C3 and Myalgia: Spearman correlation analysis was performed to analyze the correlation between the top five differential genera, including Lactobacillus, Bacteroides, Streptococcus, Roseburia, and Coprococcus, and 22 clinical indicators with (1) sex, BMI, and disease course of IMNM; (2) myositis antibodies, including anti-SRP antibodies, anti-HMGCR antibodies, ANA, SSA, and Ro52; (3) clinical symptoms and signs, including myasthenia, myalgia, and amyotrophy; (4) disease activity parameters, including AST, ALT, CK, LDH, HBDH, MYO, CKMB, cTnT, ESR, CRP C3 and C4; and (5) involvement of ILD (Figure 4).