Evaluation of a Novel Dry Latex Preparation for Demonstration of Infectious Mononucleosis Heterophile Antibody in Comparison with Three Established Tests

A new, dried antigen-coated latex preparation for the demonstration of infectious mononucleosis (IM) heterophile antibody (Dryspot IM kit; Oxoid, Ltd., Basingstoke, Hampshire, United Kingdom) was compared with the IM kit (a liquid latex reagent from the same source), an immunoassay (ImmunoCard Mono; Meridian Diagnostics), and an absorption test (Monospot; Meridian Diagnostics). The latter was used as a standard for initial statistical comparisons. Discrepancies were resolved by using Epstein-Barr virus serology. Of the 328 routine samples tested, 77 were positive and 222 were negative by all IM heterophile antibody-based kits. Twenty-nine samples gave discrepant results. Following resolution of discrepant results, the sensitivity and specificity values for the IM Dryspot kit were 87.0 and 98.7%, those for the Oxoid liquid latex IM kit were 83.0 and 99.6%, and those for the ImmunoCard Mono immunoassay were 85.0 and 100.0%, respectively. The evaluation shows that the Dryspot kit, which is uniquely straightforward to use and may be stored at room temperature, is comparable in performance to other rapid heterophile tests for the confirmation of IM.     

Comparative evaluation of two test methods (enzyme immunoassay and latex fixation) for the detection of heterophil antibodies in infectious mononucleosis.

The present study evaluated the Ventrescreen Mono enzyme immunoassay (Ventrex Laboratories) and Monolatex (Wampole Laboratories) for detection of infectious mononucleosis-specific heterophil antibodies by comparing test results on sera of 247 symptomatic patients. The purpose of this study was to compare not only the two different test systems but also the two different methods they represent for accuracy in detecting infectious mononucleosis-specific heterophil antibodies. Discrepancies in the test results of the two kits were arbitrated by determining the Epstein-Barr virus antibody profiles of the samples. The study showed that the Ventrescreen Mono enzyme immunoassay is as good as the Monolatex test for detecting heterophil antibodies. After discrepancies were resolved, the sensitivity and specificity of the Ventrescreen assay were 100 and 98%, respectively.     

Appearance and some unusual features of Epstein-Barr virus antibody production in infectious mononucleosis and other health disorders.

The indirect immunofluorescence (IF) test and the complement-fixation reaction (CFR) were used in examination of over 1500 sera obtained from patients with infectious mononucleosis (IM) and other health disorders. The evidence obtained supports a direct aetiological relationship between Epstein-Barr virus (EBV) and IM and points on a relationship of EBV to some other lymphadenopathies and health disorders. The incidence of the IgG type antibody against virus capsid antigen (EB-VCA) and soluble antigen (CF-SA) obtained from EBV genome-positive cells among different age groups of patients is described along with results of long-term examinations of serum samples from IM patients. The appearance and dynamics of production of both types of EBV antibody and their persistence in the organism varied. Long-lasting oscillations, in particular of the EB-VCA antibody levels were found in sera of patients with prolonged health disorders following IM. The diagnosis value of the IF test and the CFR is discussed.     

Evaluations of enzyme-linked immunosorbent assay procedure for determining specific Epstein-Barr virus serology and of rapid test kits for diagnosis for infectious mononucleosis.

Using the results of Epstein-Barr virus-specific immunofluorescence serology as the "gold standard," we found that the sensitivities of the five rapid test kits varied from 78 to 84% and specificities varied from 89 to 100%. Enzyme-linked immunosorbent assay-determined specific Epstein-Barr virus antibody profiles had a sensitivity and specificity of 98.6 and 95.5%, respectively.     

Enhancement of Epstein-Barr virus antibody production in systemic lupus erythematosus patients.

Two groups of 22 patients suffering from either systemic lupus erythematosus (SLE) or infectious mononucleosis (IM) were checked for Epstein-Barr virus capsid antigen antibody (EB-VCA) production. The average significant antibody levels as well as the frequency of their occurrence were clearly higher in SLE than in IM patients.     

Comparison of different approaches to measuring influenza A virus-specific hemagglutination inhibition antibodies in the presence of serum inhibitors.

