Furthermore, we measured TNF-a serum concentrations in 120 severe sepsis patients, including 104 patients with rs1800629GG genotype, 14 patients with GA genotype and 2 patients with AA genotype. Our results showed that rs1800629A allele was associated with higher TNF-a serum concentrations on the first day of severe sepsis. As shown in Figure 2 , the serum concentration of TNF-a in severe sepsis patients with AA+AG genotypes was significantly higher than that of patients with GG genotype (550.4673.6 pg/mL vs. 488.0668.5 pg/mL, P = 0.001). To control confounding variables, we used the possible confound- ing factors (age, gender and APACHE II scores) as covariates in a linear regression model and found that the rs1800629 genotypes remained associated with TNF serum concentration (P adj = 0.02).