Together, CD and ulcerative colitis are referred to as inflammatory bowel disease (IBD). The chromosomal region, 6p21, IBD3, has been identified as an IBD-susceptibility locus [99–101]. IBD3 region encompasses the tumour necrosis factor α (TNF) gene. TNF-alpha is considered as a strong candidate gene for IBD. Levels of TNF are elevated in the serum, mucosa and stool of patients with IBD. TNF production is under a strong genetic influence [102]. The positive association of TNF rs1799724

C with UC was reported CHIR-99021 concentration in Caucasians and is also supported by a small Japanese case–control study. The same study reported an association of TNF rs1799724 T with Japanese CD, although a significant effect of this allele was not observed in a larger patient cohort [103]. The associations between TNF-alpha and Fc-gamma receptor (Fc-gammaR) polymorphism with infliximab (IFX) treatment for CD are not well known. Patients with CD were given IFX 5 mg/kg intravenously and followed prospectively for 8 weeks, and the Crohn’s disease activity index (CDAI) was measured before and after 8 weeks of treatment [104]. On the basis of predicted CD activity

index, patients were grouped as responders or non-responders. The TNF-alpha, Fc-gammaRIIA and Fc-gammaRIIIA genotype distribution was not significantly different Fulvestrant in vitro between responders and non-responders 8 weeks after treatment. Fc-gammaRIIIB genotype distribution has shown significant differences between responders and non-responders after 8 weeks. Fc-gammaRIIIB polymorphism may be an important factor for clinical response to IFX treatment in CD. Asthma is a complex polygenic disease in which gene–environment interactions have shown to play important role. TNFα gene is one of the important Aprepitant candidate genes involved in pathogenesis of asthma. Several studies have investigated TNFα rs1800629 polymorphism (rs1800629 G designated as TNF1 and rs1800629 A designated as TNF2) and asthma susceptibility in different populations. A positive association between TNF2 and asthma [79, 105–112]

have been reported. Some studies have been reported a negative association [113–116], and one study reported a positive association between TNF1 and asthma [117]. Gao et al. [118] included 2409 patients with asthma and 3266 controls, in the study. They found that TNF2 allele confers a significant risk of developing asthma. Juran et al. [119] recently reported an association between primary biliary cirrhosis (PBC) and (rs231725) polymorphism of the immunoreceptor gene cytotoxic T-lymphocyte antigen 4 (CTLA4). They have detected its interaction with the rs1800629 polymorphism in which TNF2A allele has been shown to increase the TNF production. The genotyping of polymorphism was carried out in patients with PBC and in controls from US and Canada. Allele frequency for TNF2A was elevated in patients with PBC, but only borderline significance was detected.