Q. Positive DAT is not usually a feature of the hyperhemolysis syndrome associated with transfusion of sickle cell disease patients. A positive DAT is a feature of SS disease-course states not only do SS patients have elevated number of allo-antibodies especially Fya / Fyb but half have allo-antibodies especially to Kell, -E,-C and KIDD antigen stimulation. Do they not also have auto-antibodies as their own RBC’s are more easily or rapidly destroyed in the spleen post-transfusion?

A. Hyperhemolysis is uncommon but dangerous. It does not appear to be immune mediated so a positive antiglobulin test would not be found unless the patient was also one of the minority (about 10%) who have a positive DAT test. However, even if that were the case, it would not likely be relevant to the hyperhemolytic process. The mechanism of hemolysis in S/S disease is mechanically, not immunilogically, mediated.

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