[NA, a specific system for polymorphonuclear neutrophils: localization, biochemistry, genetics, frequency role in pathology].

Among the neutrophil polynuclear specific antigens (NA, NB, ND, NE, ...), NA antigen is the most common. It is a glycoprotein situated on the neutrophils FcRIIIb-receptor and presents 2 forms: NA1 and NA2. The epitope responsible of that polymorphism has got an amino acids composition that is unknown. The first techniques used for their analysis were the microagglutination and the granulocytotoxicity-later, the immunofluorescence, the chemiluminescence and the MAIGA (Monoclonal Antibody Immobilized granulocyte Antigen) were introduced. These last years, more efficient techniques appeared like Flow Cytometry and Polymerase Chain Reaction (PCR) that allowed phenotyping and genotyping of neutrophil polymorphonuclear specific antigens. The studies indicated that NA antigen frequency varies according to the populations and the ethnics. NA2 allelic form is more frequent than NA1 in the caucasian population (88% VS 46%). In human pathology, NA antigen is implicated in the physiopathological mechanisms of the alloimmune and probably auto-immune neutropenies.