Littérature scientifique sur le sujet « Anti-dengue IgM ELISA »

Dengue IgM, IgG Capture ELISAs and NS1 Ag ELISA become the most widely used serological methods for dengue diagnosis untilnow. Previous studies reported a possible use of IgA antibodies for dengue virus as a new serologic marker to make dengue infectionactive. In the present study, the performance of IgA anti-dengue rapid test as a new marker of dengue infection was assessed. In thisstudy, the sera were obtained from 30 dengue virus infection patients and 30 non dengue virus infection patients. Thirty dengue pairedsera were collected twice, at the time of hospital admission (acute) and at discharge (convalescent). All sera samples were characterizedusing dengue reference ELISAs (NS1 Ag, Dengue IgM and IgG capture ELISAs). The results of IgA anti-dengue rapid test were comparedwith the corresponding dengue reference tests. The sensitivity and specificity of IgA anti-dengue rapid test respectively were 78.3% (95%CI: 65.5–87.5%), and 73.3% (95% CI: 55,6–85,8%). Meanwhile, from acute sera, sensitivity of IgA anti-dengue rapid test was 83.3%(95% CI: 64.5–93.7), higher than IgM (73.3%, 95% CI: 53.8–87.0), IgG (66.7%, 95% CI: 47.1–82.1) and NS1 Ag ELISAs (60%,95% CI: 40.7–76.8). Positive IgA anti-dengue rapid test results in acute sera was higher in the secondary (91%) than primary infection(57%). IgA anti-dengue rapid test can be considered as a new marker for dengue infection, because it gives a high sensitivity, especiallyin the acute phase and in the secondary infections as well.

ABSTRACT Two easy-to-use commercial diagnostic assays, a dipstick enzyme-linked immunosorbent assay (ELISA) (Integrated Diagnostics, Baltimore, Md.) and an immunochromatographic card assay (PanBio, Brisbane, Australia) were evaluated for detection of immunoglobulin M (IgM) antibody to dengue virus with an in-house IgM antibody capture microplate ELISA as a reference assay. The dipstick ELISA was based on the indirect-ELISA format using dengue 2 virus as the only antigen and enzyme-labeled goat anti-human IgM antibody as the detector. The total assay time was 75 min. The immunochromatographic card assay was based on the antibody capture format and separately measured both anti-dengue virus IgM and IgG in the same test. Colloidal-gold-labeled anti-dengue virus monoclonal antibody bound with dengue virus 1 to 4 antigen cocktail was the detector, and anti-human IgM and IgG were the capture antibodies. The total assay time was <10 min. Sera from 164 individuals classified as either anti-dengue virus IgM positive (94) or anti-dengue virus IgM negative (70) in the reference microplate ELISA with a dengue virus 1 to 4 antigen cocktail were tested in the two commercial assays. The dipstick ELISA missed 7 of 94 positive samples, for a sensitivity of 92.6%, while the immunochromatographic card assay missed two positive samples, for a sensitivity of 97.9%. Of the 70 negative samples, four were false positive by the dipstick ELISA and two were false positive in the immunochromatographic card assay, resulting in specificities of 94.3 and 97.1%, respectively. Both commercial assays provide sensitive and specific detection of anti-dengue virus IgM antibody and could prove useful in settings where the microplate ELISA is impractical.

