The clinico-serological spectrum of overlap myositis.

PURPOSE OF REVIEW: To provide the most recent evidence on the overlap myositis.

RECENT FINDINGS: Several new evidences on the overlap myositides have recently emerged. Regarding the classical myositis associated antibodies, several contributions focused on a better definition of the clinical associations and the disease course associated with these autoantibodies. Moreover, in the last years, new autoantibodies in idiopathic inflammatory myositis or other connective tissue diseases have been identified [namely anti-RuvBL1/2, poly-U-binding factor 60 kDa protein (PUF-60) and cytosolic 5'-nucleotidase 1A (NT5C1A)], and an increasing number of publications allow now to consider them as new myositis-associated antibodies with probably their own peculiar clinical profile.

SUMMARY: Overlap myositis is probably the largest subgroup within the idiopathic inflammatory myositis, with a prevalence that can reach 50% of all adult patients. The serological spectrum of overlap myositis has recently been enriched by the discovery of new autoantibodies. The spread of multiparametric methods has facilitated the identification of the autoantibody marker of overlap myositis and the better definition of the clinical profiles associated with them.