弓形虫病的免疫诊断研究进展

刚地弓形虫(Toxoplasma gondii)可感染多种哺乳动物,侵犯除红细胞以外的任何有核细胞.弓形虫病是广泛分布的人畜共患病, 据报道全球约1/3 感染弓形虫[1],我国人群的平均感染率也高达12.3%[2].一般认为弓形虫是机会性致病寄生虫,免疫功能正常的人群感染后多呈隐性感染,而在免疫受损者体内则引起眼部和中枢神经系统损害乃至全身性弓形虫病,严重时可致患者死亡.孕妇感染弓形虫常导致流产、畸胎和死胎[3].由于弓形虫的广泛流行以及其与围产医学、优生优育学和免疫缺陷疾病的密切关系,因此,有效的弓形虫病的防治尤为重要, 而及时有效的诊断是防治工作开展的前提.免疫学诊断因其敏感性高、特异性强、操作简便快速等优点成为弓形虫病的最常用诊断方法[4].弓形虫的免疫学诊断方法包括检测抗体和抗原两大方面.本文就弓形虫病的免疫学诊断方法的研究进展加以概述.     

弓形虫病免疫学诊断研究进展

弓形虫病是严重危害人类健康的人兽共患病,临床表现缺乏特异性,且弓形虫病原学检出率低.免疫学检测具有敏感、特异、快速、简便等特点,已成为辅助诊断弓形虫病的常用方法.该文综述了弓形虫病免疫学诊断方法的研究进展.     

重组抗原用于弓形虫病免疫诊断研究进展

弓形虫是一种世界范围内寄生的原虫,全世界大约有1/3的人感染弓形虫[1].正常人感染弓形虫后无明显的临床症状,但对孕妇来说,弓形虫可以穿过胎盘屏障,引起流产、畸胎或死胎;尤其对AIDS患者,弓形虫性脑炎可能是致命的[2].除了感染人,弓形虫还可以感染家畜,引起羊和猪的流产[3].目前虽已建立了多种弓形虫病诊断试剂盒,但至今似还没有令人十分满意的弓形虫病诊断试剂盒,所以,研制高质量的血清检测试剂盒,对于弓形虫病的防治具有较为重要的意义.弓形虫病诊断方法大致可分为病原学检查、免疫学方法、分子生物学技术等3类.     

弓形虫病实验诊断研究的进展

人体弓形虫感染多数呈无症状带虫状态,但妊娠期的感染常可导致流产、死胎、胎儿畸形。弓形虫感染也是艾滋病(AIDS)患者死亡的主要原因之一。弓形虫病无特定临床表现,其诊断主要根据实验室的检查结果。目前所用的病原学和免疫学检查方法均存在某些缺点。近年来,DNA技术发展迅速,尤其是聚合酶链反应(PCR)用于弓形虫病的实验诊断很有前途,但尚有一些有待解决的问题。本文就近年来弓形虫病实验诊断的研究进展作一综述。     

弓形虫病诊断方法研究进展

弓形虫病是由弓形虫感染引起的一种严重的人兽共患寄生虫病,对人类健康造成极大威胁。本文对弓形虫病诊断技术,包括不依赖DNA检测诊断方法、血清学检测以及基于寄生虫核酸的分子生物学方法进行综述,为弓形虫病诊断技术和方法的发展提供新的思路。     

重组抗原在弓形虫病诊断中的应用

刚地弓形虫感染危害严重,研究敏感性高和特异性好的弓形虫感染检测方法对于弓形虫病的诊断至关重要。弓形虫病的诊断一般依赖于检测患者血清中弓形虫特异性IgM和IgG。目前,商业试剂盒大多采用天然抗原,其检测精确性较差。重组抗原已经被发展用来诊断弓形虫病,且具有潜在的应用价值。本综述主要介绍重组抗原在弓形虫病诊断中的应用。     

弓形虫病的诊断技术及其研究进展

弓形虫人体感染越来越多,刚地弓形虫感染诊断的快速和特异是发现和治疗此病的关键。本文对病原学、免疫学和核酸等弓形虫检测技术及其最新的研究进展进行了综述。     

弓形虫病实验诊断研究的进展

人体弓形虫感染多数呈无症状带虫状态，但妊娠期的感染常可导致流产，死胎，胎儿畸形。弓形虫感染也是艾滋病患者死亡的主要原因之一。弓形虫病无特定临床表现，其诊断主要根据实验室的检查结果。目前所用的病原学和免疫学检查方法均存在某些缺点。     

