The effect of CD40 message activation on the renal tubular epithelial cells CHEN Yanjie², LI Xiaozhong¹, MEI Jun², GU Li² (1.Department of Kidney, Soochow University Affiliated Children's Hospital, Suzhou 100034, Jiangsu, China; 2.Department of Pediatrics, The Tenth People's Hospital Affiliated to Tongji University, Shanghai 200072, China)