The A/Los Angeles/2/87 (H3N2) (A/LA/2/87) virus is sensitive to inhibitors of hemagglutination present in certain human sera. It was found that the effect of these inhibitors could be removed by treating sera with high-concentration receptor-destroying enzyme or trypsin-periodate or by using inhibitor-resistant viruses in the hemagglutination inhibition (HAI) test. Inhibitor-resistant viruses were not effective for detecting rises in antibody titers in the sera of volunteers infected with the A/LA/2/87 wild-type virus, while rises in antibody titer were readily detected in sera treated with trypsin-periodate and tested against A/LA/2/87 wild-type virus in an HAI test. It is therefore suggested that chemical or enzymatic methods be used to inactivate serum inhibitors and that standard virus be used in the HAI test for the currently circulating H3N2 viruses.     

Comparison of latex agglutination test with enzyme-linked immunosorbent assay for detection of antibody to varicella-zoster virus.

A new latex agglutination (LA) test (VZVscan; Becton Dickinson, Cockeysville, Md.) was compared with an enzyme-linked immunosorbent assay (ELISA) (Varicella STAT; Whittaker Bioproducts, Walkersville, Md.) for detection of varicella-zoster virus (VZV) antibody. Of 165 samples tested, 126 (76%) were positive by LA, 123 (73%) were positive by ELISA, and 35 (21%) were negative by both methods. Six samples (4%) were LA positive and ELISA negative or equivocal; three samples (2%) were ELISA positive and LA negative. However, LA failed to detect seroconversions in four adults with varicella in samples obtained 14 to 17 days after the onset of rash. These same samples had ELISA values in the high-positive range. In addition, the recommended LA screening dilution (1:2) is not supported by published data and should be changed.     

Effect of primary Epstein-Barr virus infection on human herpesvirus 6, cytomegalovirus, and measles virus immunoglobulin G titers.

Immunoglobulin G antibody titers to human herpesvirus 6 (HHV-6), measles virus, and cytomegalovirus (CMV) were examined in serum samples from 31 patients with Epstein-Barr virus (EBV)-induced infectious mononucleosis (IM). Sera were drawn sequentially from the same patients less than or equal to 7 days until 3 years after onset of IM. In seropositive patients, there was a significant decrease with time after IM of the immunoglobulin G titers to the three viruses in the majority of patients; HHV-6 IgG titers decreased in 80%, measles virus IgG titers decreased in 75%, and CMV IgG titers decreased in 67%. Four patients contracted CMV infection during the observation period after IM. In these, HHV-6 IgG titers increased, while EBV and measles virus IgG titers remained essentially stationary. Polyclonal B-cell stimulation during IM is suggested to augment antiviral titers in general, but the increases of HHV-6 IgG titers during EBV and CMV infections may also be due to selective stimulation of memory B cells by related antigens or to reactivation of HHV-6 during infection with these herpesviruses.     

Determination of varicella-zoster virus (VZV) immune status with the VIDAS VZV immunoglobulin G automated immunoassay and the VZVScan latex agglutination assay.

The VIDAS varicella-zoster virus (VZV) immunoglobulin G immunoassay and the VZVScan latex agglutination (LA) test were compared for the detection of VZV antibody in patient sera. Of 625 samples tested, 554 were positive for VZV antibody by one or both methods. Five hundred thirteen (82.1%) samples were positive by both methods, 71 (11.4%) were negative by both methods, and there were 41 (6.6%) discrepant samples. Statistically significant differences in sensitivity and specificity were not found (P = 0.37); however, several observations were made. All 23 VIDAS repeat equivocal samples were LA positive. Fifty-four samples showed prozone effects with the LA assay, all of which resolved as positive.     

Evaluation of commercially available third-generation anti-hepatitis C virus enzyme-linked immunosorbent assay in patients on haemodialysis

Restricted antibody reactivity to hepatitis C virus (HCV) synthetic peptides has been observed in HCV-infected patients on haemodialysis (HD). The aim of this study was to evaluate third-generation anti-HCV enzyme-linked immunosorbent assay (ELISA) test systems containing either synthetic peptide HCV antigens or recombinant HCV antigens or a combination of synthetic and recombinant antigens in screening of 69 chronic renal failure patients on HD for HCV infection. Seven patients were detected to have antibodies to HCV by the 'recombinant HCV antigens'-containing kits, of which the recombinant immunoblot assay for HCV confirmed four cases. The recombinant kits had a sensitivity of 100% and a specificity of 66%. However, the ELISA kits with only synthetic HCV antigens failed to detect antibodies in any of the cases (zero sensitivity). Hence a recombinant protein containing ELISA test system is ideal for screening of HCV infection in patients on hemodialysis.     

