IgM Assays Research Articles

A-138 Implications of native protein conformation in the IgM quantification: total Ig vs HLC methods comparison

Abstract Background For IgM monoclonal gammopathies such as Waldenström Macroglobulinemia, the diagnosis, risk stratification and monitoring response to therapy is based on the detection and quantification of the secreted IgM monoclonal protein. Accurate IgM measurement is challenging due to its complex nature and the occurrence in higher polymeric structures (i.e., pentamers or hexamers), as well as heterogeneity and inherent subjectivity of the selected common methodologies. The recently developed Heavy/Light chain assay (Binding Site, part of Thermofisher Scientific) allows the separate determination of the IgM-Kappa and IgM-Lambda molecules, offering an alternative method to the serum electrophoresis (SPE) with reported higher sensitivity (Ref. Boyle E. et al, Clin Cancer Research 2016). In this study we explore the effect of the molecular structure on 3 different analytical techniques for accurate IgM measurements Methods 214 serum samples from patients (age median 63yo) under follow-up at our hospital were tested for: IgG, IgA, and IgM levels (immunoturbidimetry, either on a Beckman Coulter AU5800 analyser; Nyon, Switzerland; or a Cobas c 702 system, Roche Diagnostics); Hevylite assay (on an Optilite, Binding Site); and SPE and Immunofixation (Capillarys 3 Octa and Hydrasys 2, Sebia Inc.). The effect of the molecular conformation was evaluated through sample depolymerization with N-Acetylcysteine (NAC) according to the manufacturer’s instruction (Sebia Inc.) and IgM quantification by: tIgM (immunoturbidimetric total Ig); red-Ig (idem after NAC reduction); and, HLC-Ig (i. e. sum of the IgM-K+IgM-L heavy/light chain pair measured by Hevylite (Binding Site)). Results Total-Ig, red-Ig, and HLC-Ig returned similar results for IgG and IgA immunoglobulins (Kruskal-Wallis test, p-value > 0.05), and Passing Bablok regression analysis showed good agreement between the three methods, except for higher IgA levels. In the later, both HLC-IgA levels red-IgA values were higher than total-IgA. Regarding the IgM, PB regression revealed a significant proportional bias, with obtained values approx. 2,5x higher by red-IgM and approx. 1,4x by HLC-IgM methods than tIgM (red-IgM=-5.5+2.42*tIgM, Spearman’s r=0.995; HLC-IgM=-0,77+1.34*tIgM, Spearman’s r=0.978; red-IgM=-6.29+1.82*HLC-IgM, Spearman’s r=0.98). So, both red-IgM and HLC-IgM results are higher than total IgM. Of note, 1 sample presented antigen excess, resulting in unusually low IgM levels by tIgM but high red-IgM and high HLC-IgM levels coherent with the patient’s clinical condition. 75 samples had monoclonal protein measurable by SPE, showing good correlation with the three methods, however with greater proportional errors between measurements with other techniques Conclusions IgM molecular conformational status may affect the epitopes exposed and, therefore, available for the different assays’ recognition. Higher IgM complexes depolymerization into monomeric conformation results in higher IgM levels, which agree better with the Hevylite than with the total IgM measured previous NAC reduction, reflecting the impact of the native protein conformation in the IgM precise detection. Although also affected by the conformational status, Hevylite IgM results were closer to the reduced IgM levels than the obtained by the total IgM assay, therefore offering a sensitive assay that does not need a reduction treatment for a more accurate IgM quantification, optimizing the laboratory workflow

Clinical Evaluation of the VirClia IgM/IgG Chemiluminescence Tests for the Diagnosis of Tick-Borne Encephalitis in an Endemic Part of Norway.

The aim of this study was to evaluate the clinical usefulness of VirClia IgM/IgG single-assay chemiluminescence tests for the diagnosis of tick-borne encephalitis (TBE) in an endemic part of Norway. Patients hospitalized at Vestfold or Telemark Hospitals with suspected infection in the central nervous system (CNS) in the period between May 2021 and December 2023 were included, with 85 TBE cases identified. The VirClia IgM assay was positive in the initial serum sample in 75/85 cases, giving a sensitivity of 88.2% (95% CI, 79.4-94.2). The ReaScan TBE IgM rapid test was positive in 80/85 cases, with an estimated sensitivity of 94.1% (95% CI, 86.8-98.1). Vaccine breakthrough infections were the predominant cause of non-reactive IgM cases. The calculated specificity for the VirClia IgM was 95.8% (95% CI, 92.5-98.0). In conclusion, the sensitivity of the VirClia IgM was non-inferior to the ReaScan TBE IgM rapid test. However, isolated IgM reactive results must be interpreted with caution, since false-reactive results occur.

