title: High-frequency expression of a conserved kappa light-chain variable-region gene in chronic lymphocytic leukemia.
abstract: Malignant B lymphocytes from several patients with chronic lymphocytic leukemia (CLL) were examined for reactivity with murine monoclonal antibody 17.109. This antibody, prepared against the rheumatoid factor (RF) paraprotein Sie, recognizes a crossreactive idiotype on 48% of human IgM RF paraproteins, but does not react with IgM paraproteins without RF activity or substantially with normal pooled immunoglobulin. The 17.109-reactive idiotype is a marker for a kappa III variable-region gene, designated V kappa RF, that is conserved in outbred human populations. In a limited study of 31 CLL patients, the leukemic cells from 5 of 20 patients with kappa light chain-expressing CLL were recognized by the 17.109 monoclonal antibody. Despite having malignant cells specifically reactive with this antibody, patients with 17.109-positive CLL did not have elevated serum levels of circulating antibody bearing 17.109-reactive determinants. Total RNAs isolated from the CLL B lymphocytes, or from hybridomas produced by fusing the CLL cells with the WI-L2-729-HF2 cell line, were fractionated electrophoretically and examined by blot hybridization. Under stringent hybridization conditions capable of discerning a single base-pair mismatch, RNA from the 17.109-idiotype-positive CLL cells hybridized to synthetic oligonucleotide probes corresponding to framework and complementary-determining regions in the V kappa RF gene. The high frequency of the 17.109-associated idiotype and the V kappa RF gene in CLL suggests that the disease may arise from B lymphocytes that express a restricted set of inherited immunoglobulin variable-region genes with little or no somatic mutation.
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D005796:Genes; D006801:Humans; D007074:Immunoglobulin G / Q000235:genetics; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007075:Immunoglobulin M / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D007945:Leukemia, Lymphoid / Q000235:genetics / Q000276:immunology*; D009693:Nucleic Acid Hybridization
chemical_list: D007074:Immunoglobulin G; D007147:Immunoglobulin Light Chains; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains