Role of IgG avidity in eyes with active Toxoplasma retinochoroiditis.

Abstract

To study the role of Toxoplasma IgG avidity in evaluating the stage of systemic infection during manifestation as toxoplasma retinochoroiditis and its clinical implications in eastern India. Retrospective chart review of Toxoplasma retinochoroiditis cases with Toxoplasma serology for IgG, IgM, and IgG avidity. Included in this study were 17 eyes of 17 patients who had active retinitis located in the macula (14), mid-periphery (2), or periphery (1). They were either primary lesions (12) or reactivations (5). All the cases had Toxoplasma IgG positive; one case had IgM positivity, while all the cases had high IgG avidity values. IgG avidity had a positive correlation with the duration of symptoms. We observed high IgG avidity values in active retinochoroiditis in both primary ocular Toxoplasmosis and reactivation subgroups. These results indicate a late ocular manifestation after initial systemic infection with a possible incubation period ranging from 5 weeks to 5 months.