Transfusion-related acute lung injury-associated HNA-3a antibodies recognize complex determinants on choline transporter-like protein 2

Transfusion. 2014 Dec;54(12):3208-15. doi: 10.1111/trf.12717. Epub 2014 May 21.

Abstract

Background: HNA-3a-specific antibodies can cause severe, sometimes fatal, transfusion-related acute lung injury when present in transfused blood. The HNA3-a/b antigens are determined by an R154Q polymorphism in the first of five extracellular (EC) loops of the 10-membrane-spanning choline transporter-like protein 2 (CTL2) expressed on neutrophils, lymphocytes, and other tissues. Approximately 50% of HNA-3a antibodies (Type 1) can be detected using CTL2 Loop 1 peptides containing R154; the remaining 50% (Type 2) fail to recognize this target. Understanding the basis for this difference could guide efforts to develop practical assays to screen blood donors for HNA-3 antibodies.

Study design and methods: Reactions of HNA-3a antibodies against recombinant versions of human, mouse, and human/mouse (chimeric) CTL2 were characterized using flow cytometry and various solid-phase assays.

Results: The findings show that, for binding to CTL2, Type 2 HNA-3a antibodies require nonpolymorphic amino acid residues in the third, and possibly the second, EC loops of CTL2 to be in a configuration comparable to that found naturally in the cell membrane. In contrast, Type 1 antibodies require only peptides from the first EC loop that contain R154 for recognition.

Conclusion: Although Type 1 HNA-3a antibodies can readily be detected in solid-phase assays that use a CTL2 peptide containing R154 as a target, development of a practical test to screen blood donors for Type 2 antibodies will pose a serious technical challenge because of the complex nature of the epitope(s) recognized by this antibody subgroup.

Publication types

  • Clinical Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Acute Lung Injury / chemically induced
  • Acute Lung Injury / genetics
  • Acute Lung Injury / immunology*
  • Animals
  • Autoantibodies / immunology*
  • Autoantibodies / toxicity
  • Blood Donors
  • Blood Transfusion*
  • Disease Models, Animal
  • Donor Selection / methods
  • Female
  • HEK293 Cells
  • Humans
  • Isoantigens / genetics
  • Isoantigens / immunology*
  • Male
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / immunology*
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / immunology*
  • Mice
  • Protein Structure, Secondary
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology

Substances

  • Autoantibodies
  • HNA-3a antigen, human
  • Isoantigens
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Recombinant Fusion Proteins
  • SLC44A2 protein, human
  • SLC44A2 protein, mouse