鸡卵黄抗体（IgY）的性质、提纯及应用于寄生虫学的研究

免疫学IgY技术是近几年发展起来的一种新的生物技术领域及医药研究中的热点技术。本文简要综述鸡卵黄抗体（IgY）的特性、提纯及应用于寄生虫病免疫诊断及免疫治疗等方面,以开拓寄生虫病防治。弓形虫病（toxoplas mosis）危害严重,感染方式多种多样,常规检测方法包括免疫学检测、分子生物学检测及病原学检测等。病原学培养和动物接种操作复杂,却是弓形虫检测的金标准。     

弓形虫病免疫学诊断研究进展

目前诊断弓形虫的方法大致分为3类：1）病原学检查方法;2）免疫学方法;3）分子生物学方法。本文综述了免疫学方法在弓形虫感染诊断中的应用及弓形虫抗原研究进展。     

Toxoplasma pneumonitis: fatal presentation of disseminated toxoplasmosis in a patient with AIDS.

Toxoplasma gondii infection is an uncommon cause of pneumonitis in patients with acquired immune deficiency syndrome (AIDS). We report a case of fatal pulmonary toxoplasmosis, which clinically resembled Pneumocystis carinii pneumonia (PCP). Conventional diagnostic methods for toxoplasmosis lack sensitivity. Bronchoscopy and histological evaluation of transbronchial biopsy specimens failed to identify the infecting organism. At autopsy there was evidence of disseminated infection.     

分子诊断技术在弓形虫检测和基因分析中的研究进展

弓形虫是一种专性细胞内寄生的寄生虫,人感染后多呈隐性感染,临床表现缺乏特异性,检测及诊断较为困难.分子诊断是应用分子生物学方法,检测患者体内遗传物质结构或表达水平的变化,继而做出诊断的技术,它为疾病的预防、诊断、治疗和转归提供更为准确的信息.目前,分子诊断技术主要有核酸探针技术、PCR及其衍生技术、环介导等温扩增技术、基因芯片技术等.该文对分子诊断技术在弓形虫中的应用进行综述.     

Prevalence of toxoplasmosis and methods for its laboratory diagnosis

The review presents data on the prevalence of toxoplasmosis in different countries and regions. It gives a comparative assessment of the methods of serodiagnosis of toxoplasmosis, which permit identification of specific immunoglobulins G, M, A, and E. The authors show a role of laboratory diagnostic techniques in the differentiation of the acute form of toxoplasmosis from its chronic form. They provide the currently available modifications of the basic procedure for enzyme immunoassay, molecular genetic methods, and a direct fluorescent antibody test for the detection of Toxoplasma gondii antigens. The current view of a cellular immune response and its role in monitoring the development of toxoplasmosis are considered.     

弓形虫感染免疫诊断抗原研究进展

诊断抗原历来是弓形虫病免疫诊断研究的重点。随着分子生物学技术的发展,弓形虫诊断抗原由最初的粗抗原发展成为组分抗原以及重组抗原。本文综述了近年来弓形虫病诊断抗原的研究现状与进展。     

New methods in the diagnosis and management of cerebral toxoplasmosis associated with the acquired immune deficiency syndrome

Cerebral toxoplasmosis is a life-threatening condition associated with the acquired immune deficiency syndrome (AIDS). Current diagnostic and therapeutic methods have serious limitations. The diagnosis of cerebral toxoplasma infection in a patient with AIDS was assisted by the detection of specific IgM in a highly sensitive immunosorbent agglutination assay and by the demonstration of Toxoplasma gondii nucleic acid in a brain biopsy specimen by means of the polymerase chain reaction. Following initial failure of the patient to respond to treatment with sulphadiazine and pyrimethamine, clinical improvement was observed during treatment with clindamycin followed by dapsone. Further assessment of novel methods in the management of cerebral toxoplasmosis is required.     

