Jackman and colleagues evaluated transfusion-associated microchimerism (TA-MC) in a prospective cohort study of trauma patients. Index samples were collected upon admission, prior to transfusion and at periodical intervals up to one year. TA-MC was detected by real-time quantitative allele-specific PCR assays at the HLA-DR locus and at several polymorphic insertion deletion sites screening for non-recipient alleles.

A total of 378 adult trauma patients (324 transfused and 54 non-transfused) were studied (80% suffered blunt trauma). The median number of red cell units transfused was 6 units. The investigators identified only one case of long-term (>180 days) TA-MC in transfused subjects, and short-term TA-MC in 6.5% of transfused and 5.6% of control patients.

Interestingly, in contrast to previous studies, persistent TA-MC was not observed in this cohort of trauma subjects, and short-term TA-MC was detected at a lower frequency. The reduction in TA-MC occurrence may be attributable to changes in leukoreduction or other blood processing methods, which are highly variable across centres.

– Jill M. Cholette (SABM reviewer)