Recent studies have shown that a series of structural and functional changes would occur during the process of platelet collection, storage and transfusion. The storage of platelets would induce the production of extracellular vesicles. During the process of platelet transfusion, extracellular vesicles play a critical role by carrying diverse substances under various pathophysiological conditions, which causes adverse reactions to blood transfusion. Ceramide and soluble CD40L (sCD40L) carried by platelet-derived extracellular vesicles may lead to transfusion-related acute lung injury (TRALI). Extracellular vesicles containing mtDNA are considered as damage-associated molecular patterns (DAMPs), which can mediate local and systemic inflammation and promote inflammation through interactions with leukocytes and monocytes. Platelet derived extracellular vesicles contain lots of procoagulant substances, which are considered as prethrombotic substances. The RNA of varying species or content carried by vesicles during the process of platelet storage may also related to the occurrence of adverse reactions to blood transfusion.

【Objective】 To analyze the genetic background of RhD-negative blood donors by detecting RHD and RHCE genes of those donors. 【Methods】 From March 2021 to May 2022, the blood samples of RhD-negative blood donors, who had been screened out by RhD primary screening and confirmatory experiments in the Yaan Blood Center, were firstly identified whether the RHD allele was completely deleted, then whether there were deletions in 10 exons of non-RHD allele complete deletion samples, finally, the remaining samples without RHD alleles and exon deletions were further analyzed by DNA sequencing. RHCE gene was detected by SSP-PCR method. 【Results】 Among the RHD gene test results of 104 RhD-negative samples, 65 cases were completely deleted (d/d), 33 were RHD partially deleted (one allele deletion), and 6 were without RHD gene deletion. The RHD alleles of 33 samples with partial deletion were detected by 10 exons, 13 had partial exon deletion, with genotype as RHD^*D-CE(3-9)-D/d and phenotype as RhD negativity, and the remaining 20 samples had no exon deletion. The exon sequencing results of the non-deletion samples showed RHD^*1227A/RHD^*1227A in 6 samples, RHD^*1227A/d in 19, RHD^*3A/d in 1; both of the last two were considered D^el by ISBT. The RHCE gene test results showed that all cc genotype blood donors were RhD true negative, while D^el blood donors had no cc genotype. 【Conclusion】 Through the genetic background study of RhD negative blood donors, it is found that there is a high proportion of D^el with weak expression of RhD antigen, whether this blood type affects clinical blood safety needs further researches.