Acta Tropica 95 (2005) 67–73 American tegumentary leishmaniasis: A quantitative analysis of Langerhans cells presents important differences between L. (L.) amazonensis and Viannia subgenus Mar´ ılia Brasil Xavier a,d , Fernando Tobias Silveira b , Sˆ amia Demachki c , M´ arcia Milene Rodrigues Ferreira d , Jos´ e Luiz Martins do Nascimento e,* a Departamento de Medicina Comunit ´ aria, Universidade do Estado do Par´ a, Perebebu´ ı 2623, 66087-670 Bel´ em, Par´ a, Brazil b Departamento de Parasitologia, Instituto Evandro Chagas, Almirante Barroso 492, 66093-020 Bel´ em, Par´ a, Brazil c Departamento de Anatomia Patol´ ogica, Centro de Ciˆ encias de Sa ´ ude, Universidade Federal do Par´ a, Camilo Salgado 01, 66050-060 Bel´ em, Par´ a, Brazil d N´ ucleo de Medicina Tropical, Universidade Federal do Par´ a, General´ ıssimo Deodoro 92, 66055-240 Bel´ em, Par´ a, Brazil e Departamento de Fisiologia, Universidade Federal do Par´ a, Campus Universit´ ario do Guam ´ a, Augusto Corrˆ ea 01, 66075-110 Bel´ em, Par´ a, Brazil Received 3 August 2004; received in revised form 1 April 2005; accepted 6 April 2005 Abstract A quantitative study was conducted on the density of Langerhans cells (LCs) CD1a+ in specimens obtained from patients with American tegumentary leishmaniasis (ATL) lesions without previous treatment, as well as from control healthy individuals. LC density was significantly higher among infected patients when compared to controls and also higher in longer term ones. Regarding parasite quantities, these were proportionally inverse and diminished in chronic patients. Localized cutaneous leishmaniasis (LCL) showed an increase in cell population when compared to diffuse cutaneous leishmaniasis (DCL). A tendency towards density increase was observed in LC Leishmania (Leishmania) amazonensis patients when compared to Leishmania (Viannia) sp. Regarding the delayed hypersensitivity test (DTH, Montenegro skin test), L.(L.) amazonensis demonstrated a peculiar behavior because it is a poor cell immune inducer, presenting – among LCL patients – higher density in negative Montenegro patients than in positive ones. Negative DTH responses are usually poor in LC, although this was not evidenced in this study, possibly due to cell reposition, in order to stimulate immune response. Such results confirm the important role of LC in ATL, while suggesting that L.(L.) amazonensis may be a good model for LC studies as APC in ATL, due to its spectral immunological and clinical behavior. © 2005 Elsevier B.V. All rights reserved. Keywords: Dendritic cells; Cutaneus leishmaniasis; Langerhans cell CD1a+; Immunopathology * Corresponding author. Tel.: +55 91 3183 1545; fax: +55 91 3241 0032. E-mail address: jlmn@ufpa.br (J.L.M. do Nascimento). 0001-706X/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.actatropica.2005.04.016