Acute hemolysis of transfused A2 red cells by an auto‐HI antibody

Abstract

This case illustrates that anti-HI autoantibodies rarely may behave like alloantibodies and cause AHTRs. Subsequent RBC transfusion with an appropriate ABO group or subgroup through a blood warmer is well tolerated.

Anti‐HI can cause a severe delayed hemolytic transfusion reaction with hyperhemolysis in sickle cell disease patients

“…Seven other cases of posttransfusion hemolysis with anti-HI with a large thermal amplitude have been reported in five publications [16][17][18][19][20] and one abstract 21 (Table 1). Three of these cases involved SCD patients.…”

Multiple hemolytic transfusion reactions misinterpreted as severe vaso‐occlusive crisis in a patient with sickle cell disease

“…Cold autoantibodies with anti‐IH specificity can be found in those with low amounts of H antigen on their RBCs, most commonly blood group type A 1 , and are usually reactive only at immediate spin and generally clinically insignificant . However, there are case reports of clinically significant anti‐IH antibodies causing AHTRs, DHTRs, and even hyperhemolysis in some cases . In this case, the patient's cold autoantibody (CAA) was thought to be clinically insignificant initially, because it was only reactive at immediate spin on the crossmatch and compatible RBCs were found after prewarming the sample.…”

Anti IH: An antibody worth mention

“…Anti-IH found more commonly in A 1 , A 1 B, and B blood group individuals, present as a benign antibody and have occasionally caused acute or delayed hemolytic reactions. [234567] The severity of hemolysis depends on the amount of H antigen substance hence follows the following order of reactivity O > A 2 > B > A 2 B > A 1 > A 1 B. [12]…”

“…Unlike earlier case reports, we detected and characterized anti-IH during grouping itself, hence averting a hemolytic transfusion reaction by transfusing A 1 B PRBCs. [23456] Depending on electronic cross-match rather than conventional cross-match could place the patient at risk of being transfused with other subgroups (e.g. A 2 for A 1 ) unless the antibody picked up during grouping and antibody screening is strictly evaluated.…”

“…[1] Rarely anti-IH presents as a clinically significant antibody resulting in cold agglutinin syndrome and hemolytic transfusion reactions. [234567] This case describes a clinically significant anti-IH antibody with a wide thermal amplitude which was recognized during pretransfusion testing.…”