Infeksi Virus Dengue (IVD) dibedakan menjadi infeksi primer dan sekunder berdasarkan respons antibodi yang dihasilkan. Infeksisekunder perlu dibedakan dari infeksi primer karena umumnya menimbulkan manifestasi klinis yang berat. Uji hemaglutinasi inhibisisebagai baku emas untuk menentukan infeksi primer atau sekunder dirasa tidak praktis karena membutuhkan sepasang sera denganselang waktu waktu yang cukup lama. Penelitian ini bertujuan mengetahui cut-off rasio IgG/IgM anti dengue untuk infeksi denguesekunder dewasa di Surabaya. Subjek adalah pasien IVD dengan hasil NS1 dan/atau PCR dengue positif. Rasio IgG/IgM anti-denguediperoleh dari pembagian nilai indeks IgG dan IgM metode ELISA. Nilai cut-off rasio ditentukan berdasarkan kurva ROC. Berdasarkanpola reaktivitas IgM dan IgG ELISA, 19 (31,1%) pasien dikelompokkan sebagai infeksi primer dan 42 (68,9%) infeksi sekunder. HasilPCR didominasi DEN-3. Nilai cut-off optimal rasio IgG/IgM ≥0,927 sebagai peramal infeksi sekunder memiliki kepekaan 66,7% dankekhasan 63,2%. Dianalisis pula nilai cut-off optimal IgM dan IgG anti dengue, yaitu IgM ≥1,515 dan IgG ≥2,034 sebagai peramalinfeksi sekunder memiliki kepekaan dan kekhasans masing-masing 85,7% dan 84,2%; 100% dan 100%. Disimpulkan bahwa rasioIgG/IgM ≥0,927 tidak dapat digunakan sebagai tolok ukur tunggal peramal infeksi sekunder sedangkan cut-off IgG ≥2,034 dapatdipertimbangkan sebagai peramal infeksi sekunder.

The clinical manifestations of dengue virus infection are varied and thus a specific diagnostic examination is required. Usually antidengueIgM is often used, but the presence in the circulation is 3−8 months long. NS1 is sensitive in the detection of primary infection,whereas IgG is more better used in secondary infection. The examination of anti-dengue IgA as a new marker is estimated to be ableto detect the acute primary and secondary infection, however the diagnostic value of anti-dengue IgA is not much well known for theIndonesian population. This study was done at the Tropical Infectious Disease Ward of Dr. Soetomo Hospital, Surabaya during February– April 2013. The samples consisted of 37 sera from patients infected by dengue virus and 37 sera from those non one (dengue virusinfection patients). The NS1 serum, anti-dengue IgM and anti dengue IgG were examined by ELISA and anti-dengue IgA was examined byan indirect immunochromatography method using Assure@ Dengue IgA Rapid Test (MP Biomedicals Asia Pacific Pte Ltd). The diagnosticvalue was analyzed by 2x2 table with a confidence interval of (CI) 95%. The used gold standards were from the 1997th WHO criteriaand one of the positive dengue serological tests by ELISA (NS1/anti dengue IgM/anti dengue IgG). AUC and anti-dengue IgA cut-off weredetermined by ROC curve. The Diagnostic value of anti-dengue IgA showed a sensitivity and specificity of 83.8% (67.3 to 93.2) and 81.1%(64.3 to 91.4). A positive predictive value of 81.6% (65.1 to 91.7) and a negative predictive value of 83.3% (66.5 to 93.0) was found. Thepositive likelihood ratio was 4.4 times (2.2 to 8.8) and negative likelihood ratio of only 0.2 times (0.09 to 0.42). The best cut off valueof 0.2 was shown by the area under the curve of 83.5%. Based on this study, the diagnostic value of anti-dengue IgA had a good validityfor the diagnosis of dengue virus infection.

Dengue fever (DF) is usually diagnosed by testing for dengue virus immunoglobulin M (IgM) by a capture enzyme-linked immunosorbent assay (ELISA) (MAC-ELISA). However, IgM can last for months, and its presence might reflect a previous infection. We have tested the use of anti-dengue virus IgA capture ELISA (AAC-ELISA) for the diagnosis of DF by comparing the results of MAC-ELISAs and AAC-ELISAs for 178 serum samples taken from patients with confirmed cases of DF. IgM appears more rapidly (mean delay of positivity, 3.8 days after the onset of DF) than IgA (4.6 days) but lasts longer; the peak IgA titer is obtained on day 8. The specificity and the positive predictive value of AAC-ELISA are 100%; its sensitivity and negative predictive value (NPV) are also 100% between days 6 and 25 after the onset of DF, but they decrease drastically when data for tests conducted with specimens from the first days of infection are included, because the IgA titers, like the IgM titers, have not yet risen. AAC-ELISA is a simple method that can be performed together with MAC-ELISA and that can help in interprating DF serology.

