Evidence for the biclonal nature of a Waldenstrom's macroglobulinemia

The serum of a patient with Waldenstrom's macroglobulinemia was shown to contain two IgM(kappa) paraproteins of different electrophoretic mobilities on cellulose acetate and immunoelectrophoresis and were designated IgM slow (s) and IgM fast (f). Both existed as high molecular weight polymers and contained a J chain. The two pentameric IgM monoclonal proteins were shown to be completely distinct in carbohydrate composition as determined by gas chromatography and periodic acid-Schiff staining, in molecular weight, by physicochemical properties, peptide mapping, amino-acid composition, NH2-terminal sequence, subgroup of light chains, and by lack of shared idiotypic determinants as determined by hemagglutination inhibition studies. Our study presents strong evidence for the 'bioclonal' nature of this gammopathy. We conclude that both paraproteins are distinct and originated from different B cells.