Emmanuelle Delair

Clinical Manifestations of Ocular Toxoplasmosis

Clinical manifestations of ocular toxoplasmosis are reviewed. Findings of congenital and acute acquired ocular toxoplasmosis include retinal scars, white-appearing lesions in the active phase often associated with vitritis. Complications can include fibrous bands, secondary serous or rhegmatogenous retinal detachments, optic neuritis and neuropathy, cataracts, increased intraocular pressure during active infection, and choroidal neovascular membranes. Recurrences in untreated congenital toxoplasmosis occur in teenage years. Manifestations at birth are less severe, and recurrences are fewer in those who were treated promptly early in the course of their disease in utero and in the first year of life. Severe retinal involvement is common at diagnosis of symptomatic congenital toxoplasmosis in the United States and Brazil. Acute acquired infections also may be complicated by toxoplasmic retinochoroiditis, with recurrences most common close to the time of acquisition. Suppressive treatment can reduce recurrent disease.

Ophthalmologic Manifestations of Systemic Necrotizing Vasculitides at Diagnosis: A Retrospective Study of 1286 Patients and Review of the Literature

OBJECTIVE To determine the frequencies and types of ophthalmologic manifestations in patients with systemic necrotizing vasculitides (SNV), including polyarteritis nodosa (PAN) and ANCA-associated vasculitides (granulomatosis with polyangiitis (Wegeners, GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA); Churg-Strauss syndrome (CSS)) and review the literature on eye involvement in these diseases. METHODS This retrospective analysis was conducted on the ophthalmologic manifestations of SNV patients entered into the French Vasculitis Study Group database between July 1955 and August 2008. RESULTS Among the 1286 identified patients, 214 (16.6%) had ophthalmologic manifestations at diagnosis, significantly more often in GPA (117/343, 34.1%) than in EGPA (30/270, 11.1%; P = 0.0001), PAN (42/393, 10.7%; P = 0.0001) or MPA (25/280, 8.9%; P = 0.0001). The 3 most common recorded ophthalmologic manifestations were conjunctivitis (89, (7%)), episcleritis (56, (4%)), and/or blurred vision (44, (3%)), mainly caused by retinal vasculitis in 5, oculomotor nerve palsy in 4, uveitis in 4 and/or optic neuropathy in 3. Orbital inflammatory tumor, another common feature was rather specific to GPA (23/349, 6.6% (P = 0.0001)) compared to other SNV. The literature on ophthalmologic manifestations of SNV is limited to case reports except for GPA, in which the eye involvement frequency ranged from 29% to 57%. CONCLUSIONS Eye manifestations were more common in GPA than MPA, PAN and EGPA, but can be sight-threatening in any SNV. Given the heterogeneity of ophthalmologic involvement in SNV, close collaboration between the ophthalmologists and internists is critical.

A New HLA Extended Haplotype Containing the A*2910 Allele in Birdshot Retinochoroidopathy: Susceptibility Narrowed to the HLA Molecule Itself

PURPOSE Birdshot retinochoroidopathy (BSRC) is a rare posterior uveitis characterized by distinctive, multiple, hypopigmented choroidal and retinal lesions. Most, if not all, patients are white and share the major histocompatibility antigen HLA-A29. Furthermore, the A*2902 subtype is closely associated with BSRC, and only a very few patients share the A*2901 subtype. Surprisingly, although A*2901 and A*2902 differ only by a single mutation (D102H), studies of microsatellites located near HLA-A have shown that two strong A*2901 and A*2902 extended haplotypes are observed in patients and control subjects. The present study analyzes the HLA-A extended haplotype of two patients who were HLA-A*2910 carriers. METHODS Among 180 patients who fulfilled internationally defined criteria for the diagnosis of BSRC and who were HLA-A29 subtyped, two patients were found to be HLA-A*2910 carriers. These patients were tested for the microsatellite alleles MOGa, -b, -c, and -e (of the myelin oligodendrocyte glycoprotein [MOG] gene) and D6S265, D6S510, RF, C5_4_5, and D6S105. RESULTS Although A*2902 and A*2910 differed by only a single mutation, (E177K) a new A*2910 extended haplotype was found to be distinct from the A*2901 and A*2902 extended haplotypes previously described in patients and control subjects. Among all studied microsatellite markers, no allele was shared by these extended haplotypes. CONCLUSIONS These results suggest that susceptibility to BSRC is linked to the histocompatibility HLA-A29 molecule itself, although the development of the disease also involves inherited or probably acquired factors not linked to the major histocompatibility complex.

In vitro effect of TNF-α and IFN-γ in retinal cell infection with Toxoplasma gondii.

PURPOSE Toxoplasma gondii is an intracellular protozoan parasite and the most common cause of infectious uveitis. This study was conducted to evaluate the in vitro effect of tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma in rat retinal cells infected with T. gondii. METHODS Rat retinal cells, retinal pigment epithelial (RPE) cells, and retinal Müller glial (RMG) cells were in vitro infected with T. gondii RH strain tachyzoites. Cultured cells were stimulated with various concentrations of TNF-alpha and IFN-gamma. The effect of TNF-alpha and IFN-gamma in T. gondii invasion and replication between retinal cells was determined through two different methods: measuring [(3)H]-uracil incorporation and counting infected cells by microscopic examination. RESULTS Infection by T. gondii was lesser within RPE cells than within RMG cells. IFN-gamma significantly inhibits [(3)H]-uracil incorporation in RMG and RPE cells (respectively, 35%, 83%, and 87% inhibition at 0.1, 1, and 10 ng/mL for RMG cells and 0%, 30%, and 75% for RPE cells). TNF-alpha significantly inhibits [(3)H]-uracil incorporation in RPE cells (23% and 38% inhibition at 1 and 10 ng/mL), but not in RMG cells. These results were confirmed by confocal microscopic data. The percentage of infected cells decreased from 20% to 7% after IFN-gamma stimulation. CONCLUSIONS Both cytokines IFN-gamma and TNF-alpha inhibited T. gondii replication in the RPE cells, whereas only IFN-gamma had an anti-Toxoplasma activity within the RMG cells. The differences in cytokine response may be the reason that RPE cells are less efficiently infected by T. gondii than are RMG cells.

Risk Factors, Pathogenesis and Diagnosis of Ocular Toxoplasmosis

Ocular toxoplasmosis (OT) is a major cause of posterior uveitis worldwide but its incidence and prevalence are difficult to establish precisely. In 1993, a survey in a French Hospital Service of Ophthalmology showed that OT was seen in less than 1 per thousand outpatients [1]. In a study performed in Germany, toxoplasmosis accounted for 4.2 % of all cases of uveitis at a referral centre [2]. Around 5000 people develop symptomatic OT each year in the United States [3]. OT is a complication of both acute acquired and reactivated congenital in immunocompetent but particularly in immunocompromissed individuals and its severity can be influenced by variation in parasite isolates, parasitic load, route of infection and hostrelated factors such as immune function, age and pregnancy. Diagnosis is usually based on ophthalmological examination and is confirmed by the response to specific treatment, but also by biological assays including local antibody production, PCR and western blot. All these points will be detailed below.