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In response to the emergence of the monkeypox virus (MPXV) in Australia in May 2022, we developed and evaluated indirect immunofluorescence assays (IFA) for MPXV and Vaccinia virus (VACV) IgG and IgM antibodies using serum samples from patients with nucleic acid amplification test (NAAT)‐confirmed mpox and uninfected unvaccinated controls. Additionally, 47 healthcare workers receiving two doses of the third‐generation smallpox vaccine Modified Vaccinia Ankara‐Bavarian Nordic (MVA‐BN) undertook serial serum collection to describe the serological response to vaccination. MPXV antibodies were detected in 16/18 individuals with NAAT‐confirmed mpox (sensitivity 0.89, specificity 1.00), and VACV antibodies were detected in 28/29 individuals who received two doses of MVA‐BN vaccine (sensitivity 0.97, specificity 1.00). Detectable antibody in subjects historically vaccinated with early‐generation vaccines against smallpox was found in 7/7 subjects, at a median of 48 years following vaccination. MPXV NAAT‐positive patients with serum samples collected within the first 14 days after rash onset had detectable IgG and IgM in 9/12 and 5/12 of patients, respectively, with maintenance of IgG and disappearance of IgM titers after 60 days. While specificity was high when testing unvaccinated and uninfected subjects, significant cross‐reactivity between MPXV and VACV antibodies was observed. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (COVID‐19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, was first reported in Wuhan, China, in December 2019. Diagnostic methods for the detection of the virus and seroconversion of neutralizing antibodies (NAbs) in plasma have been developed specifically, but some of them require a BSL3 facility. In this study, we used the SARS‐CoV‐2 Surrogate Virus Neutralization Test Kit to determine the presence or absence of NAbs anti‐receptor binding domain of the viral spike (S) glycoprotein in a BSL2 facility. The sample population was chosen in Quito, Ecuador, with a total of 88 COVID‐19 positive convalescent patients. We determined that 97.7% of the analyzed convalescent sera maintained the presence of NAbs with neutralizing activity, and this activity remained until 10 months after the infection in some cases. In addition, the relationship between the presence of NAbs and immunoglobulin G was significant compared to immunoglobulin M, which tended to be absent over time. [ABSTRACT FROM AUTHOR]

Fully automated immunoassays for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies that are strongly correlated with neutralization antibodies (nAbs) are clinically important because they enable the assessment of humoral immunity after infection and vaccination. Access SARS-CoV-2 immunoglobulin M (IgM) and immunoglobulin G (IgG) II antibody tests are semiquantitative, fully automated immunoassays that detect anti-receptor-binding domain (RBD) antibodies and might reflect nAb levels in coronavirus disease 2019 (COVID-19). However, no studies have investigated the clinical utility of these tests in association with nAbs to date. To evaluate the clinical utility of Access SARS-CoV-2 IgM and IgG II antibody tests and their correlation with the SARS-CoV-2 surrogate virus neutralization test (sVNT) that measures nAbs in patients with COVID-19, we analyzed 54 convalescent serum samples from COVID-19 patients and 89 serum samples from non-COVID-19 patients. The presence of anti-RBD antibodies was detected using Access SARS-CoV-2 IgM and IgG II antibody tests, while nAbs were measured by sVNT. The sensitivity and specificity of sVNT were 94.4% and 98.9%, respectively. There were strong positive correlations between the inhibition values of sVNT and the results of the Access SARS-CoV-2 IgM (R = 0.95, R² = 0.90, p < 0.001) and IgG II antibody tests (R = 0.96, R² = 0.92, p < 0.001). In terms of the presence of nAbs, the sensitivity and specificity were 98.1% and 98.9% in the IgM assay and 100.0% and 100.0% in the IgG II assay, respectively. The Access SARS-CoV-2 IgM and IgG II antibody tests showed high sensitivity and specificity for the detection of nAbs in COVID-19 patients and might be alternatives for measuring nAbs. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is sweeping the world since the end of 2019. The titer change of antibodies against SARS‐CoV‐2 needs to be further clarified, the clinical and preventive value of antibodies still needs to be further investigated. An enzyme‐linked immunosorbent assay (ELISA) was established by coating with SARS‐CoV‐2 recombinant spike protein and used to detect serum immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies against SARS‐CoV‐2 in coronavirus disease 2019 patients to evaluate the pattern of changes of antibodies. The specificity of the ELISA for detection SARS‐CoV‐2 IgM and IgG were 96% (144/150) and 100% (150/150), respectively. The sensitivity of ELISA was 100% (150/150) for IgM, and 99.3% (149/150) for IgG. SARS‐CoV‐2‐SP‐IgM and SP‐IgG antibodies could be detected on Day 1 of hospitalization in 12.5% patients, and SP‐IgM began to decrease after reaching its peak at around 22–28 days, and become negative at Month 3 in 30% patients and negative at Month 7 in 79% of these patients after onset; IgG reached its peak around Day 22–28 and kept at a high level within the longest observation period for 4 months, it dropped very sharply at 7 months. The positive rates of SP‐IgM and SP‐IgG were higher than those of reverse transcription‐polymerase chain reaction on Day 7 and 4. The established indirect ELISA has good specificity and sensitivity. IgM and IgG against SARS‐CoV‐2 appeared almost simultaneously in the early stage, and the level of IgG antibodies could not maintain a high plateau in the observation period of 7 months. Our data will help develop the diagnosis and vaccine of SARS‐CoV‐2. [ABSTRACT FROM AUTHOR]

