title: The B cell IgM Fc receptor: further evidence for the B cell origin of "null" chronic lymphocytic leukemia.
abstract: Fifty-three cases of chronic lymphocytic leukemia (CLL) were studied for the presence of the B cell IgM Fc receptor (Fc microR) using an aggregated IgM reagent. Restricted surface immunoglobulin, using conventional immunofluorescent techniques and FACS analysis, was detected in 43 cases (81%). The cells in the remaining ten cases (19%) expressed negligible surface immunoglobulin (slg-) and did not form E rosettes (E-), but this "null" subset clearly expressed the B cell Fc microR. The coincident membrane expression of the B1 antigen and the la-like antigen, as well as serial studies showing surface membrane light chain acquisition (in one patient), provided additional evidence for the B cell origin of this slg-E- subset. This subgroup of CLL appears to correspond phenotypically to a normal counterpart at a stage of B cell differentiation between the pre-B cell and the slgM+ early B cell. The B cell Fc microR appears to be a consistent and potentially useful marker for sl gE ("null") CLL.
mesh_terms: D000954:Antigens, Surface / Q000032:analysis / Q000235:genetics; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007945:Leukemia, Lymphoid / Q000235:genetics / Q000276:immunology*; D008215:Lymphocytes, Null; D010641:Phenotype; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D011961:Receptors, Fc / Q000032:analysis* / Q000235:genetics; D011971:Receptors, Immunologic / Q000032:analysis* / Q000235:genetics; D012397:Rosette Formation
chemical_list: D000954:Antigens, Surface; D011947:Receptors, Antigen, B-Cell; D011961:Receptors, Fc; D011971:Receptors, Immunologic; C035311:immunoglobulin M receptor