IgG Enzyme Immunoassay Research Articles

Relationship Between HSV-1 Serostatus and HSV-2 IgG Confirmation Results using an Inhibition Assay

Abstract Background: Approximately 2% of HerpeSelect Herpes Simples Virus type 2 (HSV-2) IgG enzyme immunoassay (screen assay) sera positive samples do not confirm using an HSV-2 IgG inhibition assay. Of these, roughly 1.33% are confirmed negative and a small proportion (0.2%) are indeterminate due to inhibition observed with HSV-1 and HSV-2 lysate. The objective of this study was to assess the relationship between HSV-1 IgG serostatus and HSV-2 IgG confirmation results using the HSV-2 IgG inhibition assay. Methods: This study included consecutive HSV-2 IgG screen-positive specimens regardless of index value. Specimens were also tested for HSV-1 IgG. The HSV-2 IgG confirmation results from the inhibition assay were evaluated to assess the relationship between inhibition results and HSV-1 serostatus. Results: Of the 21,006 positive HSV-2 IgG specimens, 13,237 (63%) were also positive for HSV-1 IgG. The proportion of HSV-1 IgG-positive samples among inhibition-indeterminate samples (33/40, 83%) was higher than among inhibition-negative (167/279, 60%) and inhibition-positive (13,041/20,691, 63%) samples. Among HSV-1 IgG-positive samples, the median HSV-1 IgG index was also significantly higher for the inhibition-indeterminate group (median = 48.8) than for the inhibition-negative (median = 30.7) and inhibition-positive groups (median = 31.2) (P = 0.00013 and P = 3.1e-05, respectively). Conclusion: These findings suggest that HSV-2 IgG inhibition-indeterminate, but not inhibition-negative, results are associated with higher index values of HSV-1 IgG. Further studies are needed to understand other factors associated with inhibition-indeterminate results.

Salivary immune responses after COVID-19 vaccination.

mRNA-based COVID-19 vaccines have played a critical role in reducing severe outcomes of COVID-19. Humoral immune responses against SARS-CoV-2 after vaccination have been extensively studied in blood; however, limited information is available on the presence and duration of SARS-CoV-2 specific antibodies in saliva and other mucosal fluids. Saliva offers a non-invasive sampling method that may also provide a better understanding of mucosal immunity at sites where the virus enters the body. Our objective was to evaluate the salivary immune response after vaccination with the COVID-19 Moderna mRNA-1273 vaccine. Two hundred three staff members of the U.S. Centers for Disease Control and Prevention were enrolled prior to receiving their first dose of the mRNA-1273 vaccine. Participants were asked to self-collect 6 saliva specimens at days 0 (prior to first dose), 14, 28 (prior to second dose), 42, and 56 using a SalivaBio saliva collection device. Saliva specimens were tested for anti-spike protein SARS-CoV-2 specific IgA and IgG enzyme immunoassays. Overall, SARS-CoV-2-specific salivary IgA titers peaked 2 weeks after each vaccine dose, followed by a sharp decrease during the following weeks. In contrast to IgA titers, IgG antibody titers increased substantially 2 weeks after the first vaccine dose, peaked 2 weeks after the second dose and persisted at an elevated level until at least 8 weeks after the first vaccine dose. Additionally, no significant differences in IgA/IgG titers were observed based on age, sex, or race/ethnicity. All participants mounted salivary IgA and IgG immune responses against SARS-CoV-2 after receiving the mRNA-1273 COVID-19 vaccine. Because of the limited follow-up time for this study, more data are needed to assess the antibody levels beyond 2 months after the first dose. Our results confirm the potential utility of saliva in assessing immune responses elicited by immunization and possibly by infection.

Diagnosis of Coccidioidomycosis with the Second-Generation Miravista IgG and IgM Enzyme Immunoassay and the Role of Adding Miravista Coccidioides Antigen Detection to Immunodiagnostic Assays.

