Polydermatomyositis with anti-PL7 antibody: clinical and laboratory follow-up over a five year period.

Anti-PL7 antibodies to threonyl-tRNA synthetase purified from beef liver were observed in the serum of a dermatopolymyositis patient. They were identified by CIE and DID using a standard anti-PL7 antiserum and quantified by ELISA in serum samples taken over a five year period. The level of antibodies against not only threonyl-tRNA synthetase but also several muscle proteins including tropomyosin, was strongly correlated with disease activity and treatment. This correlation may prove important both in monitoring the response of the patient to treatment and to our understanding of the aetiology of the disease.