88 sera from patients with dengue fever were examined with the use of two test systems: Pilot Production kit «ELISA- IgM-dengue», delivered in the D.I. Ivanovsky Institute of Virology (Russian Federation) and. All 88 samples were positive for specific IgM in «ELISA-IgM-dengue», but 8 cases examined with the test kit «Anti-Dengue virus ELISA (IgM)» (Euroimmun, Germany) appeared to be negative. The ratio between the titers of anti-dengue IgM determined in patients’ blood samples by "ELISA-IgM-dengue" and «Ratio» (index, recommended by the company «Euroimmun» for differentiation of positive, equivocal or negative results, was evaluated. 53 blood sample containing M antibodies to cytomegalovirus (n = 43), Epstein-Barr virus (n = 6), herpes simplex virus (n = 2) and rubella virus (n = 2) were tested by both ELISA kits to compare their specificity. When «ELISA- IgM-dengue» kits were applied all observed samples were negative, but under the application of the «Anti-Dengue virus ELISA (IgM)» kit (Euroimmun, Germany) 17 samples (32.1%) were false positive or equivocal.

Dengue is a serious tropical disease caused by the mosquito-borne dengue virus (DENV). Performant, rapid, and easy-to-use assays are needed for the accurate diagnosis of acute DENV infection. We evaluated the performance of three prototype assays developed for the VIDAS® automated platform to detect dengue NS1 antigen and anti-dengue IgM and IgG antibodies. Positive and negative agreement with competitor enzyme-linked immunosorbent assays (ELISA) and rapid diagnostic tests (RDT) was evaluated in 91 Lao patients (57 adults, 34 children) with acute DENV infection. The VIDAS® NS1 assay showed the best overall agreement (95.6%) with the competitor NS1 ELISA. Both VIDAS® NS1 and NS1 ELISA assays also demonstrated high sensitivity relative to DENV RNA RT-PCR set as gold standard (85.7% and 83.9%, respectively). In contrast, NS1 RDT was less sensitive relative to DENV RNA RT-PCR (72.7%). The overall agreement of VIDAS® IgM and IgG assays with the competitor assays was moderate (72.5% for IgM ELISA, 76.9% for IgG ELISA, and 68.7% for IgM and IgG RDT). In most analyses, test agreements of the VIDAS® assays were comparable in adults and children. Altogether, the VIDAS® dengue prototypes performed very well and appear to be suitable for routine detection of dengue NS1 antigen and anti-dengue IgM/IgG antibodies.

In Brazil, chikungunya emerged in 2014, and by 2016, co-circulated with other arbovirosis, such as dengue and zika. ELISAs (Enzyme-Linked Immunosorbent Assays) are the most widely used approach for arboviruses diagnosis. However, some limitations include antibody cross reactivities when viruses belong to the same genus, and sensitivity variations in distinct epidemiological scenarios. As chikungunya virus (CHIKV) is an alphavirus, no serological cross reactivity with dengue virus (DENV) should be observed. Here, we evaluated a routinely used chikungunya commercial IgM (Immunoglobulin M) ELISA test (Anti-Chikungunya IgM ELISA, Euroimmun) to assess its performance in confirming chikungunya in a dengue endemic area. Samples (n = 340) representative of all four DENV serotypes, healthy individuals and controls were tested. The Anti-CHIKV IgM ELISA test had a sensitivity of 100% and a specificity of 25.3% due to the cross reactivities observed with dengue. In dengue acute cases, the chikungunya test showed an overall cross-reactivity of 31.6%, with a higher cross-reactivity with DENV-4. In dengue IgM positive cases, the assay showed a cross-reactivity of 46.7%. Serological diagnosis may be challenging and, despite the results observed here, more evaluations shall be performed. Because distinct arboviruses co-circulate in Brazil, reliable diagnostic tools are essential for disease surveillance and patient management.