SPECT thallium-201 combined with Toxoplasma serology for the presumptive diagnosis of focal central nervous system mass lesions in patients with AIDS

OBJECTIVE: To determine the utility of brain thallium-201 single photon emission computerized tomography (Tl-201 SPECT) combined with Toxoplasma serology for the diagnosis of focal CNS lesions in patients with AIDS. METHODS: Sixty-one consecutive HIV-infected patients with focal CNS lesion(s) on head computed tomography (CT) or MRI scan who underwent brain Tl-201 SPECT and serum Toxoplasma serology were evaluated, retrospectively. Thallium-201 uptake ratios were calculated by comparing lesion activity to contralateral scalp activity. Diagnoses were made by a combination of histology, serology, PCR, and empirical response to therapy. Toxoplasma serologies (IgG IFA) were compared in the patients with central nervous system (CNS) toxoplasmosis and those without CNS toxoplasmosis. RESULTS: Fifty-six patients were evaluable and a definitive diagnosis was made in 38 patients: toxoplasmosis (17), lymphoma (14), PML (three), Aspergillus (one), tuberculoma (one), Cryptococcus (one), varicella-zoster virus (one). Patients with lymphoma had significantly higher lesion/contralateral scalp ratios compared to patients without lymphoma: 1.03 vs. 0.67, P < 0.05. Using a cut-off of 0.90 for the lesion/scalp uptake ratios (based on analysis of ROC curves) the sensitivity and specificity for the diagnosis of lymphoma were 86% and 83%, respectively. Serum Toxoplasma IgG titres were significantly higher in patients diagnosed with toxoplasmosis compared to those with a diagnosis other than toxoplasmosis, 1:5444 vs. 1:15, P < 0.05. Only one patient with confirmed toxoplasmosis had a Toxoplasma serology < 1:256, while no patients without toxoplasmosis (including all lymphoma patients) had serologies > 1:256. CONCLUSIONS: In a series of HIV-infected patients, Tl-201 SPECT was able to accurately differentiate primary brain lymphoma from other causes of focal CNS lesions in most patients; however, both false positive and false negative results occurred. By combining Tl-201 SPECT with serum Toxoplasma IgG, diagnostic accuracy was improved.     

Evaluation of a nested-pCR to detect 18S rDNA for the diagnosis of toxoplasmic meningoencephalitis

To detect an 18S ribosomal DNA fragment of Toxoplasma gondii Nested-PCR was used to detect an 18S ribosomal DNA fragment of Toxoplasma gondii in the CSF of 13 patients at 6 facilities in whom Toxoplasma meningoencephalitis had been suspected between January 2001 and Feburary 2005. Based on the diagnostic criteria of the CDC, all patients were treated with the anti-toxoplasmic chemotherapy based on the clinical diagnosis. Clinical improvement was observed in 11 patients, and the final diagnosis was toxoplasmosis, but the conditions of 2 patients deteriorated, and they were ultimately diagnosed with malignant lymphoma. Based on the results of the clinical diagnosis, we assessed the effectiveness of the nested-PCR method of examining the CSF for making the diagnosis of Toxoplasma meningoenephalitis. The results of the nested-PCR were positive in 8 of the 13 cases, and all 8 cases had been diagnosed with Toxoplasma encephalitis clinically. The results were negative in 5 of the 13 cases, but 3 of the 5 negative cases had been clinically diagnosed as toxoplasmosis, indicating that the test was false-negative in some cases (27.3%; 3/11). Toxoplasma meningoencephalitis is so difficult to diagnose that the development of the new, high-specificity diagnostic methods is being eagerly awaited.     

Disseminated toxoplasmosis associated with hemophagocytic syndrome after kidney transplantation: A case report and review

Disseminated toxoplasmosis is infrequent after kidney transplant transmission but life‐threatening because of a lack of diagnostic suspicion as well as specific chemoprophylaxis recommendations. Solid organ transplantation has resulted in few cases of disseminated toxoplasmosis presenting with associated hemophagocytic syndrome. Herein, we report, within the context of a donor/receiver mismatch, a case of a toxoplasmosis associated with hemophagocytic syndrome in a kidney transplant recipient. Molecular and serological investigations confirmed Toxoplasma gondii transmission through the kidney graft.     

Role of bronchoalveolar lavage in diagnosis of disseminated toxoplasmosis

In three cases of acute disseminated toxoplasmosis developing soon after renal (two patients) or hepatorenal (one patient) transplantation, Toxoplasma gondii trophozoites were visualized on Giemsa-stained smears of bronchoalveolar lavage fluid. Trophozoites were also found in bone marrow smears in one instance. Seroconversion occurred late in two cases and was not detected before the patient's death in the third. These observations underline the potential of bronchoalveolar lavage as a diagnostic procedure for disseminated toxoplasmosis.