Increased ferritin predicts development and severity of acute interstitial lung disease as a complication of dermatomyositis

Acute/subacute interstitial pneumonia (A/SIP) is an intractable and fatal complication of DM. Since a useful indicator predicting the complication of A/SIP has not been found, the aim of this study was to determine whether serum ferritin is a potential predictive indicator of the occurrence of A/SIP in 64 patients with DM.Of the total patients enrolled, 19 had A/SIP, 24 had chronic interstitial pneumonia and 21 were without interstitial lung disease (ILD). Clinical manifestations and laboratory data were obtained from medical records on admission.Serum ferritin levels were extremely high in patients with DM with A/SIP. It was significantly higher in DM with A/SIP than that in DM without A/SIP (median 790 vs 186 ng/ml; P0.0001). The cumulative survival rate for 6 months was 62.7% in patients with DM with A/SIP. Moreover, the cumulative survival rate was significantly (P = 0.016) lower in the group with ferritin levelsor =1500 ng/ml than the rate in the group with ferritin levels1500 ng/ml.Serum ferritin can be useful as a predictor of the occurrence of A/SIP and correlates with the prognosis of A/SIP in DM. The intensive treatment using combination therapy with various immunosuppressant agents should be chosen for patients with ILD with DM showing hyperferritinaemia, especially levels1500 ng/ml.