We aimed to evaluate the rates of false‐positive test results of three rapid diagnostic tests (RDTs) for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2)‐specific immunoglobulin G (IgG) and IgM detection. Two serum panels from patients hospitalized in Paris, France, and from patients living in Bangui, Central African Republic, acquired before the 2019 COVID‐19 outbreak, were tested by 3 CE IVD‐labeled RDTs for SARS‐CoV‐2 serology (BIOSYNEX® COVID‐19 BSS [IgG/IgM]; SIENNA™ COVID‐19 IgG/IgM Rapid Test Cassette; NG‐Test® IgG–IgM COVID‐19). Detectable IgG or IgM reactivities could be observed in 31 (3.43%) of the 902 IgG and IgM bands of the 3 RDTs used with all pre‐epidemic sera. The frequencies of IgG/IgM reactivities were similar for European (3.20%) and African (3.55%) sera. IgM reactivities were observed in 9 European and 14 African sera, while IgG reactivity was observed in only 1 African serum (15.1% vs. 0.66%). The test NG‐Test® IgG–IgM COVID‐19 showed the highest rates of IgG or IgM reactivities (6.12% [18/294]), while the test BIOSYNEX® COVID‐19 BSS (IgG/IgM) showed the lowest rate (1.36% [4/294]). Some combinations of 2 RDTs in series allowed decreasing significantly the risk of false‐positive test results. Our observations point to the risk of false‐positive reactivities when using currently available RDT for SARS‐CoV‐2 serological screening, especially for the IgM band, even if the test is CE IVD‐labeled and approved by national health authorities, and provide the rational basis for confirmatory testing by another RDT in case of positive initial screening. [ABSTRACT FROM AUTHOR]

