IgA Pyroglobulin, Hyperviscosity Syndrome and Coagulation Abnormality in a Patient With Multiple Myeloma

A 48-yr-old woman with a bleeding diathesis and complaining of blurred vision, headache, paresthesias, and vomoting was diagnosed as having IgA, kappa type multiple myeloma. Markedly increaesed serum viscosity was noted. After plasmapheresis the signs and symptoms of high serum viscosity disappeared. Pyroglobulin was found in the M protein. The M protein had a prominent 15.5S peak and smaller 17.0 and 20S peaks, which decreased to a 6.7S peak after in vitro reduction with 0.1 M 2-mearcptoethanol, 2-mercaptoethylamine hydrochloride, or glutathione. The serum viscosity was decreased by treatment with these reducing agents. Pyroglobulin formation was presumably a noncovalent intermolecular reaction, as it was inhibited by 5.0 M guanidine hydrochloride, acidification and alkalinization, but not by reduction with sulfhydryl reagents. The M protein also had an antithrombin activity causing interference with the conversion of fibrinogen to fibrin and the phenomenon of gelification noted on blood clotting.