At present, the most reported etiology of IAS involves the production of IAAs induced by external factors due to the HLA-DRB1 genotype and some autoimmune diseases (such as Graves’ disease, systemic lupus erythematosus, and systemic sclerosis).[8] Viruses and drugs are the 2 most important causes. Here, HLA-DRB1 is linked to systemic lupus erythematosus.