ABSTRACT
In human cutaneous leishmaniasis (CL), the immune response is mainly mediated by T-cells. The role of CD8+ T-lymphocytes, which are related to healing or deleterious functions, in affecting clinical outcome is controversial. The aim of this study was to evaluate T-cell receptor diversity in late-differentiated effector (LDE) and memory CD8+ T-cell subsets in order to create a profile of specific clones engaged in deleterious or protective CL immune responses. Healthy subjects, patients with active disease (PAD) and clinically cured patients were enrolled in the study. Total CD8+ T-lymphocytes showed a disturbance in the expression of the Vβ2, Vβ9, Vβ13.2, Vβ18 and Vβ23 families. The analyses of CD8+T-lymphocyte subsets showed high frequencies of LDE CD8+T-lymphocytes expressing Vβ12 and Vβ22 in PAD, as well as effector-memory CD8+ T-cells expressing Vβ22. We also observed low frequencies of effector and central-memory CD8+ T-cells expressing Vβ2 in PAD, which correlated with a greater lesion size. Particular Vβ expansions point to CD8+ T-cell clones that are selected during CL immune responses, suggesting that CD8+ T-lymphocytes expressing Vβ12 or Vβ22 are involved in a LDE response and that Vβ2 contractions in memory CD8+T-cells are associated with larger lesions.
.Subject(s)
Adolescent , Adult , Female , Humans , Male , Middle Aged , Young Adult , /immunology , Leishmaniasis, Cutaneous/immunology , Receptors, Antigen, T-Cell/immunology , T-Lymphocyte Subsets/immunology , Brazil , Lymphocyte Activation/immunology , Receptors, Antigen, T-Cell/analysisABSTRACT
American tegumentary leishmaniasis presents as two major clinical forms: localized cutaneous leishmaniasis (LCL) and mucocutaneous leishmaniasis (MCL). The immune response in leishmaniasis is efficiently evaluated by the response to Leishmania antigen through the Montenegro skin test (MST). Both LCL and MCL present positive response to MST, indicating that the patients present cell-mediated immunity against the parasite - Leishmania. In spite of the presence of immunity in MCL, this is not sufficient to stop disease progression and prevent resistance to treatment. In this study we demonstrated interleukin (IL) 2, 4, 5 and interferon (IFN) gamma expression in biopsies of MST of ten patients with American tegumentary leishmaniasis. The obtained results were compared between LCL (n = 5) and MCL (n = 5) patients. The MST of MCL patients displayed a higher expression of IL-2, IL-4 and IL-5, in comparison to LCL. There was no significant difference in IFN-gamma expression between groups. The obtained results suggest the role of IL-4 and IL-5 in the maintenance of the immunopathogenic mechanism of the destructive lesions that characterize MCL.
A leishmaniose tegumentar americana apresenta duas formas clínicas mais comuns: a leishmaniose cutânea localizada e a leishmaniose cutâneo-mucosa. A imunidade da leishmaniose é avaliada pela resposta ao antígeno Leishmania através da Intradermorreação de Montenegro. Estas duas formas apresentam resposta positiva, indicando que o paciente apresenta imunidade celular contra o parasita Leishmania. Apesar da presença da imunidade celular na leishmaniose cutâneo-mucosa, esta não é suficiente para barrar a progressão da doença e a resistência ao tratamento. Neste estudo, detectamos quatro citocinas por imunohistoquímica, IL-2, IL-4, IL-5 e IFN-gama nas biópsias da intradermorreação de Montenegro de pacientes com leishmaniose tegumentar americana (n = 10), cinco com leishmaniose cutânea e cinco com cutâneo-mucosa. Os resultados mostraram uma alta expressão significativa de IL-2, IL-4, IL-5 na leishmaniose cutâneo-mucosa comparada com a leishmaniose cutânea localizada, mas sem diferença significante na expressão do IFN-γ entre os grupos. Estes resultados sugerem a importância da participação da citocina IL-4 e IL-5 na manutenção do mecanismo imunopatogênico das lesões destrutivas da forma cutâneo-mucosa.