Immunodiagnosis of filariasis

The sensitivity and specificity of the enzyme-linked immunosorbent assay (ELISA), the indirect haemagglutination (IHA) test and the counter-current immuno-electrophoresis test (CIEP) were assessed in the diagnosis of filariasis. Positive reactions were observed in 91% and 86% of cases by ELISA and IHA respectively. CIEP detected only 31.5% of cases. Cross-reaction due to intestinal nematodes was observed in 80% of cases by both ELISA and IHA whereas with CIEP cross-reaction was observed in 10% of cases. The microfilaria count was inversely proportional to the antibody titre among asymptomatic carriers. ELISA was the most sensitive test, followed by IHA and then CIEP. CIEP, though it detected only a small number of cases, was observed to be the most specific.     

A comparison of the ELISA with other serological tests in the serodiagnosis of amoebiasis

The sera of 78 patients with invasive amoebiasis were tested for antiamoebic antibodies by the techniques of enzyme-linked immunosorbent assay (ELISA), indirect haemagglutination (IHA), indirect fluorescent antibody (IFA) and counterimmunoelectrophoresis (CIEP). Results showed that the ELISA compared favourably with IHA and IFA tests in terms of sensitivity and specificity. ELISA, IHA and IFA detected 97.4%, 96.2% and 98.7% of the patients respectively. CIEP was the least sensitive of the 4 serological methods with a sensitivity of 88.5%. The advantages and disadvantages of the 4 serodiagnostic procedures are discussed.     

Evaluation of counterimmunoelectrophoresis for serodiagnosis of human cysticercosis

Counterimmunoelectrophoresis (CIEP) was evaluated in comparison to the indirect haemagglutination test (IHA) for serodiagnosis of human cysticercosis. It was found that CIEP detected antibodies in 7 of 11 (64%) and IHA detected them in 6 of 11 (55%) confirmed cysticercosis sera. Only 2 of 130 control sera were positive by each technique. Taenia saginata adult worm extract was found to be satisfactory for use in CIEP in place of Taenia solium cysticercus extract, with only little loss of sensitivity. Finally, CIEP in combination with IHA greatly increased the diagnostic sensitivity for human cysticercosis.     

Serologic tests for diagnosis and post-treatment evaluation of patients with alveolar hydatid disease (Echinococcus multilocularis)

The indirect hemagglutination (IHA) and immunoelectrophoresis (IEP) tests were used for diagnosis and follow-up evaluation of 17 patients with alveolar hydatid disease caused by Echinococcus multilocularis. Follow-up periods ranged from 2 to 22 years. At the time of diagnosis 16 (94%) patients' sera gave IHA titers greater than or equal to 1:128. Serum specimens from 13 patients were examined by IEP; nine (69%) revealed the arc 5, and three of the four arc 5-negative sera revealed one or more non-characterized bands. Titers declined markedly during the first year following radical surgical resection of the larval lesions; in three cases clinical evidence of recurrence was preceded by rising serologic titers. Antibody has persisted at high levels in non-resected patients treated continuously with high doses of mebendazole.     

Immunodiagnosis of amoebiasis

Serological studies were done on 127 cases using three different techniques namely indirect haemagglutination (IHA), indirect fluorescent antibody test (IFT) and counter immunoelectrophoresis (CIEP) to detect antiamoebic antibodies. All amoebic liver abscess cases showed significant titre of antibodies by all the three tests used. In the group of patients suffering from amoebic pathology of liver, 90.47 per cent were positive by IHA, 100 per cent by IFT and 85.71 per cent by CIEP respectively. Among amoebic dysentry and amoebic colitis cases 81.81 per cent and 80.64 per cent respectively were positive by IHA. The corresponding figures for IFT were 100 per cent and 74.19 per cent and for CIEP 90.90 per cent and 64.51 per cent respectively. Follow up study showed no significant fall in antibody titre in nine cases studied upto 10 weeks after treatment. Amoebic antigen could be detected in pus from all the nine cases with amoebic liver abscess by CIEP test.     

Evaluation of whole and purified hydatid fluid antigens in the diagnosis of human hydatidosis by the immunoelectrophoresis test.

