Abstract
Various techniques have been described for quantitating IgG or complement (C3) and red cell (RBCs). The techniques either are cumbersome, as the complement consumption test, or use radioactivity. This paper describes an antiglobulin consumption assay using an enzyme-linked immunosorbent method that can be used to quantitate IgG, IgM, and C3. With this technique RBCs from normal, healthy donors gave a mean value of 106 .+-. 60 molecules of IgG per RBC, 4.5 .+-. 3 molecules of IgM per RBC, and 37 .+-. 28 molecules of C3 per RBC, respectively. The RBCs of hospital patients particularly of those with infections or inflammatory conditions, conain increased amounts of nonspecifically bound immunoproteins. The availiability of a common method to quantitate RBC-associated IgG, IgM, and C3 allows easy monitoring or study of the immune mechanism of autoimmune hemolytic anemia.