scholarly journals Laboratory Diagnosis of Toscana Virus Infection by Enzyme Immunoassay with Recombinant Viral Nucleoprotein

1999 ◽  
Vol 37 (3) ◽  
pp. 649-652 ◽  
Author(s):  
Dario Soldateschi ◽  
Grazia Maria Dal Maso ◽  
Marcello Valassina ◽  
Laura Santini ◽  
Silvia Bianchi ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Nested Pcr ◽  
Immune Status ◽  
Laboratory Diagnosis ◽  
Summer Season ◽  
Immunoglobulin M ◽  
Toscana Virus ◽  
Serum Samples ◽  
Rna Sequences ◽  
Specific Serum

A recombinant enzyme immunoassay (rEIA) to detect serum immunoglobulin M (IgM) and IgG to Toscana virus (TOSV) was developed with the aim of establishing a simple and easily available assay for diagnosing acute and/or previous infections. The rEIA, based on the recombinant nucleoprotein of TOSV expressed in Escherichia coli, was evaluated with 97 serum samples collected in an area where TOSV is endemic and compared to an analogous assay based on cell-derived TOSV. Discordant results were resolved by immunoblotting (IB). Twenty-two of these samples, obtained from subjects hospitalized during the summer season with meningitis of suspected TOSV etiology, were further characterized by indirect immunofluorescence and IB, and detection of specific TOSV RNA sequences in the cerebrospinal fluid of these patients was attempted by nested PCR. The results indicated that rEIA was able to diagnose acute TOSV infection by detection of specific serum IgM in all of the subjects with TOSV meningitis confirmed by nested PCR or serology. The overall sensitivity and specificity of rEIA were both 100% for IgM detection and 100 and 96.6%, respectively, for IgG detection. Thus, rEIA appears to be a simple and reliable laboratory test for the diagnosis of acute TOSV infection and for the assessment of immune status.

Comparison of three anti-coccidioides antibody enzyme immunoassay kits for the diagnosis of coccidioidomycosis

2020 ◽  
Vol 58 (6) ◽  
pp. 774-778 ◽  
Author(s):  
Joshua Malo ◽  
Eric Holbrook ◽  
Tirdad Zangeneh ◽  
Chris Strawter ◽  
Eyal Oren ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Diagnostic Testing ◽  
High Risk Patient ◽  
Immunoglobulin M ◽  
Antibody Detection ◽  
Serum Samples ◽  
Igg Antibody ◽  
Igm Antibodies ◽  
Igm Antibody ◽  
Detection Specificity

Abstract Coccidioidomycosis is a common cause of community-acquired pneumonia in endemic areas of the southwestern United States. Clinical presentations range from self-limited disease to severe, disseminated disease. As such, early and accurate diagnosis is essential to ensure appropriate treatment and monitoring. Currently available diagnostic testing has variable accuracy, particularly in certain patient populations, and new tests may offer improved accuracy for the diagnosis of coccidioidomycosis. Serum samples from patients with coccidioidomycosis and controls were tested for immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies using the MVista Coccidioides antibody detection EIA and two commonly used commercial enzyme immunoassay (EIA) kits: the IMMY Omega EIA and the Meridian Premier EIA. The sensitivity of the IgG antibody detection was 87.4% using the MVista test compared to 46.6% for IMMY and 70.9% for Meridian. The sensitivity for IgM antibody detection was 61.2% for the MVista test, 22.3% for IMMY and 29.1% for Meridian. For IgG antibody detection, specificity was 90% for the MVista EIA, 94.6% for IMMY, 96.4% for Meridian. For IgM antibody detection, specificity was 95.3% for the MVista test 98.2% for IMMY and 99.1% for Meridian. The MVista Coccidioides antibody EIA offers improved sensitivity, including among high-risk patient populations, for the detection of IgG and IgM antibodies in comparison to other currently available EIAs.

scholarly journals Humoral Response in Toscana Virus Acute Neurologic Disease Investigated by Viral-Protein-Specific Immunoassays

1999 ◽  
Vol 6 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Fabio Magurano ◽  
Loredana Nicoletti
Keyword(s):  
Central Italy ◽  
Humoral Response ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Neurologic Disease ◽  
Nonstructural Proteins ◽  
Toscana Virus ◽  
Serum Samples ◽  
Virus Family ◽  
Nucleoprotein N

