CRP and interstitial lung disease: Moreover, the concentrations of C-reactive protein (CRP) [median (IQR) 9.4 (2.9–23.5) vs 4.5 (2.4–7.5) mg/l, P = 0.032] and ferritin [median (IQR) 968.5 (853.4–1231.4) vs 538.6 (215.3–906.9) ng/ml, P = 0.011] were notably elevated in the RP-ILD patients, compared to individuals without RP-ILD.