A simple method for the rapid and selective absorption of warm-reactive erythrocyte autoantibodies from serum.

A new technique has been developed to absorb selectively autoantibodies from sera. Red cells maximally coated with IgG antibodies are subjected to discontinuous, combined density and pH gradient centrifugation. The method yields a large quantity of antibody-poor, intact red cells that retain antigenicity. Red cells prepared in this manner absorb antibody as efficiently as do uncoated red cells and nonspecific absorption does not occur. Preliminary studies show that the method can be used to identify alloantibodies present in the sera of patients with 'warm' antibody-induced hemolytic anemia because the sera can be absorbed free of autoantibodies.