In the present study, we validate and compare the second-generation Miravista Coccidioides IgG and IgM enzyme immunoassays (EIA) (MiraVista Diagnostics [MVD] Ab EIA) to Meridian Diagnostics Coccidioides IgG and IgM EIA (Meridian Ab EIA), immunodiffusion (ID) and complement fixation (CF). We also evaluated whether the addition of Coccidioides antigen testing to anti-Coccidioides antibody testing increased the sensitivity for the diagnosis of currently active coccidioidomycosis. We retrospectively studied 555 patients evaluated at Valleywise Health Medical Center between January 2013 and May 2017 for whom coccidioidomycosis was suspected and samples were submitted to MVD for testing. Specimens were tested for antigen in the MVD antigen enzyme immunoassay (MVD Ag EIA) and for IgG and IgM antibodies with MVD and Meridian Diagnostics EIAs. ID and CF were obtained from medical records. Sensitivity and specificity were 83.0% and 91.1% or MVD Ab EIA, 69.3% and 99.7% for Meridian Ab EIA, 85.4% and 100% for ID and 65.5% and 100% for CF. Combined MVD antigen and antibody detection by EIA and ID resulted in increased sensitivity in disseminated and pulmonary disease (MVD Ag/MVD Ab: 100%, 88.3%; MVD Ag/Meridian Ab: 98.2%, 78.6%; and MVD Ag/ID: 100%, 91.7%). The detection of antibodies by MVD EIA was more sensitive than Meridian EIA or CF but similar to ID. This study supports the use of antigen testing in immunocompromised patients and those with suspected disseminated disease. Furthermore, the addition of antigen detection by EIA to antibody detection resulted in higher sensitivity of all serological tests.

Histoplasmosis in domestic cats: new minimally invasive diagnostic techniques.

The aim of the present study was to evaluate minimally invasive diagnostic techniques, such as the semi-quantitative indirect IgG antibody enzyme immunoassay (EIA) using blood serum and the urinary lateral flow assay (LFA), for the detection of Histoplasma capsulatum in cats with histoplasmosis. Eight client-owned domestic cats diagnosed with histoplasmosis were selected based on cytological, histopathological, mycological, molecular or antigenic techniques. The blood serum of these animals was tested in a semi-quantitative indirect IgG antibody EIA for the detection of H capsulatum. Urine samples were tested for H capsulatum antigen using LFA. Five cats were seropositive on IgG EIA (5/8, with diagnostic sensitivity equal to 62.5%; 95% confidence interval [CI] 24.5-91.5) and five cats were positive on H capsulatum antigen LFA (5/7, with diagnostic sensitivity equal to 71.4%; 95% CI 29.0-96.3). The combined diagnostic sensitivity when interpreted in parallel was 87.5% (7/8, 95% CI 47.3-99.7). The specificity for the anti-Histoplasma IgG EIA was 100% (95% CI 71.5-100) and for the H capsulatum antigen LFA it was also 100% (95% CI 71.5-100). The semi-quantitative indirect IgG antibody EIA for the detection of H capsulatum in blood serum and the urinary LFA for the detection of the same agent emerge as new minimally invasive diagnostic techniques that can assist in the approach to disseminated and pulmonary feline histoplasmosis, especially when both techniques are considered together.

The Sero-prevalence and Risk Factors of Chlamydiosis among Women of Reproductive Age in Port Harcourt, Nigeria

Aim: This study is aimed to determine the association between chlamydiosis and some selected risk factors among women of reproductive age in Port Harcourt, Nigeria.
 Study Design: The study was a cross-sectional study conducted at Rivers State University teaching hospital.
 Place and Duration of the Study: The study was conducted at Rivers State University teaching hospital, Rivers State, Nigeria between March, 2022 and August, 2022.
 Methodology: This cross-sectional study included 450 women who ranged in age from 15 to 55 years and met the inclusion criteria after obtaining ethical approval from Rivers state teaching hospital ethics committee. The women were divided into four subgroups: outpatients, immunocompromised patients (HIV clinic patients), pregnant women, and healthy volunteers. Well-structured questionnaires were used to obtain data on risk factors of chlamydiosis on consultancy basis. Healthy volunteers were those who showed no symptoms otherwise regarded as apparently healthy volunteers. The data obtained were analyzed using Chlamydia trachomatis IgG Enzyme Immunoassay test kit.
 Results: Out of the 450 samples examined, 45 (10%) tested positive to chlamydia antibodies with the highest prevalence among the immunodeficiency virus subjects (4.2%) and this was followed by the outpatient (2.4%) and healthy volunteers (2.2%). Pregnant women had the lowest seroprevalence rate of 1.1%. The study further revealed that about 78% of the study population heard about chlamydiosis while 22% had no knowledge of it. Statistically, there was no association (p=.06) between awareness parameters and sero-prevalence of chlamydiosis. Similarly, there was no association (p=.08) between person hygiene parameters and sero-prevalence of chlamydiosis. The study equally revealed that there was an association between self-screening for sexually transmitted infection and ever screened for Chlamydia trachomatis as life styles for chlamydiosis (p=.05).
 Conclusion: The results of this study indicate a strong correlation between self-screening for Sextually transmitted infections and chlamydia infection and those who have ever had a Chlamydia trachomatis screening. In order to lessen the harmful effects chlamydiosis has on society, particularly among those who are of reproductive age, awareness of the risk factor associated with the disease should also be increased.

