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.     

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.     

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.     

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 the micro enzyme-linked immunosorbent assay for antibodies to Trypanosoma cruzi

A micro enzyme-linked immunosorbent assay (ELISA) for antibodies to Trypanosoma cruzi was evaluated and the results obtained by ELISA were compared with those obtained by the complement fixation test (CF) and indirect fluorescent antibody test (IFA). Fifty sera collected from residents of the southeastern United States all had reciprocal ELISA titers less than or equal to 320. Similarly, serum samples from 17 patients with T. cruzi infection proven by xenodiagnosis had reciprocal ELISA titers of greater than or equal to 1,280. Specimens from 302 El Salvador Army recruits were tested by ELISA, IFA, and CF. Excellent correlation was observed between results obtained by the three serologic tests; 62.9% of the samples were negative by each of the three tests and 24.5% were positive by all. Overall, 29.5% of the sera were positive for antibodies to T. cruzi by ELISA, 29.5% by IFA, and 31.5% by CF. The data suggest that the micro ELISA is a promising serologic test for measuring antibodies to T. cruzi in individuals and in populations.     

Evaluation of enzyme linked immunosorbent assay in the immunodiagnosis of schistosomiasis.

Eighty-six bilharzial patients divided into 5 clinical groups were studied. Enzyme linked immunosorbent assay (ELISA), indirect fluorescent antibody (IFA) and indirect haemagglutination (IHA) test were performed for all the patients. ELISA gave the most sensitive results (82.6% and 80.2% positivity rate in Egypt and Lille respectively), followed by IFA (79.1% positivity rate) and IHA (77.9% and 75.6% positivity rate in Egypt and Lille respectively). The humoral antibodies detected by all methods (ELISA, IFA and IHA) showed increasing values with the progress of the disease which is parallel to the antigenicity of the disease. Both the positivity rate and the mean value of antibody titres recorded by the 3 diagnostic techniques (ELISA, IFA and IHA) were significantly higher in mansoni than haematobium infection. This may be explained by species specificity of antibody response. The superiority of ELISA over IFA and IHA techniques was discussed.     

Application of indirect hemagglutination test and indirect fluorescent antibody test for IgM antibody for diagnosis of melioidosis in Thailand

In hyperendemic areas such as Thailand, rapid diagnosis of melioidosis depends upon both bacteriological culture and serological methods. However, interpretation of indirect hemagglutination (IHA) for melioidosis which is the only test available, is seriously hampered by increased IHA titers present in one-third to one-half of the population. In order to get the best results from the available tests, IHA and indirect fluorescent antibody for IgM (IFA-IgM) were evaluated in controls and patients in Thailand. IHA titers of greater than or equal to 1:40 were considered remote or recent exposure to P. pseudomallei. IHA titers of this level were found in 47.1% of 227 blood donors and 29.5% of 210 sera submitted for other tests, while IFA-IgM was positive in only one donor who had an IHA titer of 1:1,280. IHA was positive in eight out of nine patients with melioidosis with IHA titers of less than 1:20 to 1:2,560. IFA-IgM was positive in six out of seven melioidosis patients whose sera were available for this test including a serum with IHA titer of less than 1:20. Six patients were predisposed by diabetes mellitus. Among sera serologically tested for melioidosis, 33 had IHA titers of 1:80-1:1,280, 10 of which were positive for IFA-IgM. This study demonstrates high background IHA titers among IHA titers among Thai people which greatly limits its use for serodiagnosis of melioidosis. In sharp contrast, serodiagnosis by IFA-IgM was more successful. Positive IFA-IgM among healthy Thais did exist indicating that serologic tests for melioidosis at best are only supplementary to bacteriological culture and clinical awareness.     

A comparison of the complement fixation, indirect fluorescent antibody, and microagglutination tests for the serological diagnosis of rickettsial diseases.

