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Title: Increased Expression of Regulatory T Cells and Down-Regulatory Molecules in Lepromatous Leprosy
Authors: PALERMO, Maria L.PAGLIARI, CarlaTRINDADE, Maria Angela B.YAMASHITAFUJI, Tania M.DUARTE, Alberto Jose S.CACERE, Camila R.BENARD, Gil
Abstract: T regulatory cells (Tregs) play an important role in the mechanism of host's failure to control pathogen dissemination in severe forms of different chronic granulomatous diseases, but their role in leprosy has not yet been elucidated; 28 newly diagnosed patients (16 patients with lepromatous leprosy and 12 patients with tuberculoid leprosy) and 6 healthy Mycobacterium leprae-exposed individuals (contacts) were studied. Tregs were quantified by flow cytometry (CD4+ CD25+ Foxp3+) in peripheral blood mononuclear cells stimulated in vitro with a M. leprae antigenic preparation and phytohemagglutinin as well as in skin lesions by immunohistochemistry. The lymphoproliferative (LPR), interleukin-10 (IL-10), and interferon-gamma (IFN-gamma) responses of the in vitro-stimulated peripheral blood mononuclear cells and the in situ expression of IL-10, transforming growth factor-beta (TGF-beta), and cytotoxic T-lymphocyte antigen 4 (CTLA-4) were also determined. We show that M. leprae antigens induced significantly lower LPR but significantly higher Treg numbers in lepromatous than tuberculoid patients and contacts. Mitogen-induced LPR and Treg frequencies were not significantly different among the three groups. Tregs were also more frequent in situ in lepromatous patients, and this finding was paralleled by increased expression of the antiinflammatory molecules IL-10 and CTLA-4 but not TGF-beta. In lepromatous patients, Tregs were intermingled with vacuolized hystiocyte infiltrates all over the lesion, whereas in tuberculoid patients, Tregs were rare. Our results suggest that Tregs are present in increased numbers, and they may have a pathogenic role in leprosy patients harboring uncontrolled bacillary multiplication but not in those individuals capable of limiting M. leprae growth.
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Artigos e Materiais de Revistas Científicas - FM/MDT
Departamento de Dermatologia - FM/MDT

Artigos e Materiais de Revistas Científicas - FM/MPT
Departamento de Patologia - FM/MPT

Artigos e Materiais de Revistas Científicas - HC/ICESP
Instituto do Câncer do Estado de São Paulo - HC/ICESP

Artigos e Materiais de Revistas Científicas - HC/ICHC
Instituto Central - HC/ICHC

Artigos e Materiais de Revistas Científicas - LIM/03
LIM/03 - Laboratório de Medicina Laboratorial

Artigos e Materiais de Revistas Científicas - LIM/06
LIM/06 - Laboratório de Imunopatologia da Esquistossomose e outras Parasitoses

Artigos e Materiais de Revistas Científicas - LIM/56
LIM/56 - Laboratório de Investigação em Dermatologia e Imunodeficiências

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