Detection, quantitation, and specificity of antiparasite IgE antibodies in human schistosomiasis mansoni

Sera from 15 patients with acute or chronic Schistosoma mansoni infection were evaluated for IgE antibodies directed against soluble cercarial, adult worm, and egg antigens. Both the antigen-induced release of histamine from passively sensitized human basophils and specific radioimmunoassays were used to detect these IgE antibodies, and determination of serum IgE levels before and after specific immunosorption permitted their quantification. While chronically infected patients made IgE antibodies to all three stages of the parasite, only egg antigens induced an appreciable IgE antibody response in acutely infected individuals. Despite the fact that patients with chronic infection had significantly greater levels of total serum IgE than patients with acute disease, the percentage of this IgE that was parasite specific was similar for both groups, ranging between 4% and 28%. An ancillary observation was the fact that soluble egg antigen can trigger basophil histamine release through IgE-dependent reactions and through "nonimmunologic" mechanisms that require further characterization.     

Idiotypic/anti-idiotypic interactions in schistosomiasis and Chagas' disease

Immunoaffinity-purified antibodies against soluble Schistosoma mansoni egg antigens (SEA) were isolated from the sera of patients with schistosomiasis mansoni. Similarly, antibodies against Trypanosoma cruzi epimastigote antigens were obtained from sera of patients with Chagas' disease. These antibody preparations were used in culture to demonstrate the presence of anti-idiotypic T lymphocytes in peripheral blood mononuclear cell preparations from patients with either schistosomiasis mansoni or Chagas' disease, or with both of these infections. Only cells from patients with schistosomiasis or both infections proliferated upon exposure to the anti-SEA antibodies. Conversely, only cells from patients with Chagas' disease or both infections responded to anti-epimastigote antibodies. Western blot analysis of SEA and epimastigote antigens, developed by patients' sera or by immunoaffinity-purified antibody preparations, substantiated that anti-SEA immunoaffinity-purified antibodies only reacted with components of SEA, and anti-epimastigote immunoaffinity-purified antibodies only reacted with components of epimastigote antigenic preparation. These studies demonstrate the presence of anti-idiotypic T lymphocytes in the peripheral blood of patients with schistosomiasis or Chagas' disease which are specific for idiotypes generated during these infections.     

Human IgG1 and IgG3 recognition of Schistosoma mansoni 14kDa fatty acid-binding recombinant protein

The Schistosoma mansoni gene coding for a 14-kDa fatty acid-binding protein was amplified by PCR and subcloned into the prokaryotic expression vector pMAL-c2. Escherichia coli DH5alpha was transformed with the pMAL-Sm14 construct, and gene expression was induced hr isopropyl-beta-D-thiogalactopyranoside. The resulting recombinant (r) fusion protein was purified by affinity chromatography and confirmed by immunoblot analysis using antimaltose-binding protein or anti-Sm14 antibodies. Additionally, an antibody isotype profile was determined in sera of schistosomiasis patients to rSm14 or soluble adult worm antigen preparation. IgG1 and IgG3 subclass antibodies to rSm14 were predominant in sera of all patients studied whereas low levels of IgM, IgA or IgE were measured. Expression of a S. mansoni gene encoding a vaccine candidate is an important step to better study human immune responses to defined antigens.     

Immunological studies in human schistosomiasis. III. Immunoglobulin levels, antibodies, and delayed hypersensitivity.

Levels of IgG, IgE, IgM, and IgA were determined, specific antibodies were detected by the fluorescent antibody test, hemagglutination test, complement fixation test and immunoelectrophoresis, and intradermal tests for delayed hypersensitivity to Schistosoma mansoni antigens were performed in Brazilian patients with schistosomiasis mansoni. The results were compared according to the clinical forms of the disease. IgG levels and antibody titers increased progressively in the subclinical, hepatomegalic, and hepatosplenic forms and there was a statistical relationship between IgG levels and the intensity of responses to the four serological tests; Delayed hypersensitivity (DHS) was found more frequently in hepatosplenic patients and more particularly in those with splenomegaly. DHS also correlated with age, but not with sex or with skin color. The strongest DHS reactions were observed in patients 20 to 34 years old, and in those having the highest fecal egg output. IgG levels, antibody titers, and DHS responses decreased after splenectomy and portal filtration of the worms. No significant variation was observed between untreated subjects, patients who were splenectomized and a group not subject to reinfection for 4 yearsk0     

