β-thalassemia minor is a beneficial determinant of red blood cell storage lesion.

Blood donor genetics and lifestyle affect the quality of red blood cell (RBC) storage. Heterozygotes for beta-thalassaemia (βThal+) constitute a non-negligible proportion of blood donors in the Mediterranean and other geographical areas. The unique haematological profile of βThal+ could affect capacity of enduring storage stress, however, the storability of βThal+ RBCs is largely unknown. In this study, RBCs from 18 βThal+ donors were stored in the cold and profiled for primary (haemolysis) and secondary (phosphatidylserine exposure, potassium leakage, oxidative stress) quality measures, and metabolomics, versus sex- and age-matched controls. The βThal+ units exhibited better levels of storage haemolysis and susceptibility to lysis following osmotic, oxidative and mechanical insults. Moreover, βThal+ RBCs had a lower percentage of surface removal signaling, reactive oxygen species and oxidative defects to membrane components at late stages of storage. Lower potassium accumulation and higher urate-dependent antioxidant capacity were noted in the βThal+ supernatant. Full metabolomics analyses revealed alterations in purine and arginine pathways at baseline, along with activation of pentose phosphate pathway and glycolysis upstream to pyruvate kinase in βThal+ RBCs. Upon storage, substantial changes were observed in arginine, purine and vitamin B6 metabolism, as well as in the hexosamine pathway. A high degree of glutamate generation in βThal+ RBCs was accompanied by low levels of purine oxidation products (IMP, hypoxanthine, allantoin). The βThal mutations impact the metabolism and the susceptibility to haemolysis of stored RBCs, suggesting good post-transfusion recovery. However, haemoglobin increment and other clinical outcomes of βThal+ RBC transfusion deserve elucidation by future studies.