rhd+ blood transfusion to asian-type del recipients

Conditions: Blood Transfusion; Rhesus Isoimmunisation Due to Anti-D; Blood Group Antigen Abnormality

Summary: red blood cells (rbcs) from asian-type del blood group express very weak rhd antigen and are falsely typed as rhd-negative blood group in routine rhd testing. until now, asian-type del (d-eluate) patients still be treated as rare rhd-negative patients in the clinic. previous study from the asian-type del pregnant women with rhd+ fetus showed no occurrence of alloanti-d immunization. this result, however, does not directly be applied for asian-type del patients receiving rhd+ blood transfusions, as lacking of direct evidence regarding the safety and underlying mechanism. in this study, the patients with asian-type del were identified and received rhd+ blood transfusion, then evaluations of any adverse reactions, especially the active follow-up alloantibody test, were prospectively conducted.

red blood cells (rbcs) from asian-type del individuals express very weak rhd antigen and are falsely typed as rhd-negative in routine rhd testing. recent studies have shown that 9-30% of individuals with a serologically apparent rhd-negative phenotype in east and southeast asian populations, including chinese, korean, japanese, thai and myanmar, actually are not truly rhd-negative but exhibit the del (d-eluate) phenotype, which represents almost 1.7 million asian-type del individuals in china, 250,000 in korea, japan, thailand, and myanmar as well as at least 90,000 in the us among asian immigrants. nowadays, asian-type del patients are conventionally transfused with rhd-negative rbc, which are difficult to organize because of the undersupply of the rare rhd-negative blood in these asian countries, due to low frequency distribution (0.3-0.4%). however, our previous study demonstrated that asian-type del pregnant women with rhd+ fetus did not develop alloanti-d during the pregnancy. latter, this phenomenon was confirmed by different medical centers in china. accordingly, asian-type del patients may also not be able to produce alloanti-d after transfusion with rhd+ rbc and consequently the use of rhd-negative rbcs for the transfusion management of asian-type patients may be superfluous. however, this hypothesis needs to be carefully proved. in this study, we were able to verify this assumption. blood samples from 2,011 chinese patients with a primary rhd-negative phenotype from the hospitals in guangzhou of china were typed for asian-type del blood group in the guangzhou blood center. del phenotyping was performed by the serological adsorption/elution antibody testing and genotyping for the asian-type del specific allele (rhd\*1227a) detection was conducted using a well validated high-resolution melting (hrm) approach. then, transfusions of rhd+ rbc were performed in a cohort of asian-type del patients. after rhd+ blood transfusion, evaluations of any adverse reactions, especially the active follow-up alloantibody test, were conducted to evaluate the alloanti-d immunization. besides, effectiveness of transfusion (hb changes) was also recorded.

Eligibility criteria:
inclusion criteria for eligible participants were as follows: (1) asian-type del blood group; (2) male patients, or female patients ≥ 49 years of age, or female with severe illness and no plan for further pregnancy; (3) needing blood transfusion in line with guidelines for internal medicine or surgery; and (4) signed voluntary informed consent for blood transfusion treatment before the trial. the exclusion criteria were: (1) adverse reaction in a previous transfusion; (2) allergies to blood products or immunodeficiency diseases; (3) needing massive blood transfusion for acute blood loss; (4) positive pregnancy test results; (5) conscious dysfunction or severe mental illness; and (6) unsuitability for the study, as estimated by the principal investigators.