Clinical Characteristics of Patients With Anti-Jo-1 Antibodies

Abstract

The idiopathic inflammatory myopathies (IIM) are a group of autoimmune disorders, including polymyositis (PM), dermatomyositis (DM), inclusion body myositis, and myositis associated with malignancy and other connective tissue diseases. Both DM and PM can have associated interstitial lung disease (ILD).1,2 A number of autoantibodies, called myositis-specific autoantibodies, have been described. These include antibodies to aminoacyl-tRNA synthetases, to signal recognition particle, and to the nuclear helicase Mi-2. The most common of these is the anti Jo-1 antibody directed against the antihistidyl–tRNA synthetase. It is detectable in approximately 15% to 30% of myositis patients overall, and is more common in PM.3 The presence of these antibodies has been associated with a clinical subset characterized by myositis, ILD, arthritis, fever, Raynaud phenomenon and mechanic’s hands, referred to as the antisynthetase syndrome.2 There is a well-established association of antisynthetase antibodies and the presence of ILD. Patients may present first with ILD and then later develop myositis. One series reported 10 patients with antisynthetase antibodies and ILD with no clinical evidence of myositis. Of these patients, 2 had anti Jo-1 antibodies. In patients with the antisynthetase syndrome, the lung involvement usually determines the prognosis of the disease.3 In another series, 3 patients with Jo-1 antibodies developed fatal acute respiratory distress syndrome.4 While not all patients develop rapidly progressive fatal lung disease, the presence of antisynthetase antibodies has been associated with a poor prognostic outcome.2– 4 Despite the limited number of randomized controlled studies, the mainstay of therapy for PM and DM is corticosteroids plus either methotrexate or azathioprine.5 Other agents such as cyclosporine, tacrolimus, cyclophosphamide, intravenous immunoglobins, and rituximab have been used with some success.5– 8 Frequently, weakness improves more than pulmonary symptoms following treatment.2,9 The clinical characteristics of African American (AA) patients with anti-Jo-1 antibody ILD and/or myositis have not been well described in the literature. We describe the clinical characteristics of our patients with anti-Jo-1 antibody disease, more than half of whom are AA reflecting the demographics of our medical center.