Introduction:
The vitamin D metabolic pathway has been shown to play a pivotal role in the pathogenesis of pulmonary tuberculosis (PTB), and vitamin D receptor (VDR) and CYP2R1 gene variation are known to affect vitamin D status. Hence, this study aimed to evaluate VDR and CYP2R1 mRNA expression in peripheral blood mononuclear cells (PBMCs) in PTB patients.

Material and methods:
We measured VDR and CYP2R1 mRNA levels in 75 PTB patients and 63 healthy controls by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). The associations of VDR and CYP2R1 mRNA levels with clinical characteristics and laboratory indexes of PTB patients were also examined in this study.

Results:
Compared to healthy controls, the VDR mRNA level was significantly higher, and the CYP2R1 mRNA level was significantly lower in PBMCs from PTB patients (p = 0.047, p = 0.008, respectively). The CYP2R1 mRNA level in PTB patients with drug-resistant, unilateral tuberculosis foci was significantly higher than that in PTB patients without these clinical characteristics (p = 0.005, p = 0.048, respectively). In addition, our results demonstrated that the VDR mRNA expression level was positively correlated with erythrocyte sedimentation rate (ESR) (p = 0.045), while the CYP2R1 mRNA level was negatively correlated with ESR in PTB patients (p = 0.020).

Conclusions:
Altered VDR and CYP2R1 mRNA expression levels among PTB patients suggest their involvement in this disease.