Alloimmunization of a dog erythrocyte antigen 1− dog transfused with weakly dog erythrocyte antigen 1+ blood

BACKGROUND: Acute hemolytic transfusion reactions because of dog erythrocyte antigen (DEA) 1 sensitization after mismatched transfusions are serious complications. Dog erythrocyte antigen 1 expression varies from negative to weakly to strongly positive. OBJECTIVES: To assess alloimmunization after transfusion of weakly DEA 1+ blood to a DEA 1− dog. ANIMALS: One DEA 1− recipient and 1 weakly DEA 1+ donor, and 106 control dogs. METHODS: Long‐term follow‐up study. Matched for DEA 3, 4, 5, and 7, Dal, and Kai 1 and 2, weakly DEA 1+ donor packed red blood cells (RBCs) were transfused 3 times (0.45 mL/kg at Day 0, 16, and 37) to a DEA 1− recipient. Alloantibodies against RBCs from donor and 106 controls were determined in recipient's plasma samples using a commercial antiglobulin‐enhanced immunochromatographic strip and gel tube crossmatches. Alloantibody titers were determined. RESULTS: The DEA 1− recipient was sensitized after 16 days to ≥1657 days after transfusion to weakly DEA 1+ and otherwise matched RBCs. Strong to moderate crossmatch incompatibilities were observed between recipient's plasma and all 61 DEA 1+ crossmatched controls. Moderate to weak incompatibilities were also observed to DEA 1− controls. Anti‐DEA 1 and other alloantibodies were detected over the 4.5 year observation period. CONCLUSIONS AND CLINICAL IMPORTANCE: Blood from a weakly DEA 1+ donor induces a strong and durable alloimmunization in a DEA 1− recipient dog. Additional alloantibodies developed against yet to be defined RBC antigens. Those results support the recommendation of typing dogs against DEA 1, considering weakly DEA 1+ as immunogenic, and crossmatching all previously transfused dogs.