胶体染料试纸条试剂盒检测曼氏血吸虫病的初步研究

目的探索日本血吸虫胶体染料试纸条试剂盒(DDIA)用于检测曼氏血吸虫病的可行性。方法采用日本血吸虫DDIA检测从埃及尼罗河地区曼氏血吸虫病流行区采集的曼氏血吸虫病人血清及当地健康人血清。结果34份曼氏血吸虫病人血清DDIA均呈阳性,14份当地健康者血清均为阴性。与用曼氏血吸虫IHA和ELISA法检测结果相同。结论日本血吸虫DDIA也可用于检测曼氏血吸虫病。     

Immunoenzyme assay of parasite-specific IgG4 antibodies in schistosomiasis using the monoclonal antibody BL-IgG4/1

Sera from 251 children living in endemic areas (Schistosoma mansoni or Schistosoma haematobium) and from 188 hospital outpatients in Ethiopia were evaluated for specific IgG4 antibodies reacting with Schistosoma mansoni adult worm antigen employing an enzyme-immunoassay. Patients with schistosomiasis (n = 140) possessed a significantly higher mean value of specific IgG4 antibodies than normal controls (n = 30) and individuals from different countries who had no schistosomiasis but are infected with other parasites (n = 114). Blood samples dried on filter paper were also acceptable in these test. The use of the test in diagnosis is compared and assessed with parasitological methods.     

Antibody responses in schistosomiasis haematobium in Somalia. Relation to age and infection intensity

Antibody responses in schistosomiasis haematobium were studied in relation to age and infection intensity in Somalia. The area is highly endemic for Schistosoma haematobium but free of S. mansoni. Antibodies of the IgG class against particulate antigens of S. mansoni adult worms were investigated by immunofluorescence (gut and somatic associated antigens) and against soluble egg and adult worm antigens by ELISA. Total IgE levels were examined by Pharmacia IgE RIA, and specific IgE against soluble adult worm antigen by enzyme immunoassay. The IgG antibody response showed a characteristic pattern with highest reactivity against both gut associated and soluble egg antigens in the age group 10-14 years, when both prevalence and intensity of the infection were highest. Reactivity against somatic associated antigen was also high in this age group, but it increased slightly and remained at high level in the older ages. It is thought that such antigen is exposed mainly after the death of the parasite and that the antigenic stimulation may remain throughout most of the life of infected individuals. On the other hand, the IgG antibody reactivity against soluble adult worm antigen was low during childhood, but it increased significantly with age. It is suggested that repeated booster effects are needed for more potent response against these antigenic components. The finding of high levels of total IgE already in the youngest age groups, together with low specific IgE response, indicates that mainly other antigens are involved in the IgE production. The specific IgE response against soluble adult worm antigen was low but increased significantly with age.     

Species specificity of the immediate hypersensitivity to schistosomal proteolytic enzyme

An acidic proteolytic enzyme which digests host haemoglobin can be isolated and purified from schistosomes. This small glycoprotein is an allergen which sensitizes the host, as shown by immediate hypersensitivity reactions. These are specific for either Schistosoma haematobium or S. mansoni and can be demonstrated by mast cell degranulation in mice or by intradermal skin tests in monkeys. Although high levels of total IgE may be found in acute and chronic schistosomiasis, there was no evident relationship between the worm burden in monkeys and immediate hypersensitivity reactions to either purified enzyme or crude schistosomal extracts. It is suggested that an in vivo correlation between worm burden and manifestations of the allergic response may be perturbed by high titres of non-specific IgE or other homocytotropic antibodies, thus accounting for false negative skin test reactions. Alternatively, a return to low or subnormal IgE levels may allow the restoration of the allergic response, giving rise to false positive reactions. Purified schistosomal antigens offer certain advantages over crude skin test preparations in terms of uniformity of antigen content, dosage and specificity. In addition, the enzyme may represent a species-specific tool for new immunochemical analyses of schistosomiasis.     

Diagnosis of human schistosomiasis by detection of circulating cathodic antigen with a monoclonal antibody.

Monoclonal antibody (MAb) 5H11 reacted with repeating epitopes on Schistosoma mansoni circulating cathodic antigen (CCA) and detected CCA in sera of Egyptian S. mansoni-infected patients. MAb 5H11 was both capture and biotinylated detection antibody in a sandwich ELISA of trichloroacetic acid-pretreated serum samples. Sera of patients with 7-500 eggs/g of stool were positive by MAb 5H11-CCA sandwich ELISA. Stool egg counts and CCA serum levels correlated (r = .52), and CCA levels decreased by 4 weeks after praziquantel treatment in patients with pretreatment egg counts of greater than or equal to 50/g of stool (P less than .05). Sera of Schistosoma haematobium-infected patients, uninfected individuals, and most patients with other helminths were negative in this assay. The MAb 5H11-CCA sandwich ELISA appears sensitive and specific for immunodetection of active schistosomiasis mansoni and useful for monitoring its chemotherapy.     

