CX3CL1 and interstitial lung disease: Although serum CX3CL1 was also compared between the patients with ILD and without ILD, CX3CL1 levels were not significantly different (serum concentration of CX3CL1: patients with ILD, 7,457.9 ± 1,341.9 pg/ml; patients without ILD, 5,960.9 ± 2,376.3 pg/ml).