Role of IgG avidity in the eyes with active Toxoplasma retinochoroiditis

Abstract Purpose: To study toxoplasma IgG avidity to evaluate the stage of infection and clinical implications in cases of toxoplasma retinochoroiditis in eastern India. Methods: Retrospective review of toxoplasma retinochoroiditis cases with toxoplasma serology for IgG, IgM, and IgG avidity. Results: Included in this study were 17 eyes of 17 patients which 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. Conclusions: 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.