Garweg J G, Jacquier P, Boehnke M
Department of Ophthalmology, University of Bern, Inselspital, CH-3010 Bern, Switzerland.
J Clin Microbiol. 2000 Mar;38(3):996-1001. doi: 10.1128/JCM.38.3.996-1001.2000.
To evaluate the diagnostic sensitivity of a panel of laboratory tests for ocular toxoplasmosis performed at the time of presentation, paired samples of aqueous humor and serum were collected from 49 consecutive episodes of ocular toxoplasmosis with a clinical course of less than 3 weeks. Total immunoglobulin G (IgG) and Toxoplasma gondii-specific IgG, IgM, and IgA were quantified by enzyme-linked immunosorbent assay. The avidity of T. gondii-specific IgG was determined, and DNA extracted from aqueous humor was amplified for detection of a glycoprotein B gene sequence of T. gondii. The diagnosis was confirmed for 73% (36 of 49) of the patients; this rate rose to 79.5% if data from a later analysis of aqueous humor derived from five of the negative patients were included. The analysis of serum (detection of T. gondii-specific IgM and analysis of consecutive serum samples) alone did not contribute to the diagnosis. Calculation of local antibody production lacked diagnostic sensitivity when it was determined less than 3 weeks after the manifestation of clinical symptoms (28 of 49 patients [57%]), but this rose to 70% after an analysis of a second aqueous humor sample. The antibody avidity index attained diagnostic significance in only 8 of 43 instances (19%), and T. gondii DNA was amplified from no more than 6 of 39 (16%) aqueous humor samples. However, T. gondii-specific IgA was found within the aqueous humors of 11 of 43 patients (26%); measurement of the T. gondii-specific IgA level thus contributed substantially to the diagnostic sensitivity of the laboratory tests.
为评估就诊时进行的一组实验室检查对眼弓形虫病的诊断敏感性，从49例临床病程少于3周的连续性眼弓形虫病病例中采集了房水和血清配对样本。通过酶联免疫吸附测定法定量总免疫球蛋白G（IgG）以及弓形虫特异性IgG、IgM和IgA。测定弓形虫特异性IgG的亲和力，并对从房水中提取的DNA进行扩增，以检测弓形虫的糖蛋白B基因序列。73%（49例中的36例）的患者诊断得到证实；如果纳入5例阴性患者后期房水分析的数据，这一比例升至79.5%。仅分析血清（检测弓形虫特异性IgM以及连续血清样本）对诊断没有帮助。在临床症状出现后不到3周进行测定时，计算局部抗体产生缺乏诊断敏感性（49例患者中的28例[57%]），但在分析第二份房水样本后这一比例升至70%。抗体亲和力指数仅在43例中的8例（19%）具有诊断意义，并且在39份房水样本中不超过6份（16%）扩增出弓形虫DNA。然而，在43例患者中的11例（26%）房水中发现了弓形虫特异性IgA；因此，测定弓形虫特异性IgA水平对实验室检查的诊断敏感性有很大贡献。
