G allele at -924 A > G position of FoxP3 gene promoter as a risk factor for tuberculosis.

BACKGROUND: Forkhead box protein 3 (FoxP3) is an important factor for development and function of Regulatory T cells (Treg). Studies have found an association between common gene polymorphisms in FoxP3 and some infectious diseases. The aim of this study was to evaluate possible associations between two Single nucleotide polymorphisms (SNPs) in the promoter of the FoxP3 gene to susceptibility to tuberculosis (TB) and the alteration of Foxp3 gene expression. METHODS: The pattern distribution of genotype at two position, -3279 A > C (rs3761548) and -924 A > G (rs2232365) on the promoter of FoxP3 gene was evaluated using polymerase chain reaction-single specific primer (PCR-SSP) method in 183 tuberculosis patients and 183 healthy control. In addition the quantity of FoxP3 gene expression at mRNA level was identified by the real-time PCR. RESULTS: The frequency of G allele at -924 A > G was significantly higher was higher in TB patients (59.5%) than control group (39.5%) (P ≤ 0.05). In addition, our data viewed approximately 5- folds more FoxP3 gene expression in female patients with GG genotype in comparison to female healthy cases with the same genotype (P ≤ 0.001). There was no statistically significant differences between the distribution pattern of -3279 A > C polymorphism in patients and healthy individuals along with it effect on the FoxP3 gene expression among both groups (P > 0.05). CONCLUSIONS: Our outcome suggests that the -924 A > G polymorphism leads to enhance FoxP3 gene expression and susceptibility to tuberculosis in the sex dependent manner. This event may rise the count of Treg cells and modulate the immune response against tuberculosis.

Single nucleotide polymorphisms of IFNγ (+874 A/T) and IFNγR1 (-56 C/T) in Iranian patients with TB.

BACKGROUND: Two important genes for controlling TB are IFNγ and IFNγR1. However, little information exists regarding genetic susceptibility of the Iranian TB population. METHODS: We investigated the single nucleotide polymorphisms (SNPs) in genes of IFNγ (+874 A/T) and IFNγR1 (-56 C/T) and serum level of IFNγ and their influence on TB in patients; 300 patients with TB and 300 healthy controls were enrolled in this study. PCR-restriction fragment length polymorphism was used to identify SNPs and serum level of IFNγ was measured by ELISA. RESULTS: The allelic and the genotypic form of IFNγ+874 A/T SNP of the studied population were not significant (p>0.05). Allele T frequencies of IFNγR1 -56 C/T promoter region in patients with pulmonary TB (PTB) or extrapulmonary TB (EPTB) were significantly greater than allele C. The -56 TT motif of IFNγR1 is associated with both forms of TB (p<0.05). The serum level of IFNγ was significantly higher in patients with TB than in controls, but there was no significant difference between serum level of IFNγ and the studied genotypes (p>0.05). CONCLUSIONS: The cause of active TB in the patients seems to be due to the lack of effective IFNγ function or the lack of effective signaling connection between IFNγ and its receptor in presence of -56 C/T polymorphism in promoter region of IFNγR1 gene.

The Study of HFE Genotypes and Its Expression Effect on Iron Status of Iranian Haemochromatosis, Iron Deficiency Anemia Patients, Iron-Taker and Non Iron-Taker Controls.

The role of HFE gene mutations or its expression in regulation of iron metabolism of hereditary haemochromatosis (HH) patients is remained controversial. Therefore here the correlation between two common HFE genotype (p.C282Y, p.H63D) and HFE gene expression with iron status in HH, iron deficiency anemia (IDA) and healthy Iranian participants was studied. For this purpose genotype determination was done by polymerase chain reaction--restriction fragment length polymorphism (PCR-RFLP). Real-Time PCR was applied for evaluation of HFE gene expression. Biochemical parameters and iron consumption were also assessed. Homozygote p.H63D mutation was seen in all HH patients and p.C282Y was not observed in any member of the population. A significant correlation was observed between serum ferritin (SF) level and gender or age of HH patients. p.H63D homozygote was seen to be able to significantly increase SF and transferrin saturation (TS) level without affecting on liver function. Our results also showed that iron consumption affects on TS level increasing. HFE gene expression level of IDA patients was significantly higher than other groups. Also the HFE gene expression was negatively correlated with TS. Finally, the main result of our study showed that loss of HFE function in HH is not derived from its gene expression inhibition and much higher HFE gene expression might lead to IDA. However we propose repeating of the study for more approval of our finding.

Increased expression of forkhead box protein 3 gene of regulatory T cells in patients with active tuberculosis.

Cell mediated immunity is the most important response against Mycobacterium tuberculosis (MTB). Regulatory T cells (Treg) play a vital role in suppressing the effector T cell response in tuberculosis (TB) patients. Forkhead box protein 3 (Foxp3) is an important regulator of Treg cells development and function. In this study, we showed that the expression of Foxp3 gene in Treg cells is increased in patients with active tuberculosis. In a case-control study, 183 TB patients and 183 controls were recruited according to ethnicity, gender and living area. Then, after isolation of peripheral blood mononuclear cells (PBMCs), FoxP3 gene expression was studied by real-time PCR. The expression of this gene in patients with pulmonary and extra-pulmonary tuberculosis was 2.8 fold higher than normal subjects (CI=1.29±2.37, P≤0.001). Also comparing the patients with pulmonary tuberculosis and the control group, a significant difference was observed (CI=1.81±2.96, P≤0.001). FoxP3 gene expression was 1.5 fold higher in women with pulmonary and extrapulmonary tuberculosis than in men with tuberculosis (CI=0.12±2.01, P=0.02). According to this study, the increased Foxp3 gene expression in patients with TB was observed and this may play as a contributing factor to suppression of Th1-type immune responses.