Granulocyte immunology.
Antibodies directed against antigens on the granulocyte (neutrophil) membrane can cause a variety of disorders including neonatal immune neutropenia, immune neutropenia after bone marrow transplantation, autoimmune neutropenia, and drug-induced immune neutropenia. Since granulocyte alloantibodies can lead to severe pulmonary transfusion reactions (TRALI), febrile transfusion reactions and refractoriness to granulocyte transfusions, they also play an important part in blood transfusion. The implicated human neutrophil alloantigens (HNA) have been renamed in the recently introduced HNA nomenclature which is based on the antigen's glycoprotein location. The Fc gamma Receptor IIIb (CD16, HNA-1) and the NB1 glycoprotein (CD177, HNA-2) represent the major immunogenic molecules of the neutrophil membrane. They bear the clinically most important antigens HNA-1a,-1b,-1c (NA1, NA2, SH) and HNA-2a (NB1), respectively. For the detection of granulocyte antibodies, a combination of immunofluorescence and agglutination tests together with a panel of freshly isolated, typed test neutrophils has been shown to represent the best means of detection. The introduction of the glycoprotein-specific assay "MAIGA" has improved alloantibody identification considerably. To facilitate and improve neutrophil typing, PCR-SSP techniques have been established for HNA-1a,-1b, and -1c genotyping.