© 2008 The Authors 637 Journal compilation © 2008 Blackwell Publishing Ltd Parasite Immunology , 2008, 30, 637–640 DOI: 10.1111/j.1365-3024.2008.01056.x Blackwell Publishing Ltd ORIGINAL ARTICLES Mast cells and leishmaniasis Brief Definitive Report Histopathology of mast cells and cytokines during healing of human mucosal leishmaniasis V. S. AMATO, 3 F. F. TUON, 1 A. C. NICODEMO 1 & M. I. S. DUARTE 2 1 Department of Infectious Diseases, 2 Laboratory of the Discipline of Pathology of Transmissible Disease, 3 Clinic of Infectious Diseases, Hospital das Clinicas, University of Sao Paulo, Faculty of Medical Sciences, Sao Paulo, Brazil SUMMARY Mast cells (MCs) are associated with chronic inflammatory diseases. However, there is no study evaluating the importance of MCs in the mucosal leishmaniasis (ML). The aim of this study was to quantify the most important cytokines associated with mucosal leishmaniasis, before and after disease treatment, correlating with the healing. A cohort of 12 patients with ML was evaluated, and biopsies were taken before and after the treatment. A quantitative estimation of MCs and some cytokines was analysed by density of the labelled cells through immunohistochemistry. The MCs count in the tissue from patients with ML before treatment showed a mean of 29·3 ± 37·9 cells/mm 2 . The MCs count in patients with ML after healing decreased to 14·8 ± 23·9 cells/mm 2 . There was an inverse relation of MCs with IFN-γ and IL-4 expression (r 2 = 29·4 and r 2 = 22·3 with P < 0·05). The expression of IL-10 and TNF-α was not related with MCs count. MCs decrease after treatment associated with decrease of IL-4 and IFN-γ. The explanations of cytokine correlation are discussed in the article. Keywords leishmaniasis, Leishmania, mucosal leishmaniasis, immune response, mast cell Mast cells (MCs) in the inflammatory infiltrate of the leishmaniasis have been described a long time ago (1). Nevertheless, the importance of this cell had been always neglected. Mast cells in the skin or even mucosal lesions are important, however, only recently studies evaluating the function of mast cells were published. In the first step of leishmaniasis, unspecific antibodies bind to the parasite surface, which will attach on MC by Fc receptors, promoting degranulation with cytokines release (TNF-α, IFN-γ, IL-4, IL-10, IL-12 and IL-6) and other molecules (2). Several aspects of the immune response of mucosal leishmaniasis (ML) have been recently discovered (3), but the importance of MCs was never described. Studies evaluating the immune response before and after treatment have described the importance of some cytokines in the ML, as TNF-α by Amato et al. (4). However, the presence of MCs in ML was limited to histopathological description without correlation with immune response. There is no study evaluating the importance of MCs in the mucosal leishmaniasis by correlation of cytokine’s expression. Considering the importance of MC in chronic inflammatory process, mainly in healing process, the aim of this study was quantify the most important cytokines evolved in the immune response of ML before and after treatment, correlating with the healing. A cohort of 12 patients with confirmed mucosal leish- maniasis was evaluated during a long-term follow-up. Patients treated for previous leishmaniasis or receiving immuno- suppressive drugs during the last year before the study were excluded. Two fragments of mucosal lesions were obtained: the first before treatment and the second at least 6 months after the detection of mucosal lesion healing (after the specific treatment). The criterion of mucosal lesion healing was defined previously (5). These patients were followed up for 5 years to be classified as cured. Correspondence: Valdir Sabbaga Amato, Infectious and Parasitic Diseases Clinic, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, Avenida Dr Enéas de Carvalho Aguiar 255, 4° andar. Sala 4028 – ICHC, Cerqueira César, ZIP code 05403-010, São Paulo, Brazil (e-mail: valdirsa@netpoint.com.br). Received: 4 June 2008 Accepted for publication: 21 July 2008