Japanese encephalitis virus is a leading cause of neurological infection in the Asia-Pacific region with no means of detection in more remote areas. We aimed to test the hypothesis of a Japanese ...encephalitis (JE) protein signature in human cerebrospinal fluid (CSF) that could be harnessed in a rapid diagnostic test (RDT), contribute to understanding the host response and predict outcome during infection. Liquid chromatography and tandem mass spectrometry (LC–MS/MS), using extensive offline fractionation and tandem mass tag labeling (TMT), enabled comparison of the deep CSF proteome in JE vs other confirmed neurological infections (non-JE). Verification was performed using data-independent acquisition (DIA) LC–MS/MS. 5,070 proteins were identified, including 4,805 human proteins and 265 pathogen proteins. Feature selection and predictive modeling using TMT analysis of 147 patient samples enabled the development of a nine-protein JE diagnostic signature. This was tested using DIA analysis of an independent group of 16 patient samples, demonstrating 82% accuracy. Ultimately, validation in a larger group of patients and different locations could help refine the list to 2–3 proteins for an RDT. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD034789 and 10.6019/PXD034789.
Pyrexia of unknown origin in clinical practice Bharucha, Tehmina; Cockbain, Beatrice; Brown, Michael
British journal of hospital medicine (London, England : 2005)
77, Številka:
10
Journal Article
Recenzirano
This article revisits concepts of pyrexia of unknown origin to reflect current clinical practice. It describes the evolution of the term, in line with the changing spectrum and pace of ...investigations, and introduces key questions that may be used to evaluate a pyrexia of unknown origin.
The mainstay of diagnostic confirmation of acute Japanese encephalitis (JE) involves detection of anti-JE virus (JEV) immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA). Limitations ...in the specificity of this test are increasingly apparent with the introduction of JEV vaccinations and the endemicity of other cross-reactive flaviviruses. Virus neutralization testing (VNT) is considered the gold standard, but it is challenging to implement and interpret. We performed a pilot study to assess IgG depletion prior to VNT for detection of anti-JEV IgM neutralizing antibodies (IgM-VNT) as compared with standard VNT.
We evaluated IgM-VNT in paired sera from anti-JEV IgM ELISA-positive patients (JE n=35) and negative controls of healthy flavivirus-naïve (n=10) as well as confirmed dengue (n=12) and Zika virus (n=4) patient sera. IgM-VNT was subsequently performed on single sera from additional JE patients (n=76).
Anti-JEV IgG was detectable in admission serum of 58% of JE patients. The positive, negative and overall percentage agreement of IgM-VNT as compared with standard VNT was 100%. A total of 12/14 (86%) patient samples were unclassified by VNT and, with sufficient sample available for IgG depletion and IgG ELISA confirming depletion, were classified by IgM-VNT. IgM-VNT enabled JE case classification in 72/76 (95%) patients for whom only a single sample was available.
The novel approach has been readily adapted for high-throughput testing of single patient samples and it holds promise for incorporation into algorithms for use in reference centres.
Molecular epidemiological data are key for dengue outbreak characterization and preparedness. However, sparse
(DENV) molecular information is available in Laos because of limited resources. In this ...proof-of-concept study, we evaluated whether DENV1 RNA extracted from rapid diagnostic tests (RDTs) could be amplified and sequenced. The protocol for envelope gene amplification from RNA purified from RDTs was first assessed using viral isolate dilutions then conducted using 14 dengue patient sera. Envelope gene amplification was successful from patient sera with high virus titer, as was sequencing but with lower efficiency. Hence, based on our results, RDTs can be a source of DENV1 RNA for subsequent envelope gene amplification and sequencing. This is a promising tool for collecting molecular epidemiology data from rural dengue-endemic areas. However, further investigations are needed to improve assay efficiency and to assess this tool's level of efficacy on a larger scale in the field.
•HEV prevalence is higher in the transplant population than the general population.•Dietary transmission of HEV is an important consideration.•Baseline screening of blood and organ donors for HEV ...should be employed.
Hepatitis E Virus (HEV) is a common cause of acute viral hepatitis worldwide. Typically associated with a self-limiting illness, infection may persist in immunosuppressed populations with significant morbidity and mortality. Based on clinical data published world-wide, UK blood safety guidance recommends the universal screening for HEV RNA of blood donors and donors of tissue, organs and stem cells.
This cross-sectional study aimed to determine the point prevalence of HEV viraemia and clinical course of viraemic patients in the peri-transplant period in solid organ transplant (SOT) and haematopoietic stem cell transplant (HSCT) recipients transplanted over a 3-year period (2013–2015).
