Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a heterogeneous, indolent lymphoproliferative neoplasm characterized by the accumulation of monoclonal, mature-appearing B lymphocytes in the blood, bone marrow, and lymphoid tissues. It is the most common leukemia in adults in the Western hemisphere, arising from a clonal expansion of mature B cells with distinct immunoglobulin gene rearrangements. CLL and small lymphocytic lymphoma (SLL) are considered manifestations of the same disease at different stages, differing primarily by the extent of peripheral blood and bone marrow involvement. The disease exhibits significant clinical and molecular diversity, with some patients experiencing a slow, asymptomatic course while others develop aggressive, rapidly progressing disease. Genetic markers such as IGHV mutation status, del(13q), del(11q), del(17p), and trisomy 12 contribute to prognostic stratification. CLL is associated with immune dysfunction, including hypogammaglobulinemia and autoimmune complications, which stem from the clonal B-cell origin. Although the exact etiology remains unclear, risk factors include age, family history, and genetic predisposition, with the disease being rare in children and predominantly affecting older adults. Diagnosis relies on flow cytometry, peripheral blood smear, and clinical evaluation, with treatment strategies tailored to disease stage, symptoms, and molecular features—ranging from observation to chemotherapy, targeted therapies (e.g., BTK inhibitors, BCL-2 inhibitors), and immunotherapy. Despite advances, CLL remains incurable, but effective management can induce remission and prolong survival.