ABSTRACT The Toscana virus (family Bunyaviridae, genusPhlebovirus) is the only sandfly-transmitted virus that demonstrates neurotropic activity. Clinical cases ranging from aseptic meningitis to meningoencephalitis caused by Toscana virus are yearly observed in central Italy during the summer, and several cases have been reported among tourists returning from zones of endemicity (Italy, Portugal, Spain, and Cyprus). In Toscana virus patients, immunoglobulin M (IgM) antibodies, usually present at the onset of symptoms, can reveal elevated titers by enzyme-linked immunosorbent assay and can persist for at least 1 year. IgG antibodies can be absent at the onset of symptoms: titers rise in convalescent sera and persist for many years. At least five proteins have been identified in Toscana virus-infected cells: nucleoprotein N, glycoproteins G1 and G2, a large protein (L) assumed to be a component of the polymerase, and two nonstructural proteins, NSm and NSs. We report results of a study on the antibody response to individual viral proteins in patients with Toscana virus-associated acute neurologic disease. Immunoblotting and semiquantitative radioimmunoprecipitation assay (RIPA) allow identification of nucleoprotein N as the major antigen responsible for both IgM and IgG responses. Antibodies to proteins other than nucleoprotein N are detected only by RIPA. Antibodies to glycoproteins are detected in about one-third of patients, and whereas their presence always predicts neutralization, some serum samples with neutralizing activity have undetectable levels of antibodies to G1-G2. Antibodies to nonstructural proteins NSm and NSs are also identified. The results obtained raise some questions about antigenic variability and relevant neutralization epitopes of Toscana virus.

scholarly journals Rapid Diagnosis of Japanese Encephalitis by Using an Immunoglobulin M Dot Enzyme Immunoassay

1998 ◽  
Vol 36 (7) ◽  
pp. 2030-2034 ◽  
Author(s):  
Tom Solomon ◽  
Le Thi Thu Thao ◽  
Nguyen Minh Dung ◽  
Rachel Kneen ◽  
Nguyen The Hung ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Japanese Encephalitis ◽  
Predictive Value ◽  
Interobserver Agreement ◽  
Dengue Infection ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Rural Settings ◽  
Specialized Equipment

Japanese encephalitis (JE) occurs in rural settings in southern and eastern Asia, where diagnostic facilities are limited. For the diagnosis of JE virus (JEV) infection, we developed a nitrocellulose membrane-based immunoglobulin M (IgM) capture dot enzyme immunoassay (MAC DOT) that is rapid, simple to use, requires no specialized equipment, and can distinguish JEV from dengue infection. In a prospective field study in southern Vietnam, 155 cerebrospinal fluid (CSF) and 341 serum samples were collected from 111 children and 83 adults with suspected encephalitis. The JEV MAC DOT, performed on site, was scored visually from negative to strongly positive by two observers, and the results were compared subsequently with those of the standard IgM capture enzyme-linked immunosorbent assay. For the 179 patients with adequate specimens, the MAC DOT correctly identified 59 of 60 JEV-positive patients and 118 of 119 JEV-negative patients (sensitivity [95% confidence intervals], 98.3% [92.1 to 99.9%]; specificity, 99.2% [95.9 to 100.0%]; positive predictive value, 0.98; negative predictive value, 0.99). The MAC DOT also correctly identified three patients with dengue encephalopathy. Admission specimens were positive for 73% of JE patients. Interobserver agreement for MAC DOT diagnosis was excellent (kappa = 0.94). The JEV MAC DOT is a simple and reliable rapid diagnostic test for JE in rural hospitals.

scholarly journals Performance of Indirect Immunoglobulin M (IgM) Serology Tests and IgM Capture Assays for Laboratory Diagnosis of Measles

2000 ◽  
Vol 38 (1) ◽  
pp. 99-104
Author(s):  
Samuel Ratnam ◽  
Graham Tipples ◽  
Carol Head ◽  
Micheline Fauvel ◽  
Margaret Fearon ◽  
...  
Keyword(s):  
Measles Virus ◽  
False Negative ◽  
Laboratory Diagnosis ◽  
Immunoglobulin M ◽  
Confirmatory Test ◽  
Serum Samples ◽  
Negative Results ◽  
Capture Assay ◽  
Specimen Collection ◽  
Control And Prevention

