PROPERTIES OF IGA MYELOMA PROTEINS ISOLATED FROM SERA OF PATIENTS WITH HYPERVISCOSITY SYNDROME

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 89  (5) , 919-927
Abstract
Sera, purified myeloma proteins and urinary proteins obtained from 8 patients with Ig[immunoglobulin]A multiple myeloma were studied by physical-chemical and immunochemical methods. In 6 patients whose serum viscosity was increased, the sedimentation constants of the principal component of myeloma proteins ranged from 9.1-10.2 S. In 2 patients with nearly normal serum viscosity, the sedimentation constants of these proteins were 6.2 and 7.2 S. IgA-albumin complexes were detected in most sera, but in varying amounts; no complexes of Ig with amylase, secretory component or .alpha.1-antitrypsin were observed. Studies on isolated myeloma proteins revealed that all IgA proteins from sera with increased viscosity represented true polymers, linked by disulfide bonds, rather than noncovalently associated aggregates. J chain was detectable by alkaline-urea disc electrophoresis and immunoelectrophoresis with a monospecific anti-J chain serum. Increased serum viscosity was not related to the IgA subclass, L chain type or the carbohydrate compositions of individual IgA myeloma proteins. The urine of 5 patients contained free L chains corresponding in type to the L chain of the particular IgA myeloma protein. Free J chain was not detected. The immunoelectrophoretic analysis for the presence of J chain in sera of myeloma patients may be used for early and simple detection of polymeric forms of myeloma proteins.