The results showed that FeNO50 levels were significantly higher in the IPF group compared to both the CTD-ILD (p = 0.0024, 95% CI for the mean difference = [1.83, 6.18], Bonferroni-corrected p-value = 0.0061) and IPAF (p = 0.0357, 95% CI for the mean difference = [20.03, 23.27], Bonferroni-corrected p-value = 0.0324) groups. This evidence concerns the gene NLRC4 and idiopathic interstitial pneumonia.