Three techniques for the serological diagnosis of Rocky Mountain spotted fever were compared by testing 417 sera from 178 patients who very probably did not have rickettsial infections and 88 sera from 41 patients who very probably had Rocky Mountain spotted fever (SF). The techniques were complement fixation (CF), indirect fluorescent antibody (IFA), and microagglutination (MA). To avoid possible degradation during unnecessary purification, the antigens were prepared by methods that were as simple as possible. In the CF tests of 417 sera from patients with nonrickettsial diseases there was only one titer of 8 and none at higher dilutions, whereas with the IFA and MA tests 4-8% of the sera reacted with SF antigens and 4-20% reacted with murine typhus (MT) antigens; the evidence indicated that these reactions were not caused by specific rickettsial antibody. With the SF sera, it could be seen that the IFA test was the most sensitive and the MA test was the least sensitive at each interval after infection. Moreover, the IFA results showed the least number of confusing cross-reactions with MT antigens and the MA test showed the most. The relative advantages of the three tests in serodiagnosis of rickettsial diseases are discussed.     

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.     

Development and persistence of antibodies to Entamoeba histolytica in patients with amebic liver abscess. Analysis of 216 cases

The antibody patterns--obtained by enzyme immunoassay (EIA), complement fixation (CF), indirect hemagglutination (IHA), and latex agglutination (LA)--of 216 patients with amebic liver abscess (ALA) were related to the time of onset of illness and to epidemiological data. The usual period between the stay in an Entamoeba histolytica-endemic area and clinical manifestation of the disease was 8-20 weeks. Increasing antibody concentration affected the sensitivity rates for CF and LA in the first 3 weeks of clinical ALA. In comparison with CF, IHA, and LA, EIA was the most sensitive test, showed the most substantial changes in antibody concentration according to the stage of disease, and measured persisting antibodies for the longest period. Neither the duration of previous stay in tropical countries nor the time when specific chemotherapy was started influenced development or persistence of antibodies in ALA patients. ALA occurred with similar frequency regardless of whether the patient was a long-term resident of the tropics or a short-term visitor to an E. histolytica-endemic area.     

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.     

Schistosomiasis: assessment of the sensitivity, specificity and reproducibility of serological methods for the diagnosis of schistosomiasis in Nigeria.

Three groups of sera were tested by indirect fluorescent antibody (IFA), complement fixation (CF) and counter-current immunoelectrophoresis (CCIE) techniques; 56 (10.1%) of 554 sera from Nigerians were anticomplementary and so could not be tested by the CF. Crude antigen extract of adult Schistosoma mansoni was used in the CF and CCIE tests and cercarial antigen in the IFA test. IFA was the most sensitive test and CF the most specific. The reproducibility of both these tests was good. The CCIE was the least sensitive and specific, and its reproducibility was poor. The IFA test was the most suitable for Nigerian conditions. Cross-reactions to S. haematobium antibodies were consistently present in all three tests and it was not possible to differentiate serologically S. mansoni from S. haemotobium. The interpretations of the results presented some difficulties because of the frequency of cross-reactions and false-positives, but the data fell within the infection prevalence rate of 50% reported earlier from south-western Nigeria. The IFA test was more specific and is considered ideal for serodiagnosis.     

Enzyme-linked immunosorbent assay for the diagnosis of clinical and subclinical melioidosis

