Dziemian E, Zarnowska H, Kołodziej-Sobocińska M, Machnicka B
W. Stefański Institute of Parasitology of the Polish Academy of Sciences, Warsaw, Poland.
Parasite Immunol. 2008 Mar;30(3):187-90. doi: 10.1111/j.1365-3024.2007.01010.x. Epub 2008 Jan 3.
Human toxocariasis is a zoonosis caused by infection with larvae of the ascarid nematode Toxocara canis and, less frequently, T. cati. Our study developed a method for distinguishing distant from recent human toxocariasis by assessing the avidity of the IgG antibodies. The avidity of specific antibodies increases with time after antigen challenge and assessment of the degree of avidity can be used to discriminate between recent and distant infections. The relative avidity was measured in 150 sera from children with visceral toxocariasis and in 46 sera from children with ocular toxocariasis. The probable time of infection was estimated on the basis of the medical history and clinical syndrome. Our study showed that 94.2% of positive sera collected from patients reporting infection > 6 months ago had high IgG avidity values, confirming distant toxocariasis, whereas 25.9% of positive sera taken < 6 months after infection showed low indices of IgG avidity. Our results suggest that measurement of the specific IgG avidity may assist in discriminating between recent and distant toxocariasis. The method can be used effectively to rule out (because of high avidity) a recently acquired infection. Low avidity is less reliable in discriminating between recent and distant infections.
人体弓蛔虫病是一种人畜共患病，由感染蛔虫线虫犬弓首蛔虫的幼虫引起，感染猫弓首蛔虫的情况较少见。我们的研究开发了一种通过评估IgG抗体亲和力来区分近期和远期人体弓蛔虫病的方法。抗原刺激后，特异性抗体的亲和力会随时间增加，评估亲和力程度可用于区分近期和远期感染。对150份内脏弓蛔虫病患儿的血清和46份眼弓蛔虫病患儿的血清进行了相对亲和力测定。根据病史和临床综合征估计可能的感染时间。我们的研究表明，从报告感染超过6个月前的患者中收集的94.2%的阳性血清IgG亲和力值较高，证实为远期弓蛔虫病，而感染后不到6个月采集的阳性血清中有25.9%的IgG亲和力指数较低。我们的结果表明，测定特异性IgG亲和力可能有助于区分近期和远期弓蛔虫病。该方法可有效地排除（由于高亲和力）近期获得的感染。低亲和力在区分近期和远期感染方面不太可靠。
