Immunopathology of the uveitis in canine leishmaniasis

Abstract

Particular immunopathological features and their effects on the vascular permeability of different ocular structures were analysed in two dogs naturally infected by Leishmania infantum. The existence of specific anti-Leishmania immunoglobulin G (IgG) in the aqueous humour was confirmed by the ELISA technique. There was no correlation between antibody levels in the aqueous humour and the related serum. The histopathological study of the eyes showed the existence of lesions in various ocular structures. The ciliary processes, ciliary body, sclerocorneal limbus, iris and lacrimal duct showed intense inflammatory zones with lymphocyte infiltrates, plasmatic cells and macrophages with amastigote forms of Leishmania. In addition vasculitis with dilation and thrombi were also detected in both cases, with consequent oedema and hyalinization. The immunohistochemistry analysis revealed the presence of granular and diffuse IgG deposits in the ciliary body, ciliary processes, sclerocorneal limbus and iris. Furthermore, numerous thrombosed vessels were observed in the sclerocorneal zone and iris. Complement 3 (C3) fraction deposits were not present in the ocular structures. The present data suggest that the ocular lesions may have an immunopathological origin.

Histopathological findings and detection of parasites in the eyes of dogs infected naturally with Leishmania chagasi

“…were detected in the ciliary body and iris, uveitis was present, and staining of the parasite was discrete. The presence of Leishmania amastigotes in ocular structures has also been investigated by immunohistochemistry in two dogs with uveitis, in which parasite forms were detected in the lacrimal duct, ciliary body and processes, iris and sclera (GARCÍA-ALONSO et al, 1996). The presence of the parasite in intraocular tissues is probably due to the breakdown of the blood-aqueous humor barrier and its passage to the anterior chamber or migration inside parasitized macrophages.…”

“…The main findings in the third eyelid gland were granulomatous or pyogranulomatous infiltrates mainly located around ducts and the marked presence of macrophages, lymphocytes and plasma cells. GARCIA- ALONSO et al (1996), describing the histopathological alterations in two dogs with visceral leishmaniasis, observed an intense inflammatory reaction characterized by granulation around the lacrimal ducts and a predominance of lymphocytes, plasma cells and macrophages, associated with epithelial necrosis and partial epithelial ulceration.…”

“…Studies have shown that both segments of the eye might be affected, but that lesions predominate in the anterior segment (MOLLEDA et al, 1993;BRITO, 2004;BRITO et al, 2004). Histopathological alterations can affect different structures of the eye and are mainly characterized by the presence of an inflammatory infiltrate and, less commonly, by amastigote forms of the parasite, which permeates ocular tissues (MOLLEDA et al, 1993;LAUGIER & VERRO-BOULANGER, 1992;GARCÍA-ALONSO et al, 1996).…”

Neurologic Manifestations ofLeishmania spp.Infection

“…Although there is a spectra of clinical forms seen with different species of Leishmania parasite, this infection is not classically associated with neurologic manifestations. Despite this, there is a wealth of clinical information on neurological effects of leishmaniasis in animal models [14,15,37] and human case studies [21], which indicates that both central nervous system (CNS) and ocular manifestations are common and often underreported. There are historical [5] and recent reports [1] of both CNS and ocular alterations with visceral leishmaniasis (VL), particularly.…”

Amastigota forms resembling Leishmania sp. on corneal ulceration in a dog: case report

“…The mechanism which explains the presence of amastigota forms of Leishmania sp. in ocular tissues is unknown (Garcia-Alonso et al, 1996), although some admit that the parasites are carried to the cornea by antigen presenting cells (Saint-André Marchal et al, 1997). The main mononuclear cell population present at the ocular surfaces is represented by the Langerhans cells, especially at the conjuntival and corneal tissues (Wu and Zhang, 1991;Bielory, 2000).…”