Lack of utility of specific immunoglobulin G antibody avidity for serodiagnosis of reactivated toxoplasmosis in immunocompromised patients

The avidities of Toxoplasma-specific immunoglobulin G serum antibodies were measured in immunocom-promised patients presenting with cerebral or extrac erebral toxoplasmosis and/or serological reactivation. Since avidity remain ed high and stable in 39 of 40 patients with toxoplasmosis and 27 of 28 pat ients with serological reactivation, we conclude that this test cannot help diagnose toxoplasmosis in these patients.