CD4 and idiopathic pulmonary fibrosis: However, in our patients with end-stage COPD and IPF, the levels of iNKT cells were low and highly comparable to those of healthy donor lungs (0.6% to 0.8% [0.1-16.5] for iNKT cells; 0.1% [0.0–1.4] for CD4+iNKT cells, 0% to 0.1% [0.0–2.2] for CD8+iNKT cells and 0.4 to 0.8% [0.0–16.4] for DN iNKT cells; Table 2).