Performance Comparison of Four Hepatitis E Antibodies Detection Methods.

HEV antibody detection constitutes the main screening test for HEV infection. The aim of this study is to compare the sensitivity and specificity of four techniques: LIAISON® MUREX DiaSorin anti-HEV IgG and anti-HEV IgM assays, Hepatitis E VIRCLIA® IgM and IgG monotests, WANTAI HEV-IgM and IgG ELISA and VIDAS® anti-HEV IgM and IgG tests in five panels of samples configurated according to the immunoblot (RecomLine, Mikrogen, Neuss, Germany). Anti-HEV IgM sensitivity in the acute phase was 100% in all techniques, while sensitivity, including the immediate convalescence phase, was 96.74% for LIAISON®, 83.14% for VIRCLIA®, 84.78% for WANTAI and 88.04% for VIDAS®. Anti-HEV IgM specificity was 100% for both LIAISON® and VIRCLIA®. Anti-HEV IgM WANTAI agreed with VIRCLIA® with a good Kappa coefficient (κ = 0.71). Anti-HEV IgG post-infection sensitivity was 100% for LIAISON®, VIDAS® and VIRCLIA® and 99% for WANTAI. Anti-HEV IgG specificity reached 97.17% for LIAISON and 88.68% for VIRCLIA®. Our results demonstrated a better capacity of LIAISON® MUREX anti-HEV IgM than that of competitors for detecting acute infections as well as accurate anti-HEV IgG results and in how to resolve them.

Human Orthohantavirus disease prevalence and genotype distribution in the U.S., 2008–2020: a retrospective observational study

In the United States (U.S.), hantavirus pulmonary syndrome (HPS) and non-HPS hantavirus infection are nationally notifiable diseases. Criteria for identifying human cases are based on clinical symptoms (HPS or non-HPS) and acute diagnostic results (IgM+, rising IgG+ titers, RT-PCR+, or immunohistochemistry (IHC)+). Here we provide an overview of diagnostic testing and summarize human Hantavirus disease occurrence and genotype distribution in the U.S. from 2008 to2020. Epidemiological data from the national hantavirus registry was merged with laboratory diagnostic testing results performed at the CDC. Residual hantavirus-positive specimens were sequenced, and the available epidemiological and genetic data sets were linked to conduct a genomic epidemiological study of hantavirus disease in the U.S. From 1993 to 2020, 833 human hantavirus cases have been identified, and from 2008 to 2020, 335 human cases have occurred. Among New World (NW) hantavirus cases detected at the CDC diagnostic laboratory (representing 29.2% of total cases), most (85.0%) were detected during acute disease, however, some convalescent cases were detected in states not traditionally associated with hantavirus infections (Connecticut, Missouri, New Jersey, Pennsylvania, Tennessee, and Vermont). From 1993 to 2020, 94.9% (745/785) of U.S. hantaviruses cases were detected west of the Mississippi with 45.7% (359/785) in the Four Corners region of the U.S. From 2008 to 2020, 67.7% of NW hantavirus cases were detected between the months of March and August. Sequencing of RT-PCR-positive cases demonstrates a geographic separation of Orthohantavirus sinnombreense species [Sin Nombre virus (SNV), New York virus, and Monongahela virus]; however, there is a large gap in viral sequence data from the Northwestern and Central U.S. Finally, these data indicate that commercial IgM assays are not concordant with CDC-developed assays, and that "concordant positive" (i.e., commercial IgM+ and CDC IgM+ results) specimens exhibit clinical characteristics of hantavirus disease. Hantaviral disease is broadly distributed in the contiguous U.S, viral variants are localised to specific geographic regions, and hantaviral disease infrequently detected in most Southeastern states. Discordant results between two diagnostic detection methods highlight the need for an improved standardised testing plan in the U.S. Hantavirus surveillance and detection will continue to improve with clearly defined, systematic reporting methods, as well as explicit guidelines for clinical characterization and diagnostic criteria. This work was funded by core funds provided to the Viral Special Pathogens Branch at CDC.

