Department of Ophthalmology, Federal University of São Paulo, São Paulo, São Paulo, Brazil.
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.
Br J Ophthalmol. 2014 Jul;98(7):937-40. doi: 10.1136/bjophthalmol-2013-304184. Epub 2014 Feb 11.
BACKGROUND/AIMS: To determine if patients with inactive chorioretinitis lesions who experience chronic toxoplasmic uveitis test PCR positive for Toxoplasma in their ocular fluids.
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.
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.
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.
背景/目的：确定患有静止性脉络膜视网膜炎病变且患有慢性弓形虫性葡萄膜炎的患者，其眼内液中是否存在 PCR 阳性的弓形虫。
两名接受长期抗弓形虫治疗的患者出现慢性葡萄膜炎和眼色素层炎。他们接受了经睫状体平坦部的玻璃体切除术。通过实时 PCR 和巢式 PCR 检测患者标本中的弓形虫。还检测了患者标本中识别寄生虫血清型等位肽模体的弓形虫抗体的存在。
1 号患者的玻璃体和房水实时 PCR 检测到 B1 基因的弓形虫阳性，但 2 号患者只有玻璃体阳性。患者的血浆和血液中未通过实时 PCR 检测到寄生虫血症。手术中仅观察到陈旧的色素沉着性弓形虫瘢痕，没有活动性视网膜炎的迹象。B1、NTS2 和 SAG1 基因座的多位点 PCR-DNA 序列基因分型表明，1 号和 2 号患者感染了两种不同的非原型性弓形虫株。基于肽的血清分型 ELISA 证实了分子发现。
虽然没有观察到活动性病变，但两名患者的玻璃体中均存在足够的寄生虫 DNA，可进行基因分型。讨论了几种解释在没有活动性视网膜炎的情况下持续性前葡萄膜炎和玻璃体炎的假说。
