Objective:To observe the influences of functions of chemokine receptor 9(CCR9) on leukemia patients,we analyzed 38 typical T cell lymphocytic leukemia cases.Methods:The functions of T ALL and T CLL CD4+T cells towards TECK/CCL25 were determined by chemotaxis assay and adhesion assay.Results:Almost in all of the T ALL patients,TECK/CCL25(a ligand for CCR9)could induce a high chemotactic migration of T ALL CD4+ cells as well as a high adhesion.Conclusion:It indicates that CCR9 and its ligands may promote survival or proliferation of T ALL cells. [