Seroprevalence of Dengue and Hepatitis B infections among young adults attending a secondary health care facility at Olabisi Onabanjo University, Ogun State, Nigeria

Hepatitis B and Dengue virus infections carry significant public health implications due to their potential to cause illness and death. This study focused on examining the prevalence of these infections among young adults seeking care at a secondary health facility at Olabisi Onabanjo University. Ninety samples obtained from study participants underwent screening using Enzyme-linked Immunosorbent Assay (ELISA) for both HBsAg and Dengue IgM. The participants, predominantly female, were aged between 15 and 30 years. The analysis revealed a 13.3% prevalence of Dengue IgM, a 4.5% prevalence of HBsAg, and a 4.4% prevalence for both infections. Regarding age distribution, the highest prevalence occurred among participants aged 15-20 years for both single infections and the co-occurrence of Hepatitis B and Dengue viral infections. Examining gender distribution, female participants exhibited higher seropositivity across all infection categories. Although not statistically significant, these findings lay the groundwork for a comprehensive surveillance study on the Hepatitis B and Dengue viral infections in young adults. This study provides valuable insights into the prevalence patterns of Hepatitis B and Dengue virus, offering a basis for further research and public health interventions in this population.

Different aspects of immunological profile in patients with Non-Alcoholic Fatty liver disease.

NAFLD is thought to affect approximately one-fourth of the world's population. Therefore, we evaluated the role of serum complement and immunoglobulins in the NAFLD pathogenesis. 200 participants were used in this study, divided into two groups; Group I: 100 NAFLD patients and Group II: 100 healthy volunteers. The diagnosis of NAFLD is based on non-invasive methods, following the EASL guideline 2022. IgG, IgM, IgA, C3, and C4 assays were performed on all participants. When the immunological profiles of patients with NAFLD and healthy controls were compared, it was found that the mean IgA in NAFLD patients was (4.20±5.07), whereas the mean IgA in healthy controls was (2.22±1.05) (P=0.000). Additionally, a significant increase in IgG was found in NAFLD patients (17.08±3.87) compared with healthy controls (11.59±3.34), with a P value of (p<0.001). complement C3 and complement C4 levels significantly increased in nonalcoholic fatty liver disease patients (1.28± 0.61 and 0.40 ± 0.19, respectively), compared to healthy controls (0.90 ±0.27 and 0.30 ±0.12, respectively), with a significant P value (p<0.001 for each). Elevated IgA, IgG, C3 and C4 exist in patients with NAFLD and could be associated with fatty liver development and progression of hepatic fibrosis in patients with NAFLD.

#3090 Parvovirus infection in renal transplant recipients: a systematic review of clinical profile and treatment strategies

Abstract Background and Aims Parvovirus B 19 (PVB-19) virus infection can cause severe, persistent and/or refractory anaemia in kidney transplant recipients (KTR). There is paucity of data on the clinical manifestations, diagnosis and management of this infection and limited to case reports and case series. Method We performed a literature search of kidney transplant recipients infected with PVB-19 in MEDLINE, EMBASE and Cochrane databases and 93 articles were identified as suitable for assessment. The review was conducted in accordance with PRISMA statement. Results A total of two hundred and eighty-two patients were included from the studies assessed in the review. The mean age of the cohort was 37.05 years. The infection was more common in males when compared to females. The median onset of PVB-19 infection post transplantation was at 5 weeks (2, 15 weeks). One fourth of the recipients had at least one episode of rejection prior to PVB-19 infection. Majority of the patients were on Tacrolimus, MMF and corticosteroids maintenance. One third of the patients had co-infections with other organisms (EBV, CMV, etc.). Anemia and fever were the most common manifestations among all the kidney transplant patients infected with PVB-19 while CNS manifestations and rash were least reported. Hemoglobin was low (&amp;lt;10 mg/dl) in ninety eight percent of the patients (n=151). The lowest hemoglobin reported in the due course of illness was 6 mg/dl (5, 7.2 mg/dl) and with corrected reticulocyte count being only 0.2% (0.1%, 0.6%). The most consistent finding on peripheral smear was normocytic, normochromic anemia while a few reported helmet cells too. Pure Erythroid hypoplasia alone (45.3%) combined with giant pronormoblasts and inclusion bodies (49%) were the most common findings on bone marrow aspirate. Majority of PVB-19 diagnosis was made with the help of multiple methods of detection like IgM assay, PCR—qualitative and quantitative (42.2%). The average PCR copies detected were 1.3*107 (4.28*105, 2.53*109). IVIG only (47.2%) and combined IVIG + immunosuppression reduction (41.2%) was the mainstay of the treatment in majority. The median time to recover was 8 weeks (3, 16 weeks). One fourth of the patients had recurrence after recovery. A majority of the patients (96.7%) recovered from reactivation of PVB-19. Conclusion Parvovirus infection is not uncommon in the early post-transplant period. Though data is insufficient, immunosuppression reduction with IVIG remains the treatment of choice for affected patients. Prospective studies to assess the hemoglobin cutoffs and dose of IVIG are needed to frame screening and treatment protocols.

