Background: The methods of granulocyte antibody and antigen detection have improved considerably since the First International Granulocyte Serology Workshop.
Study design and methods: Thirteen laboratories participated in the Second International Granulocyte Serology Workshop. The study was designed to meet five goals: 1) establishment of antigen-typed granulocyte panels, 2) determination of the proficiency of granulocyte antibody detection by laboratory and by technique, 3) identification of granulocyte antibodies present in uncharacterized sera, 4) genotyping of NA antigens by DNA-based techniques, and 5) collection and exchange of information to standardize granulocyte antibody screening.
Results: NA1-, NA2- and NB1-specific antibodies were detected by more than two-thirds of the participants with the granulocyte immunofluorescence test (GIFT) but by fewer than two-thirds with the granulocyte agglutination test (GAT). The determination of the NB2-, 5b-, and Fc gamma RIIIb-specific antibodies was the most problematic. Ninety percent of the participants were not able to identify NB2 antibodies in sera with suspected NB2 specificity. The 5b antibodies were only detected by laboratories that performed the GAT. Isoantibodies to Fc gamma RIIIb were identified when the monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA) assay or an Fc gamma RIIIb-deficient panel cell was available. In 4 of 11 uncharacterized sera, the presence of NA1, NA2, and Fc gamma RIIIb antibodies could be confirmed by the MAIGA assay. In polymerase chain reaction with sequence-specific primers (PCR-SSP), the NA genotypes of all DNA samples were correctly determined.
Conclusion: A combination of the GIFT and GAT is still the best means of antibody detection. The MAIGA assay allows identification of isoantibodies to Fc gamma RIIIb or alloantibodies to NA antigens. The NA genotype can be reliably determined by PCR-SSP. Cell panels should cover NA1, NA2, NB1, 5b, and, if possible, SH.