Background: Dengue virus (DENV) infection remains a global public health concern. Enzyme-linked immunosorbent assays (ELISAs), which detect antibodies targeting the envelope (E) protein of DENV, serve as the front-line serological test for presumptive dengue diagnosis. Very few studies have determined the serostatus by detecting antibodies targeting the nonstructural protein 1 (NS1), which can function as diagnostic biomarkers to distinguish natural immunity from vaccine-induced immunity. Methods: We used community-acquired human serum specimens, with the serostatus confirmed by focus reduction microneutralization test (FRμNT), to evaluate the diagnostic performances of two NS1-based ELISA methods, namely, immunoglobulin G antibody-capture ELISA (NS1 GAC–ELISA) and indirect NS1 IgG ELISA, and compared the results with an E-based virus-like particle (VLP) GAC–ELISA. Results: NS1-based methods had comparable accuracies as VLP GAC–ELISA. Although the sensitivity in detecting anti-NS1 IgM was poor, indirect NS1 IgG ELISA showed similar limits of detection (~1–2 ng/mL) as NS1 GAC–ELISA in detecting anti-NS1 IgG. Combining the results from two or more tests as a composite reference standard can determine the DENV serostatus with a specificity reaching 100%. Conclusion: NS1-based ELISAs have comparable accuracies as VLP GAC–ELISA in determining dengue serostatus, which could effectively assist clinicians during assessments of vaccine eligibility.

Background: The assessment of antibody responses to severe acute respiratory syndrome coronavirus-2 is potentially confounded by exposures to flaviviruses. The aims of the present research were to determine whether anti-dengue antibodies affect the viral load and the detection of anti-coronavirus nucleocapsid (N)-protein antibodies in coronavirus infectious disease 2019 (COVID-19) in Bangladesh. Methods: Viral RNA was evaluated in swab specimens from 115 COVID-19 patients by real-time reverse transcription polymerase chain reaction (rT-PCR). The anti-N-protein antibodies, anti-dengue virus E-protein antibodies and the dengue non-structural protein-1 were determined in serum from 115 COVID-19 patients, 30 acute dengue fever pre-COVID-19 pandemic and nine normal controls by ELISA. Results: The concentrations of viral RNA in the nasopharyngeal; Ct median (95% CI); 22 (21.9–23.3) was significantly higher than viral RNA concentrations in oropharyngeal swabs; and 29 (27–30.5) p < 0.0001. Viral RNA concentrations were not correlated with-dengue IgG levels. The anti-nucleocapsid antibodies were IgA 27% positive and IgG 35% positive at days 1 to 8 post-onset of COVID-19 symptoms versus IgA 0% and IgG 0% in dengue patients, p < 0.0001. The levels of anti- nucleocapsid IgA or IgG versus the levels of anti-dengue IgM or IgG revealed no significant correlations. Conclusions: Viral RNA and anti-nucleocapsid antibodies were detected in COVID-19 patients from dengue-endemic regions of Bangladesh, independently of the dengue IgG levels.

