Specific Analysis of Immunoglobulins. Techniques and Clinical Value

Abstract

Abstract We recommend that routine screening of sera for immunoglobulin disorders consist of a combination of electrophoresis in agarose and immunochemical quantitation of serum IgG, IgA, and IgM. Abnormalities detected by this procedure may be classified as (a) immune deficiencies, (b) polyclonal hyperimmunoglobulinemias, or (c) monoclonal immunoglobulin disorders. The analyst can contribute to the diagnosis of immune deficiency by detecting evidence for plasma protein losses in the urine, unsuspected monoclonal immunoglobulin disorders, and abnormalities in the immunoglobulin content and spectrum of secretions. Polyclonal hyperimmunoglobulinemia —seen in infections, autoimmune disease, liver disease, sarcoidosis, or other conditions—is frequently associated with an imbalance between the different immunoglobulin classes, and with the appearance of discrete inhomogeneities in the immunoglobulin zones of the electrophoretic spectrum. Factors involved in this process are listed, and examples are indicated. Monoclonal immunoglobulin disorders may not be detected if the tumor protein is masked by normal serum-protein fractions or misdiagnosed by confusion with nonimmunoglobulin components. Diagnosis of immunocyte malignancy is aided by detection of Bence Jones protein in the urine; measurements of serum IgG, IgA, and IgM concentrations; and monitoring the concentration of the abnormal component in the serum as the disease evolves.