Whole sheep hydatid cyst fluid (WHF) and purified hydatid fluid antigens (PHF) were evaluated in the immunoelectrophoresis (IEP) test for the diagnosis of human hydatid disease. A higher sensitivity was obtained using the PHF than with the WHF antigen but false positive results were observed with the former in 22.4% of the 102 non-hydatid sera examined. Using the presence of arc 5 as the criterion of positivity however, no false positives were observed in non-hydatid sera with the WHF antigen. It is postulated that the number of bands other than arc 5 may be of value in the diagnosis of hydatid disease by the IEP test, in cases where this diagnostic arc is absent.     

Diagnosis of human hydatid disease in surgically-confirmed cases by the use of the indirect haemagglutination test based on a thermo-stable lipoprotein and on unfractionated hydatid cyst fluid

A total of 204 sera, taken from healthy individuals or from individuals with various parasitic and bacterial infections, were examined by the indirect haemagglutination test. The tests were carried out using either a thermo-stable lipoprotein or unfractionated hydatid cyst fluid, and a titre of 1:64 or above was considered positive. Sixty-two of 70 sera from individuals with surgically-confirmed hydatid disease showed positive reactions with the thermo-stable lipoprotein--a sensitivity of 88%. No false positive reactions were obtained with sera from healthy individuals or from individuals with parasitic or bacterial infections, and no cross-reactions were observed with sera from individuals with multiple myeloma. The lipoprotein antigen thus showed a specificity of 100%. A sensitivity of 88% was obtained with the indirect haemagglutination test using whole hydatid cyst fluid; but positive reactions were obtained from healthy individuals and from individuals with schistosomiasis, leishmaniasis, taeniasis and malaria. No cross-reactions were obtained with sera from patients with gonorrhoea, syphilis or multiple myeloma. Because of the high sensitivity and specificity shown by the thermo-stable lipoprotein ('Antigen 880'), it is considered that this antigen is more useful than unfractionated hydatid cyst fluid in the diagnosis of human hydatidosis in Kenya.     

Native and recombinant antigens in the immunodiagnosis of human cystic echinococcosis

To evaluate the diagnostic sensitivity and specificity of immunoelectrophoresis (IEP), indirect haemagglutination (IHA), enzyme-linked immunosorbent assay (ELISA) and immunoblotting (IB), we compared their ability in detecting IgG antibodies to a hydatid fluid fraction (HFF) and to native and recombinant antigen B of Echinococcus granulosus. We tested sera from patients who had cystic echinococcosis (CE) grouped according to their type of cysts (n = 204), from patients with other parasitic diseases (n = 21), lung or liver carcinomas (n = 6) or serous cysts (n = 26) and from healthy controls (n = 90). HFF-IB gave the highest sensitivity (80%) followed by ELISA (72%), IHA (54%) and IEP (31%), respectively. The diagnostic sensitivity significantly (P < 0.01) decreased as cysts matured from type I-II to type VII. Recombinant and native antigen B-IB yielded similar sensitivity (74%). A large number of clinically or surgically confirmed CE patients (20%) resulted negative. In these patients' sera, IB to assess the usefulness of the recombinant E. granulosus elongation factor-1 beta/delta in detecting IgE antibodies yielded 33% of positivity. Our findings underline the need to standardize techniques and antigenic preparations and to improve the performance of immunodiagnosis by characterizing new antigens and detecting distinct immunoglobulin classes.     

A comparative study of four methods for detecting antibody in asymptomatic giardiasis

Four immunological methods for diagnosis of giardiasis comprising complement fixation (CF) test, indirect hemagglutination (IHA) test, enzyme-linked immuno sorbent assay (ELISA) and lectin immuno test (LIT) were studied. Fifty sera from asymptomatic giardiasis patients, 40 from patients with other diseases and 50 from healthy controls were evaluated. The seropositive rates in asymptomatic giardiasis were 36% for CF, 58% for LIT, 30% for IHA and 72% for ELISA. The seropositive rates in patients with other diseases were 22.5% for CF, 52.5% for LIT, 12.5% for IHA and 67.5% for ELISA. The results suggest that the test of choice for giardiasis was CF with 88% specificity, nevertheless this test showed low sensitivity (36%). Other two tests, ELISA and LIT were more sensitive than CF with percent sensitivity of 72 and 58 respectively, but these two tests had severe disadvantages in being less specific with percentage specificity of 48 and 60 respectively.     