Performance of the Architect EBV Antibody Panel for Determination of Epstein-Barr Virus Infection Stage in Immunocompetent Adolescents and Young Adults with Clinical Suspicion of Infectious Mononucleosis

The Architect EBV antibody panel is a new chemiluminescence immunoassay system used to determine the stage of Epstein-Barr virus (EBV) infection based on the detection of IgM and IgG antibodies to viral capsid antigen (VCA) and IgG antibodies against Epstein-Barr nuclear antigen 1 (EBNA-1). We evaluated its diagnostic accuracy in immunocompetent adolescents and young adults with clinical suspicion of infectious mononucleosis (IM) using the RecomLine EBV IgM and IgG immunoblots as the reference standard. In addition, the use of the antibody panel in a sequential testing algorithm based on initial EBNA-1 IgG analysis was assessed for cost-effectiveness. Finally, we investigated the degree of cross-reactivity of the VCA IgM marker during other primary viral infections that may present with an EBV IM-like picture. High sensitivity (98.3% [95% confidence interval {CI}, 90.7 to 99.7%]) and specificity (94.2% [95% CI, 87.9 to 97.8%]) were found after testing 162 precharacterized archived serum samples. There was perfect agreement between the use of the antibody panel in sequential and parallel testing algorithms, but substantial cost savings (23%) were obtained with the sequential strategy. A high rate of reactive VCA IgM results was found in primary cytomegalovirus (CMV) infections (60.7%). In summary, the Architect EBV antibody panel performs satisfactorily in the investigation of EBV IM in immunocompetent adolescents and young adults, and the application of an EBNA-1 IgG-based sequential testing algorithm is cost-effective in this diagnostic setting. Concomitant testing for CMV is strongly recommended to aid in the interpretation of EBV serological patterns.     

Comparison of five different methods of rubella IgM antibody testing.

Five tests for the detection of rubella specific IgM antibody were compared. They were the conventional method of sucrose density gradient fractionation, followed by haemagglutination inhibition; an anti-mu capture radioimmunoassay; and three commercially available enzyme linked assays: Rubazyme M, Rubenz M I, and its successor, Rubenz M II. The five methods detected similar numbers of rubella positive samples between seven and 35 days after the onset of symptoms; in the earlier stages, however, the radioimmunoassay and Rubenz M II were more sensitive. All three commercial kits were straightforward to use but produced misleading positive results with sera containing heterophil antibody. In considering sensitivity, specificity, and cost effectiveness together the Rubenz M tests were the most appropriate for routine use. With the recent withdrawal of Rubenz M I from the market only Rubenz M II is now available. If Epstein-Barr virus infection is excluded, Rubenz M II provides a reliable test for the diagnostic laboratory.     

Contribution to rapid diagnosis of infectious mononucleosis

By indirect immunofluorescence (IF) technique humoral antibodies to Epstein-Barr virus capsid antigen (EB-VCA) and to cytomegalovirus (CMV) were detected in 47% and 9% of persons with infectious mononucleosis (IM), respectively. In 23% of the patients examined, IgM antibodies to both viruses were detected, while in 8% of them high titres of IgG only were found in the absence of IgM class antibodies to EB-VCA or to CMV. The finding of IgM antibody to EB-VCA was in good correlation with the persisting symptoms of the disease. Discrepancy between the presence of specific IgM and the absence of heterophilic antibodies was observed in some children and in all persons with persistent or recurrent signs of IM. In the latter, specific IgM was found only during exacerbation of the disease, but during remissions IgG antibodies persisted in high levels. Antibodies to Epstein-Barr virus nuclear antigen (EBNA) were detected in all chronically ill persons and antibodies to the R-component of Epstein-Barr virus early antigen (EA) were present in the majority of them.     

Psychosocial risk factors in the developmental of infectious mononucleosis.

