Immunoglobulin changes in disease: quantitation on the basis of heavy polypeptide chains, IgG (gammaG), IgA (gammaA), and IgM (gammaM), and of light polypeptide chains, type K (I) and type L (II).

Abstract

Quantitative IgG ( [gamma] G-, 7 S [gamma] 2-globulin), IgA ([gamma] A-, [beta]2 A-globulin), and IgM ( [gamma] M-, 18 S [gamma] 1-macroglobulin) measurements were made in serum from 224 patients. The levels of Type K (Type I) and Type L (Type II) immunoglobulins were also determined. Increases of one or more immunoglobulins were noted in many disorders. Chronic infections characteristically showed increased IgG. Trypanosomiasis showed a markable increase of IgM. In Laennec''s cirrhosis IgA increases were especially notable. Quantitative abnormalities of serum IgA (both high and low levels) were confirmed in ataxia telangiectasia. The nephrotic syndrome usually showed low serum IgG and IgA levels with normal or slightly elevated IgM. This difference is presumed to relate to the differential loss of the smaller immunoglobulins via the kidney and urine. In protein-losing enteropathy, however, all serum immunoglobulins (IgG, IgA, and IgM) were low, indicating that all immunoglobulins were lost at the same rate. The lowest serum immunoglobulin concentrations were found in agammaglobulinemia. All immunoglobulins were reduced in many sera of chronic lymphocytic leukemia, but the serum IgM was relatively lower than the IgG. This difference is compatible with differences in the catabolism of the separate classes of immunoglobulin. The anomalous proteins of multiple myeloma and Waldenstrom''s macroglobulinemia were class specific (IgG, A, or M) and type specific, i.e., Type K (I) or Type L (II). The remaining immunoglobulins in the serum of these patients were decreased. Type K (Type I) and Type L (Type II) immunoglobulins were identified in all sera. In multiple myeloma and macroglobulinemia the normal ratio of Type K: Type L immunoglobulins was markedly altered by the myeloma protein or macroglobulin.