Schistosomiasis mansoni: immunoblot analysis to diagnose and differentiate recent and chronic infection.

One hundred seven patients classified into three different groups (11 with acute schistosomiasis, 58 with chronic schistosomiasis, and 38 children with high IgM-specific antibody titers against schistosome gut-associated antigens living in an endemic schistosomiasis area) were studied by immunoblotting for the presence of IgG, IgM, and IgA antibodies against Schistosoma mansoni soluble adult worm antigen preparation. We used sera from 15 individuals infected with various intestinal parasites, as well as sera from 19 uninfected individuals, as controls. An immunogenic fraction with a molecular weight of 31-32 kD (Sm31/32) was the most frequently recognized by the different antibody isotypes. In the group with acute disease, this fraction was recognized by IgG and IgM antibodies of all patients, and by 10 (90.9%) of 11 samples for IgA antibodies. Approximately 98% of the patients with chronic infections had IgG antibodies against Sm31/32, but only about 10% had IgM and IgA antibodies against this fraction. The IgG immunoblot profiles of the children from the endemic area were similar to those obtained for the group with acute schistosomiasis. This observation suggests recent infection of these children. Our data show that the Sm31/32 protein fraction is highly immunogenic and may be a useful serologic marker for diagnosing and differentiating between acute and chronic schistosomiasis infection.     

Specific isotype immune response in the diagnosis of human schistosomiasis pathology?

Since the few indirect markers available for assessing the development and the stage of intestinal schistosomiasis morbidity are weakly specific, endoscopy is still the only method able to detect severe forms of pathology. Therefore, we evaluated the isotype antibody response to the current schistosome antigen preparation (soluble egg antigens [SEA]) in 142 Senegalese patients infected with Schistosoma mansoni. They were stratified into three different stages of pathology according to ultrasonographic, endoscopic, and clinical parameters (stage 1 = no detectable pathology; stage 2 = moderate morbidity; stage 3 = severe forms of pathology). Only median specific IgG4, IgE, and IgA responses changed according to the stage of pathology. The IgA level was significantly higher in stages 2 and 3 compared with stage 1, and the IgE level was higher in stage 3 compared with stage 1. A high specific IgG4 level was observed only in stage 3 and was significantly different compared with stage 2. We show an association between the variability of the specific response to SEA and the degree of morbidity, and demonstrate that IgA and IgG4 responses could be combined markers to easily discriminate the different stages of pathology due to infection with S. mansoni.     

北京市6例输入性曼氏血吸虫病临床特点分析

目的分析6例输入性曼氏血吸虫病患者的临床特点,为提高临床医师的诊治水平提供资料依据。方法收集2009年1月-2016年7月确诊的6例输入性曼氏血吸虫病患者的临床资料,并进行分析。结果 6例输入性曼氏血吸虫病患者均有明确的流行病学史。主要临床表现为发热和嗜酸性粒细胞增高,50%患者伴有腹泻;肠黏膜组织压片均可以找到曼氏血吸虫卵,但日本血吸虫IgG抗体阳性率仅为33.3%。所有患者CD3~+CD8~+T细胞比例明显下降,B细胞比例明显上调,血免疫球蛋白以IgG抗体为主;16.6%的患者腹部超声见腹腔积液或脾脏增厚,16.6%患者磁共振检查见肝脏出现多发小结节或肠壁增厚,所有患者电子结肠镜检查均可见结肠炎,其中66.6%的患者合并多发溃疡,肠黏膜病理学均可见大量嗜酸性粒细胞浸润。6例患者经吡喹酮治疗后均达到临床治愈标准。结论本文通过系统总结6例输入性曼氏血吸虫病患者的流行病学史、临床和实验室多方面资料,为提高临床医师对该病的认知及诊治水平提供依据。     

Granulomatous hypersensitivity to Schistosoma mansoni egg antigens in human schistosomiasis. III. In vitro granuloma modulation induced by immune complexes