Development and comparison of immunologic assays to detect primary RSV infections in infants.

Effective respiratory syncytial virus (RSV) vaccines have been developed and licensed for elderly adults and pregnant women but not yet for infants and young children. The RSV immune state of the young child, i.e., previously RSV infected or not, is important to the conduct and interpretation of epidemiology studies and vaccine clinical trials. To address the need for sensitive assays to detect immunologic evidence of past infection, we developed, characterized, and evaluated 7 assays including 4 IgG antibody enzyme immunoassays (EIAs), two neutralizing antibody assays, and an IFN-γ EliSpot (EliSpot) assay. The four IgG EIAs used a subgroup A plus subgroup B RSV-infected Hep-2 cell lysate antigen (Lysate), an expressed RSV F protein antigen (F), an expressed subgroup A G protein antigen (Ga), or an expressed subgroup B G protein (Gb) antigen. The two neutralizing antibody assays used either a subgroup A or a subgroup B RSV strain. The EliSpot assay used a sucrose cushion purified combination of subgroup A and subgroup B infected cell lysate. All seven assays had acceptable repeatability, signal against control antigen, lower limit of detection, and, for the antibody assays, effect of red cell lysis, lipemia and anticoagulation of sample on results. In 44 sera collected from children >6 months after an RSV positive illness, the lysate, F, Ga and Gb IgG EIAs, and the subgroup A and B neutralizing antibody assays, and the EliSpot assays were positive in 100%, 100%, 86%, 95%, 43%, and 57%, respectively. The Lysate and F EIAs were most sensitive for detecting RSV antibody in young children with a documented RSV infection. Unexpectedly, the EliSpot assay was positive in 9/15 (60%) of PBMC specimens from infants not exposed to an RSV season, possibly from maternal microchimerism. The Lysate and F EIAs provide good options to reliably detect RSV antibodies in young children for epidemiologic studies and vaccine trials.

Seroprevalence of Helicobacter pylori infections in children and adults in Poland in the years 2020-2023.

Helicobacter pylori is a common cause of gastrointestinal infections in people around the world. Various microbiological methods are used in the laboratory diagnosis of infections, including determining the presence of specific antibodies in the serum. Serological tests can also be used in epidemiological studies aimed at determining the incidence of H. pylori infections. The aim of the study was to obtain insight into the incidence of antibodies to H. pylori in subjects of different ages living in Poland in the years 2020-2023. The research used serum samples obtained between January 2020 and September 2023 from 600 subjects living in Poland. The Anti-Helicobacter pylori ELISA IgG enzyme immunoassay from Euroimmun was used to test the level of IgG antibodies to H. pylori antigens. Additionally, selected serum samples were tested for the presence of antibodies to the most important protein virulence factors of H. pylori by Western Blot. IgG antibodies to H. pylori, at a diagnostically significant level, were detected in 28.3% of the examined persons. Antibodies to H. pylori were least frequently detected in children under 10 years of age (12.1%) and teenagers (13.2%). In adults aged 20 to 50, these antibodies were more common (23.9% to 29.5%). Statistically, H. pylori antibodies were most often detected in subjects over 50 years of age (52.3%). There were no statistically significant differences in the frequency of antibodies to H. pylori depending on the gender of the examined persons. In most serum samples tested by Western Blot, the presence of antibodies to the CagA protein was detected (66.7%). The conducted research and analysis of literature data showed a similar percentage of serum samples with a diagnostically significant level of antibodies to H. pylori in people living in Poland as in people living in other European countries. The epidemiology of infections is also very similar, characterized by low morbidity in children and adolescents and an increase in the incidence of infections with the age of the examined persons. Importantly, compared to research conducted in our country several years ago, the percentage of positive results is much lower, which may be due to the improvement of social and living conditions and hygiene habits.

