Prevalance of Anti-HLA antibodies in parous female blood donors: A pilot study from tertiary care hospital of North India.

Background: Various studies have implicated that plasma causing transfusion-related acute lung injury is from alloimmunized females. The frequency of sensitization to human leukocyte antigen (HLA) was found to correlate with their parity score. No literature on the prevalence of anti-HLA antibodies in Indian blood donors is available to date. Hence, this pilot study was done to know the frequency of HLA alloimmunization in Indian blood donors. Materials and Methods: A total of 192 consenting voluntary blood donors from blood donation camps were enrolled in the study. Test group: Parous female donors (n = 96) and control group: Nulliparous female donors (n = 48) and male donors (n = 48). HLA alloimmunization was tested on the Luminex platform by screening assay to detect IgG antibodies to HLA Class I and II molecules of human origin. A mean fluoresence index of more than 2000 was considered as a positive reaction, considering the high sensitivity of Luminex assay. Results: Sixty-three out of 192 donors (32.8%) tested positive for anti-HLA antibodies, out of which 23 donors were in the control group (23.9%), and 40 donors were in the test group (41.7%); P = 0.002. On gender-based comparison, 9 out of 48 male donors (18.7%), as compared to 54 out of 144 female donors (37.5%), tested positive for HLA antibodies (P = 0.02). Based on an increase in parity score, the frequency of HLA alloimmunization was found to be significantly correlated (P = 0.002). A decrease in the trend of HLA alloimmunization was observed as the duration from the last pregnancy increased. A higher frequency of HLA alloimmunization was observed in female donors with a history of transfusion and bad obstetric history. Conclusion: The present study substantiates that plasma from parous female donors has a higher chance of containing anti-HLA antibodies as compared to nulliparous female and male donors.