Granulomatous hypersensitivity to parasite eggs of Schistosoma mansoni is an important factor in the development of morbidity in chronic schistosomiasis. It has been demonstrated previously that the chronic, well-tolerated, intestinal form of schistosomiasis is associated with the establishment and maintenance of a variety of immunoregulatory mechanisms. We have used an in vitro model of granuloma formation for the purpose of studying the regulation of granulomatous hypersensitivity to S. mansoni egg antigens, mediated by immune complexes (IC). Our results show that the peripheral blood mononuclear cells (PBMCs) from patients with active schistosome infections, when treated with sera from chronic schistosomiasis patients, were able to induce an inhibitory activity on in vitro granuloma formation. Significant modulation of the in vitro granuloma reaction remained after treatment of PBMCs with isolated IC or manufactured IC with soluble egg antigen (SEA) and purified IgG from pooled chronic schistosomiasis sera. In contrast to granuloma modulation stimulated with whole molecule IgG-SEA IC, the incubation of PBMCs with F(ab')2 IgG-SEA IC did not induce any suppression of the granulomatous hypersensitivity to SEA. It appears in this model system that IC may inhibit the activity of granuloma formation by stimulating macrophages to release suppressive mediators. We have demonstrated this possibility by inhibition of prostaglandin activity using indomethacin. The addition of indomethacin to the granuloma culture significantly reduced in vitro granulomatous hypersensitivity to S. mansoni eggs in patients with chronic intestinal schistosomiasis and do so by inducing macrophages to secrete prostaglandins.     

Serodiagnosis of human intestinal schistosomiasis

We developed an enzyme linked-immunosorbent assay (ELISA) for serodiagnosis of Schistosoma mansoni infection using a purified immunogenic fraction from schistosome adult worm, obtained by SDS-polyacrylamid gel electrophoresis. Sera from patients with active schistosomiasis (egg passers; n=10); inactive schistosomiasis previously treated with praziquantel (not passing eggs; n=10); fascioliasis, hydatosis (n=5); and healthy controls (n=10) were examined. Western blot analysis revealed that the Sm 31/32 KDa fraction of Schistosoma mansoni is recognized by sera from of both active and inactive schistosomiasis. ELISA IgG reactivity (optical density, OD) to Sm 31/32 KDa fraction by ELISA was significantly higher in sera of schistosomiasis patients (active and inactive), (p<0.001) compared to normal controls, while no significant difference was detected between active (OD=0.79 +/- 0.23) & inactive (OD=0.87 +/- 0.37) patients. No reactivity was detected using facioliasis or hydatosis sera. The overall level of specificity and sensitivity attained was 90% and 93%, respectively. It is concluded that the developed Sm 31/32 KDa ELISA may be of value in serodiagnosis of active and inactive intestinal Schistosoma mansoni infection in humans.     

Laboratory diagnosis of schistosomiasis mansoni: Current status and future trends

Schistosomiasis is a neglected tropical disease that affects about 290 million patients worldwide. Children aged between 5 and 14 years represent 45.8% of the affected patients, in addition, schistosomiasis has been reported in Schistosoma-free areas, mostly because of tourism and immigration from endemic countries. Intestinal schistosomiasis caused by Schistosoma mansoni is mainly diagnosed via direct stool examination for egg detection. Immunological methods are favoured for disease monitoring and preliminary checking for communities in areas with low infection rates, and for patients with light and chronic infections where parasitological tests are negative. PCR-based diagnostic techniques are more sensitive, but expensive. Tegument proteins and miRNAs are promising markers for diagnosis of schistosomiasis. Here we review the diagnostic methods for schistosomiasis mansoni aiming to reach a standardized technique for diagnosis of early infection to help better control of the disease.     

金标免疫渗滤法(DIGFA)快速检测血吸虫循环抗原的研究

目的　建立一种简便、快速的血吸虫病诊断方法。方法　在已建立的检测血吸虫抗体的ＤＩＧＦＡ基础上,以抗血吸虫重组蛋白ＳＶＬＢＰ多抗为捕捉抗体,金标抗ＳＥＡ多抗为覆盖抗体,建立快速检测病人血清中血吸虫循环抗原的双夹心ＤＩＧＦＡ。结果　用该法检测了急性血吸病人血清３０ 人份和慢性血吸病人血清３８ 人份,其阳性检出率分别为１００ ％ 和５２－６ ％ ;１２０ 人份流行区健康人血清全为阴性;１００ 人份非流行区健康人群血清的阴性符合率为１００％ ,与１０ 例华支睾病人血清无交叉反应;１５ 例肺吸虫病人血清有１ 例阳性,交叉反应率为６－７ ％ ;与双夹心ＥＬＩＳＡ的符合率为９７－４％ ,经χ２ 检验表明两法检测效果无显著性差异。结论　用ＤＩＧＦＡ检测血吸虫循环抗原具有较高的敏感性和特异性,并且方法简便、快速、不需特殊仪器设备,有广阔的应用前景。     

Schistosomal myelopathy mimicking spinal cord neoplasm

We describe a 48-y-old male with chronic progressive myelopathy suggesting thoracic intramedullary neoplasm but in whom laboratory workup disclosed Schistosoma mansoni myelopathy. The case illustrates the need for careful investigation of schistosomiasis in patients from endemic regions with myeloradiculopathy signs.     

