Interplay of Chemo Attractant Peptides (Cathelicidin and Chemerin) with Vitamin- D in Patients with Pulmonary Tuberculosis

Aim: Both Cathelicidin and Chemerin are chemo-attractant proteins and possess antimicrobial activity. Sufficient level of Vitamin D is important for optimum response of Cathelicidin for its anti-mycobacterial activity. Studies on the role of these antimicrobial peptides and their relationship with Vitamin D level are limited in tuberculosis. The aim of this study was to investigate an association of Vitamin D with antimicrobial peptide (Cathelicidin) and an adipokine (Chemerin) in patients with pulmonary tuberculosis (TB).
Methods: In a case control study we estimated level of Vitamin D, Chemerin, Cathelicidin and TNF α in pulmonary TB patients (n=22) and healthy endemic controls (n=17) using sandwich ELISA methodology. The study was conducted at Aga Khan University Karachi during 2011.
Results: TB group had higher proportion of subjects above median level of Cathelicidin (median test; p=0.034) and fewer number of subjects with Chemerin (median test; p=0.001). Pairwise comparison also showed significant differences between average ranks of Vitamin D vs. Cathelicidin (p<0.0001), Chemerin vs. Cathelicidin (p=0.04) and Vitamin D vs. TNFα (p<0.0001). Cathelicidin was identified as most discriminatory marker between TB disease and healthy group (ROC, AUC 0.780; p=0.007).
Conclusion: Our results highlight the role of Cathelicidin as a potential biomarker of active TB disease. The role of Cathelicidin and Chemerin as plausible biomarkers requires further studies in both inflammatory and non-inflammatory conditions.