BENIGN MONOCLONAL B-CELL LYMPHOCYTOSIS - A BENIGN VARIANT OF CLL - CLINICAL, IMMUNOLOGICAL, PHENOTYPIC, AND CYTOGENETIC STUDIES IN 20 PATIENTS

  • 1 January 1984
    • journal article
    • research article
    • Vol. 64  (1) , 244-252
Abstract
Cases (20) of stage O chronic lymphocytic leukemia (CLL) without disease progression for 6.5-24 yr are presented. The cohort included 7 males and 13 females, aged 48-77 yr at diagnosis. None presented with anemia, thrombocytopenia or neutropenia nor developed cytopenias during follow-up. Mean total lymphocyte count in these patients was 20,100/.mu.L (range 10,000-43,700) at diagnosis, and was 20,600 (range 1000 to 47,200) at last follow-up. Of 12 patients studied, 8 and 4 were phenotyped as H chain .mu..delta.- and .mu.-type, respectively, with 7 .kappa.- and 4 .lambda.-type (no L chain was detectable in 1 patient). Of 13 patients studied, 1 had a slightly elevated IgG level and 2 had slightly depressed serum IgA and IgM levels. All patients had positive delayed hypersensitivity responses. Each of 7 patients studied for an in vitro leukocyte thymidine uptake had a low level of [3H]thymidine incorporation. Nine of 12 patients studied had elevated total T cells, and the remainder had normal counts. In vitro unseparated lymphocyte response to phytohemagglutinin showed normal kinetics of DNA synthesis in 4 patients studied and depressed and/or delayed kinetics in 8. Cytogenetic analyses of polyclonal B cell mitogen-stimulated lymphocytes in all 6 patients studied showed normal karyotypes. These data are consistent with a previously undescribed syndrome involving a monoclonal B cell lymphocytosis, a prolonged asymptomatic or benign clinical course, and essentially normal humoral and cellular immunity and normal karyotype. These 20 patients with stage O CLL have a benign clinical course and they may also be designated as benign monoclonal B cell lymphocytosis (BMBL), a benign variant of CLL.