Nomenclature for Factors of the HLA System

Nomenclature of HLA Alleles

Early in their study, it was recognised that the genes encoding the HLA molecules were highly polymorphic and that there was a need for a systematic nomenclature. The HLA complex is located within the 6p21.3 region on the short arm of human chromosome 6 and contains more than 220 genes of diverse function. Many of the genes encode the proteins of the immune system. The naming of new HLA genes, allele sequences, and their quality control is the responsibility of the WHO Nomenclature Committee for Factors of the HLA System. This commitee first met in 1968 and laid down the criteria for successive meetings. The committee meets regularly to discuss issues of nomenclature and has published 19 major reports documenting the HLA antigens and, more recently, the genes and alleles. The standardisation of HLA antigenic specifications has been controlled by the exchange of typing reagents and cells in the International Histocompatibility Workshops.

In 1989, a large number of HLA allele sequences were first analysed and named. Since then, the job of curating and maintaining a database of sequences has been of the utmost importance. The dissemination of new allele names and sequences is essential in clinical settings, and through the work of the HLA Informatics Group (in collaboration with the European Bioinformatics Institute) we are able to provide public access to the data through the EBI web site ( and here at The IPD-IMGT/HLA Database collects both new and confirmatory sequences that are then expertly analysed and curated before being named by the WHO Nomenclature Committee for Factors of the HLA System. Those sequences that pass our stringent criteria for acceptance are then included in the tools and files available both on the IPD-IMGT/HLA Database and on this site through regular updates that ensure the new and confirmatory sequences are dispersed to the HLA community and the wider research and clinical communities.

Prof. Steven GE Marsh, BSc PhD ARCS
Chair of the WHO Nomenclature Committee for Factors of the HLA System

Graph of HLA Alleles and Antigens named by year

Graph showing the number of alleles named by year from 1987 to the end of June 2024.
(A higher resolution version is available from here)

If you wish to cite any information from this website in a publication, please see our citations page for further details on how you can do this.

This site has been tested in Safari, Firefox and Google Chrome, we recommend using one of these browsers for optimal viewing. IE8 users are advised to either turn off "Compatiblity View" or remove from the list of sites which use this option.