Multicenter Study on Differential Human Neutrophil Antigen 2 Expression and Underlying Molecular Mechanisms

Brigitte K Flesch; Angelika Reil; Núria Nogués; Carme Canals; Peter Bugert; Torsten J Schulze; Elly Huiskes; Leendert Porcelijn; Petter Höglund; Paul Ratcliffe; Marlies Schönbacher; Hans Kerchrom; Josina Kellershohn; Behnaz Bayat

doi:10.1159/000505523

Multicenter Study on Differential Human Neutrophil Antigen 2 Expression and Underlying Molecular Mechanisms

Transfus Med Hemother. 2020 Oct;47(5):385-395. doi: 10.1159/000505523. Epub 2020 Jan 22.

Authors

Brigitte K Flesch^{1

2}, Angelika Reil², Núria Nogués³, Carme Canals³, Peter Bugert⁴, Torsten J Schulze^{4

5}, Elly Huiskes⁶, Leendert Porcelijn⁶, Petter Höglund⁷, Paul Ratcliffe⁷, Marlies Schönbacher⁸, Hans Kerchrom⁹, Josina Kellershohn¹⁰, Behnaz Bayat¹⁰

Affiliations

¹ German Red Cross Blood Service Rhineland-Palatinate and Saarland, Bad Kreuznach, Germany.
² German Red Cross Blood Service West, Hagen, Germany.
³ Immunohematology Laboratory, Blood and Tissue Bank, Barcelona, Spain.
⁴ Institute of Transfusion Medicine and Immunology, Medical Faculty Mannheim, Heidelberg University, German Red Cross Blood Service of Baden-Württemberg, Hessen gGmbH, Mannheim, Germany.
⁵ Institute Springe, German Red Cross Blood Service NSTOB, Springe, Germany.
⁶ Department of Immunohematology Diagnostics, Sanquin, Amsterdam, The Netherlands.
⁷ Center for Hematology and Regenerative Medicine, Karolinska University Hospital, Stockholm, Sweden.
⁸ Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria.
⁹ Centre Hospitalier Universitaire de Nantes, Nantes, France.
¹⁰ Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany.

Abstract

Background: The human neutrophil antigen 2 (HNA-2), which is expressed on CD177, is undetectable in 3-5% of the normal population. Exposure of these HNA-2_null individuals to HNA-2-positive cells can cause immunization and pro-duction of HNA-2 antibodies, which can induce immune neutropenia and transfusion-related acute lung injury. In HNA-2-positive individuals, neutrophils are divided into a CD177^pos. and a CD177^neg. subpopulation. The molecular background of HNA-2 deficiency and the bimodal expression pattern, however, are not completely decoded.

Study design: An international collaboration was conducted on the genetic analysis of HNA-2-phenotyped blood samples, including HNA-2-deficient individuals, mothers, and the respective children with neonatal immune neutropenia and regular blood donors.

Results: From a total of 54 HNA-2_null individuals, 43 were homozygous for the CD177 *787A>T substitution. Six carried the CD177 *c.1291G>A single nucleotide polymorphism. All HNA-2-positive samples with >40% CD177^pos. neutrophils carried the *787A wild-type allele, whereas a lower rate of CD177^pos. neutrophils was preferentially associated with *c.787AT heterozygosity. Interestingly, only the *c.787A allele sequence was detected in complementary DNA (cDNA) sequence analysis carried out on all *c.787AT heterozygous individuals. However, cDNA analysis after sorting of CD177^pos. and CD177^neg. neutrophil subsets from HNA-2-positive individuals showed identical sequences, which makes regulatory elements within the promoter unlikely to affect CD177 gene transcription in different CD177 neutrophil subsets.

Conclusion: This comprehensive study clearly demonstrates the impact of single nucleotide polymorphisms on the expression of HNA-2 on the neutrophil surface but challenges the hypothesis of regulatory epigenetic effects being implicated in the bimodal CD177 expression pattern.

Keywords: Human neutrophil antigens; Molecular analysis; Monoallelic expression; Neutropenia.