To verify reliability of antibody detection and investigate population immunity to severe acute respiratory syndrome‐related coronavirus 2 (SARS‐CoV‐2) in the local Chinese population. A cross‐sectional study was conducted in Shenzhen to detect anti‐coronavirus antibodies including, immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A (IgA). In the COVID‐19 group, nine patients were enrolled after diagnosis. In the control group, 1589 individuals without clinical symptoms (cough, fever, and fatigue) and returning from outside Shenzhen were enrolled. The first study enrollment occurred at the end of February 2020; the final study visit was 18 March 2020. In the COVID‐19 group, the seven of nine patients were positive for IgM, IgG, and IgA. Meanwhile, six of the 1589 healthy individuals were found to be weakly positive for IgG. According to SARS‐CoV‐2 nucleic acid tests, the six individuals were all negative. Strong supplemental support for clinical information can be provided by antibody detection, especially for IgA. According to comparison with overseas reports, the infection rate of the Chinese population outside Shenzhen, China, is significantly low, so most of the population in China is still susceptible. Hence, social distancing measures are still inevitable until a vaccine is developed successfully. Highlights: As seven patients were found to be positive for IgA antibodies, we speculated that the detection of serum IgA antibody could help with the diagnosis of COVID‐19.IgM, IgG and IgA performed well in serodiagnosis for COVID‐19 with great specificity as detected by ELISA kits.Combined with our findings of 0.38% positivity for anti‐SARS‐CoV‐2 IgG antibody, the infection rate of these individuals from local areas is significantly low than that of overseas reports. [ABSTRACT FROM AUTHOR]

The development of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) serological tests is massive. The external validation of their performance is needed before use in clinical routine practice. Our study aims at assessing the analytical and clinical performance of two enzyme‐linked immunosorbent assay tests detecting antibodies directed against the virus nucleocapsid protein: The NovaLisa SARS‐CoV‐2 immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) test (NovaTec) allowing a separate detection of each antibody and the Platelia SARS‐CoV‐2 Total Ab test (Bio‐Rad) detecting total antibodies (IgM, IgA, and IgG). Two‐hundred and eight coronavirus disease 2019 samples from 48 quantitative reverse transcription‐polymerase chain reaction (RT‐qPCR) confirmed patients were used to perform the sensitivity analysis. Non‐SARS‐CoV‐2 sera (n = 79) with a potential cross‐reaction to SARS‐CoV‐2 immunoassays were included in the specificity analysis. In addition, using receiver operator characteristic curves, adapted cut‐off for improvement of the performances were proposed. The kinetics of these antibodies was also assessed over 8 weeks. Two weeks after the RT‐qPCR positive detection, the NovaLisa test shows a sensitivity and specificity of 94.9% (95% confidence interval [CI]: 83.1%‐98.6%) and 96.2% (95% CI: 89.4%‐98.7%) for IgG, of 89.7% (95% CI: 76.4%‐95.9%) and 98.7% (95% CI: 93.2%‐98.8%) for IgA, and of 48.7% (95% CI: 33.9%‐63.8%) and 98.7% (95% CI: 93.2%‐99.8%) for IgM. With the Platelia system, the specificity and sensitivity were 97.4% (95% CI: 92.1%‐99.7%) and 94.9% (95% CI: 87.7%‐98.0%) for total antibodies using the adapted cut‐offs. The NovaLisa and the Platelia tests have satisfactory analytical performances. The clinical performances are excellent for IgG, IgA, and total antibodies especially if the cut‐off is optimized. Highlights: The sensitivity and the specificity of the NovaLisa (for immunoglobulin G [IgG] and immunoglobulin A [IgA]) and the Platelia were excellent.Cut‐off optimizations improve the clinical performances of both assays.Over a period of 8 weeks, IgM and IgA gradually disappeared while IgG remain persistent. [ABSTRACT FROM AUTHOR]

The coronavirus disease 2019 (COVID‐19) pandemic has spread to various regions worldwide. As of 27 April 2020, according to real‐time statistics released by the World Health Organization, there have been 84 341 confirmed cases and 4643 deaths in China, with more than 2 979 484 confirmed cases and 206 450 deaths outside China. The detection of antibodies produced during the immune response to severe acute respiratory syndrome coronavirus 2 infections has become an important laboratory method for the diagnosis of COVID‐19. However, at present, a little research on these specific antibodies has been conducted. In this study, a retrospective analysis was used to explore the dynamic changes of serum immunoglobulin M (IgM) and IgG antibody and factors affecting diagnostic efficacy, so as to provide a theoretical basis for clinical diagnosis and treatment. Highlights: This is a retrospective analysis describing the dynamic changes of serum IgM and IgG antibody levels in patients with COVID‐19.And the innovation point is analysis of factors (the severity of illness, whether the patient had symptomatic infection, albumin levels)influencing antibody levels on admission. [ABSTRACT FROM AUTHOR]

