(P-CB-17) The Prevalence of Transfusion-Associated Microchimerism in Participants of The Sax Institute’s 45 and Up Study, a Large Ongoing Study of Health and Ageing from Australia.

Sunday, October 20, 2024

12:00 PM - 1:00 PM

Presenting Author(s)

Rena Hirani, PhD

Australian Red Cross Lifeblood
Sydney, New South Wales, Australia

Background/Case Studies: In Australia, universal leukodepletion of red blood cell (RBC) units has occurred since October 2008. Despite leukodepletion it has been shown that donor leukocyte engraftment (microchimerism) is one long-term transfusion related outcome found to occur in some patient groups. The clinical consequences of microchimerism and the mechanism of cell survival following blood transfusion is not well understood. Furthermore, the incidence of transfusion-associated microchimerism (TAM) may be affected by international differences in blood processing methods or transfusion practices. In Australia, 10-12% of trauma and burns patients are reported to have TAM. However, TAM has not been extensively studied outside of the trauma setting. To explore the incidence of TAM in other settings, this study aimed to obtain blood samples from participants of a large ongoing study of health and ageing.

Study

Design/Methods: From the baseline cohort of The Sax Institute’s 45 and Up Study recruited from 2005-2009 (n = 267,357), selected participants who were known to have been transfused with at least one RBC unit were approached from 8 February 2022 to 8 December 2022 to provide blood samples for TAM analysis (n = 350). Transfusion history was ascertained using procedure codes from the Admitted Patient Data Collection. The NSW Registry of Births Deaths & Marriages death registrations database was used to ensure patients were alive at the time of invitation. All data linkage was conducted using the Centre for Health Record Linkage and data analysis was conducted in the Sax Institute’s Secure Unified Research Environment (SURE). Analysis of TAM was conducted using real-time PCR analysis with a panel of 12 biallelic insertion/deletion sequences.

Results/Findings:

Of the approached 45 and Up Study participants, 72 (20.6%) provided blood samples for analysis. Nineteen (26.4%) participants had blood transfusions prior to October 2008 and 53 (73.6%) participants had blood transfusion after October 2008 or blood transfusion across both periods.

Preliminary analysis indicates 11 (15.5%) participants had PCR results indicating the presence of TAM. Of these, 7 (63.6%) participants had transfusion after 2008 and the remainder had transfusion before 2008 or across both periods. The reason for transfusion for all participants included trauma (n = 11), anaemia (n = 43) or surgery (n = 22).

Conclusions: The incidence of TAM in this longitudinal cohort is similar to previous studies conducted in trauma patients. However, further analysis of cohort demographics is required. This study is limited by the availability of participant data prior to July 2001 and the reason for transfusion is being inferred through recorded diagnosis codes.