Geno- and phenotyping and immunogenicity of HNA-3.
BACKGROUND
Alloantibodies directed against the human neutrophil alloantigen (HNA)-3a are frequently implicated in severe and fatal transfusion-related acute lung injury (TRALI). The HNA-3a/3b system results from a single-nucleotide exchange (461G>A; Arg154Gln) in the choline transporter-like protein 2 gene. Genotyping may allow identification of blood donors at risk to develop HNA-3a antibodies.


METHODS
A polymerase chain reaction using sequence-specific primers (PCR-SSP) for genotyping of HNA-3a and -3b alleles was designed. Results of genotyping and phenotyping were compared in 40 randomly selected individuals and in blood donors and recipients of six TRALI cases associated with HNA-3a antibodies. Phenotyping was performed by granulocyte immunofluorescence and granulocyte agglutination using typing sera for HNA-3a and two recently found HNA-3b-reactive sera. Immunogenicity of HNA-3a was determined by the rate of HNA-3a alloantibodies in HNA-3b homozygous parous women.


RESULTS
Genotyping and phenotyping results correlated to 100% and were in accordance with alloantibody formation and binding in HNA-3a antibody associated TRALI cases. Gene frequencies of HNA-3a and -3b were 0.792 and 0.207 in the German population with 64.1% homozygous individuals for the HNA-3a allele, 5.5% for the HNA-3b allele, and 30.4% heterozygous individuals, in accordance with the Hardy-Weinberg equilibrium and the gene frequencies of 0.819 and 0.181 reported in 1964. Immunization rates were estimated to be of 7% for HNA-3a and 0.5% for HNA-3b.


CONCLUSIONS
The PCR-SSP method allows reliable determination of the HNA-3a and -3b genotypes; approximately 7% of HNA-3b homozygous women develop antibodies when exposed to the HNA-3a antigen during pregnancy.
Reil
Angelika
A
DRK Blood Service West, Hagen, Germany. a.reil@bsdwest.de
Wesche
Jan
J
Greinacher
Andreas
A
Bux
Juergen
J
D000372:Agglutination Tests; D000483:Alleles; D005260:Female; D005455:Fluorescent Antibody Technique; D005838:Genotype; D006801:Humans; D007518:Isoantibodies / Q000097:blood / Q000276:immunology; D007519:Isoantigens / Q000235:genetics* / Q000276:immunology; D008297:Male; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011247:Pregnancy
C518134:HNA-3a antigen, human; D007518:Isoantibodies; D007519:Isoantigens