Expression of CD4 (+) and CD8 (+) Cells in Uveal Tract of the Eye from Dogs Naturally Infected by Leishmania (L.) Chagasi
Curso de Medicina Veterinária - UNESP - campus de Araçatuba, São Paulo, Brazil, *campus de Botucatu, São Paulo
Leishmaniasis is a zoonosis with various manifestations, one of the being ocular lesions. The main characteristics of these ocular lesions are their high incidence1, 2, a predisposition for the anterior segment of the eye 3 and their persistence despite specific treatments. Some of the most important ophthalmological manifestation of the disease are blepharitis, conjunctivitis, keratoconjunctivitis and kerato uveitis. The purpose of this study was to evaluate the histolocal lesions and expression of CD4(+) and CD8(+) cells in uveal tract of the eye from dogs naturally infected by Leishmania (L.) chagasi
Material and Methods
Eyes from twenty five dogs naturally infected by Leishmania (L.) chagasi from Araçatuba city, São Paulo State, Brazil, and euthanatize d were studied. All animals were parasitologically confirmed as positive by observation of amastigote forms in samples obtained from aspirative needle biopsy of lymph nodes and/or serologic exam by ELISA-assays. Sections (5µm) of eyes with uveitis (20) and eyes without uveitis (5) were submitted to H.E. staining and analysis of the CD4(+) and CD8(+) subsets of T cells by immunohistochemistry.
The ocular signs more observed were: intense iritis, corneal opacity, ciliary injection, flare and íris oedema. Microscopically, the ciliary body and ciliary process exhibited intense inflammatory foci. Areas with abundant round cells, lymphocytes and plasma cells infiltrate were found the ciliary body. Groups of amastigote forms of Leishmania were also seen in these areas, as well as, in nervous layer of retina. The CD4(+) and CD8(+) cells were observed in uveal tract. A higher proportion of CD4(+) T cells expressing was noted in dogs with anterior uveitis, although the CD8(+).
T cells expressing also was observed in all anterior uveal tract.
On basis in this study, the uveitis by Leishmania (L.) chagasi, the presence of CD4(+) cells in major number suggest that B-cells maturation (humoral immunity). Although in minor number, the CD8(+) cells, suggest increase of immune response with destruction of the antigens (Leishmania spp).
Acknowledgements: FUNDUNESP for financial support.