Unexpected occurrence of alloantibodies and delayed hemolytic reaction early after bone marrow transplantation
Abstract
In a 14 year old male patient with the diagnosis of acute lymphoblastic leukemia the allogeneic bone marrow transplantation (HLA-matching sibling) was performed in the second remission. In the pre-transplant period of one year the patient received multiple transfusions of red cell and platelet concentrates.
The pretransfusion tests were negative. At the day +7 and +9 two units of red cell concentrate were transfused.
Results of alloantibody screening and compatibility testing were both negative. At the day +24 the antibody screening revealed presence of alloantibodies.
Anti-E and anti-Lea were identified. The anti-E was reactive only in enzyme tests (titre 16 in the gel test with papain treated red cells), antiglobulin tests both in tube and gel tests were negative.
The anti-Lea was a cold antibody. The direct antiglobulin test was positive, showing double population in the gel test.
There was hemolysis when the patients' red cells were resuspended in the bromelin solution (DiaMed), At day +30 there was drop in hemoglobin (from 92 to 67 g/I) and increase of bilirubin (from 16 to 35 umol/I). The first transfused unit was found to be E+, but at the day +30 almost no E+ red cells were detected in the patients blood.
This case shows a suspect clinical significance of this "enzyme-only" antibody.