Coronavirus disease (COVID‐19), caused by a novel betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has rapidly developed into a pandemic since it was first reported in December 2019. Nucleic acid testing is the standard method for the diagnosis of viral infections. However, this method reportedly has a low positivity rate. To increase the sensitivity of COVID‐19 diagnoses, we developed an IgM‐IgG combined assay and tested it in patients with suspected SARS‐CoV‐2 infection. In total, 56 patients were enrolled in this study and SARS‐CoV‐2 was detected by using both IgM‐IgG antibody and nucleic acid tests. Clinical and laboratory data were collected and analyzed. Our findings suggest that patients who develop severe illness might experience longer virus exposure times and develop a more severe inflammatory response. The IgM‐IgG test is an accurate and sensitive diagnostic method. A combination of nucleic acid and IgM‐IgG testing is a more sensitive and accurate approach for diagnosis and early treatment of COVID‐19. Highlights: Combined detection of IgM and IgG is of great value to improve the clinical sensitivity of early diagnosis of COVID‐19.Numerous differences were found between patients in severe group and those who were not.IgM may be an indicator of inflammation severity in acute infection in COVID‐19 patients. [ABSTRACT FROM AUTHOR]

Enterovirus A71 (EV‐A71) is one of the main pathogens causing hand, foot, and mouth disease, and often causes diseases of the central nervous system. Early diagnosis is important to prevent EV‐A71 outbreaks. The detection of serum immunoglobulin M (IgM) is widely used for the early diagnosis of EV‐A71 in clinics, especially in rural areas. However, this technique requires the extraction of blood from children who have thin blood vessels and who might fear the use of needles. Therefore, difficulties in the detection process are often encountered. This study developed a noninvasive method to detect EV‐A71‐specific immunoglobulin A (IgA) in saliva for the diagnosis of EV‐A71 infection. The sensitivity and specificity of IgA detection did not differ significantly compared with IgM detection. IgA antibodies were present in saliva for a relatively shorter period than IgM antibodies were present in serum. The sensitivity of IgA detection was higher than that of IgM detection for secondary EV‐A71 infections. These results suggest that the detection of EV‐A71‐specific IgA in the saliva allows the effective early diagnosis of EV‐A71 and may be suitable for detecting EV‐A71 infections in children. Highlights: Anti‐EV‐A71 IgA antibodies are present in saliva for 3 weeks, less than IgM antibodies are present in serum.Saliva IgA is more sensitive than serum IgM in detecting secondary EV‐A71 infections.Detection of EV‐A71‐specific IgA in saliva is noninvasive.Saliva EV‐A71‐specific IgA is a suitable diagnostic method for EV‐A71 infection in children. [ABSTRACT FROM AUTHOR]

Background: West Nile virus (WNV) is a neurotropic arbovirus that can also be transmitted through blood transfusion. Even though its geographic distribution has been expanding, there has not yet been any epidemiological data on WNV in northern Cyprus. The aim of our study is to fill this gap by using donated blood samples. Methods: Samples collected from the main government hospital blood bank in Nicosia were analyzed by anti‐WNV enzyme‐linked immunosorbent assay (ELISA) (immunoglobulin M [IgM] and immunoglobulin G [IgG]). Seropositive samples were subjected to plaque reduction neutralization test (PRNT) for confirmation and analyzed by ELISA IgG avidity test and reverse transcription real‐time polymerase chain reaction (rRT‐PCR). Results: Of the 760 sera samples, 2 (0.3%) were IgM+ and 31 (4.1%) were IgG+. Neutralization activity was detected in none (0.0%) of the IgM+ and 26 (83.9%) of IgG+ donor specimens. ELISA IgG avidity test reported high avidity in 21 (67.7%) and low avidity in one (3.2%) IgG+ sample. PRNT‐confirmed anti‐WNV IgG+ samples exhibited only borderline (19.2%) or high avidity (80.8%) values. rRT‐PCR results were negative for both IgM+ and IgG+ samples. Conclusion: Anti‐WNV antibodies were detected in northern Cyprus among blood donors. The establishment of preventive measures and evaluation of the geographic extent of the WNV in northern Cyprus are highly recommended. Highlights: This is the first study in literature documenting the presence of WNV infections in Northern Cyprus.Anti‐WNV antibodies were detected in Northern Cyprus among blood donors, while rRT‐PCR results were negative for seropositive samples. [ABSTRACT FROM AUTHOR]