Presence of the schistosome circulating anodic antigen (CAA) in urine of patients with Schistosoma mansoni or S. haematobium infections

We investigated the presence of the circulating anodic antigen (CAA) in the urine of schistosomiasis patients. This genus specific antigen was hitherto demonstrated only in the serum of schistosomiasis patients. The urine of 80 patients with Schistosoma mansoni infections, 33 patients with S. haematobium infections, and 2 patients with mixed S. haematobium and S. mansoni infections were screened by a quantitative enzyme-linked immunosorbent assay (ELISA). CAA was demonstrated in 81% of those with intestinal schistosomiasis and in 97% of those with urinary schistosomiasis. CAA titers were less than 1:0.2-1:51.2. Results were compared with circulating cathodic antigen (CCA) titers in urine obtained in an indirect hemagglutination assay (IHA). CCA was generally not detectable in the urine of patients with S. haematobium infection, but was demonstrated in the urine of 85% of the patients with S. mansoni infection. Both CAA titers and CCA titers correlated positively with the number of S. mansoni eggs excreted in the feces, but CAA titers did not show a significant correlation with the number of S. haematobium eggs in urine. Both antigen titers showed a moderate correlation with the serum CAA level in schistosomiasis mansoni. The discovery of CAA in the urine of the majority of schistosomiasis patients tested suggests the use of urine samples for non-invasive immunodiagnosis of the disease.     

Different cytokine patterns in patients coinfected with hepatitis C virus and Schistosoma mansoni

Schistosoma mansoni (S. mansoni) and hepatitis C virus (HCV) coinfection is common in Egypt and other developing countries. Patients coinfected with HCV and schistosomiasis exhibit a unique clinical, virological and histological pattern manifested by viral persistence with high HCV RNA titers as well as higher necroinflammatory and fibrosis scores in their liver biopsy samples. Dual infections of schistosomiasis and viral infections display significant influences on host immune reactions including cytokine shift pattern alteration, cytotoxic T lymphocyte response and other impaired immunologic functions with diminished capacity to clear the virus. We investigated the cytokine pattern against HCV and S. mansoni antigens in patients coinfected with HCV and S. mansoni and compared them with responses in patients infected with HCV or S. mansoni alone. This study included 4 groups; (Gr I) included 20 patients infected with chronic HCV, their sera were reactive for anti-HCV antibodies, samples were verified for RNA detection to identify those who have viremia. (Gr II) included 15 patients infected with schistosomiasis alone, they were subjected to detection of S. mansoni ova in stool, rectal snip or serological test. (Gr III) included 20 patients with chronic HCV and schistosomiasis coinfection, which were diagnosed by the above-mentioned criteria. (Gr IV) included 15 healthy individuals, who were matched for age and sex and have no evidence of liver diseases served as control subjects. The results showed that a highly significant increase in serum IFN-gamma and IL-18 levels in patients infected with HCV alone compared with the other patient groups and control. On the other hand, a highly significant increase was found in serum IL-4 and IL-10 levels in coinfected patients and patients with schistosomiasis alone compared with the control but a significant increase was found in the two groups compared with HCV patients. A significant increase in serum IL-4 and IL-10 were also found in HCV patients compared with the control. In conclusions, our data showed that coinfected patients have dominant Th2 cytokine profile induced by S. mansoni and this Th2 antagonized and down-regulated the antiviral activities of Th1 cytokine profile in HCV infection that probably acquired after S. mansoni infection resulting in failing to mount significant HCV specific Th1 response and thereby fail to clear the virus in coinfected, compared with patients infected with HCV or schistosomiasis alone.     

Elution of renal antischistosome antibodies in human schistosomiasis mansoni.

Elution of complexed immunoglobulins was carried out in renal tissue obtained at autopsy from schistosomiasis mansoni and control cases. Substantial amounts of IgG were found in acid eluates of 2 of 5 schistosomiasis cases and 2 of 3 controls. The IgG from schistosomiasis cases produced specific indirect immunofluorescence reactions in gut and tegument of sections of adult Schistosoma mansoni; no reactivity was present against egg granulomas, cercariae, or mouse liver tissue. Control case eluates produced no fluorescence with S. mansoni antigens.