A-267 Evaluation of the Quidel Sofia 2 Rapid Lyme Test in a Modified Two-tier Testing Protocol

Abstract Background Several Modified two-tier testing algorithms (MTTT) for Lyme disease involving sequential enzyme immunoassays (EIA) have been approved by the FDA as an alternative to conventional two-tiered testing using EIA followed by immunoblot. The MTTT algorithms are reported to be more sensitive than conventional two-tiered algorithm’s especially in early Lyme disease. The Quidel Sofia 2 Lyme assay utilizes lateral flow with fluorescence detection (FIA) providing a rapid on-demand instrument-read alternative to central laboratory batch mode testing We compared the Quidel assay as a first-tier test in an MTTT algorithm to the Zeus Scientific VlsE1/pepC10 IgG/IgM enzyme immunoassay (EIA) followed by the Zeus monovalent IgM and IgG EIA as the confirmatory test. Methods Serum specimens (n = 179) were obtained from consecutive samples sent to our clinical laboratory for Lyme serology testing. For the first-tier the samples were tested using the Zeus EIA VlsE1/pepC10 lgG/IgM test and the Quidel Sofia 2 Lyme FIA assay. Positive or equivocal first-tier tests were then tested using the Zeus monovalent IgM and IgG EIA as the confirmatory test. Results The positive percent agreement was 100%, the negative percent agreement 97.9 % with an overall agreement of 98.3%. The Kappa statistic was 0.945 (95% confidence interval 0.883–1.000 indicating “almost perfect” agreement). Conclusion The Quidel Sofia Lyme test performs well when compared to the Zeus test in a two-tiered testing MTTT algorithm. Obtaining samples to evaluate Lyme serologic tests can be challenging. Our data should prove useful for facilities considering the use of the Quidel assay.

Comparison of measles IgG enzyme immunoassays (EIA) versus plaque reduction neutralization test (PRNT) for measuring measles serostatus: a systematic review of head-to-head analyses of measles IgG EIA and PRNT

BackgroundAs countries move towards or achieve measles elimination status, serosurveillance is an important public health tool. However, a major challenge of serosurveillance is finding a feasible, accurate, cost-effective, and high throughput assay to measure measles antibody concentrations and estimate susceptibility in a population. We conducted a systematic review to assess, characterize, and – to the extent possible – quantify the performance of measles IgG enzyme-linked assays (EIAs) compared to the gold standard, plaque reduction neutralization tests (PRNT).MethodsWe followed the PRISMA statement for a systematic literature search and methods for conducting and reporting systematic reviews and meta-analyses recommended by the Cochrane Screening and Diagnostic Tests Methods Group. We identified studies through PubMed and Embase electronic databases and included serologic studies detecting measles virus IgG antibodies among participants of any age from the same source population that reported an index (any EIA or multiple bead-based assays, MBA) and reference test (PRNT) using sera, whole blood, or plasma. Measures of diagnostic accuracy with 95% confidence intervals (CI) were abstracted for each study result, where reported.ResultsWe identified 550 unique publications and identified 36 eligible studies for analysis. We classified studies as high, medium, or low quality; results from high quality studies are reported. Because most high quality studies used the Siemens Enzygnost EIA kit, we generate individual and pooled diagnostic accuracy estimates for this assay separately. Median sensitivity of the Enzygnost EIA was 92.1% [IQR = 82.3, 95.7]; median specificity was 96.9 [93.0, 100.0]. Pooled sensitivity and specificity from studies using the Enzygnost kit were 91.6 (95%CI: 80.7,96.6) and 96.0 (95%CI: 90.9,98.3), respectively. The sensitivity of all other EIA kits across high quality studies ranged from 0% to 98.9% with median (IQR) = 90.6 [86.6, 95.2]; specificity ranged from 58.8% to 100.0% with median (IQR) = 100.0 [88.7, 100.0].ConclusionsEvidence on the diagnostic accuracy of currently available measles IgG EIAs is variable, insufficient, and may not be fit for purpose for serosurveillance goals. Additional studies evaluating the diagnostic accuracy of measles EIAs, including MBAs, should be conducted among diverse populations and settings (e.g., vaccination status, elimination/endemic status, age groups).

