Samantha Kurniawan^1,2, Sue Hull¹, Melanie Janus³, Laura Gerhardy⁴, Nina Dhondy^1,5-6, Lisa Clarke^1,7

¹ Australian Red Cross Lifeblood, Sydney, Australia

² Department of Haematology, Liverpool Hospital, Sydney, Australia

³ Department of Obstetrics and Gynaecology, Orange Hospital, Orange, Australia

⁴ Department of Obstetrics and Gynaecology, Nepean Hospital, Sydney, Australia

⁵ NSW Health Pathology

⁶ Department of Haematology, St George Hospital, Sydney, Australia

⁷ Department of Haematology, Sydney Adventist Hospital, Sydney, Australia

A 30-year-old G4P2 woman previously typed as group B RhD positive had a newly identified anti-D on antenatal testing with a positive auto control and direct antiglobulin test. Previously, she had two normal vaginal births and one miscarriage with no prior transfusions or autoimmune disease. The antibody exhibited high titre, low avidity behaviour with D specificity on indirect antiglobulin test and did not enhance with papain. Reactions persisted with dithiothreitol (DTT), excluding Lw. Antepartum ultrasound monitoring showed no signs of fetal anaemia. Titres remained elevated at 1:512 throughout pregnancy with progressive anti-D quantitation 11.3 IU/mL to 14.4 IU/mL. The neonate was born at 38+3 with no jaundice, normal haemoglobin and was group B RhD positive. Cord DAT was positive with anti-D on elution. Genotyping by BeadChip and NGS excluded RhD variants.

 

Anti-D is typically alloimmune with potential for severe haemolytic disease of the fetus and newborn. However, autoimmune anti-D in pregnancy is rare with limited literature to guide its transfusion and obstetric management¹. For transfusion laboratories, learning points include using DTT to exclude anti-Lw mimicking anti-D², genotyping to exclude RhD variants³, and careful selection of Rh phenotype matched blood if required to avoid alloimmunization for future pregnancies.  

 

References:

1.               Kusnierz-Alejska G, Bugajna I, Seyfried H. Auto-anti-D blocking D determinants on red cells in pregnancy. Mater Med Pol 1990;22(1):17-20. (https://www.ncbi.nlm.nih.gov/pubmed/1706816).

2.               Lee MY, Lee WI, Kang SY, Kim MH. Anti-LW Confused with Anti-D: a Case Transfused RhD-positive RBCs and Literature Review. Clin Lab 2022;68(2). DOI: 10.7754/Clin.Lab.2021.210603.

3.               Keith JT, Hastings, H. Allo-Anti-D vs. Auto-Anti-D in Females of Child Bearing Years: The Critical Role of Rh Genotyping. American Journal of Clinical Pathology 2021;156:1:S164. (https://doi.org/10.1093/ajcp/aqab191.350).

Author Contribution Statement
The authors confirm contribution to the paper as follows: study conception and design: S.K., L.G., N.D., L.C. Data collection: S.H., Data analysis and interpretation of results: S.H., S.K., L.C. Draft manuscript
preparation: S.K. All authors reviewed the results and approved
the final version of the manuscript.