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Distinct Roles of Th17 and Th1 Cells in Inflammatory Responses Associated with the Presentation of Paucibacillary Leprosy and Leprosy Reactions Th17 Immune Response in Leprosy.

Abstract

It is well established that helper T cell responses influence resistance or susceptibility to Mycobacterium leprae infection, but the role of more recently described helper T cell subsets in determining severity is less clear. To investigate the involvement of Th17 cells in the pathogenesis of leprosy, we determined the immune profile with variant presentations of leprosy. Firstly, IL-17A, IFN-γ and IL-10 were evaluated in conjunction with CD4(+) T cell staining by confocal microscopy of lesion biopsies from tuberculoid (TT) and lepromatous (LL) patients. Secondly, inflammatory cytokines were measured by multiplex assay of serum samples from Multibacillary (MB, n = 28) and Paucibacillary (PB, n = 23) patients and household contacts (HHC, n = 23). Leprosy patients were also evaluated for leprosy reaction occurrence: LR+ (n = 8) and LR- (n = 20). Finally, peripheral blood mononuclear cells were analyzed by flow cytometry used to determine the phenotype of cytokine-producing cells. Lesions from TT patients were found to have more CD4(+) IL-17A(+) cells than those from LL patients. Higher concentrations of IL-17A and IL-1β were observed in serum from PB than MB patients. The highest serum IFN-γ concentrations were, however, detected in sera from MB patients that developed leprosy reactions (MB LR(+) ). Together, these results indicate that Th1 cells were associated with both the PB presentation and also with leprosy reactions. In contrast, Th17 cells were associated with an effective inflammatory response that is present in the PB forms but were not predictive of leprosy reactions in MB patients. This article is protected by copyright. All rights reserved.

More information

Type
Journal Article
Author
Santos MB
Oliveira DT
Cazzaniga RA
Varjão CS
Santos PLD
Santos M
Correia CB
Faria D
Simon MV
Silva JS
Dutra WO
Reed S
Duthie M
Almeida RP
Jesus AR