Serology

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Tim Waterboer - One of the best experts on this subject based on the ideXlab platform.

  • validation of monoplex assays detecting antibodies against corynebacterium diphtheriae and clostridium tetani toxins rubella virus and parvovirus b19 for incorporation into multiplex Serology
    Methods, 2019
    Co-Authors: Paul Schnitzler, Michael Pawlita, Nicole Brenner, Julia Butt, Izaura Lima Bomfim, Julia Tabatabai, Tim Waterboer
    Abstract:

    Serological assays detecting antibodies in serum or plasma samples are useful and versatile instruments to investigate an individual's infection and vaccination history, e.g. for clinical diagnosis, personal risk evaluation, and seroepidemiological studies. Multiplex Serology is a suspension bead array-based high-throughput methodology for simultaneous measurement of antibodies against multiple pathogens in a single reaction vessel, thus economizing sample volume, measurement time, and costs. We developed and validated bead-based pathogen-specific Monoplex Serology assays, i.e. assays including only antigens for the respective pathogen, to detect antibodies against Corynebacterium diphtheriae and Clostridium tetani toxins, rubella virus and parvovirus B19. The developed assays expand the portfolio of existing pathogen-specific bead-based Serology assays and can be efficiently incorporated into larger Multiplex Serology panels. The newly developed Monoplex Serology assays consist of only one antigen per infectious agent, expressed as Glutathione S-transferase-fusion proteins in E. coli. Specificity, sensitivity and Cohen's kappa statistics in comparison with routine clinical diagnostic assays were calculated for serum dilutions 1:100 and 1:1000. All pathogen-specific assays were successfully validated at both serum dilutions with the exception of rubella Monoplex Serology which showed impaired sensitivity (57.6%) at dilution 1:1000. Specificities of successfully validated Monoplex Serology assays ranged from 85.6% to 100.0% (median: 91.7%), and sensitivities from 81.3% to 95.8% (median: 90.9%); agreement with the reference assays ranged from substantial to almost perfect (kappa: 0.66-0.86, median: 0.78). Statistical performance and slim assay design enable efficient incorporation of the developed assays into Multiplex Serology.

  • hepatitis c virus seroprevalence in mongolian women assessed by a novel multiplex antibody detection assay
    Cancer Epidemiology Biomarkers & Prevention, 2015
    Co-Authors: Bolormaa Dondog, Paul Schnitzler, Kristina M Michael, Gary M Clifford, Silvia Franceschi, Michael Pawlita, Tim Waterboer
    Abstract:

    Background: Hepatitis C virus (HCV) infection causes hepatocellular carcinoma and is an important cause of mortality in both industrialized and developing countries. We developed a single-step high-throughput multiplex Serology assay for HCV antibody detection and determined HCV prevalence in a highly endemic country. Methods: Five proteins (Core, NS3, NS4A, NS5A, NS5B) each from the three most common subtypes of HCV (1a, 1b, 2a) were recombinantly expressed and used as antigens in a multiplexed antibody detection assay. Multiplex HCV Serology was validated with 432 reference sera whose HCV status was established by commercial ELISA, Western blot, and RNA assays. HCV antibodies were determined in 1,023 sera representative for the adult female population of Mongolia. Results: In reference sera, detection of HCV (mostly Core and NS3) antibodies by multiplex Serology showed 100% sensitivity and 99.6% specificity, and was in very good agreement with the commercial diagnostic assays (kappa, 0.96; 95% confidence interval, 0.92–0.99). The role of antibodies to NS4 and NS5 remains to be evaluated. In Mongolia, overall HCV antibody prevalence was 18.9% (17.8% when age-standardized to the world population). HCV seroprevalence increased with age from 10% in women <30 years to 32% in women ≥50 years, but was not related to sexual risk factors. Conclusions: The single-step high-throughput multiplex HCV Serology assay performs similarly to conventional HCV antibody screening followed by secondary confirmation assays. A very high HCV seroprevalence was confirmed across all socio-economic groups in the female population of Mongolia. Impact: Multiplex HCV Serology facilitates large seroepidemiologic studies of HCV infection. Cancer Epidemiol Biomarkers Prev; 24(9); 1360–5. ©2015 AACR .

