title: Patients with diffuse uveitis and inactive toxoplasmic retinitis lesions test PCR positive for Toxoplasma gondii in their vitreous and blood.
abstract: OBJECTIVE
  To determine if patients with inactive chorioretinitis lesions who experience chronic toxoplasmic uveitis test PCR positive for Toxoplasma in their ocular fluids.
  
  
  METHODS
  Two patients undergoing long-term anti-toxoplasmic treatment developed chronic uveitis and vitritis. They underwent therapeutic and diagnostic pars plana vitrectomy. Patient specimens were tested for toxoplasmosis by real-time PCR and nested PCR. Patient specimens were also tested for the presence of Toxoplasma antibodies that recognise allelic peptide motifs to determine parasite serotype.
  
  
  RESULTS
  Patients tested positive for Toxoplasma by real-time PCR at the B1 gene in the vitreous and aqueous humours of patient 1, but only the vitreous of patient 2. Patients were not parasitemic by real-time PCR in plasma and blood. During surgery, only old hyperpigmented toxoplasmic scars were observed; there was no sign of active retinitis. Multilocus PCR-DNA sequence genotyping at B1, NTS2 and SAG1 loci established that two different non-archetypal Toxoplasma strains had infected patients 1 and 2. A peptide-based serotyping ELISA confirmed the molecular findings.
  
  
  CONCLUSIONS
  No active lesions were observed, but both patients possessed sufficient parasite DNA in their vitreous to permit genotyping. Several hypotheses to explain the persistence of the vitritis and anterior uveitis in the absence of active retinitis are discussed.
authors: Department of Ophthalmology, Federal University of São Paulo, São Paulo, São Paulo, Brazil.
authors: Eduardo A
authors: EA
authors: Novais
authors: Department of Ophthalmology, Federal University of São Paulo, São Paulo, São Paulo, Brazil Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA.
authors: Alessandra G
authors: AG
authors: Commodaro
authors: Department of Ophthalmology, Federal University of São Paulo, São Paulo, São Paulo, Brazil Hospital Albert Einstein, São Paulo, São Paulo, Brazil.
authors: Fábio
authors: F
authors: Santos
authors: Department of Ophthalmology, Federal University of São Paulo, São Paulo, São Paulo, Brazil.
authors: Cristina
authors: C
authors: Muccioli
authors: Department of Ophthalmology, Federal University of São Paulo, São Paulo, São Paulo, Brazil.
authors: André
authors: A
authors: Maia
authors: Department of Ophthalmology, Federal University of São Paulo, São Paulo, São Paulo, Brazil.
authors: Heloisa
authors: H
authors: Nascimento
authors: Department of Ophthalmology, Federal University of São Paulo, São Paulo, São Paulo, Brazil.
authors: Cecilia T A
authors: CT
authors: Moeller
authors: Hospital Albert Einstein, São Paulo, São Paulo, Brazil.
authors: Luiz V
authors: LV
authors: Rizzo
authors: Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA.
authors: Michael E
authors: ME
authors: Grigg
authors: Department of Ophthalmology, Federal University of São Paulo, São Paulo, São Paulo, Brazil.
authors: Rubens
authors: R
authors: Belfort
mesh_terms: D000890:Anti-Infective Agents / Q000627:therapeutic use; D000913:Antibodies, Protozoan / Q000097:blood*; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D002908:Chronic Disease; D016054:DNA, Protozoan; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D060005:Genotyping Techniques; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011241:Prednisone / Q000627:therapeutic use; D060888:Real-Time Polymerase Chain Reaction; D012173:Retinitis / Q000188:drug therapy / Q000276:immunology / Q000469:parasitology*; D012703:Serotyping; D014122:Toxoplasma / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D014126:Toxoplasmosis, Ocular / Q000188:drug therapy / Q000276:immunology / Q000469:parasitology*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D014605:Uveitis / Q000188:drug therapy / Q000276:immunology / Q000469:parasitology*; D014821:Vitrectomy; D014822:Vitreous Body / Q000469:parasitology*
chemical_list: D000890:Anti-Infective Agents; D000913:Antibodies, Protozoan; D000981:Antiprotozoal Agents; D016054:DNA, Protozoan; D005938:Glucocorticoids; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D011241:Prednisone
keywords: Diagnostic tests/Investigation; Immunology; Infection; Inflammation; Treatment Surgery