Identification of genetic polymorphisms that predict responder/non-responder profiles to the RhD antigen

• Published in: Molecular immunology Vol. 68; no. 2; pp. 628 - 633
• Main Authors: Tan, Joanne C.G., Armstrong, Nicola J., Yuan, Fang Fang, Flower, Robert L., Dyer, Wayne B.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-12-2015
• Subjects: Blood Donors; Female; Genotype; High-Resolution Melt (HRM); Humans; Immunization; Immunoglobulin (Ig); Logistic Models; Male; Polymorphism, Single Nucleotide; Red blood cell (RBC); Rh-Hr Blood-Group System - immunology; Rho(D) Immune Globulin - genetics; Rho(D) Immune Globulin - immunology; Single nucleotide polymorphism (SNP); Immunoglobulin (Ig); High-Resolution Melt (HRM); Red blood cell (RBC); Single nucleotide polymorphism (SNP)
• ISSN: 0161-5890; 1872-9142
• DOI: 10.1016/j.molimm.2015.10.005

•Anti-D donors exhibit a wide range of responder profiles to the RhD antigen.•Immunological and inflammatory SNPs are associated with responder profiles.•A predictive model was validated to predict high responders with 60% accuracy.•Identified polymorphisms could help to elucidate immunomodulatory pathways in alloimmunisation.
Regular plasma donors who produce high titre anti-D immunoglobulin (Ig) are overseen by the Australian Red Cross Blood Service RhD Program. New donors to the program are immunised with small amounts of RhD-positive RBCs, whilst donors who have developed anti-D due to previous RhD-incompatible blood transfusion or pregnancy are boosted with RhD-positive RBCs to maintain a high level of serum anti-D Ig. A significant proportion of primarily immunised individuals do not respond to RhD immunisation and are therefore unnecessarily exposed to the risks involved in RBC sensitisation.
We genotyped 184 anti-D donors for ∼9000 immunological and inflammatory genetic polymorphisms on an Affymetrix GeneChip, and validated the results with a High-Resolution Melt analysis assay. We built and validated a predictive logistic regression model using High Responder and Non-Responder anti-D donors that incorporated highly-associated polymorphisms and gender.
High Responder and Non-Responder profiles in anti-D donors were significantly associated with a shortlist of 13 genetic polymorphisms and sex of the donor. The derivation of a logistic regression model showed an accuracy rate of 92.6% that was subsequently validated as 60.0% with an independent set of donor samples.
This study has developed a logistic regression model and a genotyping assay that can predict the responder profiles of anti-D donors and could potentially be applied to new donors and transfusion-dependent patients in a clinical setting. Additionally, target polymorphisms identified in immunological genes could help to elucidate the immunomodulatory pathways regulating the immune response to the RhD antigen, and to other RBC antigens.