DMD and Duchenne muscular dystrophy: The rationale to study the role of IL-6 on the pathogenesis of muscular dystrophy was based on the evidence that: (i) the inflammatory cytokine IL-6 concentrations are significantly higher in the serum of DMD patients compared with healthy age-matched (12,17); (ii) IL-6 concentrations follow the disease time-course in human DMD (12); (iii) among pro-inflammatory cytokines, IL-6 was the only one significantly down-regulated in the muscle of 24-week-old mdx mice (Fig. 1), compared with younger mice, which represents a stage normally spared from the absence of dystrophin (7,72,73).