An enzyme-linked immunosorbent assay (ELISA) for the detection of specific IgG and IgM antibody to Pseudomonas pseudomallei was developed. The IgG-ELISA was compared with the indirect fluorescence assay for IgG antibody (IgG-IFA) and the indirect hemagglutination (IHA) test in studies with serum specimens from persons from endemic areas for melioidosis and from persons from nonendemic areas of Australia. The sensitivity and specificity of the IgG-ELISA were 90% and 99%, respectively, comparable to those obtained with the IgG-IFA. The IgG-ELISA was more sensitive than the IHA test (74%) and was more suitable than the IgG-IFA as a serologic screening test for melioidosis. The IgM-ELISA was compared with the IgM-IFA as a marker of disease stage in patients with melioidosis. There was good diagnostic agreement between the tests; 92% of patients with active disease gave IgM-ELISA titers greater than or equal to 1:5,120 and 93% of patients with subclinical melioidosis had IgM-ELISA titers less than or equal to 1:1,280. Of the overlap group of patients with a borderline IgM-ELISA titer of 1:2,560, approximately 33% were clinical cases. An uncommon disease stage consisting of a self-limited, short-term, flu-like, pyrexial illness accompanied by elevated serum IgM-ELISA titers (greater than or equal to 1:5,120) was seen in a small number of patients residing in endemic Australia.     

Short report: Melioidosis in Myanmar: forgotten but not gone?

A serologic survey of adults resident in Myanmar was conducted to define the presence of antibodies to Burkholderia pseudomallei, the cause of melioidosis. Antibodies were detectable by indirect hemagglutination assay (IHA) in 757 (78%) of 968 adults, of whom 69 (7%) had an IHA titer > or =1:160.     

Detection of antibodies against Opisthorchis viverrini in patients before and after treatment with praziquantel

Levels of antibody in sera of 78 patients with opisthorchiasis, 30 patients with other liver diseases, 10 patients with schistosomiasis and 30 healthy individuals were compared using three serodiagnostic tests, namely indirect haemagglutination (IHA), enzyme-linked immunosorbent assay (ELISA) and lectin immuno test (LIT). The geometric mean reciprocal titer in sera of opisthorchiasis patients was significantly higher than patients with other diseases, patients with schistosomiasis and healthy individuals (p less than 0.00001). After treatment with praziquantel, the antibody titers were decreased and became lowest 120 days after treatment. A statistically significant decrease from the pre-treatment sample was observed only at 120 days after infection and not earlier and only with ELISA (p = 0.03) and not with IHA and LIT (p greater than 0.05). Even with ELISA, significant decrease in antibody titer was apparent only when the pre-treatment sera had high enough antibody titer. ELISA was therefore better than the other two tests for the assessment of cure provided that the titer of pre-treatment sera was high.     

免疫学抗体检测结合影像学检查诊断脑囊尾蚴病的研究

目的提出脑囊尾蚴病免疫学抗体检测阳性新的诊断标准,以减少漏诊、误诊。方法对资料完整的1160例脑囊尾蚴病住院病例血清抗体检测结果,结合其CT(1160例)、磁共振(MRI)(538例)影像学表现综合分析。按囊尾蚴寄生部位将其分为脑实质型(1087例占93.7％)、脑室型(42例占3.6％)、脑膜型(22例占1.9％)、混合型(9例占0.8％)等4型。脑实质型根据CT或MRI显示囊尾蚴数又分为轻(1～2个)、中(3～9个)、重度感染(10个以上)等3个亚型。轻度脑实质型(552例,占50.8％)中表现为脑脓肿型441例(40.6％),中度脑实质型433例(39.8％),重度脑实质型102例(9.4％)。所有病例均进行血清抗体检测(IHA,ELISA)。结果IHA检测血清抗体最高凝集效价1:8及以上635例(54.7％),1:8以下525例。ELISA检测阳性700例(60.3％),弱阳性460例(39.7％)。CT或MRI显示轻度脑实质型的552例中,IHA效价1:8以下523例(94.7％),1:8及以上29例(5.3％)。ELISA检测,阳性94例(17％),弱阳性458例(83％)。中度脑实质型433例及重度脑实质型102例,IHA效价均在1:8以上,ELISA检测均为阳性或强阳性。结论血清免疫学检测囊尾蚴抗体效价高低与影像学显示囊尾蚴数量多少呈正相关关系。根据目前使用标准,上述轻度脑实质型的523例(IHA效价1:8以下,占94.7％)以及ELISA检测弱     

Longitudinal study of serological response to Bartonella henselae by indirect fluorescence assay in cat scratch disease

