[Successful combination therapy of cyclosporine and steroids in two cases with interstitial pneumonitis associated with polymyositis].

Cyclosporine is an immunosuppressive agent which is well-established in the transplantation of organs including kidney, liver and bone marrow. It acts by inhibiting the production of interleukin 2, thereby blocking both the development of cytotoxic lymphocytes, and the proliferation of helper T cells. T cell-mediated muscle damage is thought to be important in the pathogenesis of polymyositis. And activated cytotoxic T cells are thought to play an important role of polymyositis/dermatomyositis with active pneumonitis. It is thereby likely that cyclosporine would be effective in the management of polymyositis with interstitial pneumonitis. We have used cyclosporine in two cases of corticosteroids resistant polymyositis associated with pneumonitis. The first case was admitted because of the relapse of polymyositis. She was partially responded by the high dose of steroid, but showed decreased %DLCO and increased AaDO2 during the therapy. And oral cyclosporine was given with steroid. Within two weeks, serum creatinine kinase level was reduced to normal range, and the improvement of pneumonitis was observed. The second case was admitted because of the flare of pneumonitis. She was treated with high dose of steroid with insufficient response. And cyclosporine was prescribed. Within two weeks of treatment, her symptom was relieved, and blood gas analysis showed an improvement of pulmonary function. And steroid could be tapered. In both cases, the initial dose of cyclosporine was 200 mg/day, and the optimal trough level was thought to be ranged 100 to 150 ng/ml. In the second case, renal dysfunction was observed but it was recovered by the reduction of the dose of cyclosporine. No other side effect was appeared.(ABSTRACT TRUNCATED AT 250 WORDS)