An evaluation of the Monosticon rapid slide test diagnosis of infectious mononucleosis

A new rapid slide test for the detection of infectious mononucleosis heterophile antibody has been compared with the Paul-Bunnell absorption test. Out of 200 sera, 46 were seropositive for infectious mononucleosis by the Paul-Bunnell test and 43 of these were detected by the Monosticon test; the three Monosticon-negative sera were of low titre. There was no problem with false positive reactions due to heterophile antibody not specific for infectious mononucleosis.     

Monospot: a differential slide test for infectious mononucleosis

Sera collected from 372 patients with suspected infectious mononucleosis were examined for heterophile antibodies by the Paul-Bunnell and the Monospot test. Comparison of results showed the latter to be simple, time saving, and of sufficient specificity for routine use in the general laboratory.     

Incidence of anti-intermediate filament antibody in serum samples of students with suspected glandular fever.

Serum samples from 40 students with suspected infectious mononucleosis were tested for the presence of antibodies to intermediate filaments (AIFA) of the cytoskeleton. Twenty had antibodies to the Epstein-Barr virus capsid antigen before their illness, and during it their sera remained negative by the Paul-Bunnell test. The other 20 patients did not have antibodies to the Epstein-Barr virus capsid antigen before their illness and seroconverted during the illness. These patients (true infectious mononucleosis group) developed positive Paul-Bunnell tests. Sera from normal subjects (blood donors) were also tested for AIFA. AIFA was present in titres greater than 1/10 in 80% of the infectious mononucleosis group (mean titre 1/40-1/80), 10% of the Paul-Bunnell negative glandular fever group, and 8.5% of the normal blood donors.     

Evaluation of latex-based heterophile antibody assay for diagnosis of acute infectious mononucleosis.

The diagnosis of an acute episode of infectious mononucleosis (IM) is made on the basis of clinical symptoms and serological evidence for development of heterophile antibodies. In an effort to obtain a very sensitive and specific assay for diagnosis of IM, we have developed MERISTAR:IM. The MERISTAR assay uses latex beads coated with purified bovine heterophile antigen. We compared the sensitivity and specificity and performance characteristics of the latex-based test to those of the commercially available erythrocyte-based Monospot test with serum samples from 363 suspected-IM patients and controls. A total of 28 samples from patients with confirmed IM were positive with the MERISTAR assay, while only 23 of the samples were positive with the Monospot assay. The two assays had equal specificity, as each test gave two false-positive results. In the technical performance of the assay, the MERISTAR assay was simpler and faster to perform than the Monospot assay.     

Persistent falsely positive rapid tests for infectious mononucleosis. Report of five cases with four--six-year follow-up data.

In many laboratories, rapid slide tests incorporating differential absorption have replaced heterophil antibody tube tests in the investigation of suspect infectious mononucleosis. The present report describes serologic data from five individuals whose Monospot tests remained falsely positive for four years or more without other evidence of infectious mononucleosis or underlying disease states. Three of the five had never been infected with the Epstein-Barr virus. All five had negative results when studied with the ox cell hemolysin and the horse cell differential absorption tube tests. False-positive test results have also been encountered in healthy controls, as frequently as in patients with underlying disease states. The authors are unable to attach any clinical significance to the findings of an isolated falsely positive Monospot test even when it persists for many months or years.     

Latex test for serodiagnosis of infectious mononucleosis

A glycoprotein was isolated from bovine erythrocytes which has 20% carbohydrate and migrates on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a single band. This glycoprotein carries the reactivity of bovine erythrocytes with Paul-Bunnell heterophile antibody of infectious mononucleosis. This bovine glycoprotein was coupled to carboxyl-modified latex particles with water-soluble carbodiimide. The resulting reagent was then used to develop a new test for the detection of infectious mononucleosis antibody. The bovine erythrocyte glycoprotein-latex reagent is more stable than sheep or horse erythrocytes, the traditional reagents for detection of infectious mononucleosis antibody. This new reagent is used in a direct slide test; no preabsorption of the sera is necessary. In the present study the glycoprotein-latex reagent compared favorably in terms of sensitivity and specificity with two standard tests for infectious mononucleosis antibody. Ninety-nine serum samples were tested. Agreement of the latex test with a stabilized horse erythrocyte spot test was 90%. Ten samples were weakly positive with the latex test and negative with the horse cell test. Only one of these was also positive with an enzyme-treated sheep cell test. This latter test was somewhate more sensitive than the latex test.     

