Evolution of Leukemic Heterogeneity of Human B-CLL Lymphocytes Between and Within Patients

B-chronic lymphocytic leukemia (B-CLL) is a disease manifested by the proliferation and accumulation of a clone(s) of medium-sized lymphocytes with mature-appearing chromatin and a characteristic surface immunophenotype. Monoclonality is usually evidenced by the presence of a single heavy and light chain immunoglobulin and or a rearranged Ig gene(s). The surface fluorescence intensity (FI) of membrane Ig is markedly diminished and ineffective rearrangements are common. Typically patients fifty years of age or older present with a stable, asymtomatic blood and marrow monoclonal B lymphocytosis. Blood lymphocytes may show considerable cytological or morphological variation between patients and within patients.