A Case of Dermatomyositis with Co-existent SAE-1 and RO-52 Antibodies
Fay J, Azhar A, O’Connell P, Kearns G, Howard D, Durcan L
Rheumatology Department, Beaumont Hospital Dublin
Dermatomyositis is characterised by muscle weakness, raised creatinine kinase(CK) and rash and is associated with an ever increasing number of specific autoantibodies. SAE-1 is a DM-related antibody, infrequently described, with a specific associated disease phenotype and response to therapy. Ro-52 also associates with myositis. The coexistence of Ro52 and SAE 1 has not previously been described. We present the case of a 79 year old female with classical SAE1 pattern DM and a co-existent Ro52 antibody.
Our patient presented with limb, facial swelling and generalised weakness with a widespread violaceous rash. CK was only mildly elevated (300) and had been elevated over many years. A diagnosis of DM was confirmed by PET CT showing axial predominant skeletal muscle uptake and cutaneous biopsy demonstrating an interface dermatitis. Her peripheral EMG was normal. Her swallow was severely impaired. Muscle biopsy showed widespread fibre atrophy with regeneration, perivascular lymphocytes and profound depletion of cytochrome oxidase in keeping with DM. She was treated with prednisone, intravenous immunoglobulin and methotrexate. Peripheral weakness resolved but her swallow has remained impaired and a PEG was inserted.
SAE-1 associates with rash, profound swallow abnormalities and mild skeletal muscle disease, responsive to therapy, as demonstrated in this case. These antibodies have not been described with Ro52 antibodies, which we feel in this clinical context are innocent bystanders. Identifying specific phenotypes which can lead to individualised therapy is essential in rheumatology.
1: Milone, M: Diagnosis and Management of Immune-Mediated Myopathies, Mayo Clinic Proceedings , Volume 92 , Issue 5 , 826 – 8372: