be staged according to the system of Rai. Only new onset patients who are not receiving therapy will be entered into the heavy water leukemic cell turnover studies.

Exclusion Criteria:

• Patients hospitalized for an acute medical problem, related or not to their leukemia, within 4 weeks of enrollment.
• A history of a second malignancy involving the hematopoietic system, or the need for extensive chemotherapy for any second malignancy; patients with active immunologic disorders (e.g., HIV and AIDS), especially autoimmune problems (e.g., autoimmune hemolytic anemia of any cause other than B-CLL).
• Patients with impaired decision-making capabilities, e.g. dementia, psychosis, alcoholism, and illicit drug use will also be excluded.

Chronic Lymphocytic Leukemia