Median CD4/CD8 ratio was significantly higher in mediastinal lymph nodes of patients with IPF compared to patients with lung cancer and patients with concomitant IPF/lung cancer (IPF: 1.9, 95% CI: 1.2 to 2.6, vs. lung cancer: 0.9, 95% CI: 0.7 to 1.3, vs. IPF and lung cancer: 0.9, 95% CI: 0.5 to 1.4, p = 0.001), (Fig. 3, Panel C). Here, CD4 is linked to lung cancer.