Background Chest CT scan of patients with MPO-ANCA positive interstitial pneumonia often identifies a UIP pattern. This condition shows UIP-dominant pathological features, accompanied by characteristics differing from idiopathic pulmonary fibrosis such as poor fibroblastic foci. If these pathological differences are taken into account, the prognosis may differ between MPO-ANCA-positive interstitial pneumonia and idiopathic pulmonary fibrosis patients. (1)
Objectives The prognosis was investigated in patients with MPO-ANCA-positive interstitial pneumonia having received immunosuppressive therapy beginning soon after disease onset.
Methods Of the patients with microscopic polyangiitis admitted to our hospital between 2001 and 2012, MPO-ANCA-positive patients complicated by interstitial pneumonia (MPA-ILD) were enrolled in this study, in accordance with the EMEA Classification (2007). The clinical data, prognosis, and other variables were investigated in these patients.
Results There were 32 cases of MPA-ILD (14 males and 18 females), with a mean age of 71.8 years (range: 48-87). The data at the start of treatment were: MPO-ANCA 379±486 EU, KL-6 692±551 U/ml, Aa-DO2 33.6±58, %FVC 80.9±18%, %DLco/VA 61.5±19%, and RV/TLC 42.0±8.4%. Chest CT scan at the start of treatment revealed a UIP pattern in 25 cases and a non-UIP pattern in 7 cases. All patients received treatment with PSL, combined with immunosuppressors in 29 cases (CY in 11 cases) and apheresis in 6 cases. After treatment, the MPO-ANCA level was below the detectable limit in most cases. On analysis of the prognosis, 5 patients died (from exacerbation of interstitial pneumonia in 1 case, infection + alveolar bleeding in 1 case, pulmonary hypertension in 1 case, and sudden death in 2 cases), with the median survival period being 124.6 months and the 5-year- survival rate being 85.5%. Following treatment, the ground glass opacity on chest CT disappeared, and the cyst tended to grow slightly.
Conclusions The prognosis of MPA-ILD patients was favorable, suggesting that is better than that of usual idiopathic pulmonary fibrosis patients. When immunosuppressive therapy at sufficiently high dose levels, started soon after disease onset, was continued, MPO-ANCA became negative and remained so thereafter. We suggest that the prognosis of MPA-ILD patients may be improved if immunosuppressive therapy is applied more effectively.
Tanaka T, Otani K, Egashira R, Fukuoka J, et al: Interstitial pneumonia associated with MPO-ANCA: clinicopathological features of nine patients. Respir Med. 2012; 106: 1765-70.
Disclosure of Interest None Declared