Anti-HNA testing of allo-exposed COVID-19 convalescent plasma donors including genetic human neutrophil antigen screening to prevent anti-HNA antibody-mediated transfusion-related acute lung injury.

Background: Transfusion-related acute lung injury caused by antibodies against human neutrophil antigens (HNA) is a serious but rare complication associated with blood transfusion. The presence of such antibodies is most probable in donors with a transfusion/pregnancy history. During the COVID-19 pandemic period convalescent plasma (CP) containing neutralizing antibodies against SARS-CoV-2 was widely used for COVID-19 patients as a therapy in the absence of any treatment. The aim of the study was to work out a simple diagnostic algorithm of anti-HNA testing of allo-exposed CP donors including genetic HNA screening.

Materials and methods: A total of 457 anti-HLA-negative allo-exposed CP donors were genotyped for HNA-1a/1b, HNA-3a/3b, and HNA-2, and only donors with homozygous HNA-1a/1a; HNA-3b/3b; or HNA-2null genotypes were tested for anti-HNA antibody using LabScreenMulti (One Lambda) and homozygous HNA-1b/1b using the granulocyte immunofluorescence test (GIFT) but verified using LabScreenMulti.

Results: Testing of 83 homozygous HNA-3b/3b; HNA-2null; or HNA-1a/1a donors revealed anti-HNA-3a antibody in one case. Testing of 181 HNA-1b/1b donors using GIFT gave 10 ambiguous results verified using LabScreenMulti which confirmed anti-HNA-1a antibody in one case. The frequency of FCGR3B*01 and *04 encoding HNA-1a was 0.34; FCGR3B*02, *03, and *05 encoding HNA-1b-0.66; SLC44A2*01 encoding HNA-3a-0.80; and SLC44A2*02 encoding HNA-3b-0.20. In 3.7% cases the HNA-2null genotype was revealed.

Discussion: Due to applying HNA genotyping as a primary test before anti-HNA antibody testing the serological work was limited only to HNA-homozygous donors revealing two anti-HNA immunized donors. The distribution of HNA genotypes in the cohort was similar to other Caucasian populations.