Hepatitis E Virus Prevalence Amongst Blood Donors in Kenya

Introduction: Hepatitis E (HEV) is an emerging cause of viral hepatitis mainly transmitted through the fecal-oral and parenteral routes. It has greatly affected populations in many parts of Kenya due to declined sanitation practices. The objective of the research was to determine IgM and IgG seroprevalence of HEV prevalence among blood donors in Kenya as well as its Anti-HEV sero-reactivity by demographic factors.
 Material and Methods: Cross sectional research design was used to collect blood samples from six from regional blood collecting centers, with blood donors selected through proportionate stratified sampling. Serum were matched to the age and gender distribution of the blood donors and tested by IgM and IgG enzyme immunoassays (EIA). The screening was carried out using human MP Diagnostics (0721150096T-96 wells) HEV ELISA kit. To test for IgM and IgM anti-HEV antibodies, microplates with 96-well plate were used. Results were averaged to generate a signal-to-noise ratio with ≥1.0 designated as positive per the manufacturer’s recommended cutoff.
 Result and Conclusion: On the analysis, IgM reactivity was associated with HEV (RR 1.66, 95%CI 1.07, 2.60; p = 0.024) while IgG reactivity was associated with increasing age (p < 0.001) and HIV (RR 1.93, 95%CI 1.52, 2.46; p < 0.001). AFI case-patients were more likely to be IgM (p = 0.002) and IgG (p<0.001) reactive compared to healthy residents. All the 19 hepatitis E virus IgM and/or IgG seropositive blood samples tested negative for HEV RNA since no bands were detected using RT-PCR technique. Serologic evidence for HEV in blood samples from selected areas suggests a high burden of infection, though age and gender exhibited no significant difference in prevalence of HEV among the blood donors in Kenya (p>0.05).

Development and Validation of an Enzyme Immunoassay for Detection and Quantification of SARS-CoV-2 Salivary IgA and IgG.

Oral fluids offer a noninvasive sampling method for the detection of Abs. Quantification of IgA and IgG Abs in saliva allows studies of the mucosal and systemic immune response after natural infection or vaccination. We developed and validated an enzyme immunoassay (EIA) to detect and quantify salivary IgA and IgG Abs against the prefusion-stabilized form of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein expressed in suspension-adapted HEK-293 cells. Normalization against total Ab isotype was performed to account for specimen differences, such as collection time and sample volume. Saliva samples collected from 187 SARS-CoV-2 confirmed cases enrolled in 2 cohorts and 373 prepandemic saliva samples were tested. The sensitivity of both EIAs was high (IgA, 95.5%; IgG, 89.7%) without compromising specificity (IgA, 99%; IgG, 97%). No cross-reactivity with endemic coronaviruses was observed. The limit of detection for SARS-CoV-2 salivary IgA and IgG assays were 1.98 ng/ml and 0.30 ng/ml, respectively. Salivary IgA and IgG Abs were detected earlier in patients with mild COVID-19 symptoms than in severe cases. However, severe cases showed higher salivary Ab titers than those with a mild infection. Salivary IgA titers quickly decreased after 6 wk in mild cases but remained detectable until at least week 10 in severe cases. Salivary IgG titers remained high for all patients, regardless of disease severity. In conclusion, EIAs for both IgA and IgG had high specificity and sensitivity for the confirmation of current or recent SARS-CoV-2 infections and evaluation of the IgA and IgG immune response.

Characterization of Serum Samples With Discordant Results in 2 Herpes Simplex Virus Type 2 IgG Assays.

