ABSTRACT
Chronic Lymphocytic Leukemia Chronic lymphocytic leukemia (CLL) is a clonal lymphoproliferative disorder of mature lymphocytes (Figure 11-19) and is primarily seen in older patients (90% of patients are older than 50). The clinical diagnosis has classically required an absolute lymphocytosis with more than 5,000 mature-appearing lymphocytes per microliter and more than 30% lymphocytes in the bone marrow, but some patients now receive a diagnosis earlier with the detection of a mature B cell clone by flow cytometry testing. The characteristic immunophenotype is CD5+ (rare in other B-cell malignancies), CD20+, and CD23+; CD20+ and CD23+ are B-cell markers. CLL is more common in men than women and is rare in Asia. B-cell CLL, unlike many hematologic malignancies, is not associated with exposure to ionizing radiation, drugs, or chemicals. The 2 widely used staging classifications are outlined in Tables 11-6 and 11-7.
