PolymyositisDermatomyositisMyositisHistidine-tRNA LigaseLung Diseases, InterstitialMyositis, Inclusion BodyPrednisoloneMuscular DiseasesAutoantibodiesParaneoplastic SyndromesCreatine KinaseBiopsyConnective Tissue DiseasesMusclesMuscle, SkeletalScleroderma, SystemicFatal OutcomeMyoglobinuriaNervous System Autoimmune Disease, ExperimentalAutoimmune DiseasesMediastinal EmphysemaAntibodies, AntinuclearMuscle WeaknessMuscular DystrophiesImmunosuppressive AgentsAdrenal Cortex HormonesMixed Connective Tissue DiseaseDelayed Diagnosis