Sequential serologic testing for IgG and IgM titers to Bartonella henselae were evaluated by an indirect fluorescence assay (IFA) in patients with CSD. The IFA test for the detection of IgG and IgM antibodies to B. henselae in 52 CSD patients showed that 40 (76.9%) were positive for IgG antibody and 9 (17.3%) were positive for IgM antibody. Two or more consecutive serum samples from 30 patients with CSD were assessed. In regard to the detection of IgG antibody, 5 patients had rapidly elevated titers in the acute phase, 12 patients had high titers from the acute phase, and 5 patients had a positive titer 24 weeks after the onset. B. henselae IgM antibody kinetics varied widely between patients with CSD. The seropositive rate for the antibody to B. henselae was analyzed at overtime after the onset and we found that the IgG-seropositive rate was high from 2 weeks after the onset and low after 25 weeks. The sensitivity of the IgM IFA was low, and IgM antibody to B. henslelae was not detected from 9 weeks. The detection from consecutive serum samples of antibodies to B. henselae by IFA is very useful for diagnosis in the case of clinically suspected CSD.     

Indirect immunoperoxidase test for the diagnosis of leptospirosis

Leptospirosis is a widespread zoonotic disease that affects all mammals, including humans, in different parts of the world. Clinical recognition of leptospirosis is challenging, and the definitive serologic diagnosis assay, the microscopic agglutination test (MAT), is time-consuming and difficult to conduct. In this study, an indirect immunoperoxidase (IIP) test to detect Leptospira-specific antibodies in human serum samples was developed. The efficacy of the IIP was compared with the indirect immunofluorescent assay (IFA) and MAT. A total of 368 human serum samples were analyzed by MAT, IFA, and IIP. Using a MAT titer of > or = 1:100 as the gold standard, the sensitivities for the detection of Leptospiral antibodies at a titer of 1:200 were 94.7% by IFA and 93.6% by IIP; specificities were 95.3% by IFA and 94.9% by IIP; and accuracies were 95.1% by IFA and 94.6% by IIP. With a titer of 1:400, the sensitivity, specificity, and accuracy were 86.2%, 98.9%, and 95.7% by IFA, respectively; whereas, for the IIP, the sensitivity was 85.1%, specificity 98.5%, and accuracy 95.1%. A further evaluation of this test with 80 unknown-febrile-disease sera was also included. We found that the sensitivity and specificity of this test were 100% and 76.8%, respectively. Therefore, the IIP test is a potentially valuable tool for the diagnosis of leptospirosis.     

135例急性血吸虫病例IHA检测抗体滴度效价分析

目的分析急性血吸虫病确诊病例间接血凝试验(IHA)检测抗体滴度效价,为诊断与治疗急性血吸虫病提供依据。方法以2001年以来收治住院的135例急性血吸虫病确诊病例为观察对象。采集病人基本情况,询问疫水接触情况等,并进行IHA抗体滴度效价检测,比较不同年龄、潜伏期与住院天数之间的相关性。结果 135例病例中IHA检测抗体滴度均1∶320,其中滴度1∶640、1∶1 280、1∶2 560、1∶5 120、1∶10 240分别占1.48%、28.15%、35.56%、20.00%、14.81%。急性感染病例的平均年龄47.70±14.58岁,平均潜伏期38.03±4.59 d,平均住院时间15.08±3.79 d。抗体滴度效价与年龄分布无相关性(r=0.109,P0.05),差异无统计学意义(F=0.64,P0.05),但与潜伏期呈负相关(r=-0.558,P0.01)、住院时间呈正相关(r=0.791,P0.01),各组差异均有统计学意义(F=17.07、64.53,P均0.01)。结论 IHA检测急性血吸虫病例抗体滴度效价均在1∶640及以上,抗体滴度效价与年龄大小无相关性,抗体滴度效价高者,血吸虫病潜伏期短、住院时间长。