Evaluation of the analytical performance of cytomegalovirus IgM, cytomegalovirus IgG, and syphilis assays on the Atellica CI analyzer

Evaluation of the analytical performance of cytomegalovirus IgM, cytomegalovirus IgG, and syphilis assays on the Atellica CI analyzer

Role of Culture Free Rapid ImmunoAssay (ELISA) and Genexpert (MTB/RIF) Technology in the Diagnosis of Tuberculosis

Introduction: Prolonged laboratory processes are major hurdles in the early diagnosis of tuberculosis. Prompt management of this disease is utmost necessary to control its spread. For this purpose, use of rapid and reliable laboratory testing methods for the diagnosis of Mycobacterium tuberculosis are crucial alongwith timely infection management and preventing its transmission to the close contact population. Aims and Objective: The aim of this study was to establish a diagnostic-connection between culture free cost effective rapid immuno-assay (IgG and IgM) and GeneXpert (MTB/RIF) technology for the detection of Mycobacterium tuberculosis within the shortest possible turnaround time. Place and Duration of Study: This cross-sectional study was carried out at Institute of Microbiology and Molecular Genetic, University of the Punjab, Pakistan in collaboration with the Department of Pulmonology and TB Outpatient Department (OPD) at Jinnah Hospital, Lahore over the time of one year (2019-2020). Material and Methods: To achieve the aim, a total of 180 (pulmonary and extra-pulmonary) samples along with blood samples were collected from clinical suspects of Tuberculosis. All collected samples were subjected to AFB microscopy, GeneXpert (MTB/RIF) assay and Enzyme-linked Immunosorbent Assay (ELISA) for IgG and IgM. The diagnostic sensitivity and specificity of both methods were determined by using the solid culture as the gold standard.Study data collected through questionnaire was entered and analyzed using Statistical Package for Social Sciences (SPSS version 20).p value of ? 0.05 was considered significant. Results: The overall sensitivity and specificity of GeneXpert (MTB/RIF) assay were 98.2 % and 82.4% respectively, whereas, for IgG (ELISA) antibodies, it was 50.0% and 76.4% and for IgM (ELISA) antibodies 50.4% and 97.1% respectively. Conclusion: It was concluded that with fully automated GeneXpert (MTB/RIF) technology, maximum sensitivity and specificity can be achieved for diagnosis of tuberculosis within 2 hours.

Scrub typhus in Indonesia: A cross-sectional analysis of archived fever studies samples.

Scrub typhus is an understudied vector-borne bacterial infection. We tested archived fever samples for scrub typhus seropositivity to begin charting its geographic distribution in Indonesia. We analysed 1033 serum samples from three sites. IgM and IgG enzyme-linked immunosorbent assay (ELISA) against Orientia tsutsugamushi was performed using Karp, Kato, Gilliam, TA 716 antigens. To determine the cutoff in the absence of a presumed unexposed population and gold standard tests, we identified the visual inflection point, performed change point analysis, and used finite mixture models. The optical density cutoff values used for IgM and IgG were 0.49 and 0.13, respectively. Across all sites, IgM seropositivity was 4.6% (95% CI: 3.4 to 6.0%) while IgG seropositivity was 4.4% (95% CI: 3.3 to 5.8%). The overall seropositivity across sites was 8.8% (95% CI: 8.1 to 11.7%). The overall seropositivity for Jambi, Denpasar, Tabanan were 9.7% (95% CI: 7.0 to 13.3%), 8.0% (95% CI: 5.7 to 11.0%), 9.0% (95% CI: 6.1 to 13.0%), respectively. We conclude that O. tsutsugamushi exposure in humans occurred at all sites analysed and could be the cause of illness in some cases. Though it was not the main cause of acute fever in these locations, it is still important to consider scrub typhus in cases not responding to beta-lactam antibiotics. Future seroprevalence surveys and testing for scrub typhus in acute febrile illness studies will be essential to understand its distribution and burden in Indonesia.

