title: IgG avidity in the serodiagnosis of acute Toxoplasma gondii infection: a multicenter study.
abstract: OBJECTIVE: To evaluate the validity of the IgG avidity test in the serodiagnosis of acute T. gondii infection; to verify the maturation of IgG avidity during the course of infection; to observe whether the kinetics of IgG maturation could be affected by antibiotic treatment. METHODS: Serial serum samples, collected in three Italian hospitals (Perugia, Treviso and Bologna), from untreated and antibiotic-treated patients with primary toxoplasmic infection, were assayed for IgG avidity, and IgM and IgA positivity. Single serum samples from patients at different stages of infection were assayed for IgG avidity and the results were correlated to the likely stage of infection. RESULTS: The IgG avidity value increased from 3.5% in the first month to 38.7% 1 year from the onset of infection. Antibiotic-treated patients showed significantly different values of IgG avidity at 2 and 4 months after the onset of infection. In single serum samples the IgG avidity values correlated with the likely stage of infection. CONCLUSIONS: The IgG avidity test was confirmed as a useful tool in the serodiagnosis of acute T. gondii infection and could be predictive of the stage of infection. Antibiotic treatment may affect the kinetics of the maturation of IgG avidity.
authors.affiliation: Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Perugia, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Sensini
authors.forename: Susanna
authors.initials: S
authors.lastname: Pascoli
authors.forename: Daniela
authors.initials: D
authors.lastname: Marchetti
authors.forename: Roberto
authors.initials: R
authors.lastname: Castronari
authors.forename: Maurizio
authors.initials: M
authors.lastname: Marangi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Sbaraglia
authors.forename: Cinzia
authors.initials: C
authors.lastname: Cimmino
authors.forename: Alberto
authors.initials: A
authors.lastname: Favero
authors.forename: Mariarosa
authors.initials: M
authors.lastname: Castelletto
authors.forename: Attilio
authors.initials: A
authors.lastname: Mottola