To evaluate the efficacy of cyclosporin A (CsA) therapy for interstitial pneumonitis (IP) associated with PM/DM, 49 patients were retrospectively analysed. Thirty seven (76%) patients had IP and 7 died of respiratory failure. The patients were subgrouped by treatment for IP; 6 patients were treated with CsA (CsA-group), 5 with azathioprin (AZ) (AZ-group) and 26 with oral steroid alone (PSL-group) . After 1 month's treatment, both PaO₂ and AaDO₂ of the CsA-group patients significantly improved in comparison with the other 2 groups. Muscle strength of 6 among 7 expired DM patients with IP was normal or mild. These patients have been reported as amyopathic DM. CsA was considered to be effective in one amyopathic DM patient (M. H.), suggesting that CsA could be effective for IP in such a poor prognostic patient. There were no serious side effects during the observation period (2-37 months) . Serum soluble IL-2 receptor (sIL2R) levels were measured in 4 CsA-group patients. Those of 3 improved patients were high before CsA therapy and retured to the normal value. However the other patient who died had low sIL2R level before CsA therapy.
[Conclusion] CsA was effective for IP in some patients with PM/DM, and could also be effective for even a poor prognostic IP associated with amyopathic DM. High serum level of sIL2R could be a marker to predict the effectiveness for CsA treatment of IP in patients with PM/DM.