Abstract
Polymorphisms in the regulatory regions of cytokine genes may not only increase susceptibility to some infectious diseases but also affect the course and prognosis of the disease. TNF-alpha is considered an important Th1 cytokines that plays critical roles in control of Brucella infection and in macrophage activation. In this study, we are going to analyze the relationship of two polymorphisms in TNF-alpha and the inherited susceptibility/resistance to brucellosis in population of Makkah region. A cases-control association study was conducted in 69 individuals with human Brucellosis and 112 healthy individuals. Genotyping of TNF-308G>A and -857C>T polymorphism in both patients and healthy controls was done by PCR-RFLP method and were assessed for potential associations with susceptibility for human brucellosis and their mode of penetrance. The findings indicate an increased risk of TNF-alpha-308 A allele for human brucellosis reliable with the recessive genetic model of penetrance (Odd Ratio: 3.222, 95% CI: 1.008-5.702, P = 0.018). There is no association between susceptibility of human brucellosis and TNF-alpha-857 C/T polymorphism was observed. The protective role of TNF-alpha-857 C/T polymorphism against human brucellosis in this study population could not be excluded.