Nucleic acid extracts of whole blood from patients undergoing SOT or HSCT were tested by an in-house real-time reverse-transcriptase polymerase chain reaction assay for HEV RNA. Samples were tested at baseline (time of transplant), 30, 60 and 90 days post-transplant.
870 patients (259 HSCT, 262 liver and 349 kidney transplant) were included with 2554 samples meeting the inclusion criteria. No kidney transplant patients had HEV viraemia at time of testing. One HSCT and three liver transplant patients were found to be HEV RNA positive. Overall this represented 0.46% of the patients testing positive for HEV viraemia.
Prevalence of HEV viraemia in SOT and HSCT patients in U.K. although higher than in the general population is low at baseline and remains low throughout the early post-transplant phase. Clearance of viraemia can be maintained despite ongoing immunosuppression. Prospective U.K. studies are necessary to inform screening policies in this population.
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Introduction:
Hepatitis E Virus (HEV) is one of the leading causes of acute infectious hepatitis worldwide; while usually a self-limiting, sub-clinical illness, genotype 3 HEV infection may become ...chronic in immunosuppressed patients such as solid organ transplant (SOT) or haematopoietic stem cell transplant (HSCT) recipients and rapid progression to cirrhosis may occur. Recent seroprevalence from screening of English blood donors shows antibody prevalence of ~13%. RNA prevalence in donors has increased in the UK from 1:2850 to 1:1460 over the past 3 years. This study examines the point-prevalence of HEV in SOT and HSCT recipients transplanted between January 2013 - December 2015 at a major UK transplant centre. Data on HEV clearance rates and risk factors for infection were collected in the patient cohort.
Methods:
Stored extracts of blood from patients undergoing liver transplant (OLT), renal transplant (RT) or HSCT were tested by real-time reverse-transcriptase polymerase chain reaction for HEV RNA. Samples were tested at baseline, 30, 60 and 90 days post-transplant +/- 7 days. Time points were chosen to give good coverage of the early post-transplant period whilst avoiding a patient becoming viraemic and clearing the infection between sample time points. All positive samples were sent to the Public Health England reference laboratory for verification, viral RNA genotyping and quantification. Patients with confirmed positive samples underwent further testing and evaluation of clinical parameters to determine chronology of infection, blood product exposure, organ function and histopathology results.
Results:
259 HSCT, 262 OLT and 349 RT patients met the inclusion criteria. Of the HSCTs there were 111 allogeneic stem cell transplants, 145 autologous transplants and 3 CD34 "top ups". The OLTs comprised 259 deceased donor, 2 live donor and 2 domino liver transplant patients. The RTs comprised 241 deceased donor, 38 live unrelated, 63 live related transplants and 1 live transplant where the relationship of the donor was unrecorded. In total 4 patients (1 HSCT and 3 OLT) were found to have HEV viraemiain our study period. This represents 0.39% of the HSCT and 1.15% of the OLT patients. All were positive with HEV genotype 3.
Virologicaland clinical data regarding these patients are presented in tables below.
Conclusion:
Chronic HEV, genotype 3 in transplant patients is associated with significant morbidity. With the increasing incidence of HEV, immunosuppressed patients with high transfusion burden have an infection risk equivalent to 7-9 years' dietary exposure.
Our results show that prevalence of HEV viraemia in OLT, RT and HSCT patients is higher than expectedbased on comparison from UK blood donors. Secondly, infection is not cleared as would be expected in the general population with 3 of the 4 patients requiring treatment to clear the virus.
The source of infection for these patients is unclear; on a population wide basis HEV is usually a dietary acquired infection, with pork products carrying the greatest risk. In the transplant patient population, the risk of iatrogenic infection via infected blood products or an infected transplanted organ is an important consideration and UK guidance has recently changed so that transplant recipients receive dietary advice and HEV-negative blood to avoid infection (SaBTO2016).
In this study 2 patients were found to be positive for HEV RNA in the baseline sample. One, the recipient of HSCT, did not acquire it through transfusion as testing of the transfused products that the patient had received were negative for the virus. It is not clear how the two OLT patients who tested positive acquired the virus. The absence of any positive results in the renal transplant recipients may reflect the lower transfusion burden in this patient group. Given the multiple routes of possible infection with HEV, a strategy if screening recipients for the virus in addition to screening blood and organ donors would be an effective way of detecting viral transmission via all routes.
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Sekhar:Novartis: Research Funding.
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