Evaluation of different cut-off points for IgG avidity and IgM in the diagnosis of acute toxoplasmosis in pregnant women participating in a congenital toxoplasmosis screening program.

The main social impact of toxoplasmosis stems from its ability to be vertically transmitted. Postnatally acquired infection is generally asymptomatic in approximately 70-90% of cases, making diagnosis often dependent on laboratory tests using serological methods to search for anti-T. gondii antibodies. This study aimed to investigate the ability of the VIDAS TOXO IgG avidity and VIDAS TOXO IgM assays to confirm recent toxoplasmosis. In total, 341 pregnant women with suspected acute toxoplasmosis were systematically monitored in the Program for Control of Congenital Toxoplasmosis in Minas Gerais State, Brazil. We conducted an observational analytical-descriptive cross-sectional study and grouped according to clinical and laboratory criteria as having acute or chronic toxoplasmosis. The VIDAS TOXO IgG avidity and VIDAS TOXO IgM assays were evaluated to investigate the capacity to identify acute infection. IgG avidity showed good performance in identifying acute toxoplasmosis when the IgG avidity index was lower than or equal to 0.1. Values greater than or equal to 3.16 according to the TOXO IgM kit were associated with a greater chance of acute infection. These results may contribute to a more adequate diagnosis of acute gestational toxoplasmosis and, consequently, the avoidance of inadequate or unnecessary treatments.

Neurodegenerative diseases associated antibody repertoire signatures in mimotope arrays based on cyclic versus linear peptides

The role of peptide probes’ conformational flexibility in extracting immunosignatures has not been sufficiently studied. Immunosignatures profile the antibody diversity and prove promising for early cancer detection and multi-disease diagnostics. A novel tool for modeling antibody repertoires, the concept of antibody reactivity graphs, proved instrumental in this respect. Serum samples from patients with Alzheimer’s disease (AD), frontotemporal dementia (FTD), dementia of unknown etiology (DUE), and healthy controls were probed using a set of 130 7-mer peptides relevant to neurodegenerative diseases. Results show that linear peptides probed with IgM yielded higher graph density compared to IgG, indicating different levels of polyspecificities. Additionally, the impact of peptide topology and antibody isotype on feature selection was studied using recursive feature elimination. Findings reveal that IgM assays on linear peptides offer superior diagnostic differentiation of neurodegenerative diseases and define the degree of agreement between IgG and IgM immunosignatures with linear or cyclic peptides.

Diagnostic Values of SARS-COV-2 Antibodies using Lifotronic ECL-8000

One of the most definitive diagnostic tests for COVID-19 infection is rRT-PCR. Another modality developed to diagnose COVID-19 infection is the antibody (serological) assay. This essay can be performed quickly and easily but requires high sensitivity and specificity. This study aims to analyze the diagnostic values of anti-SARS-CoV-2 IgM and IgG using Lifotronic ECL-8000 and the development of antibodies based on time after the onset of the symptoms of COVID-19 in patients with confirmed COVID-19 infection. The serum of the patients with confirmed COVID-19 infection by rRT-PCR was collected between day 1 and day 21 after the onset of the symptoms. Anti-SARS-CoV-2 IgM and IgG from each sample were measured using Lifotronic ECL-8000 to determine their sensitivity, specificity, PPV, and NPV. This assay detects IgM against SARS-CoV-2 N and SRBD proteins, as well as IgG against SARS-CoV-2 SRBD proteins. The anti-SARS-CoV-2 IgM serological assays using Lifotronic ECL-8000 indicated that IgM had 91.6% sensitivity, 87.03% specificity, 90.4% PPV, and 88.67% NPV. Meanwhile, the anti-SARS-CoV-2 IgG serological assays using Lifotronic ECL-8000 showed that IgG had 93.05% sensitivity, 88.88% specificity, 91.78% PPV, and 90.56% NPV. The development of antibodies was observed on days 0-7 after the onset of the symptoms, and the positivity rate of anti-SARS-CoV-2 IgM was higher than that of anti-SARS-CoV-2 IgG. Starting from day 8 after the onset of the symptoms, the positivity rate of anti-SARS-CoV-2 IgG increased and remained higher than that of anti-SARS-CoV-2 IgM. It was concluded that anti-SARS-CoV-2 IgM and IgG serological assays using Lifotronic ECL-8000 could be utilized to support the diagnosis of patients with suspected COVID-19 infection with high sensitivity and specificity.

