Analysis of haemovigilance reports reveals 12.5% of acute haemolytic transfusion reactions are attributed to antibodies to low-incidence antigens.

BACKGROUND AND

OBJECTIVES

Many transfusion centres no longer perform an antiglobulin crossmatch on patients without clinically significant red cell alloantibodies, but instead use an abbreviated crossmatch. This policy brings many benefits but has an acknowledged risk of haemolytic transfusion reactions (HTRs). Historical estimates of reactions caused by undetected antibodies to low-incidence antigens (LIAs) were in the region of 1 reaction per 500,000 red cell transfusions. This meta-analysis of haemovigilance reports compares historical estimates with recorded events.

MATERIALS AND

METHODS

This study analysed 255 acute HTR (AHTR) and 385 delayed HTR (DHTR) published in haemovigilance reports from four countries between 2006 and 2022.

RESULTS

The rate of HTRs (acute + delayed) per 100,000 red cells issued/transfused varied from 0.75 to 4.46 by country. The majority of antibodies (59.6%) causing AHTRs were uncharacterized. Antibodies to LIAs accounted for 12.5% (n = 32) of AHTRs, and of these, 59.4% (n = 19) were identified as anti-Wra (DI3 in the Diego system). Of note was one fatal reaction likely attributable to anti-Wra. Antibodies to LIAs accounted for only 1.6% of DHTRs, where antibodies from other blood group systems were responsible, notably in the Rh and Kidd systems.

CONCLUSION

The risk of HTRs caused by undetected antibodies to LIAs calculated in this study is in the region of 1 reaction per 1 million red cell transfusions.