The production and gene polymorphisms of tumor necrosis factor-alpha in patients with tuberculosis in the Vhembe District, Limpopo Province

Abstract

Background: Tuberculosis (TB) is an old, irresistible infection caused by Mycobacterium tuberculosis (Mtb). The causative agent has antigens that can stimulate the production of cytokines via the mononuclear phagocyte system. Although mutations in immune-related genes may directly impact a host’s ability to control the infection when exposed to M.tb, the pro-inflammatory cytokine Tumor Necrosis Factor- α is crucial in host defence against TB and granuloma formation. Therefore, this study aimed to assess the production and gene polymorphisms of TNF-α in patients with TB in the Vhembe district, Limpopo province. Methods: This study recruited thirteen TB patients from three healthcare facilities in the Vhembe district, Limpopo province. Collected samples (sputum) were analysed using the Allplex/Anyplex kit, to detect the presence of Mycobacterium tuberculosis. Serum was collected from the blood and used to determine the levels of TNF-α in the participants, using the DIAsource ELISA kit. Genomic DNA was extracted from blood samples and purified using the Zymo kit from Inqaba Biotec. The purified DNA was quantified using the Nanodrop 8 from Thermo Fischer. The quantified DNA was analyzed by MassARRAY system to sequence various TNF-α SNPs. Data analysis for this study was carried out using the Jamovi software for windows version 2.5.3. Results: This study found that about 69% of the participants were male and 62% were ≤48 years of age. The majority of the participants (62%) were unemployed. Additionally, 46% of the sputum samples were positive for Mtb. There was a high prevalence (69%) in participants with moderate TNF-α levels. Furthermore, this study found ten SNPs namely: rs10242595, rs1524107, rs1799724, rs1799964, rs1800629, rs1800630, rs1800750, rs3093662, rs309376, and rs361525. The following alleles were reported to have higher frequency than the other: rs10242595 A* (58%), rs1524107 C* (58%), rs1799724 C* (100%), rs1799964 T* (93), rs1800629 G* (88), rs1800630 C* (92), rs1800750 G* (85), rs3093662 A* (73%) and rs361525 A* (100). The allele frequency in rs309376 was evenly distributed G* (50%) and A* (50%). Conclusion: Our findings suggest that there’s a correlation between TNF-α levels and risk factors and also, there’s a significant association between TNF-α SNPs and TNF-α expression levels.