Prevalence of donor white blood cell survival (Transfusion-Associated Microchimerism) in a cohort of older Australians

Objective: Donor leucocyte survival, known as transfusion-associated microchimerism (TAM), following red blood cell (RBC) transfusion has been detected in adult trauma patients. Analysis of TAM prevalence in other cohorts has not been extensively analysed. The study aims to assess TAM prevalence in participants of a large ongoing Australian health and ageing study. 

Material and methods: Participants from The Sax Institute's 45 and Up Study who had been identified as being transfused with at least one RBC unit using data linkage (n = 350) were approached between 8 February-8 December 2022 to provide blood samples for TAM analysis. Analysis of TAM was conducted using real-time PCR analysis with a panel of 12 biallelic insertion/deletion sequences. 

Results: Of the approached participants, 72 (55 males and 17 females) provided blood samples for analysis. The reason for RBC transfusion included trauma (n = 7), cancer treatment (n = 13), anaemia (n = 23) or surgery/other (n = 29). PCR results from 2 male and 9 female participants indicated potential TAM. Participants with potential TAM self-reported poor health (40.0 %) compared with those who did not have microchimerism detected (11.9 %). However, there were no significant differences in general practitioner visits, prescriptions filled or hospital admissions. 

Conclusion: The prevalence of TAM in male participants in this small longitudinal cohort was lower compared to previous trauma studies. In female participants, 52.9 % indicated potential TAM, however naturally occurring sources of microchimerism remain possible. No direct long-term consequences related to potential TAM could be identified except poor self-reported health.