Antibodies against Entamoeba histolytica in individuals with intestinal amoebiasis presenting cysts and/or trophozoites in the feces.

Serum samples were obtained from 154 individuals infected with Entamoeba histolytica (78 symptomatic and 76 asymptomatic). Twelve had trophozoites in the feces whereas 142 had only cysts. The sera were used to test the existence of antibodies anti-Entamoeba histolytica employing the Indirect Hemagglutination (IHA), Indirect Immunofluorescence (IFAT), Complement Fixation Reaction (CFR) and Counterimmunoelectrophoresis (CIEP). For those individuals with trophozoites in their feces, 75.0 were positive by IHA and IFAT, 83.0 by CFR and 41.7 by CIEP. In individuals who had only cysts, positive results by the same tests were respectively, 5.6%, 12.0%, 19.0% and 5.6%. The difference in relation to the titers of antibodies detected through IHA, IFAT, CFR and CIEP and in relation to the presence of trophozoites or cysts in the feces was significative for four immunological reactions when chi 2, was employed (P < 0.05).     

酶标记抗原对流免疫电泳试验诊断棘球蚴病的研究

用戊二醛一步法以辣根过氧化物酶标记纯化人棘球蚴液抗原,对80例棘球蚴病,97例其它寄生虫病和其它疾病以及74例健康人进行了酶标记抗原对流免疫电泳试验(E-CIEP),其敏感性为85.0％,特异性为100％。E-CIEP敏感性显著高于CIEP 而低于PPA-ELISA,但其特异性显著高于PPA-ELISA。用国产辣根过氧化物酶与进口酶标记的抗原,试验敏感性相同。凝胶片先烘干后染色并不影响抗体活性。     

Echinococcus granulosus: diagnosis of hydatid disease in man

Several antigen fractions were prepared from sheep hydatid fluid and scolices of Echinococcus granulosus by salting out with ammonium sulphate. Sera from subjects with hydatid disease and from uninfected controls were assayed by the IHA, Latex, ELISA and Complement Fixation tests. The greatest sensitivity was given by the hydatid fluid 0.8 M fraction in the IHA test. This antigen also gave good results with the ELISA technique. Antigens from sheep fertile fluid were diagnostically superior to those from scolices. The specificity was excellent for all antigens examined.     

包虫病人唾液特异性抗体的检测研究与应用

目的　研究包虫病人唾液中特异性抗体的诊断方法和唾液抗体的代谢特点。方法　应用ELISA、IHA和LA法检测包虫病人和正常人唾液中的特异性抗体。以ELISA法测定唾液抗体含量与取样时间的关系。进行包虫病唾液抗体的流行病学普查验证。结果　包虫病人唾液抗体IgG -ELISA、LA和IHA试验阳性率分别为 84.4% (119/ 141)、48.94% (2 3/47)、8.75 % (7/ 80 )。包虫病人唾液中特异性IgG抗体检出率明显高于IgA(P <0 .0 0 1)。对 141例包虫病人唾液和血清进行IgG -ELISA平行检测 ,血清IgG抗体阳性率 90 .0 7% ,总符合率为 85 .82 %。对 30例包虫病人于 2 4h内 5次不同时间进行唾液采样测定IgG抗体 ,发现IgGOD均值浓度差别不明显。包虫病唾液抗体普查阳性率为 16 .8% ,与影像学检查对比符合率为 6 1.9% (13/ 2 1)。结论　包虫病人唾液抗体ELISA检测法 ,操作简便、经济、灵敏度好 ,经过标准化后适合作为包虫病临床和流行病普查的免疫学诊断方法。     

Indirect haemagglutination test using monoclonal antibody-affinity purified antigens for diagnosis of human paragonimiasis due to Paragonimus heterotremus

An indirect haemagglutination test (IHA) using antigens purified by monoclonal antibody-affinity chromatography was developed for the diagnosis of human paragonimiasis caused by Paragonimus heterotremus . Sera from patients with paragonimiasis ( n = 30) were evaluated, along with sera from other parasitic infections ( n = 92), pulmonary tuberculosis ( n = 18) and healthy controls ( n = 30). The sensitivity, specificity as well as positive and negative predictive value of the IHA, calculated at the prevalence of disease at 17.6%, were all 100%.     

