Therefore, since NK cell specific depletion by anti-asialo GM1 does not change either IFN-γ levels or fibrosis, and depletion of NK cell and NKT-cells by anti-NK1.1 results in significantly worse fibrosis, the aggregate data suggest that NKT cells but not NK cells play a protective role in pulmonary fibrosis. Here, IFNG is linked to pulmonary fibrosis.