Association of P2X7 gene common polymorphisms with pulmonary tuberculosis in Lur population of Iran

P2X7 polymorphism (rs3751143) and its reliability as a diagnostic biomarker for tuberculosis: A systematic review and meta-analysis

Tuberculosis (TB) is one of the most important infectious diseases and is accounted for as the second most common cause of death due to infectious agents after HIV. It is estimated that a quarter of the world's population is infected with Mycobacterium tuberculosis (Mtb), and 5-10% of whom will be infected with active TB. Introducing a biomarker to predict TB can help control the disease and reduces the burden of mortality from this infectious disease. P2X7/P2X7R is one of the most important axes of the innate immune system, which its activity increases the clearance of the residual bacteria in macrophages. Numerous studies have shown the association between rs3751143 polymorphism and susceptibility to TB. The present study aimed to evaluate the diagnostic value of this polymorphism in predicting TB. In the current quantitative analysis, we studied the data from twenty relevant case-control studies, consisting of 10,544 volunteers. We found that, although rs3751143 polymorphism causes susceptibility to TB, but based on statistical analysis, it cannot be considered as a reliable biomarker for the diagnosis of TB.

Associations Between the Purinergic Receptor P2X7 and Leprosy Disease

Leprosy is an infectious disease still highly prevalent in Brazil, having been detected around 27,863 new cases in 2019. Exposure to Mycobacterium leprae may not be sufficient to trigger the disease, which seems to be influenced by host immunogenetics to determine resistance or susceptibility. The purinergic receptor P2X7 plays a crucial role in immunity, inflammation, neurological function, bone homeostasis, and neoplasia and is associated with several infectious and non-infectious diseases. Here, we first compare the P2RX7 expression in RNA-seq experiments from 16 leprosy cases and 16 healthy controls to establish the magnitude of allele-specific expression for single-nucleotide polymorphisms of the gene P2RX7 and to determine the level of gene expression in healthy and diseased skin. In addition, we also evaluated the association of two P2RX7 single-nucleotide polymorphisms (c.1513A>C/rs3751143 and c.1068A>G/rs1718119) with leprosy risk. The expression of P2RX7 was found significantly upregulated at macrophage cells from leprosy patients compared with healthy controls, mainly in macrophages from lepromatous patients. Significant risk for leprosy disease was associated with loss function of rs3751143 homozygous mutant CC [CC vs. AA: p = 0.001; odds ratio (OR) = 1.676, 95% CI = 1.251–2.247] but not with heterozygous AC (AC vs. AA: p = 0.001; OR = 1.429, 95% CI = 1.260–1.621). Contrary, the polymorphic A allele from the gain function of rs1718119 was associated with protection for the development of leprosy, as observed in the dominant model (AA + AG × GG p = 0.0028; OR = 0.03516; CI = 0.1801–0.6864). So, our results suggest that the functional P2X7 purinergic receptor may exert a key role in the Mycobacterium death inside macrophages and inflammatory response, which is necessary to control the disease.

Association between P2X7 Polymorphisms and Susceptibility to Tuberculosis: An Updated Meta-Analysis of Case-Control Studies

Background and Objectives: Several studies inspected the impact of P2X7 polymorphisms on individual susceptibility to tuberculosis (TB), but the findings are still controversial and inconclusive. To achieve a more precise estimation, we conducted a meta-analysis of all eligible studies on the association between P2X7 polymorphisms and TB risk. Materials and Methods: Relevant studies were identified by searching the PubMed, Web of Science, Scopus and Google scholar databases up to November 2018. Twenty-four full-text articles were included in our meta-analysis. The strength of association between P2X7 polymorphisms and TB risk was evaluated by odds ratios (ORs) and 95% confidence intervals (95% CIs) under five genetic models. Results: The findings of this meta-analysis revealed that the rs3751143 variant significantly increased the risk of TB in heterozygous codominant (OR = 1.44, 95%CI = 1.17-1.78, p = 0.0006, AC vs. AA), homozygous codominant (OR = 1.87, 95% CI = 1.40-2.49, p = 0.0004, CC vs. AA), dominant (OR = 1.50, 95% CI = 1.22-1.85, p = 0.0002, AC + CC vs. AA), recessive (OR = 1.61, 95% CI = 1.25-2.07, p = 0.001, CC vs. AC + AA), and allele (OR = 1.41, 95% CI = 1.19-1.67, p < 0.0001, C vs. A) genetic models. Stratified analysis showed that rs3751143 increased the risk of pulmonary tuberculosis (PTB) and extrapulmonary tuberculosis (EPTB) in all genetic models. Furthermore, the rs3751143 increased risk of TB in the Asian population. The findings did not support an association between the rs2393799, rs1718119, rs208294, rs7958311, and rs2230911 polymorphisms of P2X7 and TB risk. Conclusions: The findings of this meta-analysis suggest that P2X7 rs3751143 polymorphism may play a role in susceptibility to TB in the Asian population. More well-designed studies are required to elucidate the exact role of P2X7 polymorphisms on TB development.