AIM: To investigate the association of gene polymorphism at position 196 of tumor necrosis factor receptor Ⅱ (TNFRⅡ) with systemic lupus erythematosus (SLE) in Chinese, and establish recombinant retroviral vector to analyze the function of the TNFRⅡ 196M/R. METHODS: The genotype at position 196 of TNFRⅡ was determined by PCR-RFLP in 106 SLE patients and 119 healthy controls in china. Human TNFRⅡ196M cDNA were amplified by PCR and cloned into PMD18-T vector. Then, PMD18-TNFRⅡ196R was induced by site-directed mutagenesis. The recombinant T vector, PMD18-TNFRⅡ196M and PMD18-TNFRⅡ196R, were subcloned into retroviral vector PLXSN. Both normal and variant were transfected into rat mesangial cell. The effects of TNF? on production of sTNFRⅡ and IL-6 were study by ELISA. RESULTS: (1) The frequency of TNFRⅡ196R allele was significantly higher than those in controls (35.2% vs 14.3%, P