Mycobacterial r32-kDa Ag specific T cell responses correlate with successful treatment and heightened antimicrobial response in human leprosy patients.

BACKGROUND: Immunological characterization of mycobacterial peptides may help not only in the preparation of a vaccine for leprosy but also in developing in vitro T cell assay that could perhaps be used as an in vitro correlate for treatment outcome. The main goal of this study was to evaluate the use of r32-kDa Ag stimulated T cell assay as a surrogate marker for treatment outcome and monitor Vitamin D Receptor (VDR) mediated antimicrobial responses during MDT in leprosy.

METHODS: Newly diagnosed tuberculoid & lepromatous leprosy patients were enrolled and followed-up during their course of multi-drug-therapy at 6(th) and 12(th) month. IFN-γ, IL-10, IL-17 and IL-23 levels in culture supernatants and expression of VDR, TLR2, LL37 & DEFB in r32kDa-stimulated PBMC were performed. Controls comprised of house-hold contacts and healthy endemic subjects.

RESULTS: Significant differences were observed in the levels of IFN-γ, IL-17, IL-23, VDR and antimicrobial-peptides LL37 & DEFB after treatment and when compared to that of HHC and HC respectively.

CONCLUSIONS: These findings suggest that responses to r32-kDa Ag reflect an improved immunological and antimicrobial response in leprosy patients during therapy, thereby indicating its potential use as an immune correlate in the treatment of leprosy patients.