Comparative evaluation of three commercial tests for detection of heterophile antibody in patients with infectious mononucleosis.

Infectious mononucleosis (IM) is caused by the Epstein-Barr virus. Commonly used laboratory tests used for diagnosis of IM include a screening test based on the observation that horse erythrocytes are agglutinated by the Paul-Bunnell antibody found in the serum of patients with IM. This study evaluated two latex agglutination (LA) kits for IM, Monolatex (Wampole Laboratories) and Immunoscan-IM (American MicroScan) (formerly Monogen; Biokit, S.A.), and compared them with Monospot (Ortho Diagnostic Systems) results on 220 patient sera. Discrepancies in the three test results were resolved with complete Epstein-Barr virus antibody profiles. They indicated that any of the three kits tested can be successfully used as a screening test for IM. The advantage of the LA kits is that no differential absorption step is necessary. When discrepancies were resolved, sensitivity and specificity of both LA kits were greater than 93%.     

Heterophile IgM, IgA, and IgE antibodies in infectious mononucleosis

Fifty infectious mononucleosis (IM) and 150 non-infectious mononucleosis (non-IM) sera were tested by a hemadsorption immunocapture test (HIT) for the detection of heterophile antibodies of IgM, IgA, and IgE classes. The specificity of Paul-Bunnell (PB) antibodies was ascertained by a differential absorption test. IgM PB-antibodies were demonstrated in 100% of IM sera, IgA in 92%, and IgE in 88%. PB antibodies were present only in IM sera; but other heterophile antibodies of IgM (68%), IgA (6.7%), and IgE (9.3%) classes were demonstrated in non-IM sera. IgA and IgE heterophile antibodies were thus present, especially in IM sera. HIT was found to be more sensitive than Paul-Bunnell Davidsohn test (PBD test) and suitable for the diagnosis of infectious mononucleosis.     

Reactions of Infectious Mononucleosis Sera with Glutaraldehyde-Treated Human Erythrocytes

Infectious mononucleosis sera gave positive results in enzymoimmunoassay with glutaraldehyde-treated human erythrocytes. This unexpected reaction appeared to be caused by the interaction of Paul-Bunnell (P-B) antibodies with a partial P-B antigen that apparently appears on human red blood cells in a hidden form and becomes exposed by the treatment with glutaraldehyde.     

Paul-Bunnell antigen in malignancies and rheumatoid arthritis.

By means of agglutination inhibition test, Paul-Bunnell (P-B) antigen was demonstrated in sera of patients with cancer (5%), lymphomas or leukemias (12.5%) and rheumatoid arthritis (RA) (1.4%) as well as in synovial fluids from RA patients (27%). In contrast, none of 124 normal human sera gave positive results. P-B antigen was also demonstrated in 3 of 12 perchloric acid extracts of cancer tissues and 2 of 11 saline extracts obtained at 100 degrees C from spleens of lymphoma-leukemia patients. Extracts of apparently normal tissues from 16 individuals gave negative results.     

Comparison of tests for heterophile antibodies with a test for specific IgM-antibodies to Epstein-Barr virus. Brief report

Seventy serum samples from 54 patients with clinically suspected infectious mononucleosis were examined, using the Paul-Bunnell-Davidsohn test, a rapid slide test and an ELISA for the detection of IgM antibodies against the viral capsid antigen (VCA) of Epstein-Barr virus. The ELISA technique was the most sensitive, detecting IgM in 29 sera, whereas only 19 sera were positive in the Paul-Bunnell-Davidsohn test (titre greater than or equal to 64). However, using a titre of greater than or equal to 32 as a diagnostic level, the number of positive sera was 23, the same as for the rapid slide test. There was a high agreement (91%) between the heterophile antibodies tests and the VCA-IgM ELISA. The Paul-Bunnell-Davidsohn test still holds a place in the serologic diagnosis of infectious mononucleosis, but sera should always be tested for VCA-IgM in cases of heterophile antibodies negative mononucleosis.     

