HNA Nomenclature


Introduction


The Granulocyte Immunobiology Working Party (GIWP) of the International Society of Blood Transfusion (ISBT) in 1998 established a new nomenclature of granulocyte alloantigens.

Allele nomenclature

  • In general the official gene name is followed by an asterisk and by a two digit allele number.  Genetic variations of standard alleles are numbered consecutively and are not extended by a third of fourth digit.
  • New alleles are numbered consecutively according to the first publication.
  • Only missense mutations within exons leading to an amino acid exchange are included.

Antigen nomenclature

  • Granulocyte antigens will be called HNA (human neutrophil alloantigen).
  • The antigen nomenclature is based upon the serologically defined epitope(s) on glycoproteins.
  • The glycoprotein (antigen system) is coded by a number: HNA-1, HNA-2, etc.
  • The phenotypic variation of the antigen is assigned given in lower case letters: HNA-1a, HNA-1b, etc.
  • HNA-2 is an isoantigen without allelic variation and therefore should be named HNA-2.
  • Glycoproteins, which are encoded by one allele can exhibit more than one epitope.  For example, HNA-1b and HNA-1c is encoded by FCGR3B*03 on glycoprotein FcγRIIIb (CD16).
  • One epitope can be encoded by different alleles.  For example, HNA-1a is encoded by FCGR3B*01 and FCGR3B*04.
  • Only slightly altered epitopes can be identified by adding the subscript “var” in cases which antibodies specific for the original epitope bind with reduced affinity of altered reactivity pattern.  For example, HNA-3avar for HNA-3a with an additional Leu151Phe exchange.
  • The cellular expression of HNA is not necessarily restricted to neutrophil granulocytes.  For example, HNA-3 is expressed on neutrophils, lymphocytes, platelets and tissues.
  • Antigens originally identified on other cell types and whose main clinical impact depends on cells other than neutrophils keep their original nomenclature and are not included in HNA nomenclature.  For example, Naka (GPIV, CD36) located on platelets and monocytes.

 


Table 1 HNA alleles and antigens


 

Allele Description Glyco-protein Epitopes HNA frequencies North Americans (%) HNA frequencies Africans (%) HNA frequencies Asian (%)
FCGR3B*   FcgRIIIb, CD16          
FCGR3B*01   HNA-1a   56 -62 46 - 66 90
FCGR3B*02   HNA-1b HNA-1d## 89 78 - 84 52
FCGR3B*03   HNA-1c HNA-1b 5 23 - 31 0
FCGR3B*04 FCGR3B*01 316G>A HNA-1a   NT NT NT
FCGR3B*05 FCGR3B*02 244A>G HNA-1bvar.   NT NT NT
FCGR3B*null FCGR3B gene deletion   HNA-1 null, no epitope   NT 4 0 - 0.2
               
CD177   CD177 HNA-2   97 98 99
               
SLC44A2*01   CTL2 HNA-3a   89 - 99 NT NT
SLC44A2*02   HNA-3b   NT NT NT
SLC44A2*03 SLC44A2*01 451C>T HNA-3a var.   NT NT NT
               
ITGAM*01   CD11b HNA-4a   96 NT NT
ITGAM*02   HNA-4b**   NT NT NT
               
ITGAL*01   CD11a HNA-5a   96 88 65
ITGAL*02   --   NT NT NT

 

## HNA-1d is antithetical to HNA-1c

**HNA-4b is actually under investigation

NT = Not Tested

 

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