Characterization of a New Alloantigen (SH) on the Human Neutrophil Fcgreceptor IIIb

Polymorphic structures of the neutrophil Fcgreceptor IIIb gen frequency of 5% in the white population. The same fre(FcgRIIIb) result in alloantibody formation that causes alloquency was found by genotyping, for which a technique immune neonatal neutropenia and transfusion reactions. Albased on polymerase chain reaction (PCR) using sequenceloantigens located on FcgRIIIb include the antigens NA1 and specific primers (PCR-SSP) was developed. Typing of all NA2. In four cases of alloimmune neonatal neutropenia, SH(") individuals for NA1 and NA2, and PCR-restriction fraggranulocyte-specific alloantibodies directed against a thus ment length polymorphism analysis of the NA-specific PCR far unknown antigen were detected by granulocyte agglutiproducts from five SH(") individuals using the SH-specific nation and immunofluorescence tests in the maternal sera. endonuclease SfaN I showed that SH antigen is very probaBy the use of the monoclonal antibody–specific immobilizably the result of an additional mutational event in the NA2 tion of granulocyte antigens (MAIGA) assay, the new antiform of the FcgRIIIB gene. Immunochemical studies also gen, termed SH, was located on the FcgRIIIb. Nucleotide demonstrated that the SH determinants reside on the 65to sequence analysis of the FcgRIIIb coding region from a SH(") 80-kD NA2 isoform of the FcgRIIIb. Our findings show the individual showed a single-base CrA mutation at position existence of an additional polymorphism of the FcgRIIIb, 266, which results in an Ala78Asp amino acid substitution. A which can result in alloantibody formation causing alloimfamily study confirmed that this nucleotide difference is mune neonatal neutropenia. inherited, and corresponds to the SH phenotype. Serologic q 1997 by The American Society of Hematology. typing of 309 randomly selected individuals showed an anti-