IFIH1 and dermatomyositis: In a stratified analysis according to detection method, anti-MDA5 antibodies were associated with classic DM with the ELISA method (OR = 9.06, 95% CI: 1.71–47.87, P = 0.010), yet an association was not observed when an immunoprecipitation method was used (OR = 3.66, 95% CI: 0.61–21.91, P = 0.155).