el Zayyat E A, Khalifa K E, el Gindy I M, Awad A, Azab M E
Department of Parasitology, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
J Egypt Soc Parasitol. 1998 Dec;28(3):739-52.
This work was performed to study variations of Schistosoma specific immunoglobulins between early and chronic schistosomiasis mansoni in both children and adults. A modified enzyme linked immunosorbent assay (ELISA), based on dissociation of antigen antibody complexes with 8 mol/L urea (8 M urea) solution, was used to measure levels of low avidity immunoglobulin G antibodies (IgG Abs) against Schistosoma mansoni soluble egg antigen (SEA). The study included eighty (80) patients with active mansonian schistosomiasis. They were classified according to age, history, clinical symptomatology and examination and direct parasitological methods of diagnosis into early and chronically infected children and adults. Sera of all patients were subjected to: ELISA measuring Schistosoma specific IgM and IgG., immunoglobulin G (IgG) avidity ELISA and indirect haemagglutination test (IHA). Schistosoma specific IgG avidity ELISA detected higher levels of both urea IgG inhibition percentage and low avidity IgG Abs in early cases of schistosomiasis than chronic ones in both children and adults. Levels of urea IgG inhibition percentage were higher in children than adults. Schistosoma specific IgM/IgG ratio was more than one (> 1) in early cases in both children and adults and less than one (< 1) in chronic cases in children and 70% of adults. IHA titres were statistically higher in chronic cases than early ones in children only. So, it can be concluded that IgG avidity ELISA is a valuable method that helps to differentiate early from chronic schistosomiasis mansoni infection in both children and adults.
本研究旨在探讨儿童和成人曼氏血吸虫病早期与慢性期血吸虫特异性免疫球蛋白的变化。采用一种基于用8摩尔/升尿素（8M尿素）溶液解离抗原抗体复合物的改良酶联免疫吸附测定（ELISA）法，检测针对曼氏血吸虫可溶性虫卵抗原（SEA）的低亲和力免疫球蛋白G抗体（IgG抗体）水平。该研究纳入了80例活动性曼氏血吸虫病患者。根据年龄、病史、临床症状、检查以及直接寄生虫学诊断方法，将他们分为早期和慢性感染的儿童及成人。所有患者的血清均接受：检测血吸虫特异性IgM和IgG的ELISA、免疫球蛋白G（IgG）亲和力ELISA以及间接血凝试验（IHA）。血吸虫特异性IgG亲和力ELISA检测发现，在儿童和成人中，血吸虫病早期病例的尿素IgG抑制百分比和低亲和力IgG抗体水平均高于慢性病例。儿童的尿素IgG抑制百分比水平高于成人。儿童和成人早期病例的血吸虫特异性IgM/IgG比值均大于1（>1），儿童慢性病例及70%的成人慢性病例该比值小于1（<1）。仅在儿童中，IHA滴度在慢性病例中统计学上高于早期病例。因此，可以得出结论，IgG亲和力ELISA是一种有助于区分儿童和成人曼氏血吸虫病早期与慢性感染的有价值方法。
