Abstract
BACKGROUND: Patients with idiopathic interstitial pneumonia (IIP) often exhibit positivity for myositis-specific antibodies (MSA). However, the significance of this finding remains unclear. In this study, we investigated the association of MSA with the prognosis and risk of acute exacerbation in patients with IIP. METHODS: We retrospectively reviewed the medical records of patients with IIP and examined the effect of each MSA subtype on survival and acute exacerbation. RESULTS: Of 240 patients with IIP, 48 (20%) exhibited positivity for MSA. The MSA subtypes included: PL-7 (antithreonyl; n = 16, 6.7%); signal recognition particle (n = 13, 5.4%); PL-12 (antialanyl; n = 9, 3.8%); Mi-2 (n = 8, 3.3%); OJ (anti-isoleucyl; n = 7, 2.9%). During the 382 days (382 ± 281 days) of observation, 32 (13%) patients expired, and 27 (11%) experienced an acute exacerbation. Cox proportional hazards regression analysis demonstrated that age at the initial visit (hazard ratio [HR]: 1.072; 95% confidence interval [CI]: 1.017-1.131; P = 0.01), PL-7 (HR: 4.785; 95% CI: 1.528-14.925; P = 0.007), and PL-12 (HR: 3.922; 95% CI: 1.198-12.82; P = 0.024) were independent predictors of survival time. PL-7 (HR: 3.268; 95% CI: 1.064-10; P = 0.039) and PL-12 (HR: 5.747; 95% CI: 1.894-7.544; P = 0.002) were independent predictors of time from first visit to acute exacerbation. CONCLUSION: Detecting MSA in patients with interstitial lung disease may be useful in predicting prognosis and providing a rationale for intensive treatment.