Fatal haemolytic transfusion reaction due to anti-Ena and identification of a novel GYPA c.295delG variant in a Thai family

  • Vox Sang. 2022 Nov;117(11):1327-1331. doi: 10.1111/vox.13358.
Ploymanee Suwanwootichai  1 ,  Genghis H Lopez  2  3 ,  Morakot Emthip  1 ,  Brett Wilson  4 ,  Glenda M Millard  2  4 ,  Sunisa Onpuns  5 ,  Kanchana Laemsri  5 ,  Sasitorn Bejrachandra  6 ,  Yew-Wah Liew  4
Affiliations
  • 1. Red Cell Reference Laboratory, National Blood Centre, Thai Red Cross Society, Bangkok, Thailand.
  • 2. Research and Development, Clinical Services and Research, Australian Red Cross Lifeblood, Kelvin Grove, Queensland, Australia.
  • 3. School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.
  • 4. Red Cell Reference Laboratory, Clinical Services and Research, Australian Red Cross Lifeblood, Kelvin Grove, Queensland, Australia.
  • 5. Transfusion Medicine Unit, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand.
  • 6. National Blood Centre, Thai Red Cross Society, Bangkok, Thailand.
PMID: 36102166 DOI: 10.1111/vox.13358
Abstract

Background and objectives: High-frequency antigen Ena (MNS 28) is expressed on glycophorin A (GPA). En(a-) individuals can form anti-Ena when exposed to GPA. A Thai patient formed an antibody that reacted against all reagent red blood cells (RBCs). The patient received incompatible blood resulting in a fatal haemolytic transfusion reaction (HTR). This study aimed to characterize the antibody detected in the patient and investigate the cause of HTR.

Materials and methods: Blood samples from the patient and three of his family members were investigated. Massively parallel Sequencing (MPS) and DNA-microarray were used for genotyping. Standard haemagglutination techniques were used for phenotyping and antibody investigations.

Results: DNA Sequencing showed the patient was homozygous for GYPA*M c.295delG (p.Val99Ter) predicting En(a-). Three family members were heterozygous for GYPA c.295delG. MPS and DNA-microarray predicted the patient was N- discordant with the N+ RBC phenotype. The patient's plasma was positive with enzyme/chemical-treated reagent RBCs but failed to react with En(a-) and Mk Mk RBCs.

Conclusion: The GYPA c.295delG variant prevented GPA expression on RBCs resulting in En(a-) phenotype. The N+ phenotype result was probably due to the anti-N typing reagent detecting 'N' (MNS30) on GPB. The patient's alloantibody has anti-Ena specificity.

Keywords
En(a−); Ena (MNS28); MNS blood group system; anti-Ena antibody; haemolytic transfusion reaction.
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