  • helicobacter pylori multiplex Serology
    Helicobacter, 2009
    Co-Authors: Angelika Michel, Tim Waterboer, Manfred Kist, Michael Pawlita
    Abstract:

    Background: Helicobacter pylori infection is associated with severe gastrointestinal disease including cancer. It induces complex antibody responses that might vary depending on disease state but currently cannot be assessed adequately. The objective of this work was the development of a sensitive and specific H. pylori multiplex Serology assay with high-throughput capability that allows simultaneous detection of antibodies to a protein array. Methods:  Seventeen proteins of up to three H. pylori strains (26695, G27, 151), including CagA, VacA, UreA, Catalase, Omp, and GroEL, were recombinantly expressed as glutathione-S-transferase fusion proteins, affinity-purified, and used as antigens in a fluorescent bead-based antibody-binding assay. Reference sera (n = 317) characterized by commercial assays (screening ELISA with Western blot confirmation) were used for validation. Results: H. pylori seropositivity by multiplex Serology defined as reactivity with at least four proteins showed good agreement (kappa: 0.70) with commercial serologic assay classification, and a sensitivity of 89% and specificity of 82%. For individual antigens, agreement with Western blot was good for CagA (kappa: 0.77), moderate for UreA (kappa: 0.53), and weak for VacA (kappa: 0.12). Of the 13 proteins expressed from two strains, only VacA showed serologic strain differences. High antibody reactivity to CagA (Type I infection) was negatively associated with antibodies to GroEL, Cad, CagM, catalase, HcpC, NapA, and UreA, suggesting type-specific differences in protein expression patterns and/or immune response. Conclusion:  With its high-throughput and simultaneous detection abilities, H. pylori multiplex Serology appears suited as tool for large seroepidemiologic studies assessing H. pylori prevalence, antibody patterns, and associations with specific diseases.

Maria Soderlundvenermo - One of the best experts on this subject based on the ideXlab platform.

  • comparative diagnosis of human bocavirus 1 respiratory infection with messenger rna reverse transcription polymerase chain reaction pcr dna quantitative pcr and Serology
    The Journal of Infectious Diseases, 2017
    Co-Authors: Benedict Arku, Tuomas Jartti, Janne O Koskinen, Ville Peltola, Klaus Hedman, Maria Soderlundvenermo
    Abstract:

    Background Human bocavirus (HBoV) 1 can cause life-threatening respiratory tract infection in children. Diagnosing acute HBoV1 infection is challenging owing to long-term airway persistence. We assessed whether messenger RNA (mRNA) detection would correlate better than DNA detection with acute HBoV1 infection. Methods Paired serum samples from 121 children with acute wheezing were analyzed by means of Serology. Quantitative polymerase chain reaction (PCR) and reverse-transcription (RT) PCR were applied to nasopharyngeal swab (NPS) samples from all acutely HBoV1-infected children and from controls with nonacute infection. Results By Serology, 16 of 121 children (13.2%) had acute HBoV1 infection, all of whom had HBoV1 DNA in NPS samples, and 12 of 16 (75%) had HBoV1 mRNA. Among 25 children with nondiagnostic results, 6 had HBoV1 DNA in NPS samples, and 1 had mRNA. All 13 mRNA-positive samples exhibited high DNA loads (≥106 copies/mL). No mRNA persisted for 2 weeks, whereas HBoV1 DNA persisted for 2 months in 4 children; 1 year later all 15 samples were DNA negative. Compared with Serology, DNA PCR had high clinical sensitivity (100%) but, because of viral persistence, low specificity (76%). In contrast, mRNA RT-PCR had low clinical sensitivity (75%) but high specificity (96%). Conclusions A combination of HBoV1 Serology and nasopharyngeal DNA quantitative PCR and mRNA RT-PCR should be used for accurate diagnosis of HBoV1 infection.

  • comparative diagnosis of human bocavirus 1 respiratory infection with messenger rna reverse transcription polymerase chain reaction pcr dna quantitative pcr and Serology
    The Journal of Infectious Diseases, 2017
    Co-Authors: Man Xu, Benedict Arku, Tuomas Jartti, Janne O Koskinen, Ville Peltola, Klaus Hedman, Maria Soderlundvenermo
    Abstract:

    Abstract Human bocavirus (HBoV) 1 can cause life-threatening respiratory tract infection in children. Diagnosing acute HBoV1 infection is challenging owing to long-term airway persistence. We assessed whether messenger RNA (mRNA) detection would correlate better than DNA detection with acute HBoV1 infection. Paired serum samples from 121 children with acute wheezing were analyzed by means of Serology. Quantitative polymerase chain reaction (PCR) and reverse-transcription (RT) PCR were applied to nasopharyngeal swab (NPS) samples from all acutely HBoV1-infected children and from controls with nonacute infection. By Serology, 16 of 121 children (13.2%) had acute HBoV1 infection, all of whom had HBoV1 DNA in NPS samples, and 12 of 16 (75%) had HBoV1 mRNA. Among 25 children with nondiagnostic results, 6 had HBoV1 DNA in NPS samples, and 1 had mRNA. All 13 mRNA-positive samples exhibited high DNA loads (≥106 copies/mL). No mRNA persisted for 2 weeks, whereas HBoV1 DNA persisted for 2 months in 4 children; 1 year later all 15 samples were DNA negative. Compared with Serology, DNA PCR had high clinical sensitivity (100%) but, because of viral persistence, low specificity (76%). In contrast, mRNA RT-PCR had low clinical sensitivity (75%) but high specificity (96%). A combination of HBoV1 Serology and nasopharyngeal DNA quantitative PCR and mRNA RT-PCR should be used for accurate diagnosis of HBoV1 infection.

