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Introduction: Donor leucocyte survival following red blood cell (RBC) transfusion, known as transfusion‐associated microchimerism (TAM), can occur in some patients. In Australia, despite the introduction of leucocyte filtration (leucodepletion) during RBC manufacture, TAM has been detected in adult trauma patients. However, the incidence of TAM in Australian pediatric patients has not been analyzed. Methods: Patients aged 0–16 years were recruited across two cohorts. Retrospective participants had RBC transfusion between January 1, 2002 and November 15, 2017 and prospective participants received RBC transfusion between December 1, 2016 and November 25, 2020. Twelve bi‐allelic insertion/deletion (InDel) polymorphisms were used to detect microchimerism amplification patterns using real‐time PCR (RT‐PCR) and droplet digital PCR (ddPCR). Results: Of the retrospective cohort (n = 40), six patients showed amplification of InDel sequences indicating potential microchimerism. For three patients, minor InDel sequences were detected using RT‐PCR only, two patients had minor InDel amplification using ddPCR only, and one patient had minor InDel amplification that was confirmed using both techniques. Amplification of minor sequences occurred in three patients who had received a bone marrow transplant in addition to RBC transfusion. In the prospective cohort (n = 25), no InDel amplification indicating potential microchimerism was detected using RT‐PCR. Discussion: Cell‐based therapies had been administered in three patients where microchimerism amplification patterns were detected. Three patients have microchimerism that may be attributed to RBC transfusion. In prospective patients, who received leucodepleted and gamma‐irradiated RBC units, no potential microchimerism amplification were detected. ddPCR may be a suitable technique for TAM analysis but requires further evaluation. [ABSTRACT FROM AUTHOR]

Background and Objectives: Until 25 July 2022, Australians who had spent more than 6 months in the United Kingdom or territories between 1980 and 1996 were deferred from blood donation due to the risk of variant Creutzfeldt–Jakob disease. Removal of this geography‐based donor deferral on RhD‐negative blood availability has not been reported. Materials and Methods: All donors who donated at least once from 25 July 2022 to 25 July 2023 were included. UK donor status, first‐time donor and ABO RhD data were extracted from the National Blood Management System. Results: Data from 566,447 blood donors with a valid ABO RhD result were analysed. Of these, 34,560 were new or returning lapsed donors following removal of the UK donor deferral. The median age [range] in years for all donors was 43 [75] with UK donors being older 53 [70]. There was a higher prevalence of RhD‐negative status in UK donors (20.2%) compared with first‐time blood donors (15.7%). Conclusion: UK donors were generally older, female and more likely to be RhD‐negative. Although UK donors provided a boost to RhD‐negative blood collections, the overall prevalence of ABO RhD blood groups in the total Australian blood donor panel remained similar to previous estimates. [ABSTRACT FROM AUTHOR]

Background: Several studies have described associations between ABO blood group and SARS‐CoV‐2 infection severity in hospitalized patients where group A individuals are over‐represented and group O individuals may have a lower infection rate. In convalescent individuals, group B blood donors have higher neutralizing SARS‐CoV‐2 antibody titers. We analyzed whether there was any correlation of ABO Rh(D) blood group with SARS‐CoV‐2 infection and with neutralizing antibodies in Australian convalescent plasma (CP) donors. Study Design and Methods: ABO Rh(D) distribution and demographics of CP donors (n = 765) were compared with the total blood donor panel (n = 488,028), plasmapheresis donors (n = 203,176) and whole blood donors (n = 282,437) from 2020. The presence of neutralizing antibodies in CP donors was measured using the Vero E6 cell microneutralization assay. Results: The distribution of ABO group in CP donors compared to the total donor panel was not significantly different (p =.177). There were significantly more group AB donors in the plasmapheresis subset (p =.005) and group O individuals were over‐represented in the whole blood donor subset (p <.0001). There was no significant difference in neutralizing antibody levels among CP donors with differing ABO blood groups (p =.872). Conclusion: ABO Rh(D) blood group distribution was not found to be significantly different between convalescent plasma donors and general blood donors in our large sample group. Inherent blood donor selection biases associated with clinical demand accounted for some differences within CP donors. The levels of SARS‐CoV‐2 neutralizing antibodies were also not significantly associated with ABO Rh(D) group. [ABSTRACT FROM AUTHOR]

Background: O Rh(D)− red blood cell (RBC) units can generally be transfused to most patients regardless of their ABO blood type and are frequently used during emergency situations. Detailed usage patterns of O Rh(D)− RBC units in obstetric populations have not been well characterised. With the introduction of patient blood management guidelines, historical usage patterns are important for providing comparative data. Aims: To determine how the use of O Rh(D)− RBC units in pregnant women differs between hospitals of different sizes and obstetric capabilities prior to patient blood management guidelines. Methods: Data from 67 New South Wales public hospital blood banks were linked with hospital and perinatal databases to identify RBC transfusions during pregnancy, birth and postnatally between July 2006 and December 2010. RBC transfusions were divided into O Rh(D)− or other blood types. Hospitals were classified according to birth volume, obstetric capability and location, with transfusions classified by timing and diagnosis. Results: Of the 12 078 RBC units transfused into pregnant women, 1062 (8.8%) were O Rh(D)−. Higher use of O Rh(D)− RBC units was seen in antenatal transfusions, preterm deliveries and in regional or smaller hospitals. There was wide variation in rates of O Rh(D)− RBC transfusion among hospitals. Conclusions: The rate of O Rh(D)− RBC unit use in obstetrics was lower during the period assessed than the nationally reported usage. It is encouraging that O Rh(D)− RBCs were more commonly used in emergency or specialised situations, or in facilities where holding a large blood inventory is not feasible. [ABSTRACT FROM AUTHOR]