Plasma Vitamin D Levels in Correlation with Circulatory Proteins Could Be a Potential Biomarker Tool for Pulmonary Tuberculosis and Treatment Monitoring

Background: Tuberculosis (TB), a life-threatening immune challenging disease to the global human community has to be diagnosed earlier and eliminated in the upcoming era. Vitamin D, a fat-soluble micronutrient, mainly from epidermal cells of the skin and a few dietary sources, is associated with the immune system in various disease management. Therefore, a better understanding of vitamin D metabolism and immune function in tuberculosis should be studied for the consideration of biomarkers.Methods: The study consist of Pulmonary Tuberculosis (PTB) patients (n = 32) at two-time points: Baseline (PTB BL) and after 6 months of anti-TB treatment (ATT) (PTB PT), latently Mtb infected (IFN & gamma; + ) group (n = 32) and a non-LTB healthy control (IFN & gamma;-) group (n = 32). Vitamin D levels were measured using High-performance liquid chromatography (HPLC). The cytokine data from the same participants assayed by ELISA from our earlier in-vestigations were used to correlate it with serum Vitamin D levels.Results: The assayed serum Vitamin D levels between the groups showed significantly lowered levels in PTB BL when compared with IFN & gamma; + and IFN & gamma;-groups. And, the Vitamin D levels in the PTB group after ATT were significantly lower than the baseline levels. The Vitamin D data were compared with pro-and anti-inflammatory cytokines and adipokines levels by performing a principal component regression analysis. Based on the PC scores, the study group showed distinct clusters for the TB group and control group. And, the correlation analysis be-tween the study group and immunological indices showed significant correlations. Vitamin D significantly correlated with IFN & gamma;, TNF & alpha;, IL17A, IL-4 and Resistin in the TB group, whereas IL-6 and G-CSF in the control group. Conclusion: The baseline measurement of Vitamin D levels was significantly decreased in the PTB group when compared with IFN & gamma; + and IFN & gamma;-groups showing the importance of Vitamin D as a preventive factor against the TB disease progression. The six-month post-treatment of TB showed a further decrease in Vitamin D levels in PTB. The significantly correlated immunological indices with Vitamin D levels are the biomarker profile that could predict TB.