ABSTRACT As progress is made toward elimination of measles, the laboratory confirmation of measles becomes increasingly important. However, both false-positive and false-negative results can occur with the routinely used indirect measles immunoglobulin M (IgM) serology tests. The measles IgM capture assay is considered to be more specific, and therefore, its use is indicated for confirmatory testing, but its relative performance has not been fully assessed. Four commercial indirect measles IgM serology test kits (the Behring, Clark, Gull, and PanBio assays) and a commercial IgM capture assay (the Light Diagnostics assay) were evaluated for their abilities to detect measles virus-specific IgM antibody with a total of 308 serum samples from patients involved in a measles outbreak and with confirmed cases of measles and 454 samples from subjects without measles. The Centers for Disease Control and Prevention (CDC) IgM capture assay was also used in a part of the evaluation. Among the indirect assays, the overall sensitivities ranged from 82.8% (Clark assay) to 88.6% (Behring assay) and specificity ranged from 86.6% (PanBio assay) to 99.6% (Gull assay). These rates were 92.2 and 86.6%, respectively, for the Light Diagnostics capture assay and 87.0 and 94.8%, respectively, for the CDC capture assay. While the Light Diagnostics capture assay had the best detection rate (80%) with the acute-phase samples compared with those for the rest of the tests (CDC capture assay, 77%; Behring assay, 70%; Gull assay, 69%; PanBio assay, 58%; and Clark assay, 57%), all tests showed a significantly improved sensitivity in the range of 92% (Clark and PanBio assays) to 97% (Light Diagnostics and CDC capture assays) with the convalescent-phase samples, as expected. The best seropositivity rates (in the range of 92 to 100%) were observed with samples collected 6 to 14 days after the onset of symptoms. The Gull assay showed the highest positive predictive value (99.6%), followed by the Behring assay (97.8%) and the CDC capture assay (96.1%). Overall, the Gull and Behring assays were found to be as good as or better than the capture assays. In conclusion, laboratory diagnosis of measles based on IgM serology varies depending on the timing of specimen collection and the test used, and the case for the use of the IgM capture assay as the confirmatory test appears to be uncertain.

scholarly journals Evaluation of an Enzyme Immunoassay for Detection of Dengue Virus NS1 Antigen in Human Serum

2006 ◽  
Vol 13 (11) ◽  
pp. 1185-1189 ◽  
Author(s):  
Philippe Dussart ◽  
Bhety Labeau ◽  
Gisèle Lagathu ◽  
Philippe Louis ◽  
Marcio R. T. Nunes ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Human Serum ◽  
Enzyme Immunoassay ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Diagnostic Strategy ◽  
Serum Samples ◽  
Dengue Disease ◽  
Reverse Transcription Pcr ◽  
Ns1 Antigen

ABSTRACT We evaluated a one-step sandwich-format microplate enzyme immunoassay for detecting dengue virus NS1 antigen (Ag) in human serum by use of Platelia Dengue NS1 Ag kits (Bio-Rad Laboratories, Marnes La Coquette, France). We collected 299 serum samples from patients with dengue disease and 50 serum samples from patients not infected with dengue virus. For the 239 serum samples from patients with acute infections testing positive by reverse transcription-PCR and/or virus isolation for one of the four dengue virus serotypes, the sensitivity of the Platelia Dengue NS1 Ag kit was 88.7% (95% confidence interval, 84.0% to 92.4%). None of the serum samples from patients not infected with dengue virus tested positive with the Platelia Dengue NS1 Ag kit. A diagnostic strategy combining the Platelia Dengue NS1 Ag test for acute-phase sera and immunoglobulin M capture enzyme-linked immunosorbent assay for early-convalescent-phase sera increased sensitivity only from 88.7% to 91.9%. Thus, NS1 antigen detection with the Platelia Dengue NS1 Ag kit could be used for first-line testing for acute dengue virus infection in clinical diagnostic laboratories.

scholarly journals International Multicenter Evaluation of the Clinical Utility of a Dipstick Assay for Detection ofLeptospira-Specific Immunoglobulin M Antibodies in Human Serum Specimens

1999 ◽  
Vol 37 (9) ◽  
pp. 2904-2909 ◽  
Author(s):  
Henk L. Smits ◽  
Yulia V. Ananyina ◽  
Annette Chereshsky ◽  
Louella Dancel ◽  
Rudy F. M. Lai-A-Fat ◽  
...  
Keyword(s):  
Laboratory Diagnosis ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Surveillance Systems ◽  
Serum Samples ◽  
Igm Antibodies ◽  
Paired Samples ◽  
Specific Immunoglobulin ◽  
Kappa Value ◽  
Broad Variety