Understanding of kinetics of antibody responses is crucial for developing rapid serological tests and studying the mechanisms of Zika virus (ZIKV) infection. Most of the serological diagnostic assays previously published are based on either IgM or IgG titer, little is known on the level of IgA antibody in saliva and urine. In this study, we investigated the kinetics of IgM/IgG/IgA antibody responses in serum, saliva, and urine obtained from two ZIKV infected individuals from as early as the second day of onset of symptoms to as long as 2 years postinfection. Other than detecting robust early IgM response, long lasting IgG response, we discovered strong early IgA response specific for ZIKV in saliva in both patients. This unique observation provides a novel strategy and scientific basis for the development of noninvasive rapid tests for ZIKV infection. Highlights: Longitudinal ZIKV antigen specific antibody responses were assessed in two patients. NS1 specific IgA antibodies were found in saliva and blood early in infection. IgA detection could form the basis of a non‐invasive diagnostic assay. [ABSTRACT FROM AUTHOR]

Existing literatures from developing countries show an increased mortality and morbidity related to hepatitis E virus during pregnancy as compared to the general population. Studies focusing on pregnant women are required for policy makers to improve maternal and child health. Therefore this study is aimed at determining the prevalence and associated risk factors of hepatitis E virus infection among pregnant women attending the health facilities of Tigray region, Northern Ethiopia. In this cross sectional study 846 pregnant women were included consecutively from April 2014 to February 2016. Clinical and sociodemographic were collected using structured questionnaire and blood was collected for laboratory analysis of Hepatitis E virus using IgG and IgM HEV ELISA. The data were analyzed using SPSS software version 21.0. Association with variables with the risk factors was determined using bivariate and multivariate analysis. The overall sero‐prevalence of hepatitis E virus using anti‐HEV IgG and anti‐HEV IgM antibody among pregnant women were 367 (43.4%). From this 359 (42.4%) and 8 (0.9%) were tested positive for anti‐HEV IgG and anti‐HEV IgM antibody, respectively. Then finally age, rural residence, not washing after toilet use and lack of prevention aspects to minimize contamination were associated with HEV infection. This study shows the significant public health impact of HEV during pregnancy in low income countries. [ABSTRACT FROM AUTHOR]

This study reports the seroprevalence of antibodies against GII.4 norovirus among children (≤5 years) in Pune, India. Of 191 serum specimens, 98 (51.3%) tested positive with 61, 34 and 3 having IgG, IgG-IgA and IgG-IgA-IgM, respectively. Histoblood group antigen (HBGA)-blocking antibodies were detected in 33 of the 54 tested positive specimens. IgG and blocking antibody prevalence and titer varied with age and was lowest among children aged 6-23 months. Antibody-positive children, suggesting past norovirus exposure, showed significantly lower faecal norovirus RNA detection rate than antibody-negative children. Further investigation of the seroepidemiology of norovirus infections in India is warranted. J. Med. Virol. 88:1636-1640, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