A dengue é uma doença infecciosa viral transmitida pela picada de mosquitos do gênero Aedes e é um importante problema de saúde pública mundial. A infecção por qualquer um dos quatro sorotipos (DENV 1-4) pode apresentar diferentes quadros clínicos: pode ser assintomática, causar uma síndrome febril indiferenciada, ou a febre da dengue (DF), a evolução do quadro clínico pode levar a dengue hemorrágica com ou sem choque (DHF/DSS). Um número crescente de casos de infecção por dengue em crianças têm sido observados nos últimos anos. Estudos de prevalência da dengue em regiões endêmicas são importantes para avaliar a incidência da infecção por dengue em crianças. Assim, o objetivo deste estudo é investigar a prevalência de anticorpos anti-dengue IgM e IgG em crianças atendidas no Centro de Saúde Escola Dr. Edgard Aché, localizado na região oeste de Ribeirão Preto-SP. Crianças (n = 271) de 1-15 anos de idade foram recrutadas de março de 2010 até maio de 2011. Depois de um termo de consentimento ter sido assinado pelo responsável, uma amostra de sangue das crianças, participantes deste estudo, foi coletada. As crianças foram classificadas em assintomáticas (n= 174) ou sintomáticas (n = 97), quando estas apresentavam um ou mais de um sintoma sugestivo de dengue, de acordo com critérios da Organização Mundial de Saúde. Anticorpos IgM e IgG anti-dengue foram detectado nas amostras de soro por um ELISA de captura padronizado em nosso laboratório. O ELISA de captura para IgG mostrou uma positividade de 9,23% (25/271) e o ELISA de captura para IgM de 8,49% (23/271). O ELISA de captura para IgG foi positivo em 10,31% (10/97) das crianças sintomáticas e 8,62% (15/174) das crianças assintomáticas, enquanto que o ELISA de captura para IgM foi positivo em 15,46% (15/97) das crianças sintomáticas e 4,6% (8/174) em crianças assintomáticas. Este estudo mostrou a alta prevalência de anticorpos anti-dengue em crianças da região oeste do município de Ribeirão Preto; mostrou também que a infecção pode ser causada de forma assintomática, e que a infecção por este vírus pode ser um grave problema de saúde nesta população, servindo como um alerta às autoridades de saúde.
Dengue is an infectious viral disease transmitted by the biting of mosquitoes of Aedes genus and it is an important public health problem worldwide. Infection with any of the four serotypes (DENV 1-4) may be asymptomatic or causes illness ranging from mild viral syndrome, dengue fever (DF) to dengue hemorrhagic fever (DHF). An increasing number of dengue infection cases in children have been noted in the last years. A dengue surveillance study might be an important tool in endemic region to evaluate the incidence of dengue infection in children. Thus, the aim of this study was to investigate the prevalence of anti-dengue IgM and IgG antibodies in children in the Primary Health Care Center, Dr. Edgard Aché, located in the west region of Ribeirão Preto-SP. Children (n=271) from 1 to 15 years old were recruited during March 2010 until May 2011. After a signed consent by the person responsible for the children to participate in this study, a blood sample was collected. The children were classified in asymptomatic (n=174) or symptomatic (n=97) when they had more than one symptom suggestive of dengue according to the World Health Organization criterions. Anti-dengue IgM and IgG were detected in serum samples by a capture ELISA standardized in our laboratory. IgG capture ELISA was positive in 9,23% (25/271) and IgM capture ELISA in 8,49% (23/271) of the children. IgG capture ELISA was positive in 10,31% (10/97) of the symptomatic children and 8,62% (15/174) in asymptomatic children; while IgM capture ELISA was positive in 15,46% (15/97) of symptomatic children and 4,6% (8/174) in asymptomatic children. This study showed the high prevalence of anti-dengue antibodies in children in the west region of Ribeirão Preto. In addition, a high prevalence of dengue-infected children without symptoms was observed. The present survey demonstrated that dengue virus infection might be a problem in children\'s from Ribeirão Preto city and serve as an alert to the health authorities.

