Page 113 - Resúmen - XXV Congreso Latinoamericano de Parasitología - FLAP

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Non- ulcerated or atypical cutaneous leishmaniasis by Leishmania (L.)

infantum in Central America

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Laurenti MD , Sandoval Pacheco CM , Araujo Flores GV , Sosa Ochoa W , Zúniga
Valeriano C , Silveira F T 4,5 , Castro Gomes CM , da Matta VLR , Corbett CEP
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1 Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil; Instituto de Microbiología,
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Universidad Autónoma de Honduras, Tegucigalpa, Honduras; 3 Hospital Escuela Universitario,
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Tegucigalpa, Honduras; Instituto Evandro Chagas, Belém, PA, Brasil; Universidade Federal do Pará,
Belém, PA, Brasil.

In Central America, non-ulcerated skin lesions, designated as non-ulcerated or atypical cutaneous
leishmaniasis (NUCL) caused by Leishmania (L.) infantum, has been reported. Visceral leishmaniasis and
non-ulcerated or atypical cutaneous leishmaniasis are caused by the same etiologic agent, Leishmania (L.)
infantum and occur in the same geographical area. NUCL is the most common clinical form, affecting mainly
children older than 5 years and young adults. The lesion is defined as a papule, painless nodule, non-
ulcerative, erythematous or skin color, in the presence or absence of hypopigmented halo. The most
significant histopathological changes are observed in the dermis, and they are characterized by a
lymphohistiocytic inflammatory infiltrate of variable intensity and associated to the formation of epithelioid
granulomas. Usually, the skin parasitism is discreet. The immunohistochemical analysis of the lesions
confirm the presence of mononuclear cells in the inflammatory infiltrate characterized mainly by the
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presence of T-CD8 lymphocytes, followed by T-CD4 , macrophages, B lymphocytes and NK cells, and
inflammatory cytokines as IFN- and IL-6. The involvement of FoxP3 cells and regulatory cytokines (TGF-
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β and IL-10 cells) is discrete, as well as IL-17 cells. Interesting, great part of these patients develop a
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strong and positive delayed type hypersensitivity against specific antigen and low title of specific IgG
antibodies. The data suggest a strong participation of the systemic and local inflammatory immune
response in non-ulcerated or atypical cutaneous leishmaniasis, able to control the tissue parasitism and
consequently the evolution of the lesion size; however, although discreet, the regulatory immune response
may be responsible for maintaining a balance in the cellular immune response avoiding tissue damage and
leading to low tissue parasitic persistence necessary for the maintenance of a protective and lasting
immunity.
Supported by FAPESP, CNPq, CAPES, LIM50 HCFMUSP

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