Association of serum cathelicidin and Vitamin D levels with infectiousness in patients with pulmonary tuberculosis: A prospective cohort study.

Background: The immunomodulatory effects of Vitamin D expand to induce the synthesis of an antimicrobial peptide, cathelicidin. There is evidence showing altered levels of cathelicidin in tuberculosis (TB). It has been suggested that Vitamin D-mediated antimicrobial activity depends on its ability to induce cathelicidin. The present study was designed to assess the alterations in serum anti-microbial peptide cathelicidin and 25-hydroxy Vitamin D levels in patients with newly diagnosed pulmonary TB at different treatment times and to study the association between serum Vitamin D levels and cathelicidin.

Methods: Serum 25-hydroxyvitamin D and cathelicidin levels were estimated in 147 patients with newly diagnosed pulmonary TB at different times: at the start of anti-tubercular treatment, end of the intensive phase of treatment, and at the end of treatment.

Results: There was a statistically significant difference between the levels of serum 25-hydroxyvitamin D and serum cathelicidin at different treatment periods. However, no significant correlation was found between serum Vitamin D and cathelicidin levels or between serum Vitamin D and cathelicidin levels with infectiousness in patients with pulmonary TB.

Conclusion: Serum Vitamin D levels and serum cathelicidin levels were significantly reduced at diagnosis, and there was an incremental increase following treatment. However, there was no correlation between the levels of serum cathelicidin and serum Vitamin D or with the infectiousness of the illness.