In a 4-year prospective seroepidemiological study of infectious mononucleosis (IM) of one class of some 1400 cadets at the West Point Military Academy, susceptibles and immunes were identified by the absence or presence of antibody to Epstein-Barr virus (EBV), the causative agent, and new infections by the appearance of antibody (seroconversion). On entry, about 1/3 lacked EBV antibody, of whom some 20% became infected (seroconverted); about 1/4 of seroconverters developed definite, clinical and recognized IM. Psychosocial factors that significantly increased the risk of clinical IM among seroconverters included: 1) having fathers who were "overachievers"; 2) having a high level of motivation; 3) doing relatively poorly academically. The combination of high motivation and poor academic performance interacted in predicting clinical IM. Additional data on presence of elevated titers among seroconverters with inapparent disease and on length of hospitalization among cases of clinical IM revealed that these two additional indices of infection or illness could also be predicted from the same set of psychosocial risk factors.     

Evaluation of a simultaneous HIV antigen and antibody detection test in Korean population

Current diagnosis of human immunodeficiency virus (HIV) infection relies on the detection of anti-HIV antibodies by enzyme-linked immunosorbent assay (ELISA). Recently, kits detecting both p24 antigenemia and anti-HIV/anti-HIV2 antibodies have been developed. Thus, it is necessary to compare those kits developed as such. The aim of this study was to evaluate the diagnostic efficiency of a simultaneous detection test of p24 antigen and anti-HIV1/2 antibodies in a low prevalence area. Eight hundred and four randomly selected sera proven negative for HIV infection and 110 sera from 54 patients diagnosed as HIV infected, obtained between 1999 and 2000, were used for this study. One commercial lot of panels composed of consecutive sera obtained from known HIV-infected patient was included. Anti-HIV1/2 antibodies were detected by two different commercial ELISA kits, one from Korean and the other from German manufacturer. P24 antigen test was performed by ELISA. The simultaneous HIV antigen and antibody detection test was carried out. In the meantime, HIV RNA PCR and anti-HIV and anti-HIV2 western blot assays were also performed to confirm the test results in cases the test results didn't agree. The simultaneous detection kit showed 100% sensitivity and 99.6% specificity. Furthermore, the test displayed the possibility of earlier diagnosis than conventional anti-HIV1/2 ELISA with the results obtained from a group of consecutive panel sera infected with HIV. From these results, we concluded that the simultaneous HIV antigen and antibody detection test can be applied as a substitute clinical screening test in the place of conventional anti-HIV1/2 ELISA, and there is the probable benefit of early diagnosis.     

Study on usefulness of different APTT test kit in variable coagulopathy

A number of test kits are available for measuring activated partial thromboplastin time (APTT) and are used to screen for intrinsic coagulation reactions. However, results obtained with the same sample by different test kits often vary, causing confusion regarding potential hemostatic activity in the specimen. We investigated the usefulness of 6 different APPT kits, which utilize various phospholipids and activators, to detect prolonged clotting time in plasma from subjects with abnormal coagulopathy, including lupus anticoagulant(LA). In samples from subjects with intrinsic coagulation factor deficiencies and subjects taken heparin, the abnormal APTT detection ratio was high regardless of the kit used, thus any would be acceptable for measuring APTT in such patients. In contrast, that ratio in patients with von Willebrand disease was relatively low regardless of the kit, probably because factor VIII activities in those patients were slightly decreased. The ratio of detected subjects with LA and subjects taking warfarin varied among the APTT kits, however, those that utilized synthetic phospholipids were useful for the detection of LA. Our results suggest that an APTT kit should be selected according to the kind of disorder in the patient. Further, kits that employ synthetic phospholipids are useful for detecting abnormal coagulopathy in patients with intrinsic coagulation factor deficiencies and patients taken heparin, as well as for detection of LA.     

Detection of an idiotope on a human monoclonal autoantibody by monoclonal anti-idiotypic antibody and its relationship to Epstein-Barr virus-induced autoimmunity.

We have recently described a human IgM monoclonal antibody (mAb), reactive with both self antigens, i.e., cytoskeleton filaments and smooth muscle, and Epstein-Barr virus (EBV)-induced nuclear antigen (EBNA), produced by EBV-transformed B lymphocytes isolated from a patient with infectious mononucleosis (IM). In order to achieve higher antibody secretion in culture supernatant, the mAb-producer cells were fused with ouabain-resistant mouse myeloma cells and a stable human-mouse heterohybrid, coded HY 5488, producing up to 80 micrograms/ml IgM mAb, was isolated after 4 cloning procedures. Purified HY 5844 mAb was used to immunize mice for the production of a murine anti-idiotypic mAb, which was used to probe the expression of the idiotope of HY 5488 mAb (Id 5488) in sera of IM patients and normal controls by ELISA. It was found that Id 5488 is expressed both in IM patients and normal controls, and that Id 5488 expression is significantly higher in IM patients' sera; furthermore, in IM sera a statistically significant correlation between Id 5488 expression and anti-cytoskeleton and anti-smooth muscle autoantibodies was found. It is suggested that at least part of EBV-induced IgM autoantibodies appearing during IM are secreted by B lymphocytes programmed to the production of "natural antibodies" bearing Id 5488-like idiotopes.     