Our laboratory system tests sera for herpes simplex virus type 2 (HSV-2) IgG using the DiaSorin Liaison chemiluminescent immunoassay (CIA), with the option to confirm positive samples by a laboratory-developed HerpeSelect inhibition assay. As part of the confirmation process, the HerpeSelect HSV-2 IgG enzyme immunoassay (EIA) is performed. This study investigated the relationship between DiaSorin HSV-2 IgG CIA-positive indices and HerpeSelect HSV-2 IgG EIA results. HerpeSelect HSV-2 IgG EIA results were compiled for a cohort of consecutive DiaSorin HSV-2 IgG CIA-positive (index ≥1.10) samples. To further characterize DiaSorin CIA-positive samples that were positive (concordant) or negative (discordant) by the HerpeSelect EIA, a separate composite reference study panel was constructed and also tested using the Biokit HSV-2 IgG assay and an HSV-2 IgG inhibition assay developed for the DiaSorin instrument. Samples were classified as DiaSorin HSV-2 IgG true positive or false positive based on a composite reference using HerpeSelect EIA, Biokit, and DiaSorin inhibition results. Of 2305 consecutive DiaSorin HSV-2 IgG CIA-positive samples, 411 (17.8%) were HerpeSelect HSV-2 IgG EIA negative; 343 of 411 (83%) had DiaSorin indices of 1.10 to 3.00. For the composite reference study panel (N = 120), 59 of 60 discordant samples were classified as DiaSorin HSV-2 IgG false positive based on the composite reference, whereas 58 of 60 concordant samples were classified as true positive. Nearly all DiaSorin HSV-2 IgG CIA-positive but HerpeSelect HSV-2 IgG EIA-negative sera are falsely positive in the DiaSorin CIA. Furthermore, most DiaSorin false-positive samples exhibit low-positive indices, suggesting that guidelines for confirmatory testing should include low-positive samples by CIA and EIA.

A Combination of N and S Antigens With IgA and IgG Measurement Strengthens the Accuracy of SARS-CoV-2 Serodiagnostics.

BackgroundPrimary diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is based on detection of virus RNA in nasopharyngeal swab samples. In addition, analysis of humoral immunity against SARS-CoV-2 has an important role in viral diagnostics and seroprevalence estimates.MethodsWe developed and optimized an enzyme immunoassays (EIA) using SARS-CoV-2 nucleoprotein (N), S1 and receptor binding domain (RBD) of the viral spike protein, and N proteins from SARS, Middle East respiratory syndrome (MERS), and 4 low-pathogenic human CoVs. Neutralizing antibody activity was compared with SARS-CoV-2 IgG, IgA, and IgM EIA results.ResultsThe sensitivity of EIA for detecting immune response in COVID-19 patients (n = 101) was 77% in the acute phase and 100% in the convalescent phase of SARS-CoV-2 infection when N and RBD were used as antigens in IgG and IgA specific EIAs. SARS-CoV-2 infection significantly increased humoral immune responses against the 229E and NL63 N proteins. S1 and RBD-based EIA results had a strong correlation with microneutralization test results.ConclusionsThe data indicate a combination of SARS-CoV-2 S1 or RBD and N proteins and analysis of IgG and IgA immunoglobulin classes in sera provide an excellent basis for specific and sensitive serological diagnostics of COVID-19.

Development of in-house ELISAs for the detection of anti-SARS‑CoV‑2 RBD and N IgG and IgM antibodies in biological samples

By the end of year 2019, the new virus SARS-CoV-2 appeared, causing the Coronavirus Disease 2019 (COVID-19), and spread very fast globally. A continuing need for diagnostic tools is a must to contain its spread. Till now, the gold standard method, the reverse transcription polymerase chain reaction (RT-PCR), is the precise procedure to detect the virus. However, SARS-CoV-2 may escape RT-PCR detection for several reasons. The development of well-designed, specific and sensitive serological test like enzyme immunoassay (EIA) is needed. This EIA can stand alone or work side by side with RT-PCR.In this study, we developed several EIAs including plates that are coated with either specially designed SARS-CoV-2 nucleocapsid or surface recombinant proteins. Each protein type can separately detect anti-SARS-CoV-2 IgM or IgG antibodies. For each EIAs, the cut-off value, specificity and sensitivity were determined utilizing RT-PCR confirmed Covid-19 and pre-pandemic healthy and other viruses-infected sera. Also, the receiver operator characteristic (ROC) analysis was performed to define the specificities and sensitivities of the optimized assay. The in-house EIAs were validated by comparing against commercial EIA kits. All in-house EIAs showed high specificity (98–99%) and sensitivity (97.8–98.9%) for the detection of IgG/IgM against RBD and N proteins of SARS-CoV-2.From these results, the developed Anti-RBD and anti-N IgG and IgM antibodies EIAs can be used as a specific and sensitive tool to detect SARS-CoV-2 infection, calculate the burden of disease and case fatality rates.

