Guidelines From the French‐Speaking Society for Histocompatibility and Immunogenetics ( <scp>SFHI</scp> ) for Harmonisation of <scp>HLA</scp> Genotyping in Autoimmune Diseases, Drug Hypersensitivity and Pharmacogenetics

HLA molecules play a central role in the adaptive immune response. Their high polymorphism influences individual susceptibility to various autoimmune diseases and certain drug-induced hypersensitivities. In France, HLA genotyping is classified as a medical genetics procedure and is strictly regulated. The Société Francophone d'Histocompatibilité et d'Immunogénétique (SFHI) has established national guidelines outlining clinically validated indications, required resolution levels and interpretation criteria based on robust data. These guidelines are particularly relevant for common clinical contexts, including autoimmune diseases and pharmacogenetic testing. Well-established associations include HLA-DQB1*02/DQA1*05 (DQ2) and HLA-DQB1*03:02/DQA1*05 (DQ8) with celiac disease, HLA-B*27 with spondyloarthritis, HLA-DQB1*06:02 with type 1 narcolepsy, HLA-A*29 with Birdshot chorioretinopathy and several pharmacogenetic risk alleles such as HLA-B*57:01 (abacavir), HLA-B*15:02 and HLA-A*31:01 (carbamazepine) and HLA-B*58:01 (allopurinol). In immunotherapy, the efficacy of tebentafusp has been shown to depend on HLA-A*02:01 positivity. HLA alleles must be interpreted as relative risk factors, not absolute predictors. Critical analysis of HLA-related scientific literature requires consideration of the genotyping technique, typing resolution, allele frequencies within the studied population and environmental factors. High-resolution typing is essential in pharmacogenetics and recommended in selected autoimmune disorders. Interpretation should be conducted by qualified medical biologists, integrating clinical context, allelic diversity and recent technological advances, particularly next-generation sequencing. HLA genotyping represents a valuable tool in diagnosis and risk assessment, with increasing importance in the era of personalised medicine.