Expression of Vitamin D Receptor (VDR) gene and VDR polymorphism rs11574113 in pulmonary tuberculosis patients and their household contacts

Abstract

The vitamin D receptor mediates the effect of vitamin D, which has received substantial attention in its involvement in reducing the risk of tuberculosis (TB). This study sought to see if VDR gene expression and VDR SNP rs11574113 was linked to a person's likelihood of developing tuberculosis. New Pulmonary Tuberculosis (PTB) VDR gene expression and Household Contact (HC) samples VDR gene expressions were examined by the quantitative real-time PCR (qPCR) method, while VDR SNP rs11574113 was identified by PCR followed by sequencing. Latent TB infection in household contacts was screened using an Interferon-Gamma Release Assay (IGRA). Eighty-three PTB, 77 HCs (45 positive-IGRA and 28 negative-IGRA) were involved in this study. Among the 45 positive-IGRA HC, 28 (62.2%) were spouses of index cases. IGRA results showed that 28 out of 37 (75.7%) samples of all spouses recruited have positive IGRA results. VDR gene expression of PTB was 0.2 and 0.25 downregulated compared to negative-IGRA and positive-IGRA HC, respectively (p = 0.014 and p = 0.011). VDR gene expression of positive-IGRA was also 0.788 downregulated compared to negative-IGRA HC but did not reach statistical significance (p = 0.945). The high expression of the VDR gene may be influenced by variant of VDR SNP rs11574113. G/G genotype and G/C genotype were associated with higher VDR gene expression compared to C/C genotype (ORa = 9.754 95% CI 1.482–64.195, p = 0.018 and ORa = 9.723 95% CI 1.416–66.751, p = 0.021, respectively). However, rs11574113 was not found to be associated with TB incidence and IGRA positivity. Approximately 20% of the people with PTB had higher levels of VDR gene expression than those who were not (ORa = 0.736 95% CI 0.542–0.998, p = 0.049). VDR gene expression may be associated with the susceptibility of tuberculosis. This study also shows an immense rate of TB infection among spouses of PTB patients based on IGRA.