Human Protoparvovirus DNA and IgG in Children and Adults with and without Respiratory or Gastrointestinal Infections.

Three human protoparvoviruses, bufavirus (BuV), tusavirus (TuV) and cutavirus (CuV), have recently been discovered in diarrheal stool. BuV has been associated with diarrhea and CuV with cutaneous T-cell lymphoma, but there are hardly any data for TuV or CuV in stool or respiratory samples. Hence, using qPCR and IgG enzyme immunoassays, we analyzed 1072 stool, 316 respiratory and 445 serum or plasma samples from 1098 patients with and without gastroenteritis (GE) or respiratory-tract infections (RTI) from Finland, Latvia and Malawi. The overall CuV-DNA prevalences in stool samples ranged between 0–6.1% among our six patient cohorts. In Finland, CuV DNA was significantly more prevalent in GE patients above rather than below 60 years of age (5.1% vs 0.2%). CuV DNA was more prevalent in stools among Latvian and Malawian children compared with Finnish children. In 10/11 CuV DNA-positive adults and 4/6 CuV DNA-positive children with GE, no known causal pathogens were detected. Interestingly, for the first time, CuV DNA was observed in two nasopharyngeal aspirates from children with RTI and the rare TuV in diarrheal stools of two adults. Our results provide new insights on the occurrence of human protoparvoviruses in GE and RTI in different countries.

Изменения иммунитета и микроциркуляции в почках на фоне лечения гнойного пиелонефрита

Изменения иммунитета и микроциркуляции в почках на фоне лечения гнойного пиелонефрита

Australian mumps serosurvey 2012-2013: any cause for concern?

To determine population-level immunity to mumps in Australia. We tested randomly selected specimens from people aged 1-49 years using the Enzygnost anti-parotitis IgG enzyme immunoassay from an opportunistically collected serum bank in 2012-2013. Weighted estimates of the proportion seropositive and equivocal for mumps-specific IgG antibody were determined by age group and compared with two previous national serosurveys conducted in 2007-2008 and 1997-1998. Overall, 82.1% (95% CI 80.6-83.5%) of 2,729 specimens were positive or equivocal for mumps-specific IgG antibodies (71.1% positive [95% CI 69.4-72.9%]; 10.9% equivocal [95% CI 9.8-12.2%]). The proportion positive or equivocal was higher in 2012-2013 (82.1%) than in 2007-2008 (75.5%) and 1997-1998 (72.5%), but varied by age. The proportion positive or equivocal in 2012-2013 was above 80% for all age groups older than 1 year except for 30-34 year olds, corresponding to the 1978-1982 birth cohort previously identified as most likely to have missed out on a second MMR vaccine dose. Seropositivity to mumps in 2012-2013 was well-maintained compared with previous serosurveys. Low mumps notifications over this period in Australia suggest an absence of community-based transmission of mumps infection in the general population, but recent outbreaks among Aboriginal adolescents and young adults in close-contact settings, despite high 2-dose MMR coverage, suggest that seroprotection may be insufficient in other similar settings in Australia.Seropositivity to mumps in 2012-2013 was well-maintained compared with previous serosurveys. Low mumps notifications over this period in Australia suggest an absence of community-based transmission of mumps infection in the general population, but recent outbreaks among Aboriginal adolescents and young adults in close-contact settings, despite high 2-dose MMR coverage, suggest that seroprotection may be insufficient in other similar settings in Australia.

Impact of vaccination on measles, mumps, and rubella antibody titers in Japanese healthcare workers: An observational study.

