Here, the ratio of anti‐inflammatory cytokine IL‐10 to pro‐inflammatory cytokine TNF‐α was significantly higher in MM than SM group (41.3 ± 9.4 vs. 29.2 ± 6.7; P = 0.011) on the admission day, in agreement with the clinical outcome of SM patients. Here, TNF is linked to Miyoshi myopathy.