title: PCR-based detection of Toxoplasma gondii DNA in blood and ocular samples for diagnosis of ocular toxoplasmosis.
abstract: PCR detection of Toxoplasma gondii in blood has been suggested as a possibly efficient method for the diagnosis of ocular toxoplasmosis (OT) and furthermore for genotyping the strain involved in the disease. To assess this hypothesis, we performed PCR with 121 peripheral blood samples from 104 patients showing clinical and/or biological evidence of ocular toxoplasmosis and from 284 (258 patients) controls. We tested 2 different extraction protocols, using either 200 μl (small volume) or 2 ml (large volume) of whole blood. Sensitivity was poor, i.e., 4.1% and 25% for the small- and large-volume extractions, respectively. In comparison, PCR with ocular samples yielded 35.9% sensitivity, while immunoblotting and calculation of the Goldmann-Witmer coefficient yielded 47.6% and 72.3% sensitivities, respectively. Performing these three methods together provided 89.4% sensitivity. Whatever the origin of the sample (ocular or blood), PCR provided higher sensitivity for immunocompromised patients than for their immunocompetent counterparts. Consequently, PCR detection of Toxoplasma gondii in blood samples cannot currently be considered a sufficient tool for the diagnosis of OT, and ocular sampling remains necessary for the biological diagnosis of OT.
authors.affiliation: AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Parasitologie Mycologie, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Bourdin
authors.affiliation: AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Parasitologie Mycologie, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Busse
authors.affiliation: AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Parasitologie Mycologie, Paris, France.
authors.forename: E
authors.initials: E
authors.lastname: Kouamou
authors.affiliation: AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Parasitologie Mycologie, Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Touafek
authors.affiliation: AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service d'Ophtalmologie, Paris, France.
authors.forename: B
authors.initials: B
authors.lastname: Bodaghi
authors.affiliation: AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service d'Ophtalmologie, Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Le Hoang
authors.affiliation: AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Parasitologie Mycologie, Paris, France Sorbonne Universités, UPMC Univ Paris 06, CIMI-Paris, Paris, France Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France.
authors.forename: D
authors.initials: D
authors.lastname: Mazier
authors.affiliation: AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Parasitologie Mycologie, Paris, France.
authors.forename: L
authors.initials: L
authors.lastname: Paris
authors.affiliation: AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Parasitologie Mycologie, Paris, France Sorbonne Universités, UPMC Univ Paris 06, CIMI-Paris, Paris, France Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France arnaud.fekkar@psl.aphp.fr.
authors.forename: A
authors.initials: A
authors.lastname: Fekkar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001769:Blood / Q000469:parasitology*; D016054:DNA, Protozoan / Q000235:genetics / Q000302:isolation & purification*; D005123:Eye / Q000469:parasitology*; D005260:Female; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014122:Toxoplasma / Q000235:genetics / Q000302:isolation & purification*; D014126:Toxoplasmosis, Ocular / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D016054:DNA, Protozoan