IL4 and hypersensitivity pneumonitis: Additional experiments then showed that the production of IFN-γ by Gr-1+ neutrophils in hypersensitivity pneumonitis was impaired by IL-4 produced by iNKT cells: adoptive transfer of IFN-γ-deficient, but not IL-4-deficient, iNKT cells downregulated hypersensitivity pneumonitis-related inflammation in CD1d-KO mice72.