A modified immunofluorescence test for Epstein-Barr virus-specific IgM antibody

The fluorescent antibody (FA) test for Epstein-Barr virus (EBV)-specific IgM antibody was improved by the use of sodium butyrate to induce a higher level of EBV antigen expression in P3HR-1 slide preparations and by removal of rheumatoid factor (RF) and IgG antibodies from test sera by means of adsorption with suspensions of Sepharose-IgG and Streptococcus pyogenes strain AR1. This method was compared with the Paul-Bunnell test (PB) on 1106 sera submitted to a routine virus diagnostic laboratory for infectious mononucleosis serology and 96.4% of sera showed concordant results. Thus the EBV-IgM-FA method was suitable for routine diagnostic use. However, it proved helpful to test EBV-IgM positive sera by PB to assist in the detection of cross-reacting IgM antibodies sometimes present.     

A comparison of Rubazyme-M and MACRIA for the detection of rubella-specific IgM

One-hundred and eighty-six carefully selected sera were tested for rubella-specific IgM by Rubazyme-M (Abbott Diagnostics) and an M-antibody capture radioimmunoassay (MACRIA). Eleven of these sera were from cases of infectious mononucleosis, six of which gave positive results in MACRIA, while one gave a positive result in Rubazyme-M. Of the remaining 175 sera, 158 gave concordant results whilst 17 sera gave discordant results; these 17 were also tested by serum fractionation. Problems were encountered with all assay systems used. It is therefore recommended that the results of all tests for rubella-specific IgM should be interpreted with caution.     

EBV-IgA and new heterophile antibody tests in diagnosis of infectious mononucleosis

An evaluation has been made of the EBV-IgA tests and the immune adherence hemagglutination assay (IAHA) as compared with standard diagnostic procedures in 119 serial sera from 22 clinical and 113 sera from 42 subclinical cases of EBV infectious mononucleosis. EBV-IgA antibody was demonstrable in 86.4 per cent of patients using EB3 cells as antigen and in 68.2 per cent with P3/HRIK cells. For heterophile antibody the IAHA test was more sensitive, gave higher titers, and was positive longer than the standard absorbed horse or sheep RBC tests in both clinical and subclinical EBV infections.     

Measurement of heterophil antibody and antibodies to EB viral capsid antigen IgG and IgM in suspected cases of infectious mononucleosis.

The EBV IgG titres in acute and convalescent specimens from 97 cases of infectious mononucleosis were compared with titres from acute and convalescent sera from 96 students with illnesses resembling infectious mononucleosis but without heterophil antibody, EB IgM or EB IgG seroconversion; and also with titres from 91 healthy students known to have had EB IgG antibody for at least six months. These titres were related to the titre of the Research Standard A.66/235 for infectious mononucleosis serum prepared by the National Institute for Biological Standards and Control. Serial sera were tested for heterophil antibody and EBVCA specific IgG and IgM from 61 university students with infectious mononucleosis. The period of persistence of heterophil antibody and EBV IgM after illness was outlined from the results of the tests. Single sera from 406 patients in hospital or general practice sent to the diagnostic laboratory for heterophil antibody tests were also tested for EBV antibodies without prior knowledge of the heterophil antibody result. The close agreement between heterophil antibody and EBV IgM results is shown. False positive EB IgM results were correlated with the presence of rheumatoid factor.     

Screening tests for hepatitis B antigen and antibody in two colleges of education and studies on the relationship between nonspecific positive antibody tests and EB virus infection.

