Myositis in clinical practice-relevance of new antibodies.

Novel classification schemes for idiopathic inflammatory myopathy are based on serologic and histopathologic features. The presence of specific myositis autoantibodies may correspond to particular clinical phenotypes. Patients with a known diagnosis of inflammatory myopathy require a prompt clinical evaluation and the assessment of myositis-associated autoantibodies. Patients possessing autoantibodies associated with ILD or those with any pulmonary symptoms should undergo pulmonary functions tests and high-resolution computed tomography scanning of their lungs. Despite the lack of placebo-controlled trials, systemic glucocorticoids are considered the mainstay of initial treatment of myositis-associated ILD. Glucocorticoid-sparing agents are often started concomitantly with glucocorticoids, particularly in patients with moderate or severe disease. The first-line conventional immunosuppressive drugs include either mycophenolate mofetil or azathioprine, and when they fail or if the features are rapidly progressive, more aggressive therapy includes tacrolimus or cyclosporine, rituximab, intravenous immunoglobulin, or cyclophosphamide used either alone or in various combinations.