TNF and brucellosis: Our results showed that there was no significant association between the genotypes or alleles of IL-13 (− 1112 C/T), IL-13 (− 1512 A/C), IL12 (+ 1188 A/C) and TNF-α)- 238 G/A) between patients with brucellosis and the control group, although the dominant model of IL-13 (− 1512 A/C) influence the susceptibility to brucellosis (p value: 0.041).