Scott Montgomery - One of the best experts on this subject based on the ideXlab platform.

  • symptoms and signs in individuals with Serology positive for celiac disease but normal mucosa
    BMC Gastroenterology, 2009
    Co-Authors: Jonas F Ludvigsson, Lena Brandt, Scott Montgomery
    Abstract:

    Antibody Serology is an important tool in the investigation of celiac disease (CD), but does not always correlate with mucosal appearance in the small intestine. Patients with positive CD Serology but normal mucosa (Marsh 0) are at increased risk of future CD. In this study we describe a model for identifying and characterizing individuals with normal mucosa but positive CD Serology. Such individuals are sometimes referred to as having latent CD. The records of ten Swedish pathology departments were used to identify individuals with biopsies indicating normal duodenal/jejunal mucosa. Using the national personal identification number, these data were linked with CD Serology data (antigliadin, antiendomysial and tissue transglutaminase antibodies); and we thereby identified 3,736 individuals with normal mucosa but positive CD Serology. Two independent reviewers then manually reviewed their biopsy reports to estimate comorbidity. We also randomly selected 112 individuals for validation through patient chart review. The majority of the 3,736 individuals were females (62%). Children (0–15 years) made up 21.4%. The median number of biopsy specimen was 3. Our review of biopsy reports found that other gastrointestinal comorbidity was rare (inflammatory bowel disease: 0.4%; helicobacter pylori infection: 0.2%). Some 22% individuals selected for patient chart review had a relative with CD. The most common symptoms among these individuals were diarrhea (46%) and abdominal pain (45%), while 26% had anemia. Although 27% of the individuals selected for validation had been informed about gluten-free diet, only 13% were adhering to a gluten-free diet at the end of follow-up. Individuals with positive CD Serology but normal mucosa often have CD-like symptoms and a family history of CD.

Christopher J M Whitty - One of the best experts on this subject based on the ideXlab platform.

  • clinical presentation and diagnostic sensitivity of laboratory tests for strongyloides stercoralis in travellers compared with immigrants in a non endemic country
    Tropical Medicine & International Health, 2003
    Co-Authors: Sonali Sudarshi, Richard Stumpfle, Margaret Armstrong, Thomas Ellman, Simon Parton, Prabha Krishnan, Peter L Chiodini, Christopher J M Whitty
    Abstract:

    OBJECTIVES To assess whether the clinical and laboratory methods for diagnosing Strongyloides stercoralis infection in non-endemic countries is different between those who are chronically exposed and those who travel. METHODS Analysis of laboratory and clinical data from 204 patients having S. stercoralis infection at the Hospital for Tropical Diseases, London. RESULTS Sixty-four travellers and 128 immigrants from endemic countries had laboratory-proven strongyloides. In those with microscopically proven disease, Serology was 73% sensitive in travellers and 98% sensitive in immigrants (P < 0.001). There was no difference in the eosinophil count between the two groups with 19% having a normal count. Patterns of symptoms varied between the groups, and around one-third were asymptomatic in both groups. Serology was of limited use in follow-up. CONCLUSIONS Eosinophil count and stool microscopy are insufficiently sensitive to be used alone for screening strongyloides. The sensitivity of Serology is good in immigrants with chronic infection, but lower in travellers.

Joseph A Murray - One of the best experts on this subject based on the ideXlab platform.

  • aga clinical practice update on diagnosis and monitoring of celiac disease changing utility of Serology and histologic measures expert review
    Gastroenterology, 2019
    Co-Authors: Steffen Husby, Joseph A Murray, David A Katzka
    Abstract:

    Purpose The purpose of this clinical practice update is to define key modalities in the diagnosis and monitoring of celiac disease (CD) in adults as well as in children and adolescents. Methods The recommendations outlined in this expert review are based on available published evidence, including cohort and case-control studies of the diagnostic process as well as controlled and descriptive studies of disease management. Best Practice Advice 1 : Serology is a crucial component of the detection and diagnosis of CD, particularly tissue transglutaminase–immunoglobulin A (TG2-IgA), IgA testing, and less frequently, endomysial IgA testing. Best Practice Advice 2 : Thorough histological analysis of duodenal biopsies with Marsh classification, counting of lymphocytes per high-power field, and morphometry is important for diagnosis as well as for differential diagnosis. Best Practice Advice 2a : TG2-IgA, at high levels (> ×10 upper normal limit) is a reliable and accurate test for diagnosing active CD. When such a strongly positive TG2-IgA is combined with a positive endomysial antibody in a second blood sample, the positive predictive value for CD is virtually 100%. In adults, esophagogastroduodenoscopy (EGD) and duodenal biopsies may then be performed for purposes of differential diagnosis. Best Practice Advice 3 : IgA deficiency is an infrequent but important explanation for why patients with CD may be negative on IgA isotype testing despite strong suspicion. Measuring total IgA levels, IgG deamidated gliadin antibody tests, and TG2-IgG testing in that circumstance is recommended. Best Practice Advice 4 : IgG isotype testing for TG2 antibody is not specific in the absence of IgA deficiency. Best Practice Advice 5 : In patients found to have CD first by intestinal biopsies, celiac-specific Serology should be undertaken as a confirmatory test before initiation of a gluten-free diet (GFD). Best Practice Advice 6 : In patients in whom CD is strongly suspected in the face of negative biopsies, TG2-IgA should still be performed and, if positive, repeat biopsies might be considered either at that time or sometime in the future. Best Practice Advice 7 : Reduction or avoidance of gluten before diagnostic testing is discouraged, as it may reduce the sensitivity of both Serology and biopsy testing. Best Practice Advice 8 : When patients have already started on a GFD before diagnosis, we suggest that the patient go back on a normal diet with 3 slices of wheat bread daily preferably for 1 to 3 months before repeat determination of TG2-IgA. Best Practice Advice 9 : Determination of HLA-DQ2/DQ8 has a limited role in the diagnosis of CD. Its value is largely related to its negative predictive value to rule out CD in patients who are seronegative in the face of histologic changes, in patients who did not have serologic confirmation at the time of diagnosis, and in those patients with a historic diagnosis of CD; especially as very young children before the introduction of celiac-specific Serology. Management Best Practice Advice 10 : Celiac Serology has a guarded role in the detection of continued intestinal injury, in particular as to sensitivity, as negative Serology in a treated patient does not guarantee that the intestinal mucosa has healed. Persistently positive Serology usually indicates ongoing intestinal damage and gluten exposure. Follow-up Serology should be performed 6 and 12 months after diagnosis, and yearly thereafter. Best Practice Advice 11 : Patients with persistent or relapsing symptoms, without other obvious explanations for those symptoms, should undergo endoscopic biopsies to determine healing even in the presence of negative TG2-IgA.

  • undetectable negative tissue transglutaminase iga antibodies predict mucosal healing in treated coeliac disease patients
    Alimentary Pharmacology & Therapeutics, 2017
    Co-Authors: Hongfei Fang, Katherine S King, Joseph J Larson, Melissa R Snyder, Tsungteh Wu, Manish J Gandhi, Joseph A Murray
    Abstract:

    SummaryBackground Tissue transglutaminase (tTG) immunoglobulin A (IgA) testing is a sensitive adjunct to the diagnosis of coeliac disease. The threshold for positivity was developed for diagnosis, with negative results reported as below the reference value (<4 U/mL). Aim To investigate if an undetectable (tTG IgA<1.2 U/mL) is more predictive of healing compared to patients with negative but detectable Serology (1.2-3.9 U/mL). Methods We performed a retrospective study of 402 treated coeliac disease patients seen at the Mayo Clinic with negative tTG IgA values drawn within 1 month of duodenal biopsy between January 2009 and December 2015. The Corazza-Villanacci score was used to assess mucosal healing. The presence of gastrointestinal symptoms was also collected. Logistic regression was used to assess the relationship of clinical variables with a normal biopsy. Results Patients with undetectable titres more frequently had normal duodenal histology compared to patients with detectable tTG IgA levels (117/240 vs. 53/162; OR=1.96; 1.292, 2.961). Asymptomatic patients more frequently had normal duodenum as compared to symptomatic patients (88/163 vs. 82/239; OR=2.25; CI: 1.494, 3.377). Patients with undetectable Serology and on a gluten-free diet for ≥2 years were more likely to have no villous atrophy compared to patients with detectable Serology (148/192 vs. 55/88; OR=2.02; CI: 1.17, 3.49). Conclusion In subjects recovering from coeliac disease with negative tTG IgA Serology, an undetectable titre is associated with normal histology on follow-up biopsy.

  • screening for celiac disease in a north american population sequential Serology and gastrointestinal symptoms
    The American Journal of Gastroenterology, 2011
    Co-Authors: Kent D Katz, Shahrooz Rashtak, Brian D Lahr, Joseph L Melton, Patricia K Krause, Kristine Maggi, Nicholas J Talley, Joseph A Murray
    Abstract:

    Screening for Celiac Disease in a North American Population: Sequential Serology and Gastrointestinal Symptoms