In 2014, a large outbreak of dengue occurred in Guangzhou, China. This outbreak prompted us to evaluate NS1 and RNA for the early diagnosis of acute dengue infection, in addition to the combination with IgM antibody. We aimed to find the differences of three assays about dengue diagnosis. This study was an evaluation of diagnosis test. Based on WHO criteria 2009, dengue RNA, NS1, and IgM/IgG were detected from 294 patients (180 dengue patients, 114 non-dengue patients) by three diagnostic kits made in China. The χ2 test, sensitivity, and specificity were used in statistical analysis. The ratios of dengue patients with low platelet counts (<100 × 109/L 32.2%) or white blood cell counts (<4.0 × 109/L 58.9%) were significantly higher compared to non-dengue patients ( P < 0.05). Dengue NS1 was shown sensitive (93.9%) for diagnostic use. RNA had a better performance with 98.1% of sensitivity from day 1 to day 4 after illness onset. IgM performed better at day 5 or more with 74.0% of sensitivity. The diagnostic rate using a combination of RNA and IgM was 97.8% and 96.7% using NS1 and IgM. A patient with low platelet and white blood cell counts needs additional tests for dengue during an epidemic. RNA and NS1 were most valuable for early diagnosis of dengue, whereas IgM was best suited as a supplementary method for patients at day 5 or more after illness onset. J. Med. Virol. 88:28-34, 2016. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Hepatitis E virus (HEV) acute infection is often diagnosed only by anti-HEV IgM ELISA methods, whose sensitivity varies, according to different reports. Reports assessing the specificity of commercial assays for anti-HEV IgG testing are scarce, and estimates of sensitivity and specificity are both controversial. The aim of this work is to assess the sensitivity of different commercial techniques for HEV genotype 3 antibody (anti-HEV) IgM and IgG detection in entirely specific sample panels including both high and low antibody concentrations. The anti-HEV IgM and IgG ELISA methods compared were: DSI, Mikrogen, Wantai, Euroimmun, MP, and Dia.pro. The rapid test All Diag was also included in the anti-HEV IgM comparison. Our results show that low anti-HEV IgM concentrations were better detected by DSI, Mikrogen, and All Diag, these tests being the most sensitive in our study. Euroimmun, MP and Dia.pro gave concordant results, showing lower sensitivity than the others. Regarding anti-HEV IgG our results revealed similar anti-HEV IgG sensitivity. Furthermore, there was a striking overall lack of concordance among the results. We present a thorough review of previous comparative reports, with particular reference to the anti-HEV IgG comparison, since published results differ from ours. This discrepancy may be related to the improved versions of the tests for MP and Dia.pro that we employed. J. Med. Virol. 87:1934-1939, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

El Salvador is a Central American country that has been affected by several dengue outbreaks. This study investigated the levels of IgM, IgA, and IgE anti-dengue antibodies in serum samples from children in El Salvador, with a clinical and serological diagnosis of dengue infection during the dengue 4 outbreak in 2002-2003. Seventy one serum samples were tested by ELISA and cases were classified in three groups: 13 primary dengue fever (PDF), 21 secondary dengue fever (SDF), and 37 secondary dengue hemorrhagic fever (SDHF). Also, the specificity of anti-dengue IgM for the different serotypes was tested. No significant differences in the IgM response were found between PDF and SDF, but these were detected between PDF and SDHF (P=0.0053) and between SDF and SDHF (P=0.0003). The IgA and IgE values showed a statistically significant difference between primary and secondary groups. The highest positivity percentage of IgA was between 95% (SDF) and 100% (SDHF) towards day 7 of onset of fever. All secondary cases were positive for IgE antibodies. The specificity of IgM was determined for DENV-4 virus in primary and secondary DF groups. This is the first study on dengue cases in Salvadorian children related to the immune response of different immunoglobulins to the type of infection and the clinical picture. Further prospective studies are needed to define if the pattern of immunoglobulins can determine early dengue infection and/or severity. [ABSTRACT FROM AUTHOR]

