The frequency and specificity of human neutrophil antigen antibodies in a blood donor population

Transfusion-related acute lung injury (TRALI) has been associated with both human leukocyte antigen (HLA) and human neutrophil antigen (HNA) antibodies. HNA antibody frequency, specificity, and demographic associations have not been well defined in the blood donor population.

A subset of 1171 donors (388 nontransfused males, 390 HLA antibody-negative females with three or more pregnancies, and 393 HLA antibody-positive females with three or more pregnancies) from a larger Leukocyte Antibody Prevalence Study was tested for immunoglobulin (Ig)G and IgM HNA antibody using a granulocyte immunofluorescence flow cytometry assay. Additional testing on selected samples included monoclonal antibody immobilization of granulocyte antigen-flow cytometry and granulocyte genotyping.

Eight samples were HNA antibody positive (prevalence, 0.7%; 95% confidence interval [CI], 0.3%-1.3%]). Three HNA antibodies (one IgG and two IgM) were found in nontransfused males (prevalence, 0.8%; 95% CI, 0.2%-2.2%); all were panreactive or nonspecific. One HLA antibody-negative previously pregnant female had an IgG HNA antibody with HNA-1a specificity (prevalence, 0.3%; 95% CI, 0.01%-1.4%). Four HLA antibody-positive previously pregnant females demonstrated HNA antibodies, three IgG and one IgM (prevalence, 1%; 95% CI, 0.3%-2.6%). Two of these were HNA-1a specific, one HNA-4a specific, and one nonspecific.

HNA antibodies occur with low frequency in the donor population and are present in both male and female donors. Despite the implementation of TRALI reduction strategies, HNA antibodies are still present in donor blood products. Although our data do not create a case for urgent implementation of donor HNA antibody testing, future new developments for high-throughput HNA antibody screening, including for HNA-3a, may warrant reconsideration.