A Four-Year Trend of Acute Hepatitis B Virus Infection at a Tertiary Health Facility in Lagos, Nigeria

Hepatitis B virus (HBV) infection is an important public health challenge. More than 350,000,000 people worldwide have chronic hepatitis B (CHB). Hepatitis B core ImmunoglobinM(HBc IgM) is an important marker used to classify whether an existing HBV is a new infection or an existing one, differentiating acute from chronic HBV infection. When an individual is HBc IgM positive, it shows a new infection, while negative IgM indicates a previous infection. The study aimed to determine the trend of acute HBV infections among hepatitis B-positive patients in a tertiary health facility in Lagos, Nigeria, over a four-year period. Patients accessing HBc IgM tests at a tertiary health facility in Lagos, Nigeria. Five (5) ml of blood samples were collected in K+EDTA vacutainers and centrifuged at 3500 rpm for 5 minutes. Plasma (2 ml) was collected in plain tubes, and HBc IgM assay was performed using DIA-Pro (BIORAD) kits according to the manufacturer’s instructions. The study period was from January 2014 to December 2017. The total number of patients who accessed this assay within the study period was 1,422. The male population was 896 (61.1%). Total HBc IgM positive and HBc IgM negative results were 197 (13.8%) and 1,225 (86.1%) respectively, and there was 1 (0.07%) equivocal. Rates of HBc IgM positivity, indicating acute infection, were 12.9%, 13.0%, 11.9%, and 15.1% in the years 2014, 2015, 2016, and 2017 respectively. The rate of acute HBV infection increased from 12.9% in 2014 to 15.1% in 2017, indicating likely new infection transmission ongoing in communities. These high and increasing rates require the sustenance of public health interventions.

Comparison of two serological screening strategies for cytomegalovirus primary infection in the first trimester of pregnancy

IntroductionCMV serology screening in the first trimester pregnancy is based on IgG and IgM testing followed by IgG avidity in cases with positive IgM. However, the sensitivity of this strategy to diagnose maternal primary infection has been questioned. The objective of the study was to compare this strategy 1 with a strategy 2 consisting of running avidity test on all samples with positive IgG (ignoring IgM results) using fully automated current generation CMV IgG, IgM and IgG avidity assays. Population and methods1516 consecutive pregnant women between 12 and 14 weeks were screened in one maternity. Strategy 1 was done prospectively with LIAISON® CMV IgG II and LIAISON® CMV IgM II, followed by LIAISON® CMV IgG Avidity II and VIDAS® CMV IgG avidity II testing in cases with positive or equivocal IgM. Strategy 2 was done retrospectively on the same population and consisted of running avidity with the LIAISON® CMV IgG Avidity II in all samples with positive IgG. ResultsThe sensitivity to diagnose a confirmed or a possible maternal primary infection in the first trimester was 91.6 % and 83 % for strategy 1 and 2 respectively (p > 0.99). Strategy 1 missed one possible primary infection and strategy 2 missed 2 confirmed primary infection. Inconclusive results happened in 0 and 0.7 % of samples with strategy 1 and 2 respectively. ConclusionThis study suggests that strategy 1 has better sensitivity and practicability than strategy 2. However, to achieve a good performance with strategy 1, using highly sensitive IgM assay is mandatory.

Hepatitis E Prevalence in Vulnerable Populations in Goiânia, Central Brazil.

A transversal study was conducted among 472 vulnerable individuals (recyclable waste pickers, immigrants and refugees, homeless individuals, as well as lesbian, gay, bisexual, and transexual individuals) in Goiânia City, the capital of the State of Goiás, Brazil, to investigate the prevalence of hepatitis E virus (HEV) infection. A total of 459 (97.2%) serum samples were tested for anti-HEV IgG and IgM antibodies using fully automated chemiluminescence immunoassays (Liaison® Murex Anti-HEV IgG and IgM assays, DiaSorin, Saluggia, Italy). Positive samples were tested for the presence of HEV RNA by a real-time polymerase chain reaction. A seroprevalence of 0.87% (95% confidence interval [CI]: 0.34-2.22) was found for anti-HEV IgG. Furthermore, anti-HEV IgM was detected in only one individual (0.22%; 95% CI: 0.04-1.22), who was also negative for HEV RNA. These findings revealed that HEV infection is infrequent in vulnerable individuals in Central Brazil, with low seroprevalence of past and recent HEV infections.

