While there was a tendency for the levels of KL-6 and SP-D to be higher in the patients with AE-IIPs, the levels of these biomarkers were also frequently higher (SP-D > 110 ng/mL, KL-6 > 500 U/mL) in patients with IPF and NSIP (Fig. 4b, c). This evidence concerns the gene MUC1 and idiopathic interstitial pneumonia.