Functional biomarker signatures of circulating T-cells and its association with distinct clinical status of leprosy patients and their respective household contacts

Abstract

Background: Leprosy is a chronic infectious disease classified into two subgroups for therapeutic purposes: paucibacillary (PB) and multibacillary (MB), closely related to the host immune responses. In this context it is noteworthy looking for immunological biomarkers applicable as complementary diagnostic tools as well as a laboratorial strategy to detect subclinical leprosy in household contacts. Methods: The main goal of the present study was to characterize the global cytokine signatures of CD4+ and CD8+ T-cells from leprosy patients with distinct clinical forms and their respective household contacts (HHC) upon in vitro antigen-specific stimuli. Short-term culture of peripheral blood mononuclear cells was done. After incubation, cells were harvested and prepared for surface and intracytoplasmic cytokine staining Results: The cytokine signature analysis demonstrated that leprosy patients presented a polyfunctional profile of T-cells subsets, with increased frequency of IFN-g+ T-cell subsets along with IL-10+ and IL-4+ from CD4+ T-cells. Moreover, L(PB) displayed a polyfunctional profile characterized by enhanced percentage of IFN-g+, IL-10+ and IL-4+ produced by most T-cell subsets, as compared to L(MB) that presented a more restricted cytokine functional profile mediated by IL-10+ and IL-4+ T-cells with minor contribution of IFN-g produced by CD4+ T-cells. Noteworthy was that HHC(MB) exhibited enhanced frequency of IFN-g+ T-cells, contrasting with HHC(PB) that presented a cytokine profile limited to IL-10 and IL-4. Conclusions: Together, our findings provide additional immunological features associated with leprosy and household contacts. These data provide evidence that biomarkers of immune response can be useful complementary diagnostic/prognostic tools as well as insights that household contacts may present subclinical infection.