DEFAR - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531
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Item Phenotypic features of circulating leucocytes as immunological markers for clinical status and bone marrow parasite density in dogs naturally infected by Leishmania chagasi.(2006) Reis, Alexandre Barbosa; Carvalho, Andréa Teixeira de; Giunchetti, Rodolfo Cordeiro; Guerra, Luanda Liboreiro; Carvalho, Maria das Graças; Mayrink, Wilson; Genaro, Odair; Oliveira, Rodrigo Corrêa de; Martins Filho, Olindo AssisCanine visceral leishmaniasis (CVL) manifests itself as a broad clinical spectrum ranging from asymptomatic infection to patent severe disease. Despite relevant findings suggesting changes on lymphocytes subsets regarding the CVL clinical forms, it still remains to be elucidated whether a distinct phenotypic profile would be correlated with degree of tissue parasite density.Herein, we have assessed the correlation between the clinical status as well as the impact of bone marrow parasite density on the phenotypic profile of peripheral blood leucocytes in 40 Brazilian dogs naturally infected by Leishmania chagasi. Our major findings describe the lower frequency of B cells and monocytes as the most important markers of severe CVL. Our main statistically significant findings reveal that the CD8+ T cell subset reflects most accurately both the clinical status and the overall bone marrow parasite density, as increased levels of CD8+ lymphocytes appeared as the major phenotypic feature of asymptomatic disease and dogs bearing a low parasite load. Moreover, enhanced major histocompatibility complex (MHC)-II density as well as a higher CD45RB/CD45RA expression index seems to represent a key element to control disease morbidity. The association between clinical status, bone marrow parasitism and CD8+ T cells re-emphasizes the role of the T cellmediated immune response in the resistance mechanisms during ongoing CVL. Higher levels of circulating T lymphocytes (both CD4+ and CD8+ T cells) and lower MHC-II expression by peripheral blood lymphocytes seem to be the key for the effective immunological response, a hallmark of asymptomatic CVL.Item Evaluation of the influence of tissue parasite density on hematological and phenotypic cellular parameters of circulating leukocytes and splenocytes during ongoing canine visceral leishmaniasis.(2009) Guerra, Luanda Liboreiro; Carvalho, Andréa Teixeira de; Giunchetti, Rodolfo Cordeiro; Martins Filho, Olindo Assis; Reis, Alexandre Barbosa; Oliveira, Rodrigo Corrêa deDuring Leishmania infection, tissue parasitism at different sites may differ and imply distinct immunopathological patterns during canine visceral leishmaniasis (CVL). For this reason, we have assessed by flow cytometry the impact of spleen and skin parasite density on the phenotypic profile of splenocytes and circulating leukocytes of 40 Brazilian dogs naturally infected by Leishmania chagasi categorized according to splenic and cutaneous parasite load. Our major statistically significant findings demonstrated that dogs with splenic high parasitism presented a significant decrease in absolute counts of CD5+ T lymphocytes in comparison with dogs presenting splenic medium parasitism. Moreover, a decrease in the absolute number of circulating monocytes was observed as a hallmark of high parasitism. The increased frequency of CD8+ T cells is associated with low splenic parasitism during CVL. Although we did not found any significant differences between the immunophenotypic analysis performed in circulating lymphocytes according to cutaneous parasite load, there were negative correlations between CD5+ and CD8+ T cells and cutaneous parasite density reemphasizes the role of T cell-mediated immune response in resistance mechanisms during ongoing CVL. These results add new insights about the pathogenesis of CVL and may help in the establishment of additional tools for future studies on drugs and vaccine approaches.