title: Extracellular idiotypic immunoglobulin arising from human leukemic B lymphocytes.
abstract: The peripheral blood lymphocytes of nine out of nine patients with typical surface Ig-positive chronic lymphocytic leukemia but no paraprotein visible on serum electrophoresis have been shown by radioimmunoassay to export small amounts of pentameric IgM during culture (in the range of 2.4-7.2 ng/10(7) cells per h); three out of nine also exported monomeric IgD (0.7-1.4 ng/10(7) cells per h). Immunoglobulin turned over on the cell surface did not appear to contribute to material in the culture fluid, except possibly as vesicle-bound Ig. In three cases, which included two of the IgD producers, anti-idiotypic antibody raised against the cell surface Fab mu was used to demonstrate the idiotypic nature of the exported Ig. Anti-idiotypic antibody was also used to measure levels of idiotypic Ig in the sera of these three patients as a proportion of the total Ig. Total serum IgM was depressed in all three patients, and the idiotypic IgM represented 43%, 65%, and 96% of the IgM. The findings suggest that in typical chronic lymphocytic leukemia involving B lymphocytes, the export of a small amount of idiotypic Ig by the neoplastic cells in a common or even usual occurrence.
mesh_terms: D000888:Antibodies, Anti-Idiotypic; D001402:B-Lymphocytes / Q000276:immunology*; D006801:Humans; D007072:Immunoglobulin D / Q000378:metabolism*; D007130:Immunoglobulin Idiotypes / Q000032:analysis*; D007075:Immunoglobulin M / Q000378:metabolism*; D007945:Leukemia, Lymphoid / Q000276:immunology*; D010956:Plasmapheresis; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007072:Immunoglobulin D; D007130:Immunoglobulin Idiotypes; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell