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.     

Diagnostic value of serum antibody and antigen detection in heroin addicts with systemic candidiasis

The diagnostic value of antibody detection by indirect hemagglutination (IHA), indirect immunofluorescence (IFA), and counterimmunoelectrophoresis (CIE) and of Candida albicans mannan antigen detection by latex agglutination was studied in 36 cases of systemic candidiasis in heroin addicts. The IHA and IFA techniques were highly sensitive (97% and 91%, respectively), but their specificity was low (60% and 50%). When a titer of greater than or equal to 1:2,560 was used as a criterion for IHA positivity, the specificity of the test rose to 87%, with sensitivity at 75%. CIE had a high degree of specificity (96%) but a low degree of sensitivity (58%). A good correlation was found between clinical evolution of infection and serologic data. Two of 12 patients who could be followed for 9-16 months had a rise in antibody titer detected either by IFA or by IHA and CIE. These two patients had a persistent chondrocostal tumor and C. albicans endocarditis, respectively. All of the other patients, who were cured, had a decrease in titer detected by IHA and IFA and had negative CIE results at the end of follow-up. Serum mannan antigen was not found in any case. The detection of antibody to C. albicans may be useful for diagnosis and follow-up of such patients.     

酶联免疫吸附试验检测人血清弓形体IgG,IgM抗体的研究

对ELISA检测人血清弓形体IgG、IgM抗体进行了研究。450份孕妇血清中,ELISA阳性率显著高于IHA;抗体滴度分折,ELISA一般高于IHA2～10倍。25份ELISA IgG抗体阳性血清,IFA检出19份;3份IgM抗体阳性和2份IgG、IgM抗体均阳性血清,IFA分别检出2份。2份阴性和4份含不同抗体滴度的阳性血清于第一次测定后,第7天和第21天测定的阴、阳性结果一致,OD值变异系数为2.43～16.52％。39份阳性血清抗体滴度与OD值呈直线比例关系(r=0.991,P<0.0005)。结果表明,ELISA用于弓形体感染的血清学诊断具有较好的实用性。     

Comparison of various serological test results using antigens from different strains of Plasmodium falciparum

Suitability of different strains of Plasmodium falciparum grown continuously in vitro was compared using the indirect haemagglutination (IHA) the indirect immunofluorescent (IFA) tests and ELISA. In the tests employing soluble antigens (IHA and ELISA), there was a significant higher mean log titer of the same sera tested against different strains. Ranking of the strains in term of sensitivity for the detection of malaria antibody in people in the endemic area were G-112 = SO = CC greater than SU greater than PS in the IHA test and G-112 = SO greater than CC greater than SU greater than PS in the ELISA. The difference in the mean log titers appear to relate neither to the geographical location not the isoenzyme markers tested. There was also an apparent correlation between the results of the IHA and the IFA test but not between these two tests and ELISA.     

Prevalence of Toxoplasma antibodies in Chiang Mai population

Five hundred sera from blood donors were examined for antibodies to Toxoplasma by the indirect hemagglutination antibody (IHA) and the indirect fluorescent antibody (IFA) techniques. In addition, the IHA test was used to detect Toxoplasma antibodies in 500 pregnant women's sera. It was found that 4.6% of the blood donors were positive by the IHA and only 1.2% by the IFA methods. The seroprevalence, however, was less in pregnant women as only 2.8% were positive. Interestingly, 7.5% of the blood donors and 15.2% of pregnant women showed no detectable antibodies. The frequency distribution curves of IHA titers were unimodal in both groups studied. From the basis of these findings, it was concluded that there was a low degree of Toxoplasma transmission in Chiang Mai.     

小儿脑瘫、精神发育迟滞、癫痫与弓形虫感染关系的研究

本文同时采用3种血清学方法检测了210例不明原因的脑瘫、精神发育迟滞和癫痫患儿及100例正常小儿血清和部分患儿脑脊液弓形虫抗体。结果表明:脑瘫和精神发育迟滞弓形虫感染率分别为41.3％和38.6％,明显高于对照组(14％)(P<0.01),提示弓形虫感染是不明原因的脑瘫和精神发育迟滞的重要病因之一;癫痫组弓形虫感染率为18.3％,与对照组比较差别无显著性,似提示弓形虫感染可能与该组癫痫关系不大。在弓形虫抗体阳性患儿中,抗体效价多偏低,仅提示过去感染。患儿血中弓形虫抗体与其脑脊液中抗体之间有相关性。     

Erythema chronicum migrans in Sweden: clinical manifestations and antibodies to Ixodes ricinus spirochete measured by indirect immunofluorescence and enzyme-linked immunosorbent assay

26 Swedish patients with erythema chronicum migrans (ECM) were studied regarding associated clinical symptoms and antibodies to Swedish Ixodes ricinus spirochete. 11/26 (42%) of the patients had associated symptoms, compared to more than 90% of 314 American patients with ECM, as described by Steere et al. Only 2/26 (8%) had multiple skin lesions, compared to 48% of the American patients. Elevated erythrocyte sedimentation rate and circulating immune complexes were demonstrated in 6/25 (24%) and 8/25 patients (32%), respectively, as against in 53% and 84%, respectively, of the American patients. The antibody response to Ixodes ricinus spirochete was measured by indirect immunofluorescence (IFA) and enzyme-linked immunosorbent assay (ELISA). Compared to the 95% percentile of controls, significantly high antibody titers were demonstrated in 3/25 (12%) by IFA, and 7/25 (28%) by ELISA. The ELISA antibody titers differed significantly (p less than 0.05) between ECM-patients and controls. The spirochetal antibody response in ECM was also compared with that in spirochete-associated disease of the central nervous system.     

Serodiagnosis of Rocky Mountain spotted fever: comparison of IgM and IgG enzyme-linked immunosorbent assays and indirect fluorescent antibody test

To characterize IgM and IgG antibody responses in Rocky Mountain spotted fever (RMSF), a microtiter enzyme-linked immunosorbent assay (ELISA) using density gradient-purified Rickettsia rickettsii as antigen was developed. Sera of vaccinated individuals and patients with RMSF were tested by ELISA and by indirect fluorescent antibody (IFA) tests. Diagnostic agreement between ELISA and the IFA test was 76% and 52% for IgG and IgM antibody, respectively. Diagnostic agreement between the ELISA for IgG antibody and the IFA test for total immunoglobulins was 84%. The ELISAs for IgM and IgG antibody were as specific (100%) and as sensitive (100%) as the IFA test (83%-100%) in detecting antibody increases in paired sera from persons with RMSF and were superior to the IFA test in detecting seroconversions in vaccinees. The ELISA also detected antibodies in a single convalescent-phase serum with sensitivity and reliability. The ELISA for IgG antibody is appropriate for seroepidemiology and serodiagnosis since it permits measurement of antibody at a single dilution of serum up to a year after illness.     

Comparison of serologic tests for the diagnosis and follow-up of alveolar hydatid disease

Alveolar hydatid disease is a serious and often fatal condition caused by infection with the metacestode form of Echinococcus multilocularis. Sera of 21 patients with histologically confirmed disease were tested by an enzyme-linked immunosorbent assay (ELISA) using a semi-purified E. multilocularis antigen fraction (Em2) and by indirect hemagglutination (IHA) and double diffusion (DD5) tests using antigens prepared from E. granulosus cyst fluid. At diagnosis, sera from all 21 patients were positive by Em2 ELISA, 18 (86%) by IHA, and 5 (24%) by DD5. Em2 ELISA detected an antibody response earlier than IHA in 4 of 9 patients from whom sera were available before diagnosis. Following complete surgical resection, Em2 ELISA converted from positive to negative in serum of 2 of 3 patients, while IHA results did not change. Following incomplete resection, 14 of 15 patients tested remained positive by Em2 ELISA, while 12 remained positive by IHA. Of sera from 361 healthy persons from regions free of E. multilocularis, none were positive by Em2 ELISA, while 8% were positive by IHA. Of sera from 59 patients with non-echinococcal parasitic infections, none were positive by Em2 ELISA, while 31% were positive by IHA. Thus, in comparison with tests using E. granulosus antigens, Em2 ELISA appears to be more sensitive and specific for diagnosing AHD, useful on follow-up of resected patients, and positive earlier in the course of disease.     

The sensitivity of various serologic tests in the diagnosis of Rocky Mountain spotted fever

Sensitivity indices for various serologic tests in the diagnosis of Rocky Mountain spotted fever (RMSF) were determined from RMSF surveillance data collected at the Centers for Disease Control (CDC) during 1981-1984. During these 4 years, a total of 4,141 cases of RMSF in the U.S. were reported to CDC. Case report forms, which include information on dates and results of serologic testing, were received for 3,567 of these cases; 1,774 were laboratory-confirmed according to criteria published previously by CDC. Sensitivity indices for the Weil-Felix (Proteus OX-19, OX-2), indirect fluorescent antibody (IFA), latex agglutination (LA), complement fixation (CF) and indirect hemagglutination (IHA) tests were examined by analyzing cases confirmed by other means, in which data concerning the test in question were available. Analysis of serum pairs for a 4-fold or greater increase in antibody titer or a minimum diagnostic titer indicated high sensitivity indices for IHA (96%) and IFA (94%), but lower sensitivity indices for OX-19 (70%), OX-2 (47%), CF (63%) and LA (71%). IFA and IHA appear to be the most sensitive serologic tests currently in use for the diagnosis of RMSF.     

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.     

Relation of titers of antibodies to CMV in blood donors to the transmission of cytomegalovirus infection

Titers of antibody to cytomegalovirus (CMV) of 529 persons whose blood had been supplied to 51 selected patients who underwent open-heart surgery were determined by indirect hemagglutination (IHA) and IgM-specific indirect immunofluorescence (IFA). Twenty-eight patients showed evidence of active CMV infection after transfusion (seroconversion or a fourfold rise in titer by IHA), whereas 23 showed no serological change. Patients with active CMV infections had received, on average, a greater number of blood units (12.9 vs. 7.9), of which more were seropositive (6.9 vs. 3.5), than did patients who showed no serological change. Those seropositive units of blood that had been transfused into the group that showed evidence of active infection, however, had a lower geometric mean titer than did those transfused into the group that showed no serological change (1:654 vs. 1:1,360). Seven (1.3%) of the 529 blood donors had CMV-specific IgM titers (by IFA) of greater than or equal to 1:16; each of the seven recipients of their blood subsequently showed evidence of active CMV infection. This study suggests that donor blood with high IHA titers may prevent transmission of CMV infection, whereas blood from donors with IgM antibody to CMV may transmit CMV.     

Evaluation of serodiagnostic tests for visceral larva migrans.

Four serologic techniques for the diagnosis of visceral larva migrans caused by Toxocara canis, namely indirect hemagglutination (IHA), bentonite flocculation (BF), enzyme-linked immunosorbent assay (ELISA), and double diffusion in agar (Ouchterlony), were evaluated using sera sent to the Center for Disease Control from patients with a presumptive diagnosis of visceral larva migrans (VLM). Patients having 5-6 of the clinical or laboratory criteria for VLM were designated as cases while those with 0-2 criteria served as controls. The sensitivity of the ELISA was 78.3% compared to 18.2%, 25.8% and 65.2% for the IHA, BF, and Ouchterlony, respectively; the sepcificity of all four tests was greater than 92%. The predivtive value of positive test was greater than 85% for all tests except the IHA, while the predictive value of a negative test was greater than 85% only for the ELISA. The results of a ELISA were reproducible in different laboratories. Based on these findings, the ELISA using a larval antigen appears to be the serodiagnostic method of choice for VLM.     

Evaluation of recombinant line immunoblot for detection of Lyme disease in Slovakia: comparison with two other immunoassays

In the present study the sensitivity and the specificity of three serological tests (enzyme-linked immunosorbent assay [ELISA], indirect fluorescent antibody test [IFA], and recombinant line immunoblot) were compared by examining 74 sera from patients diagnosed with Lyme disease in Eastern Slovakia. In addition, the reactivity to each of the recombinant proteins in the immunoblot was examined in order to evaluate their diagnostic value. Generally, the immunoblot (93.2%) and the ELISA (90.5%) were significantly more sensitive than the IFA (64.9%; df = 1; p < or = 0.001). Correlation between results of the ELISA, IFA, and immunoblot for IgM or IgG, when two tests were always compared, one to the other, ranged from r(s) = 0.673 to r(s) = 0.905. In the immunoblot, the highest sensitivity was observed in DbpA and VlsE proteins (76.9% and 84.6%, respectively) in IgG testing of the sera from the patient group of Lyme arthritis. VlsE proteins, together with OspC proteins, were also shown to be useful for IgM antibody detection in erythema migrans patients (up to 44.4% and 53.7% sensitivity, respectively). Our results indicate that both the ELISA and the recombinant immunoblot test were more satisfactory for seroconfirmation of Lyme disease than IFA. Moreover, the reseach confirmed diagnostic value of the in-vivo expressed proteins (VlsE and DbpA), which might have the potential to play an important role in improving whole-cell antigen-based testing.     

