What are the etiopathogenetic factors of myositis?

Genetic (autoimmune diseases, HLA II alleles defects) Environmental (infections [coxsackie, flu, retro, trypanosoma], UV exposure and vitamin D [Anti MI2 Ab [uv] and anti-Jo 1 [vitD}], Drugs [statin, fibrate, nicotinic acid, cimetidine, chloroquine. Statin induced is very rare, HMGCoA reductase inhibitors so we get HMGCR antibodies])