Coombs-negative Autoimmune Hemolytic Anemia and Immunoglobulin Deficiency

The cases of two young patients with acute idiopathic autoimmune hemolytic anemia (AIHA) with persistently negative antiglobulin tests (Coombs) associated with IgA deficiency are presented. The autoantibody eluted from the erythrocytes was IgG class, confirmed by indirect antiglobulin tests, and showed no specificity. It appears that the antibodies present on the erythrocyte surface were below the minimal quantity necessary to give a positive Coombs test. The skin window technic has been used to demonstrate IgG antibody-coated erythrocyte adherence and erythrophagocytosis by the macrophages of the reticuloendothelial system. This mechanism seems to be a contributory factor for destruction of the erythrocytes and anemia, in addition to immune hemolysis. Both patients have responded to corticosteroid therapy and recovered completely except for persistence of the IgA deficiency. The significance of the association of immunoglobulin deficiency with AI HA in the absence of organic disease is discussed.