Use of a partially purified Fasciola gigantica worm antigen in the serological diagnosis of human fascioliasis in Egypt

Crude extracts of Fasciola gigantica adult worms, when used as an antigen in indirect hemagglutination (IHA) and counterimmunoelectrophoresis (CIEP) tests, detected all independently diagnosed human F. gigantica and F. hepatica infections but cross-reacted with sera of patients with schistosomiasis and amebiasis. Fractionation of this crude worm extract using Sephadex G-200 chromatography demonstrated four major protein peaks. Antigen from the crest and descending portion of peak II (mol. wt. approximately 20 x 10(3)) and all of peak III (mol. wt. approximately 6 x 10(3)) were pooled and used as a source of partially purified antigen. This partially purified fraction, when used in the CIEP test, reacted with sera from patients with fascioliasis but not those from schistosomiasis or amebiasis patients, whether undiluted or concentrated fivefold, but failed to react by IHA with fascioliasis sera. It reacted with undiluted sera from all individuals passing F. gigantica eggs except one, a possibly spurious infection, and with eight of 20 sera from individuals passing F. hepatica eggs, while the remaining 12 sera became positive after fivefold concentration. It also reacted with two sera from individuals passing eggs of both Fasciola species and with five of 11 sera from individuals negative microscopically but positive serologically with the crude antigen.     

Antigenicity of sub-cellular components of Entamoeba histolytica.

Antigencity of the sub-cellular components of axenic Entamoeba histolytica trophozoites was studied. The cells were disrupted by means of a glass-teflon homogeniser and sub-cellular components were prepared by stepwise differential centrifugation. Four fractions were obtained, namely the 350 g, 6500 g, and 100,500 g fractions and the cell sap. Components of the sedimented fractions were examined by phase contrast and electron microscopy. The antigenicity of each fraction was studied by two different methods:-(1) By extraction with 0.5% sodium deoxycholate followed by testing against the reference sera; (2) By demonstration of the loss of immunological activity of the reference sera after absorption with fractionated components. It was found that all 4 fractions had varying antigenic activities as measured in the indirect hemagglutination (IHA), the complement fixation (CF) and the immunoelectrophoresis (IEP) tests. With the extraction technique, the following results were obtained:- The highest IHA activity was found in the cell sap, whereas this activity in other fractions clustered at lower levels. In the CF test, the activities associated with all 4 fractions were similar. In the IEP test, the highest activity was found in the cell sap and the least activity in the 100,500 g fraction. With the absorption technique, slightly different results were obtained. Whilst in the IHA and the IEP test, the results were in concordance with the extraction technique, the CF activity was slightly different, since it was highest in the cell sap and least in the 100,500 g fraction.     

Invasive amebiasis: challenges in diagnosis in a non-endemic country (Kuwait).

Invasive zymodemes of the enteric protozoan Entamoeba histolytica infect the large intestine and cause extra-intestinal lesions such as amebic liver abscess (ALA). The clinical manifestations of ALA are protean, particularly in patients presenting in a non-endemic, desert country such as Kuwait, and diagnosis becomes problematic. In this study, we present cases of ALA to illustrate the clinical and diagnostic challenges. For serodiagnosis of ALA, we compared the sensitivity and specificity of the indirect hemagglutination assay (IHA) with the ImmunoTab assay and an enzyme-linked immunosorbent assay (ELISA) for this geographic region. We tested sera of 110 patients with ALA, 1,224 patients suspected of having invasive amebic infection, and 50 Europeans with no travel history to an amebic-endemic area. The IHA was simple, rapid, easy to perform, and reliable (sensitivity = 99%, specificity > 95%). The performance of the IHA in detecting ALA in suspected cases was significantly better than that of the ELISA and the ImmunoTab test. Compared with the IHA, both the ELISA and ImmunoTab assay detected relatively higher numbers of false-positive cases (4.7% and 3.6%, respectively). With the availability of ultrasound and computed tomography scans, the serology correlates excellently with the clinical presentation. In chronic cases where fibrosis may be present around the abscess, the IHA has limitations, as in the follow-up of treated patients. Pitfalls in diagnosis are highlighted by discussing the differential diagnosis of ALA from bacterial hepatic abscesses and infected hydatid cysts. Most importantly, the IHA in such cases was invariably at a titer that is considered not significant.     