Given the complicated history of Japan’s National Immunization Program, a significant proportion of Japanese people including healthcare workers (HCWs) still lack adequate immunity against measles, mumps, and rubella (MMR), resulting in occasional outbreaks. In 2014, the Japanese Society of Infection Prevention and Control (JSIPC) published vaccination guidelines for HCWs. We evaluated antibody titers before and after MMR vaccination in HCWs at the Nara Medical University Hospital, the attainment rate of the target antibody titers defined by the JSIPC guidelines, and the safety of vaccines. We measured MMR antibody titers in HCWs, followed by inoculation with the respective monovalent vaccines and/or trivalent MMR (tMMR) vaccine according to the JSIPC guidelines. Among 467 HCWs evaluated, antibody titers against measles and mumps measured using the IgG-enzyme immunoassay increased from 11.0 [interquartile range (IQR): 8.0–13.6] to 13.7 (IQR: 11.3–16.9; P < 0.001) and from 2.8 (IQR: 2.1–3.5) to 4.8 (IQR: 3.7–5.7; P < 0.001), respectively. By evaluating a logarithmic value of log2(X + 1) converted from an antibody titer X, antibody titers against rubella measured using the hemagglutination assay increased from 3.2 (IQR: 0–4.1) to 6.0 (IQR: 4.6–8.0; P < 0.001). Antibody titer elevated following tMMR vaccination was lower than that following monovalent vaccination in a single dose of the measles-containing, a single dose of the mumps-containing, and two doses of rubella-containing vaccine groups (P = 0.01, 0.01, and <0.001, respectively). After vaccination, 20.0%, 61.5%, and 46.2% of HCWs attained target antibody titers specified by the JSIPC guidelines for measles, rubella, and mumps, respectively. The systemic response in female HCWs who underwent monovalent mumps vaccination was statistically higher than that in others. Although the vaccination program for HCWs according to the JSIPC guidelines caused increased MMR antibody titers, the rates of attaining the target criteria were low.

Cerebrospinal fluid challenges for the diagnosis of herpes simplex infection in the central nervous system.

The aim of the present study was to adapt a commercial kit anti-HSV IgG used for serum samples to be performed with a CSF sample. Forty CSF specimens from 38 patients with suspected CNS HSV infection were serially diluted for detecting anti-HSV IgG by enzyme immunoassay (EIA). The same samples were also analyzed with the polymerase chain reaction (PCR). The sensitivity of EIA test for HSV was 5% (dilution 1:40) and 65% (dilution 1:2) in CSF, and HSV DNA PCR was 15%. The combined analysis of EIA (dilution 1:2) and PCR increased the sensitivity up to 72.5%. The inflammatory CSF was associated with positive HSV PCR. We demonstrated the importance to adapt serological anti-HSV IgG EIA test for CSF assays to increase the accuracy of the analysis, considering the low concentration of specific antibodies in CSF.

Fever in the returned traveller: the utility of the Platelia Dengue NS1 antigen enzyme immunoassay for the diagnosis of dengue in a non-endemic setting

Investigating fever in the returned traveller can be difficult and costly. Dengue is one of the most frequently reported aetiologies. NS1 is a non-structural dengue virus protein detectable during acute infection. The aim of this report is to describe the utility of the Platelia Dengue NS1 antigen enzyme immunoassay (EIA) for detection of dengue in a non-endemic region compared to a composite gold standard of contemporaneous molecular testing and seroconversion. We performed a retrospective analysis of all dengue serology tests from 6 February 2012 to 5 December 2018. Dengue serology and in-house flavivirus molecular results were identified using the laboratory information management system. Dengue serology was performed using the Bio-Rad Platelia Dengue NS1 antigen EIA, and Abbott Panbio Dengue IgG and IgM EIA. True positive NS1 result was defined as positive molecular test within one week of the positive NS1 result or seroconversion within 120 days. NS1 negative samples that remained negative to all dengue markers on repeat more than 10 and up to 120 days after were labelled as true negatives. More than 75% of cases had a serology pattern consistent with primary dengue. Sensitivity and specificity of NS1 Ag EIA was 96.4% (95% CI 92.3-98.7%) and 98.4% (95% CI 94.5-99.8%), respectively. Performance was poorer in serotype 4 infections (sensitivity 50%). Platelia Dengue NS1 antigen EIA test performance in the returned traveller cohort fulfils the remit as a single diagnostic test for acute dengue infection.