immunology of infectious and parasitic diseases - XXXVII Congress ...

CYTOTOXICITY IN IMMUNOPATHOGENESIS OF AMERICAN
TEGUMENTARY LEISHMANIASIS – PRELIMINARY RESULTS
CLARISSA FERREIRA CUNHA (PG) 1 ; RAQUEL FERRAZ (PG) 1,2 ; ALDA
MARIA DA-CRUZ 3 ; ARMANDO SCHUBACH 4 ; MARIA INÊS F. PIMENTEL 4 ;
MARCELO R. LYRA (PG) 4 ; CLÁUDIA M. VALETE-ROSALINO 4 ; ÁLVARO L.
1, 2
BERTHO
1 Laboratório de Imunoparasitologia; 2 Plataforma de Citometria de Fluxo;
3 Laboratório Interdisciplinar em Pesquisas Médicas; Instituto Oswaldo Cruz,
FIOCRUZ, Rio de Janeiro, RJ; 4 Serviço de Referência em Leishmaniose,
Instituto de Pesquisa Clínica Evandro Chagas, FIOCRUZ, Rio de Janeiro, RJ.
Introduction: The clinical course of American tegumentary leishmaniasis (ATL)
depends on the interaction between the parasite and the immune response of
patients. Is well known that CD8 + T lymphocytes play a key role in this response
due to their cytotoxic potential and cytokine production. Moreover, natural killer
cells (NK), natural killer T cells (NKT) and a cytotoxic subpopulation of CD4 + T
lymphocytes present similar functions, and therefore few studies point to the
roles of these cell populations in the pathogenesis in ATL. The aim of this study
is to evaluate the frequency and the cytotoxic effector role of these cell
populations, by immunophenotyping and evaluating the expression of CD107a,
in blood samples from patients with active disease and at different stages of
treatment. Methods and Results: Peripheral blood mononuclear cells were
obtained from healthy individuals and from patients with active disease, during
and after clinical antimonial treatment. These cells were submitted to a flow
cytometry analysis to assess the distributions of CD4 + or CD8 + T lymphocytes,
NK and NKT cells, and their cytotoxicity profiles by identifying the CD107a
expression. Preliminary results have allowed us to observe that the percentage
of CD8 + T cells is higher in patients after treatment compared to patients with
active disease and, conversely, is noted a decrease in the frequency of CD4 + T
lymphocytes, NK and NKT cells in this patients. In addition, it was observed a
higher percentage in both CD8 + T and NK cells that express CD107a in patients
after treatment under specific in vitro stimulation. Conclusion: These
preliminary results corroborate the important role of CD8 + T lymphocytes in the
resolution of the disease, showing still a most remarkable cytotoxic activity of
this cells as well as NK after clinical cure of ATL. More experiments are being
performed in our laboratory so such results will be discussed further.
Support: IOC/FIOCRUZ; IPEC/FIOCRUZ; CAPES; CNPq; Beckman Coulter