Red-Cell Antibodies in Acquired Hemolytic Anemia with Negative Antiglobulin Serum Tests

Abstract

Of eight patients with acquired immunohemolytic anemia, six had persistently negative and two reversibly negative direct antiglobulin tests (Coombs tests). In five of the six, the red cells were shown by a complement-fixing antibody consumption technic to have abnormal amounts of γG globulin on their surfaces, ranging from 70 to 434 molecules per red cell. The two whose red cells gave reversible direct antiglobulin tests were found to have 160 and 700 molecules of γG per red cell respectively. Concentrated eluates prepared from red cells of six of the eight patients sensitized normal red cells; three of the eluates failed to react only with Rh-null red cells. These findings indicate that immunohemolytic anemia can occur with concentrations of red-cell autoantibodies below that necessary to produce red-cell agglutination by antihuman globulin serum.