Abstract
Purpose:
To validate real-time PCR assay (qPCR) in blood, aqueous and vitreous samples of patients with posterior uveitis clinically diagnosed as caused by Toxoplasma gondii.
Methods:
66 patients (39 men) from São Paulo, Brazil, were recruited and qPCR was performed. SYBR green and Taqman were used to detect qualitatively Toxoplasma gondii in the blood, aqueous and vitreous. Type of sample collection was determined according to patient’s clinical picture. In18 patients we had only blood samples, in 3 patients only aqueous, in 2 patients blood and vitreous samples, in 29 patients blood and aqueous samples and in 14 patients we had the 3 samples (blood, aqueous and vitreous) collected. Twenty-four patients with uveitis associated with others pathogens as well as non-infectious uveitis were used as control.
Results:
From the 66 patients, qPCR was positive in 35 (53.03%). In the group with only blood samples (n=18), qPCR was positive in 7 (41.17%) patients. In the group with only aqueous samples (n=3), qPCR was postitive in 2 (66.7%). In the group with blood and vitreous samples (n=2), qPCR was positive only in the vitreous of 2 (100%) patients. In the group with blood and aqueous samples (n=29), qPCR was positive in 19 patients (65.51%); 14 (48.27%) of which were positive only in the aqueous and 5 (17.24%) were positive in the blood and the aqueous. Regarding the group with the 3 sites studied (n=14), qPCR was positive in 5 patients (35.71%): 2 patients (14.28%) only in the vitreous, 2 patients (14.28%) in the aqueous and the vitreous, and one patient (7.14%) in the blood and the aqueous. All 24 controls were negative in the real-time PCR analysis for T.gondii.
Conclusions:
Real-time PCR showed ability to detect T. gondii not only in the vitreous but also the in the blood and aqueous in patients with ocular toxoplasmosis.
Keywords: 746 uveitis-clinical/animal model •
467 clinical laboratory testing •
427 aqueous