Variant performance of immunoglobulin M (IgM) and immunoglobulin G (IgG) hepatitis E virus (HEV) assays may impact the diagnosis. The present study aimed to evaluate four different IgM/IgG assays for HEV infection for application in national surveillance in nonendemic areas. Sera from 300 patients that were stored in the Centers for Disease Control (CDC) of Taiwan for suspected acute HEV infection from 2004 to 2008, and 18 serum samples from acute cases of HEV infection in Taipei Veteran General Hospital were evaluated. Performances of EIAgen HEV IgG/M (Adaltis, Bologna, Italy), recomWell HEV IgG/M (Mikrogen, Neuried, Germany), MP HEV IgG/M (MP Biomedicals, Singapore), and in-house kits, HEVLPs (HEV virus-like particles) IgG/M were compared. Positive results of serum RNA detected by reverse transcription-polymerase chain reaction were defined as the definite diagnosis. There were five genotype 1, one genotype 3, and nine genotype 4 HEV samples. The four different IgM/IgG assays had excellent performance in terms of negative predictive value (98.4-100%) and varying performance in relation to sensitivity (66.7-93.3%) and specificity (62.9-95.6%). RecomWell IgM had the best overall performance. In addition, the combination of anti-HEV IgM ELISA with anti-HEV IgG or another anti-HEV IgM ELISA provided better screening performance, especially the recomWell IgM and HEVLPs IgM combination (area under the receiver operating curve: 0.94; sensitivity: 100%, specificity 88.1%). In conclusion, anti-HEV IgM ELISA is a good screening test for the national surveillance of acute HEV infection in nonendemic areas and not limited by inconsistent performances of sensitivity and specificity among different assays. J. Med. Virol. 86:720-728, 2014. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

IgM antibodies bound to different cancer antigens have shown recently a higher diagnostic value, compared with the corresponding free molecule, giving rise to a new family of biomarkers. High or increasing levels of Squamous Cell Carcinoma Antigen (SCCA)-IgM immune complexes were associated with more advanced liver disease and increased risk of development of HCC. Rheumatoid factor (RF) represents a long-standing problem of interference for immunometric assays. The aim of the present study was to examine the specificity of SCCA-IgM in relation to the presence of RF reactivity in patients infected with hepatitis C virus (HCV). Sera of 73 patients with cirrhosis, infected with HCV, (mean age ± SD: 66 ± 13 years; M/F: 45/28), including 21 patients with HCC, were studied. SCCA-IgM immune complexes levels were measured by a commercial ELISA. To evaluate the possible interfering effect of RF, the standard calibrator, positive for SCCA-IgM, was spiked with serial dilutions of a RF positive or negative serum. SCCA-IgM immune complexes were positive in 35 out of 73 (48%) patients, while RF activity was found in 10 out of 73 (14%) patients. Patients with cirrhosis with RF activity had significantly higher levels of SCCA-IgM, compared to RF negative cases; however, no significant correlation between SCCA-IgM and RF values was observed. In samples created artificially the same results in terms of reactivity for SCCA-IgM were obtained, regardless of the presence of RF activity. These findings support the lack of correlation between the two parameters found in sera of patients infected with HCV. J. Med. Virol. 85: 1005-1008, 2013. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