Evaluation of serological tests for diagnosis of Bordetella pertussis infection in adolescents and adults

Background and objective: Bacterial agglutination antibodies against Bordetella pertussis, Yamaguchi and Tohama strains, are frequently measured for serodiagnosis of pertussis infection in Japan. To determine the serological criteria, the comparative titres of bacterial agglutination antibody and anti‐pertussis toxin (PT) antibody were evaluated. Methods: Antibody titres were analysed in 36 definitive (fourfold increase in agglutination antibody) and 137 presumptive (high titre of single‐antibody) cases of B. pertussis infection among adolescents and adults, and in a control group of 318 healthy volunteers. Results: When a single Yamaguchi agglutinin titre of ≥1:1280 (> three SD above the geometric mean for the control group) was taken as diagnostic, the sensitivity and specificity at 4–5 weeks after onset of cough were 58% and 98%, respectively. Using this criterion, the clinical findings in presumptive cases were almost identical to those in definitive cases. When the two tests were compared using 318 control sera, there was no association between the Tohama agglutinin titre and the anti‐PT antibody titre, whereas a weak association between the Yamaguchi agglutinin titre and the anti‐PT antibody titre was observed. When the numbers of pertussis cases with high antibody titres in the two tests were compared, 60% of cases with a Yamaguchi agglutinin titre of ≥1:1280 showed an anti‐PT antibody titre of ≥100 EU/mL. Conclusions: These results indicate that the bacterial agglutination test is a method with low sensitivity and specificity for the diagnosis of B. pertussis infection. Therefore, to yield an accurate diagnosis, anti‐PT antibody levels should be measured instead of bacterial agglutination antibody.     

三种血清学试验检测旋毛虫病抗体的研究

用免疫酶染色试验（ＩＥＳＴ）、间接血凝试验（ＩＨＡ）和玻片法环蚴沉淀试验（Ｓｌｉｄｅ）３种血清学方法检测感染旋毛虫豚鼠血清，阳性率分别为９７．１％、１００％和９６．７％。用此３种血清学方法检测正常豚鼠、血吸虫病兔、肺吸虫病大白鼠、蛔虫病人和鞭虫病人血清，除１例肺吸虫病大白鼠血清ＩＨＡ出现阳性反应外，其它血清３种方法均为阴性反应。结果表明３种方法对旋毛虫病特异性抗体的检测均有较好的敏感性和特异性。     

Comparative sensitivity and specificity of the Casoni intradermal and the immunoelectrophoresis tests for the diagnosis of hydatid disease.

The Casoni intradermal (ID) test, using two antigens, was compared with the immunoelectrophoresis (IEP) test for diagnosis in 47 surgically confirmed cases of hydatid disease and 73 non-hydatid persons. An antigen prepared from boiled hydatid cyst fluid (HF) was markedly more sensitive in the ID test than another prepared from whole HF but both produced false-positive reactions in three persons with other disease conditions. The IEP test yielded no false positives and its sensitivity was similar to the ID test using the more sensitive boiled HF antigen. Some patients were ID-positive and IEP-negative and vice-versa. Diagnostic sensitivity of both tests varied according to the localization and condition of the cyst. A detectable immune response was more frequent in patients with liver cysts than in those with lung cysts. Regardless of cyst localization, lowest diagnostic sensitivity was observed in patients whose cysts were intact and of the hyaline type, whereas recently broken cysts were associated with the most consistently detectable immune response. The limitations of the ID test are discussed and it is suggested that, until more specific antigens are available, there appears to be little value in utilizing this test where the more specific serological techniques are available.