If IFN-γ (a pro-inflammatory factor) secretion is the only function of CD8 T cells in UUO-induced renal fibrosis, then the RAG−/− mice (neither CD4 T cells nor CD8 T cells) reconstituted with CD8+ T cells would experience more mild inflammation and fibrosis compared with RAG−/− mice. Here, CD4 is linked to renal fibrosis.