TRIM33 and dermatomyositis: Regarding the MSA status of DM patients, MHC-II myofiber positivity was found in 60% (n = 6/10) of anti-TIF1γ, 40% (n = 2/5) of anti-NXP2, 100% (n = 2/2) of anti-SAE, and 22% (2/9) of seronegative cases.