两种ELISA 试剂盒对我国单采血浆中水痘-带状疱疹病毒中和抗体滴度的测定和比较

目的采用两种不同的检测抗水痘一带状疱疹病毒（VZV）中和抗体间接ELISA法试剂盒,对我国单采血浆中vZv特异性免疫球蛋白（VZIG）的效价进行测定,比较两种试剂盒测定结果的相关性和血浆筛查的适用性,并分析利用国内单采血浆研发生产VZIG的可行性。方法随机选取182份单采血浆样品,100倍稀释后,使用Virion／Serion和VaccZyme／BindingSite两种商品试剂盒同时对样品进行测定,根据评估系统公式或曲线方程计算每份样品中VZIG的效价;采用Pearson乘积矩相关性方法对两种试剂盒的线性关系进行统计学分析。结果（1）VZIG高于10IU／ml的血浆样品数量为13份（7％,Vifion）和16份（9％,VaccZyme）;②两种试剂盒检测结果之间的直线线性关系数R2为0．62（P〈0．0001）,变异系数为4％;（3）Virion与VaccZyme的工作范围有不同,前者对于低效价（0．2—0．4IU／m1）样本的测定具有很好的灵敏度,而VaccZyme适用于高效价血浆样本（〉150IU／ml）的检测。结论Virion与VaccZyme结果具有一致性和相关性;两种试剂盒的工作范围略有差异,VaccZyme较Virion更适用于高效价VZIG原料血浆的检测,可用于普通献浆员单采血浆中VZV中和抗体的筛查。     

Performance and reliability of five commercial enzyme-linked immunosorbent assay kits in screening for anti-human immunodeficiency virus antibody in high-risk subjects.

Anti-human immunodeficiency virus enzyme-linked immunosorbent assay kits marketed by Electro-Nucleonics Inc. (ENI), Genetic Systems Corp. (GSC), Organon Teknika Inc. (OTI), Ortho Diagnostic Systems Inc. (ODSI), and Wellcome Diagnostics (WD) were evaluated by using 289 randomly selected serum samples from a high-risk population and 53 serum samples likely to produce false-positive results. The radioimmunoprecipitation assay was used as the reference test. Sensitivities ranged from 96.51% (ODSI, WD) to 97.67% (ENI, GSC, OTI). Sera showing antibodies to viral glycoproteins only produced the false-negative results. Specificities ranged from 99.6% (ENI, GSC, ODSI, OTI) to 100% (WD). False-positive results were obtained with sera from patients with autoimmune disease or Epstein-Barr virus infection. Only results from GSC and OTI kits were distributed in two compact clusters well segregated on either side of the cutoff point. ODSI and GSC kits had the best intralot reproducibility. The GSC kit had the best interlot reproducibility. Cutoff values for ODSI and GSC kits were the least variable. Intraplate repeatability was good for all kits. Sample localization was not an important source of variability. Our results do not point out one outstanding kit among the five evaluated. However, the GSC kit showed the best overall results.     

A human monoclonal autoantibody isolated from a patient with infectious mononucleosis reactive with both self antigens and Epstein-Barr virus nuclear antigen (EBNA)

In order to investigate the mechanism(s) by which Epstein-Barr virus (EBV) induces the outcome of autoantibodies during infectious mononucleosis (IM), a human IgM (k) monoclonal antibody to cytoskeletal filaments of epithelial cells has been prepared by EBV transformation of peripheral blood B lymphocytes obtained from a patient with IM. The antibody was also found to react with smooth muscle of frozen sections of human stomach tissue by immunofluorescence, and with the Epstein-Barr nuclear antigen (EBNA) by an enzyme-linked immunosorbent assay. These findings demonstrate at the clonal level the epitope homology between host's cell antigens and EBV-encoded nuclear antigen, which might have relevance in EBV-induced autoimmunity.