A-264 Comparison of the ZEUS Scientific Lyme Assays to the DiaSorin Liaison Lyme Assays Using a Modified Two-Tiered Testing Algorithm for Lyme Disease

Abstract Background Lyme borreliosis is the most common vector-borne disease in the United States. Modified two-tiered testing (MTTT) strategies have recently been developed that use enzyme immunoassays as the second tier test in place of an immunoblot. We directly compared two sets of MTTT assays with samples obtained from the northeastern United States, a Lyme disease endemic area. Methods Remnant specimens from 120 patients initially tested by the ZEUS Scientific Lyme ELISAs in accordance with an MTTT algorithm were analyzed with the DiaSorin Lyme chemiluminescent immunoassays. The ZEUS assays were performed on a DYNEX DS2 and the DiaSorin assays were performed on the DiaSorin Liaison XL. Analytical concordance was evaluated. Results Of the 25 samples that were negative by the ZEUS VlsE1/pepC10 IgG/IgM assay, 100% (25/25) were negative by the DiaSorin Lyme Total Antibody Plus assay. Of the 95 samples that were presumptive positive or equivocal by the ZEUS IgG/IgM assay, 64% (61/95) were presumptive positive or equivocal and 36% (34/95) were negative by the DiaSorin Lyme Total assay. Samples that tested presumptive positive or equivocal on the ZEUS IgG/IgM or DiaSorin Lyme Total were evaluated by the respective IgG and IgM assays. Positive IgG results and negative IgM results demonstrated &amp;gt;90% agreement between the ZEUS and DiaSorin assays (Table 1). Overall clinical interpretation was concordant between the ZEUS and DiaSorin MTTTs in 57% (54/95) of patients who tested presumptive positive or equivocal on the ZEUS IgG/IgM. Twenty-four samples that tested positive for IgM by the ZEUS assay tested negative for DiaSorin Lyme Total or IgM assays. Conclusion Comparison of the DiaSorin Lyme assays to the ZEUS Lyme assays using an MTTT algorithm suggests that the DiaSorin assays would result in fewer positive screening tests, decreasing unnecessary secondary testing, and may result in fewer patients treated with antibiotics.

Comparison of β-1-3-D-Glucan and Candida Mannan Biomarker Assays with Serological Tests for the Diagnosis of Candidemia.

Invasive candidiasis, including bloodstream infection (candidemia), encompasses the most severe forms of Candida infection. Several species-specific and non-specific serological assays are commercially available to aid in diagnosis. This study compared the performance of five such biomarker assays. Serum samples from 14 patients with proven or probable invasive candidiasis, and from 10 control patients, were included in the analysis. A total of 50 serum samples were tested using C. albicans germ tube antibody (CAGTA) assay (Vircell), C. albicans IgM, C. albicans IgG and Candida mannan assays (Dynamiker Biotechnology). Among these samples, the β-1-3-D-glucan (BDG) assay (Fungitell), a laboratory standard for the diagnosis of invasive candidiasis, was positive in 20 (40%), intermediate in five (10%) and negative in 25 (50%). In cases of proven or probable candidemia, the sensitivity and specificity of the BDG assay was 86% and 80%, respectively; the Candida mannan assay, 14% and 86%; the CAGTA test, 57% and 60%; the C. albicans IgM assay, 71% and 60%; and C. albicans IgG assay 29% and 90%. In 4/8 (50%) cases with multiple serum samples, C. albicans IgM was positive sooner than BDG. Thus, when used as a rule-out test for invasive candidiasis, our data suggest that the C. albicans IgM assay may assist antifungal stewardship (over serum BDG).