To investigate the specific immunoglobulin (Ig) G subclass responses in patients with hepatitis E virus (HEV) infection, an open reading frame 2 (ORF2) protein based enzyme-linked immunosorbant assay was used to measure antibody levels in sera obtained at different phases of infection. Sera were collected at 2-31 days and at 6 months after the onset of symptoms corresponding to the acute (n = 48, 100% IgM-positive) and convalescent (n = 17/48, 53% IgM-positive) phases of infection, respectively. IgM-negative sera from 61 individuals infected at least ≥6 months ago (prior exposure) were also tested. IgG1, IgG2, IgG3, and IgG4 antibodies were detected in 100%, 6%, 56%, and 4% of acute phase sera, respectively, and in 100%, 0%, 0%, and 65% of convalescent phase sera, respectively. IgG1 antibody levels were significantly higher than those of the other detectable subclasses of IgG in the acute and convalescent sera ( P < 0.05). The IgG3 antibodies in six acute phase patients were replaced by IgG4 antibodies in the convalescent phase of infection. Patients with prior exposure to HEV had low total IgG antibody titers and decreased IgG1 seropositivity compared with those in the acute and convalescent phases. IgG1 was the only major subclass of antibody to be detected in all the three phases of infection. Other than IgG1 antibodies, the subclass antibody response was restricted to IgG3 and IgG4 antibodies in the acute and convalescent phases of infection, respectively. J. Med. Virol. 85:828-832, 2013. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Cytomegalovirus (CMV) causes congenital infection with high mortality and morbidity rates in affected neonates. The aim of this study was to assess whether prenatal clinical or laboratory findings in pregnant women who had high risks for primary CMV infection predicted the presence of congenital infection. Fifty pregnant women who had serum CMV IgG and positive or borderline tests for serum CMV IgM were included in this prospective study. Serum IgG avidity was measured, and PCR was conducted for CMV DNA in maternal serum, urine, and uterine cervical secretion. All neonates underwent PCR testing for CMV DNA in the urine for the presence of congenital infection. Risk factors were compared between congenital infection group and group without congenital infection. As a result, nine neonates (18%) were diagnosed as having congenital infection. The frequencies of ultrasound fetal abnormality and positive test for CMV DNA in cervical secretion, CMV IgM titer and IgM/IgG ratio in the congenital infection group were significantly higher than those in the group without congenital infection. Conversely, IgG avidity index in the congenital infection group was significantly lower than that in the group without congenital infection. By multivariate logistic regression analyses, IgG avidity index (Odds ratio 0.91, 95% CI: 0.83-0.99) and ultrasound fetal abnormality (291.22, 2.72-31125.05), were selected independently as significant signs predictive of congenital CMV infection. Among pregnant women with positive or borderline tests for CMV IgM, when they have findings of low serum CMV IgG avidity or ultrasound fetal abnormality, the probability of congenital CMV infection may increase. J. Med. Virol. 84:1928-1933, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Fully automated immunoassays for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies that are strongly correlated with neutralization antibodies (nAbs) are clinically important because they enable the assessment of humoral immunity after infection and vaccination. Access SARS-CoV-2 immunoglobulin M (IgM) and immunoglobulin G (IgG) II antibody tests are semi-quantitative, fully automated immunoassays that detect anti-receptor-binding domain (RBD) antibodies and might reflect nAb levels in coronavirus disease 2019 (COVID-19). However, no studies have investigated the clinical utility of these tests in association with nAbs to date. To evaluate the clinical utility of Access SARS-CoV-2 IgM and IgG II antibody tests and their correlation with the SARS-CoV-2 surrogate virus neutralization test (sVNT) that measures nAbs in patients with COVID-19, we analyzed 54 convalescent serum samples from COVID-19 patients and 89 serum samples from non-COVID-19 patients. The presence of anti-RBD antibodies was detected using Access SARS-CoV-2 IgM and IgG II antibody tests, while nAbs were measured by sVNT. The sensitivity and specificity of sVNT were 94.4% and 98.9%, respectively. There were strong positive correlations between the inhibition values of sVNT and the results of the Access SARS-CoV-2 IgM (R = 0.95, R 2  = 0.90, p < 0.001) and IgG II antibody tests (R = 0.96, R 2  = 0.92, p < 0.001). In terms of the presence of nAbs, the sensitivity and specificity were 98.1% and 98.9% in the IgM assay and 100.0% and 100.0% in the IgG II assay, respectively. The Access SARS-CoV-2 IgM and IgG II antibody tests showed high sensitivity and specificity for the detection of nAbs in COVID-19 patients and might be alternatives for measuring nAbs., (© 2021 Wiley Periodicals LLC.)