We performed a multicenter evaluation of a robust and easily performed dipstick assay for the serodiagnosis of human leptospirosis. The assay is aimed at the detection of Leptospira-specific immunoglobulin M (IgM) antibodies. The study involved 2,665 serum samples collected from 2,057 patients with suspected leptospirosis in 12 countries on five continents with different levels of endemicity and different surveillance systems. The patients were grouped as laboratory-confirmed leptospirosis case patients and noncase patients based on the results of culturing and the microscopic agglutination test. Paired samples from 27.7% of the subjects were tested. Of the 485 case patients, 87.4% had a positive dipstick result for one or more samples. Of the 1,513 noncase patients, only 7.2% had a positive result. Whereas most (88.4%) of the positive samples from the case patients showed moderate to strong (2+ to 4+) staining in the dipstick assay, most (68.1%) of the positive samples from the noncase patients showed weak (1+) staining. The sensitivity of the dipstick assay increased from 60.1% for acute-phase serum samples to 87.4% for convalescent-phase samples. The specificities for these two groups of samples were 94.1 and 92.7%, respectively. The dipstick assay detected a broad variety of serogroups. The results of the dipstick assay were concordant (observed agreement, 93.2%; kappa value, 0.76) with the results of an enzyme-linked immunosorbent assay for the detection of specific IgM antibodies, a test which is often used in the laboratory diagnosis of current or recent leptospirosis. This study demonstrated that this easily performed dipstick assay is a valuable and useful test for the quick screening for leptospirosis; has a wide applicability in different countries with different degrees of endemicity; can be used at all levels of the health care system, including the field; and will be useful for detecting and monitoring outbreaks of leptospirosis.

scholarly journals Diagnosis of Mycoplasma pneumoniaePneumonia in Children

1998 ◽  
Vol 36 (11) ◽  
pp. 3155-3159 ◽  
Author(s):  
Matti E. Waris ◽  
Pia Toikka ◽  
Taina Saarinen ◽  
Simo Nikkari ◽  
Olli Meurman ◽  
...  
Keyword(s):  
Acute Phase ◽  
Southern Hybridization ◽  
Solid Phase ◽  
Laboratory Diagnosis ◽  
Immunoglobulin M ◽  
Serum Samples ◽  
Convalescent Phase ◽  
Pcr Products ◽  
Serology Test ◽  
Time Of Admission

We evaluated a commercial immunoglobulin M (IgM)-capture immunoassay for the detection of Mycoplasma pneumoniaeinfections in 278 pediatric patients with community-acquired, radiographically defined pneumonia. Acute- and convalescent-phase serum samples were collected from all patients and were tested for M. pneumoniae-specific IgM and IgG antibodies by Platelia enzyme immunoassays (Sanofi Diagnostica Pasteur, Marnes la Coquette, France). Nasopharyngeal aspirates (NPAs) were collected at the time of admission to the hospital. A total of 227 NPAs were subjected to the detection ofM. pneumoniae DNA by PCR, and 191 NPAs were cultured by using the Pneumofast kit (International Mycoplasma, Signeswere, France). Southern hybridization of PCR products and the IgM test with solid-phase antigen (Serion Immunodiagnostica, Würzburg, Germany) were used for additional confirmation of a positive result, which required agreement of at least two different methods. A total of 24 (9%) confirmed diagnoses of mycoplasma infection were made, 5 (21%) of which were in children <5 years of age. Of the positive children, 24 of 24 (sensitivity, 100%) were positive by the IgM-capture test with convalescent-phase serum, 19 of 24 (79%) were positive by the IgM-capture test with acute-phase serum, 19 of 24 (79%) were positive by IgG serology, 10 of 20 (50%) were positive by PCR, and 8 of 17 (47%) were positive by culture. An additional 5 (of 254) children were positive by the Platelia IgM test alone (specificity, 98%). When the PCR with Southern hybridization result was combined with the IgM-capture test result with the acute-phase sera, the sensitivity of rapid laboratory diagnosis increased to 95%. In conclusion, the IgM serology test was the single most valuable tool for the diagnosis ofM. pneumoniae pneumonia in children of any age.

