Duncan SR et al. have reported that the proportion of CXCL13 and B-lymphocyte stimulating factor (BLyS) are significantly increased in lungs and peripheral blood of patients with IPF and that CXCL13 acts as a prognostic biomarker of IPF [3, 13]. The gene discussed is TNFSF13B; the disease is idiopathic interstitial pneumonia.