Serologic classification of selected cases of myeloma

Serologic and electrophoretic procedures were employed in the study of serum and urinary proteins from twenty-six patients with multiple myeloma. Hematological, radiological and other findings associated with myelomatous disease, or otherwise applicable to interpretative analyses of serological data, were reviewed. The serum and urinary proteins of these patients were found to have distinct electrophoretic properties and serologic characteristics. In this series, the M-components of four patients were classified serologically as Gamma-A paraproteins, two as Gamma-D paraproteins, fifteen as Gamma-G paraproteins and five were nonreactive with the available class specific antisera. Antigenic typing of twenty of these proteins with light chain antisera gave a 1:1 ratio; that is, ten proteins reacted with lambda type light chain antisera and ten proteins reacted with kappa type antisera. Considerable diversification was present in the electrophoretic patterns of the serum and urinary proteins. The concentration of the electrophoretic fractions varied with the degree of proteinemia or proteinuria. Hyperproteinemia was evident in only fifty per cent of the gammopathies included in this study. The evidence of an abnormal component ranged from negligible to the appearance of three distinct peaks in an electrophoretic region where only one peak usually occurs. Quantitative estimation of an M component in the sera ranged from negligible to 8.8 gm/100 ml. Proteinuria was demonstrated in the urine of eighteen of the twenty-three patients tested. The immunoglobulins were quantitated by a radial immunodiffusion technique. A correlation was apparent with the light chain antigenic type and alterations of the Gamma-G immunoglobulin level in the Gamma-A and Gamma-D myelomas. Myeloma proteins consisting of lambda type light chains were associated with reduced Gamma-G serum levels, whereas myeloma proteins consisting of kappa type light chains were associated with quantitatively normal serum Gamma-G levels.