Autoantibodies to Thrombomodulin: Development of an Enzyme Immunoassay and a Survey of their Frequency in Patients with the Lupus Anticoagulant

1992 ◽  
Vol 67 (05) ◽  
pp. 507-509 ◽  
Author(s):  
John Gibson ◽  
Margaret Nelson ◽  
Ross Brown ◽  
Hatem Salem ◽  
Harry Kronenberg
Keyword(s):  
Enzyme Immunoassay ◽  
Lupus Anticoagulant ◽  
Specific Binding ◽  
Technical Problem ◽  
Serum Samples ◽  
Citrate Buffer ◽  
The Mean ◽  
Sample Dilution ◽  
Negative Population ◽  
Serum Components

SummaryIn order to investigate the possibility that autoantibodies to thrombomodulin (TM) may exist in patients with the lupus anticoagulant (LA) and perhaps be implicated in the pathogenesis of recurrent thrombosis seen in such patients, we developed an enzyme-immunoassay to screen serum samples for anti-human TM activity. The major technical problem encountered in developing this assay was to reduce the non-specific binding of serum components from both the LA positive and the negative population. Considerable reduction of non-specific binding was achieved by use of a phosphate/citrate buffer at pH 8.0 and the use of an optimal sample dilution of 1/40. In addition, samples were always tested in parallel in blank wells and results are expressed as an OD ratio. Samples from 113 patients with the LA were assayed and compared to 78 patients referred for LA testing but found to be negative. The mean OD values for the LA positive patients (± SD) was 1.36 (0.44) with a range of 0.78-2.57. This was virtually identical to the values for the LA negative population (1.38 ± 0.40, range 0.76-2.77). The results of this study indicate that there is no evidence for the presence of a significant autoantibody activity to TM in patients with the LA when compared to LA negative patients. If such autoantibodies do exist their frequency must be quite low.

TBE in Sweden

2020 ◽  
Keyword(s):  
Genetic Characterization ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Second Phase ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Specific Immunoglobulin ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.

scholarly journals Seroprevalence of Anti-SARS-CoV-2 IgG and IgM among Adults over 65 Years Old in the South of Italy

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 483
Author(s):  
Immacolata Polvere ◽  
Alfredina Parrella ◽  
Giovanna Casamassa ◽  
Silvia D’Andrea ◽  
Annamaria Tizzano ◽  
...  
Keyword(s):  
Antibody Response ◽  
Immunoglobulin M ◽  
Molecular Testing ◽  
Elisa Assay ◽  
The South ◽  
Serum Samples ◽  
Serological Screening ◽  
Rna Detection ◽  
In Vitro Diagnostic

SARS-CoV-2 is a zoonotic betacoronavirus associated with worldwide transmission of COVID-19 disease. By the beginning of March, WHO reported about 113,820,000 confirmed cases including more than 2,527,000 deaths all over the world. However, the true extent of virus circulation or its real infection/fatality ratio is not well-estimated due to the huge portion of asymptomatic infections. In this observational study, we have estimated the prevalence of specific immunoglobulin M and G directed towards SARS-CoV-2 antigen in a cohort of 1383 adult volunteers aged over 65 years old, living in the district of Benevento, in the South of Italy. Serological screening was carried out on capillary blood in September 2020, seven months after pandemic outbreak in Italy, to evaluate virus circulation and antibody response among elderly adults, in which severe symptoms due to viral infection are more common. The overall seroprevalence of anti-SARS-CoV-2 antibodies was 4.70% (CI 3.70%–5.95%) with no statistically significant differences between sexes. Among these, 69.69% (CI 55.61%–77.80%) tested positive to IgM, 23.08% (CI 14.51%–34.64%) to IgG and 9.23% (CI 4.30%–18.71%) was positive for both. All patients that were positive to IgM underwent molecular testing through RT-qPCR on oral-rhino pharyngeal swabs and only one specimen was positive for SARS-CoV-2 RNA detection. Instead, the presence of IgG from screened volunteers was confirmed by re-testing serum samples using both an ELISA assay validated for in vitro diagnostic use (IVD) and a recently published synthetic peptide-based ELISA assay. In conclusion, our report suggests that (1) early restrictions were successful in limiting COVID-19 diffusion in the district of Benevento; (2) rapid serological analysis is an ideal testing for both determining real seroprevalence and massive screening, whereas detection of viral RNA remains a gold standard for identification of infected patients; (3) even among people without COVID-19 related symptoms, the antibody response against SARS-CoV-2 antigens has individual features.

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