Seroprevalence of SARS-CoV-2(Covid-19) Antibody Among Blood Donors in a Tertiary Care Centre in South India

Introduction The novel severe acute respiratory syndrome virus 2 (SARS-CoV-2), which is responsible Coronavirus disease (COVID-19), spread worldwide from China, causing a pandemic from late December 2019. Due to the high proportion of asymptomatic or mild infections (approximately 80%), data restricted to laboratory-confirmed cases do not capture the true extent of the spread or burden of the virus, or its infection-fatality ratio. Therefore, serological detection of specific antibodies against SARS-CoV-2 can better estimate the true number of infections. The current study aims to estimate the seroprevalence of SARS-CoV-2 antibodies among the whole blood donors without any prior COVID-19 history or symptoms. Objective To determine seroprevalence of SARS-CoV-2 (COVID-19) antibody (IgG and IgM) among asymptomatic healthy blood donors. Methods This was a cross sectional study conducted between March and July, 2021 among 300 blood donors without any prior COVID-19 history or symptoms who came to a tertiary care, multispecialty hospital in south India. Any donor who had recently travelled abroad or donors who had received COVID-19 vaccine are excluded from the study. 3 ml venous blood was drawn in EDTA tube from participants and was tested by “Access SARS CoV-2 IgG assay” and “Access SARS CoV-2 IgM assay” by UniCel DxI 800 Immunoassay analyzer (Beckman coulter). The Access SARS CoV-2 IgG assay and the Access SARS Cov-2 IgM assay detect antibodies to the Receptor Binding Domain (RBD) of the Spike Protein. Result was reported as Reactive if Signal/Cut-off (S/CO)&gt;1.0 and non-Reactive if S/CO &lt;1. Data was collected and entered into excel sheets and was analyzed by using the software SPSS version 25. Results A total of 300 healthy blood donors were included. The study reported seroprevalence of 15.3% for IgG and 4.3% for IgM (95%CI) among asymptomatic whole blood donors. No significant difference was observed across age groups, diet, BMI, ABO/Rh blood type or Ayurveda/homeo immune medicine intake with respect to IgG and IgM reactivity. Conclusion 15% of blood donors were seroconverted for COVID-19 during second wave. This reflects widespread seroprevalence in the adult population. Real-time seroprevalence studies will help to know the herd immunity among the blood donors which will assist in knowing the COVID-19 transmission dynamics and distribution of immunity levels at a particular point in time.

Diagnostic value of PCR analysis of synovial fluid for the diagnosis of Lyme borreliosis in dogs

Lyme borreliosis, also known as Lyme disease, is a chronic multiorgan disease of humans and animals transmitted by ticks of the Ixodidae family and caused by a group of spirochetes Borrelia burgdorferi sensu lato. Dogs are one of the most susceptible animal species to Lyme disease. Symptoms of the disease in dogs can range from mild lameness and fever to more severe and potentially life-threatening conditions, such as kidney damage and neurological disorders. Due to the variety of clinical manifestations and the lack of a universal diagnostic approach, veterinarians often face difficulties in accurately diagnosing the disease. Therefore, improving the algorithms for diagnosing Lyme borreliosis in dogs remains an urgent issue for practical veterinary medicine. The article describes and analyzes data on two cases of dogs from Kyiv (Ukraine) that presented with musculoskeletal disorders, including lameness, swelling of the knee joints, and tenderness, which raised suspicion of Lyme borreliosis. The diagnostic tests used to confirm the diagnosis of Lyme borreliosis included clinical blood test, C-reactive protein test, cerebrospinal fluid cytology, enzyme-linked immunosorbent assay for IgM and IgG antigens to Borrelia burgdorferi sensu lato, computed tomography and PCR analysis of synovial fluid for the presence of Borrelia burgdorferi sensu lato DNA. As a result, the clinical blood test, C-reactive protein test, and cerebrospinal fluid cytology were not diagnostically important for the diagnosis of Lyme borreliosis. In both cases, serological tests for antibodies to Borrelia burgdorferi sensu lato were not positive. Computed tomography showed the development of an inflammatory process in the knee joints with the formation of osteophytes, enthesophytes, sclerosis of the articular surfaces, and an increase in the volume of synovial bursa. The final diagnosis of Lyme arthritis in both dogs was established by PCR analysis of synovial fluid from the affected joints for the presence of Borrelia burgdorferi sensu lato DNA. This study emphasizes the importance of considering Lyme borreliosis as a potential cause of musculoskeletal disorders in dogs. We also propose an expanded algorithm for the diagnosis of Lyme borreliosis in dogs with a pronounced symptom complex of Lyme arthritis using the method of PCR analysis of synovial fluid to detect the DNA of Borrelia burgdorferi sensu lato spirochetes. Key words: Lyme borreliosis in dogs, clinical cases, diagnosis, polymerase chain reaction, Borrelia burgdorferi sensu lato.