Donor sex, pre-donation hemoglobin, and manufacturing affect CD71⁺ cells in red cell concentrates

Circulating CD71⁺ red blood cells (RBCs) have been reported to play an immunomodulatory role in vivo, which may contribute to adverse donor-recipient sex-mismatched transfusion outcomes. However, it is not clear how CD71⁺ RBC quantity in red cell concentrates (RCCs) is affected by manufacturing methods and donor factors such as donor sex, donor age, pre-donation hemoglobin (Hb), venous Hb (Hb_v ) levels, and donation frequency.

We determined CD71⁺ RBCs and Hb levels in whole blood (WB) from healthy donors (42 male/38 female). Using small-scale red cell filtration (RCF) and whole blood filtration (WBF) methods, leukoreduced RCCs were processed from WB samples (n = 6) and the CD71⁺ RBCs were determined at days 1, 7, and 28. We examined uni- and multivariate associations among CD71⁺ RBCs, donor factors, and manufacturing method.

Male donors had a higher CD71⁺ RBC concentration than females (p < .001), especially male donors aged 17-50 years with 1 or 2 WB donations over the previous 12 months. Donors with a Hb_v above 155 g/L had a higher CD71⁺ RBC concentration than an Hb_v level below 140 g/L (p < .05). There was a positive correlation between pre-donation Hb and CD71⁺ RBC concentration (Pearson r = 0.41). WBF RCCs had a higher total number of CD71⁺ RBCs than RCF-produced RCCs on day 1 (p < .05).

RCCs have variable numbers of CD71⁺ RBCs. This makes understanding the impact of donor factors and manufacturing methods on the immunomodulatory effect of CD71⁺ RBCs critical in exploring donor-recipient sex-mismatched transfusions.