The direct interaction of LFA-1 on PBMCs and ICAM-1 on HK-2 cells activated ERK1/2 signaling to accelerate the part of EMT of HK-2 cells induced by TGF-β1. These results suggested that drugs that can block the interaction of LFA-1 and ICAM-1 could be an option to treat renal fibrosis. The gene discussed is MAPK3; the disease is renal fibrosis.