They comprised giant cell arteritis or polymyalgia rheumatica (n = 16, HLA-DRB1*04 in 58% of 12 assessed GCA cases), immune-mediated necrotizing myositis or acute rhabdomyolysis, systemic vasculitis, immune thrombocytopenic purpura, rheumatoid arthritis, anti-synthetase syndrome, and adult-onset Still’s disease. This evidence concerns the gene HLA-DRB1 and polymyalgia rheumatica.