P33 Transfusion of Incompatible Units to a Patient with Anti‐U: a Case Report

Introduction  U (MNS5) is a high frequency Ag with the U- phenotype blood found mainly in people of Black African origin. Anti-U has been reported to cause immediate and delayed haemolytic transfusion reactions (HTRs) as well as haemolytic disease of the fetus and newborn (HDFN). The selection of U - RBC is recommended for patients with anti-U. We present a case of a patient with anti-U who received serologically incompatible transfusions uneventfully. Case report  A 31-year-old black male was admitted to hospital after injury to his right arm. The antibody (Ab) screen was positive and samples were referred to our laboratory for investigation. He grouped as B, D+, U- and anti-U was identified. Due to the severity of the injury the patient underwent emergency surgery without waiting for the Ab ID results. His Hb was 68 g L−1. 5 units of unmatched group O RBC were transfused. During this episode the patient was not given any IVIg cover and there were no clinical or laboratory indications of a transfusion reaction beyond the positive DAT. The patient received four further U- RBC transfusions and was treated with parenteral iron. Results  Day Group Antibodies DAT Hb (g/L) Tx Plasma Eluate Titre Subclass IgG C3d 1 B Anti-U (3+) NT 8 IgG Neg Neg 68 5 O+ U+ 2 B Anti-U NT NA NT NT NT 91 2 B+ U- 4 B Anti-U (w) Anti-U (2+) 8 IgG 2+ Neg 99   7 B Anti-U (w) Anti-U (w) 2 NT 1+ Neg 80 2 O+ U- 12 B Anti-U (2+) Neg 8 NT W Neg 77   19 B Anti-U (2+) Neg 8 NT Neg Neg 105   25 NT NT NT NA NT NT NT 117   Discussion  Anti-U antibodies are generally classed as clinically significant, with the potential to cause immediate and delayed HTRs. When U negative RBC are not available in an emergency, a decision may be taken to transfuse incompatible blood. Close monitoring for any adverse reactions should be undertaken and IVIg cover is often beneficial. In this case, the transfusion of incompatible RBC was uneventful, even without IVIg cover. There was some evidence of an immune process occurring, as over a period of 8 days the Hb fell by 22 g L−1 (22.2%), although the patient did have further bleeding from a wound. An increase in the Hb after day 12 possibly indicates sequestered RBC returning to the circulation, the DAT remained negative. This case report demonstrates that incompatible blood can be successfully transfused in an emergency to a patient with anti-U. However, severe HTRs due to anti-U have been reported and so every effort should be made to avoid this situation.