Crosstalk between vitamin D axis, inflammation and host immunity mechanisms: A prospective study

Tuberculosis (TB) remains a public health burden, after many years at attempts for its eradication. Vitamin D (VD) status has been suggested to be related to TB susceptibility because it has the ability to regulate multiple axes of the innate and adaptive host immune response. VD mediates cathelicidin (LL-37) synthesis, a cationic bactericidal peptide, through the expression of vitamin D receptor (VDR). Host innate defense mechanisms include autophagy and apoptosis of alveolar macrophages. The present study aimed to assess the relationship between VD status, inflammation and host defense mechanisms before and after two months of first-line anti-TB pharmacotherapy. The study included newly diagnosed individuals with pulmonary TB without co-morbidities (HIV infection, diabetes, cancer) and without VD supplementation or other therapies interfering with VD serum levels. We measured serum levels of 25-hydroxyvitamin D (25-(OH)-D), the major circulating form of vitamin D, VDR, LL-37, beclin-1 (an autophagy marker) and M30 (an apoptosis biomarker) before and after two months of anti-TB treatment. Individuals presented lower levels of 25-(OH)-D before receiving first-line anti-TB treatment (T0) in comparison with its plasmatic levels after two-months of therapy (T2). At T2, patients were divided in two subgroups according the results of sputum-culture conversion. After two-months of therapy, decreased values of LL-37, beclin-1 and M30 were observed in the culture-negative patients compared to the culture-positive patients. Control of anti-TB treatment outcome could be improved by appraisal of VD status and host defense mechanisms such as autophagy and apoptosis.

Automated summary

Tuberculosis (TB) remains a public health burden, and there is a suggested relationship between vitamin D (VD) status and TB susceptibility. A study found that newly diagnosed pulmonary TB patients had lower 25-(OH)-D levels before first-line anti-TB treatment, which increased after two months of therapy. Additionally, culture-negative TB patients showed lower levels of LL-37, beclin-1, and M30 compared to culture-positive patients after two months of treatment. This suggests that monitoring VD status and host defense mechanisms could improve the outcomes of anti-TB treatment.