A persistent severe autoimmune hemolytic anemia despite apparent direct antiglobulin test negativization

Background and Objectives. Not all cases of autoimmune hemolytic anemia (AI HA) are diagnosed by the direct antiglobulin test (DAT). We present and dis cuss a simple method of enhancing the sensitivity of the standard DAT. Design and Methods. We report the case of a five-month-old child diagnosed with a severe IgG-mediated AIHA, characterized by quick DAT negativization despite clinical worsening. Warm AIHA with negative DAT, possibly due to a low affinity autoantibody, unresponsive to conventional therapy, was hypoth esized. Results. The DAT resulted strongly positive with anti-IgG serum using a 4 d egrees C saline for erythrocyte washing, to reduce the dissociation of the supposed low affinity autoantibody. Very intensive cytoreductive treatment was administered twice until clinical remission was obtained. Interpretation and Conclusions. The clinical course of AIHA can be dissocia ted by the DAT. Since autoantibody-mediated hemolysis with negative DAT rar ely occurs, once other causes of high reticulocyte count anemia have been r uled out, the DAT after ice-cold saline washing could be a useful and easy means of corroborating the diagnosis of AHIA, when traditional methods fail . (C) 1999, Ferrata Storti Foundation.