Increased frequency of anti-retina antibodies in asymptomatic patients with chronic t. gondii infection

Abstract

Purpose: To search for anti-retina antibodies that serve as markers for eye disease in uveitis.

Materials and methods: Stored sera from patients with uveitis, ocular toxoplasmosis (n = 30) and non-infectious, immune-mediated uveitis (n = 50) and from asymptomatic individuals who were positive (n = 250) and negative (n = 250) for anti-Toxoplasma antibodies were tested. Serum anti-retina IgG was detected by an optimized ELISA using a solid-phase whole human retina extract, bovine S-antigen or interphotoreceptor retinoid-binding protein.

Results: Uveitis patients showed a higher mean reactivity to whole human retina extract, interphotoreceptor retinoid-binding protein and S-antigen in comparison to the asymptomatic population. These findings were independent of the uveitis origin and allowed the determination of the lower anti-retina antibody cut-off for the three antigens. Asymptomatic anti-Toxoplasma serum-positive individuals showed a higher frequency of antihuman whole retina extract antibodies in comparison to asymptomatic anti-Toxoplasma serum-negative patients. The bovine S-antigen and interphotoreceptor retinoid-binding protein ELISAs also showed a higher mean reactivity in the uveitis groups compared to the asymptomatic group, but the observed reactivities were lower and overlapped without discrimination.

Conclusion: We detected higher levels of anti-retina antibodies in uveitis patients and in a small fraction of asymptomatic patients with chronic toxoplasmosis. The presence of anti-retina antibodies in sera might be a marker of eye disease in asymptomatic patients, especially when whole human retina extract is used in a solid-phase ELISA.

Figure 1

Antibody reactivity against whole human retina extracts (WHRE) as determined using chaotrope in the serum dilution. Non-Tg uveitis: samples from patients with uveitis other than toxoplasmosis (n = 50; see Methods). Tg uveitis: Toxoplasma uveitis samples (n = 30). Tg IgG -: samples from individuals who were seronegative for T. gondii (n = 250). Tg IgG+: samples from individuals who were seropositive for T. gondii. Bars represent mean values. The y-axis was interrupted at cut-off using the mean minus 2 SD of samples from all uveitis patients.

Figure 2

Antibodies against bovine retina S-antigen in selected patients. Non-Tg uveitis: samples from patients with uveitis other than toxoplasmosis (n = 50; see Methods). Tg uveitis: samples from patients with Toxoplasma uveitis (n = 30). Tg IgG-: samples from patients who were seronegative for T. gondii (n = 250). Tg IgG+: samples from patients who were seropositive for T. gondii. Bars represent mean values. The y-axis was interrupted at cut-off using the mean minus 2 SD of samples from all uveitis patients.

Figure 3

Antibodies against bovine interphotoreceptor retinoid-binding protein (IRBP) antigen in selected patients. Non-Tg uveitis: samples from patients with uveitis other than toxoplasmosis (n = 50; see Methods). Tg uveitis: samples from Toxoplasma uveitis patients (n = 30). Tg IgG-: samples from patients who were seronegative for T. gondii (n = 250). Tg IgG+: samples from patients who were seropositive for T. gondii. Bars represent mean values. The y-axis was interrupted at cut-off using the mean minus 2 SD of samples from all uveitis patients.