**4. Conclusion**

Myopathies are neuromuscular disorders exhibiting myalgia and muscular weakness due to dysfunction of muscle fibers which are frequently seen in autoimmune diseases. We here discussed about the non-inflammatory myopathy seen in patients with pSjS and the inflammatory myopathy, that is myositis, found in patients with DM is suggested to be Immunological dysfunction in pathogenesis. Although the mechanism of the myopathy is still unclear, it might be due to inflammatory cytokines released from CD4+CD 28+ (null) cells and CD8+CD28+ (null) cells infiltrated around vessels in the muscles of patients with MD.
