Recent Advances in Idiopathic Inflammatory Myopathies (IIM) - Rapid Discoveries of Myositis-specific Antibodies (MSAS) and Myositis-Associated Antibodies (MAAS) - Moving Towards 'Precision Medicine'.

The progress in the understanding of inflammatory muscle diseases over the past several decades has been slow but steady. The classification given by Bohan and Peter's in 1975 was based on clinical features. It served well, but inadequacies were also obvious. The increasing discoveries of autoantibodies in this group of disorders have helped in refining the classification of Bohan and Peter's to a large extent. At the present state of knowledge, it is now possible to classify and sub-classify this group of diseases using distinct clinical features combined with the type of autoantibodies in well-defined subsets. Not only the subsets help predicting the type of organ involvement and comorbidities but may also help choose a specific drug for a particular subclass. This approach may lead to the practice of precision medicine for inflammatory myositis.