Sera from 627 students entering Colleges of Education between 1969 and 1972 were tested for hepatitis B surface antigen and antibody. One was found positive for antigen, none for antibody. Six for 15 positive Hepanosticon results and two positive Hepatest results occurred in sera which also gave positive heterophil antibody tests indicative of current or recent EB virus infection. One of these six sera was still positive in the Hepanosticon test after one absorption, and one of two Hepatests gave no positive reaction with the control cells. Eleven of 14 sera from cases of infectious mononucleosis gave positive Hepanosticon results and two were still positive after one absorption. Seven were positive in the Hepatest and only three of these were positive with the control cells. The control tests in the Hepanosticon and Hepatest do not clearly identify all false positives due to Paul Bunnell antibody. It is suggested that when a positive result in a passive haemagglutination test can be removed by absorption or if positive after absorption cannot be confirmed by other tests for hepatitis Bs antigen, the patient from whom the serum specimen was taken should be investigated for indications of current EB virus infection.     

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.     

EB virus-specific IgA in serum of patients with infectious mononucleosis and of healthy people of different ages.

The following sera were tested for EB virus-specific IgA: serial sera from 61 cases of infectious mononucleosis (IM) and from 195 EBV IgG positive healthy students; single sera from each of 1469 persons of different ages, 63 cases of untreated Hodgkin's disease, and 22 neonates. EBV specific IgA was found in the sera from 88% of cases of IM, from 18.5% of EBV IgG positive healthy students, and in 13.5% of repeat samples from the same students three years later. The incidence of EBV IgA varied from 5 to 30% at different ages in single sera from EBV IgG positive persons aged 2 to 70 years. The higher percentages occurred in the age groups where recent sero-conversion rates were high. Fifteen percent of sera from cases of Hodgkin's disease were positive for EBV IgA, an incidence similar to that for healthy adults in the age group 25-45 years. None of the EBV IgG positive sera from neonates gave a positive reaction for EBV IGA.     

Radioimmunoassay for detection of antibodies to Epstein-Barr virus in human infectious mononucleosis serum specimens.

A rapid microradioimmunoassay (RIA) technique was adapted for quantitatively measuring antibody titers to antigens occurring in Epstein-Barr virus (EBV)-infected lymphoid cells. In these experiments two EBV-infected cell lines, HR1K and EB-3, were used as antigen-positive cells and Molt-4 was used as the negative control cells. The antibody titers of sera from suspected infectious mononucleosis patients were compared by RIA and indirect fluorescent antibody (IFA) methods. As determined by each of the methods, 14 of 19 sera had positive antibody titers and the remainder of the sera had negative antibody titers. Thus, the two methods agreed completely in differentiating sera with antibodies to EBV antigens. To further evaluate the antibody specificity of the RIA, the antibody titers of paired sera, pre- or early infection and postinfection, from five confirmed infectious mononucleosis patients were determined by RIA and IFA. Seroconversion was demonstrated by both RIA and IFA for each of the patients. Thus, the sensitivity and specificity of the two procedures are about the same.     

Quantitative estimation by a standardized enzyme-linked immunosorbent assay of human T-cell lymphotropic virus type I antibodies in adult T-cell leukemia and acquired immune deficiency syndrome.

Sera from patients with adult T-cell leukemia and asymptomatic carriers of human T-cell lymphotropic virus type I (HTLV-I) from widely separated areas of the world reacted strongly in a standardized quantitative enzyme-linked immunosorbent assay procedure with HTLV-I viral antigen prepared from a strain isolated in the United States. There was a sharp differentiation of the values seen in the patients as compared with a normal population. Of the 35 acquired immune deficiency syndrome patients with Kaposi's sarcoma, only 2 were positive for HTLV-I antibodies in this test, and the distribution of the negative assay values in the other acquired immune deficiency syndrome patient sera was similar to that seen in the normal sera. Sera which contained extremely high levels of antibodies to other unrelated viruses (rubella virus, cytomegalovirus, and herpes simplex virus) all showed negative anti-HTLV-I results, in a pattern similar to the normal sera. Sera from patients with several autoimmune disease (systemic lupus erythematosus, rheumatoid arthritis, thyroiditis) as well as those with infectious mononucleosis or myeloma all also showed the normal distribution of negative results, in spite of the presence of very high levels of the autoantibodies, etc., associated with their illnesses.