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.     

单克隆抗体在寄生虫病免疫诊断中的应用

单克隆抗体以其特异性高、效价高、易纯化等优点得到了广泛的应用,该文对单克隆抗体应用于乳胶凝集试验、间接血凝试验、免疫荧光检测、流式细胞仪检测、免疫组织化学、放射免疫测定法、免疫印迹技术、免疫酶染色技术和斑点免疫金银染色法、酶联免疫吸附试验、金免疫渗滤法、免疫层析技术和免疫色谱技术等12种免疫学诊断方法,及其在寄生虫病诊断中的应用作一综述.     

Antibody response in patients with cutaneous leishmaniasis infected by Leishmania (Viannia) braziliensis or Leishmania (Viannia) guyanensis in Brazil

The antibody response against Leishmania (Leishmania) amazonensis crude antigen was measured through the indirect immunofluorescent assay (IFA) and the immunoenzymatic assay (ELISA) in 114 patients with cutaneous leishmaniasis (CL) in Brazil. Fifty-four patients were infected by Leishmania (Viannia) braziliensis, and 60 patients had L. (V.) guyanensis infection. Patients were comparable by age, sex, disease duration and the Montenegro skin test diameter. L. (V.) braziliensis-infected patients showed significant lower number of ulcerated lesions, greater ulcerated area and higher proportion of lymph node enlargement. Sensitivity of IFA was 79.6% (95% CI 66.1-88.9) and 71.7% (95% CI 58.4-82.2) for L. (V.) braziliensis and L. (V.) guyanensis-infected patients, respectively (P=0.324). Sensitivity of ELISA was 98.2% (95% CI 88.8-99.9) and 85.0% (95% CI 72.9-92.5) for L. (V.) braziliensis and L. (V.) guyanensis-infected patients, respectively (P=0.018). Significant differences were observed in the magnitude of the antibody response before treatment with higher levels detected in L. (V.) braziliensis-infected patients by both serologic techniques. Eighty-four patients had serologic evaluations before and 12 weeks after treatment with meglumine antimoniate, 20 mg/kg/day for 20 days. Significant lower optic density values were observed after treatment with both species independent of cure or failure. Our data showed that L. (V.) braziliensis induces a higher antibody response against L. (L.) amazonensis antigens than L. (V.) guyanensis and that down-modulation of the antibody response occurs shortly during disease evolution after treatment. Moreover the data support the use of ELISA as a better tool for detection of antibodies in CL.     

Epidemiological survey of Trypanosoma cruzi infection in north-eastern Brazil using different diagnostic methods.

A survey of the prevalence of Trypanosoma cruzi infection was carried out in Oitis, a small community in the State of Piaui, Brazil. Two hundred and sixty five individuals were screened by microscopic examination, hemoculture, indirect immunofluorescence (IFA), enzyme-linked immunosorbent assay (ELISA), and competitive enzyme-linked immunosorbent assay (C-ELISA) using the monoclonal antibody TCF87 against to a 25kd T. cruzi antigen. Seropositivity was 14.3% by the IFA test, 14.7% by ELISA, and 13.2% by C-ELISA. The C-ELISA using the TCF87 monoclonal antibody seems to be applicable in serodiagnosis of Chagas' disease.     

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.     

Serum antibody levels as risk factors in the dissemination of herpes zoster.

Serum antibody levels against varicella-zoster virus (VZV) were examined by immune adherence hemagglutination assay (IAHA), indirect fluorescent antibody (IFA) assay, and complement fixation techniques in 67 immunocompromised patients with localized and disseminated herpes zoster. In the serum obtained initially, undetectable IAHA titers were found in 56.5% of the patients with disseminated zoster compared with 18.2% of those with localized zoster. When serum obtained within the first seven days of illness was analyzed, undetectable IAHA titers and IFA titers of less than 32 were noted in 77.8% of those with disseminated zoster but in only 18.5% of those with localized disease. Peak serum antibody titers in patients with disseminated zoster were eventually equal to or greater than those in localized zoster. The patient groups were comparable in age, underlying disease, and therapy, although Hodgkin's disease was more frequent in patients with disseminated zoster. Thus, the absent IAHA or low IFA levels of circulating antibody early in illness were highly significant risk factors in dissemination of virus in herpes zoster.