HLA nomenclature and the IMGT/HLA sequence database.

Early in their study it was recognized that the genes encoding the HLA molecules were highly polymorphic and that there was a need for a systematic nomenclature. The result was the WHO Nomenclature Committee for Factors of the HLA System, which first met in 1968, and laid down the criteria for successive meetings. This committee meets regularly to discuss issues of nomenclature and has published 16 major reports documenting firstly the HLA antigens and more recently the genes and alleles. The standardization of HLA antigenic specificities has been controlled by the exchange of typing reagents and cells in the International Histocompatibility Workshops. Since 1989 when a large number of HLA allele sequences were first analysed and named, the job of curating and maintaining a database of sequences has been of prime importance. In 1998 the IMGT/HLA database became the official repository for HLA sequences. In addition to the nucleotide and protein sequences the database contains information of the cell from which the sequence was obtained. The database which provides tools for sequence analysis and the submission of new data, is updated quarterly and now contains over 1500 HLA allele sequences.