In CTD patients with ILD, BAFF concentrations were statistically significantly correlated with B-lines number (r = 0.37, 95% CI 0.13–0.56, p < 0.01), KL-6 level (r = 0.26, 95% CI 0.01–0.48, p < 0.05), and Warrick score (r = 0.33, 95% CI 0.09–0.53, p < 0.01), although the correlations were low. This evidence concerns the gene TNFSF13B and interstitial lung disease.