Short Report: Comparison of Performance of Serum and Plasma in Panbio Dengue and Japanese Encephalitis Virus Enzyme-Linked Immunosorbent Assays
ABSTRACT We examined the comparative performance of serum and plasma (in dipotassium EDTA) in Panbio Dengue enzyme-linked immunosorbent assays (ELISAs) for detection of non-structural protein 1 (NS1), IgM, and IgG, and a dengue/Japanese encephalitis virus (JEV) combination IgM ELISA in a prospective series of 201 patients with suspected dengue in Laos. Paired comparisons of medians from serum and plasma samples were not significantly different for Dengue IgM, and NS1 which had the highest number of discordant pairs (both 2%; P = 0.13 and P = 0.25, respectively). Comparison of qualitative final diagnostic interpretations for serum and plasma samples were not significantly different: only 1.5% (3 of 201 for Dengue/JEV IgM and Dengue IgG) and 2.0% (4 of 201; IgM and NS1) showed discordant pairs. These results demonstrate that plasma containing EDTA is suitable for use in these ELISAs.
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ABSTRACT: Background During last three decades, dengue (DF), an arthropod-borne viral disease is increasingly prevalent worldwide including India, resulting in serious public health problems. Objective This study was carried out during 2012–2013 to evaluate the association of WHO-classified dengue disease symptoms with viral load (VL) and serum IFN-gamma levels in dengue patients from India. Study design Blood samples were collected from dengue symptomatic febrile patients (n = 127). DEN-VL was determined by quantitative real-time RT-PCR using RNA, extracted from plasma and anti-DENV-IgM was detected by ELISA. Serum IFN-gamma level was detected by ELISA among DENV infected and age-matched control individuals. Association between DEN-VL and IFN-gamma level in patient's sera with WHO-classified disease symptoms was statistically analyzed. Results DENV RNA and anti-DENV-IgM was detected among 94% (n = 73) and 36% (n = 28) of dengue infected patients (n = 78) respectively. Fever, nausea, rash, aches & pains, leucopenia and persistent vomiting were significantly correlated with DENV infection (P-value < 0.05). Only patients with high-VL exhibited leucopenia, persistent vomiting, abdominal pain and clinical fluid accumulation, which were warning signs of dengue infection according to revised WHO-criteria (P-value < 0.05). Clinical symptoms of DENV infected patients, viz. leucopenia, abdominal pain and persistent vomiting were significantly correlated to each other (P-value < 0.05). Increased serum IFN-gamma level was detected among dengue patients compared to control individuals. DEN-VL and symptoms like nausea, leucopenia, persistent vomiting and abdominal pain were significantly negatively correlated with serum IFN-gamma level (P-value < 0.05). Conclusion Serum IFN-gamma level and dengue viremia among acute stage patients might be used as early prognostic marker for disease severity prediction.Journal of Clinical Virology 09/2014; 61(3). DOI:10.1016/j.jcv.2014.09.003 · 3.47 Impact Factor
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ABSTRACT: The flavivirus nonstructural glycoprotein NS1 is an enigmatic protein whose structure and mechanistic function have remained somewhat elusive ever since it was first reported in 1970 as a viral antigen circulating in the sera of dengue-infected patients. All flavivirus NS1 genes share a high degree of homology, encoding a 352-amino-acid polypeptide that has a molecular weight of 46-55 kDa, depending on its glycosylation status. NS1 exists in multiple oligomeric forms and is found in different cellular locations: a cell membrane-bound form in association with virus-induced intracellular vesicular compartments, on the cell surface and as a soluble secreted hexameric lipoparticle. Intracellular NS1 co-localizes with dsRNA and other components of the viral replication complex and plays an essential cofactor role in replication. Although this makes NS1 an ideal target for inhibitor design, the precise nature of its cofactor function has yet to be elucidated. A plethora of potential interacting partners have been identified, particularly for the secreted form of NS1, with many being implicated in immune evasion strategies. Secreted and cell-surface-associated NS1 are highly immunogenic and both the proteins themselves and the antibodies they elicit have been implicated in the seemingly contradictory roles of protection and pathogenesis in the infected host. Finally, NS1 is also an important biomarker for early diagnosis of disease. In this article, we provide an overview of these somewhat disparate areas of research, drawing together the wealth of data generated over more than 40 years of study of this fascinating protein.Antiviral research 03/2013; DOI:10.1016/j.antiviral.2013.03.008 · 3.43 Impact Factor