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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
Introduction. Laboratory tests are essential for dengue diagnosis, in that sense algorithms are proposed, which proposes instructions for a more effective laboratory dengue diagnosis. Aim. To evaluate the performance of laboratory tests in the confirmation of suspected dengue cases, appling an algorithm, during a dengue epidemic in Goiânia, Central West Brazil 2012-2013. Methodology. This is a retrospective analytical observational study in a database of a prospective cohort with suspected dengue cases. The algorithm applied was based on three periods in the acute phase of disease, 0-3, 4-7 and >7 days after onset of symptoms (DOS) and in detection of immunoglobulins M and G (IgM and IgG), non-structural 1 protein antigen (NS1Ag) and viral RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Positivity was seen individually and in association of tests in the algorithm and per day of infection, and used to confirm cases. The tests performance was evaluated by the sensitivity, specificity and accuracy of each test when compared to the others association, also in the algorithm. The results were statistically analyzed using SPSS Statistics 17.0, R software and OPENEPI. Results. 592 patients with suspected dengue were included, 415 (70.1%) were laboratory confirmed. In the 0-3 DOS period, the best positivities were by RT-PCR (81.6%) and NS1Ag (63.3%). While, IgM obtained the best positivities in 4-7 and >7 DOS periods (85.5% and 93.3%, respectively). Individually, RT-PCR and IgM tests were the most efficient to add positivity to diagnosis at the beginning and at the end of the acute phase of infection, respectively. Sensitivity results were similar to those of positivity, whereas NS1Ag specificities were greater than 90% at all periods. Conclusion. The algorithm sowed which laboratorial test was the best for the course of disease. Until 3 DOS, molecular is most sensitive test; between 4-7 DOS, two techniques may be required to obtain an accurate diagnostic. NS1Ag test, presented less detection in secondary infection cases, however, they was more specific test and can be used in differential diagnosis of dengue. These results contributed to diagnostic decision in the epidemiological context with concomitant arbovirus circulation.
Introdução. Testes laboratoriais são fundamentais para o diagnóstico da dengue, nesse sentido são propostos algoritmos, que propõe instruções para um diagnóstico laboratorial de dengue mais eficaz. Objetivo. Avaliar o desempenho de testes laboratoriais na confirmação de casos suspeitos de dengue, no curso de duas epidemias (2012 e 2013) em Goiânia, Goiás, Centro-Oeste do Brasil. Metodologia. Trata-se de um estudo observacional analítico que analisou uma base de dados clínicos e laboratoriais de uma coorte prospectiva de pacientes com suspeita clínica de dengue. O algoritmo aplicado baseou-se em três períodos da doença, 0-3, 4-7 e >7 dias após o início dos sintomas (DOS) e no uso de testes de detecção das imunoglobulinas M e G (IgM e IgG), do antígeno da proteína não-estrutural 1 (NS1Ag) e do RNA viral por reação em cadeia da polimerase via transcriptase reversa (RT-PCR). Foram avaliadas a positividade dos testes individualmente e em associação de testes por dia de infecção; e a sensibilidade, especificidade e acurácia dos testes. A análise estatistica usou os programas SPSS Statistics 17.0, R software e OPENEPI. Resultados. Dos 592 pacientes selecionados, 415 (70,1%) foram confirmados laboratorialmente. No período de 0-3 DOS, a RT-PCR e NS1Ag obtiveram 81,6% e 63,3% de positividade respectivamente. IgM obteve as positividade nos períodos de 4-7 e >7 DOS (85,5% e 93,3%, respectivamente). Individualmente, os testes de RT-PCR e IgM positividade ao diagnóstico no início e no final da fase aguda da infecção, respectivamente. Os resultados de sensibilidade foram semelhantes aos de positividade, enquanto os de especificidade de NS1Ag foram superiores à 90% em todos os períodos. Conclusão. O algoritmo apontou qual teste laboratorial foi o melhor para o curso da doença. Até 3 DOS, o teste molecular é o mais sensível; Entre 4-7 DOS, duas técnicas podem ser necessárias para obter um diagnóstico preciso. O teste de NS1Ag apresenta menor detecção em casos de infecção secundária, no entanto, foi o teste mais específico, podendo ser utilizado no diagnóstico diferencial de dengue. Estes resultados contribuíram para a decisão diagnóstica no contexto epidemiológico com a circulação concomitante de arbovírus.