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A persistent severe autoimmune hemolytic anemia despite apparent direct antiglobulin test negativization
1Pediatric Hematology Department, Università di Milano, Ospedale S. Gerardo, Monza, Italy.
Background And Objective:
Not all cases of autoimmune hemolytic anemia (AIHA) are diagnosed by the direct antiglobulin test (DAT). We present and discuss 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 hypothesized.
Results:
The DAT resulted strongly positive with anti-IgG serum using a 4C 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 dissociated by the DAT. Since autoantibody-mediated hemolysis with negative DAT rarely occurs, once other causes of high reticulocyte count anemia have been ruled 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.