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Chromosomal integration of HHV-6 – A diagnostic quandary
S38
Abstracts / Journal of Clinical Virology 70 (2015) S1–S126
Abstract No: 1536
Conclusion: TW/E-HIT assays using horse RBCs demonstrated the highest GMTs. Their specificity was comparable to that of standard HIT. Therefore, the TW/E-HIT assay represents a sensitive and specific alternative for the diagnosis of highly pathogenic influenza viruses. In order to evaluate this method for practicability in endemic regions, sensitivity and specificity tests should be repeated with a suitable Asian serum panel.
K. Skolimowska ∗ , I. Ramsay, C. Atkinson, S. Krichevskaya, G. Nebbia, T. Haque
http://dx.doi.org/10.1016/j.jcv.2015.07.091
Royal Free Hospital, London, UK
Abstract No: 1535
Background: Human herpes virus 6 (HHV-6) is a ubiquitous virus that infects the majority of the population by two years of age. It causes a wide spectrum of disease and has been associated with neurological dysfunction, particularly seizures and meningoencephalitis. HHV-6 is the only human herpes virus known to integrate within host cell chromosomes and is transmitted from parent to child, without causing disease. The prevalence of chromosomally integrated HHV-6 (ciHHV-6) is estimated at ∼1%. The differentiation between infection and chromosomal integration in patients presenting with neurological symptoms is paramount to correct diagnosis and appropriate management. Case: A six week old female was brought to A&E with a one day history of fever and irritability. On examination, the infant was pyrexial with a temperature of 38 ◦ C and had a blanching, erythematous maculopapular rash across the back. The rest of the examination was unremarkable. Routine bloods were normal. Lumbar puncture produced a clear cerebrospinal fluid (CSF) with a white cell count 241/cu mm (neutrophils 95%), red cell count 167/cu mm, protein 0.54 g/L, glucose 2.1 mmol/L. Gram stain did not yield any organisms. A clinical diagnosis of meningitis was made and intravenous ceftriaxone and amoxicillin were commenced. The patient remained pyrexial for 24 h, but was feeding well. Polymerase chain reaction (PCR) of CSF subsequently detected both enterovirus and HHV-6 (viral load 283,426 copies/ml). HHV-6 PCR detected a viral load of >2 million copies/ml in whole blood. PCR on cellular and plasma fractions gave HHV-6 viral load of 719,979 copies/ml and 5214 copies/ml, respectively. The patient was discharged with a diagnosis of enterovirus meningitis. Conclusion: This case illustrates the potential for misdiagnosis of active HHV-6 infection, in particular HHV-6 meningitis. In asymptomatic ciHHV-6, virus can be detected in a variety of cell types and compartments, such as CSF, and this case highlights that HHV-6 meningitis should not be diagnosed solely on the basis of a positive CSF result. It is well established that a viral load >1 million copies/ml in whole blood is highly suggestive of HHV-6 chromosomal integration, rather than active infection, given that every nucleated cell contains at least one viral genome. By additionally testing peripheral blood and its cellular and plasma fractions for HHV-6, we were able to demonstrate that these positive findings were consistent with ciHHV-6 with the conclusion that this was a bystander to enterovirus meningitis. An awareness of chromosomal integration is critical to accurately interpreting HHV-6 results.
Presentation at ESCV 2015: Poster 1 Utility of the AusDiagnostics HighPlex platform for diagnosis of respiratory viruses and atypical pneumonia pathogens E. Cunningham 1,∗ , P. Cliff 1 , S. O’Shea 1 , E. MacMahon 2 1
Viapath, United Kingdom Guy’s and St. Thomas’ NHS Foundation Trust, United Kingdom 2
Background: In our laboratory, diagnosis of respiratory viruses is carried out using the Luminex xTAG RVP Fast Version 2.0 assay, and causes of atypical pneumonia are identified using a mixture of urinary antigen testing, serology and molecular testing at a reference laboratory. An alternative approach to testing is provided by the AusDiagnostics High-Plex system. This is a high-throughput multiplex tandem PCR system that processes 24 samples using a 16plex panel within 3 h. We have conducted a comparative evaluation of the High-Plex system with our current in house assays. Methods: Extracted nucleic acid from 159 clinical specimens (136 retrospective and 23 prospective) and 69 EQA samples (QCMD) were tested with the Respiratory Virus panel, and results compared with those obtained using our routine Luminex xTAG RVP Fast Version 2.0 assay. A further 76 retrospective clinical specimens and 20 EQA samples were tested with the Atypical Pneumonia 16-plex assay, and results compared with those obtained using Legionella urinary antigen testing and referral laboratory molecular tests. Positive samples were confirmed by an external laboratory. Results: The High-Plex system was simple to use and produced results from nucleic acid extracts within a 3-h timeframe. There was evidence of improved sensitivity with the Respiratory virus panel compared to the Luminex xTAG RVP Fast version 2.0 assay for Influenza A, Influenza B, Respiratory Syncitial virus (RSV), Parainfluenza type 3, Adenovirus and human metapneumovirus. In addition, the High-Plex system demonstrated improved Influenza A subtyping. The Atypical Pneumonia panel performed well, demonstrating concordance with reference laboratory results for L. pneumophila, L. longbeachae, M. pneumoniae and C. psittaci. Conclusion: Overall, both the AusDiagnostics Respiratory Virus and Atypical Pneumonia panels demonstrated improved or equivalent sensitivity to the existing methods used in our laboratory. These results together with significantly improved workflow make the AusDiagnostics High-Plex system a suitable platform for respiratory diagnostics. http://dx.doi.org/10.1016/j.jcv.2015.07.092
Presentation at ESCV 2015: Poster 1 Chromosomal integration of HHV-6 – A diagnostic quandary
http://dx.doi.org/10.1016/j.jcv.2015.07.093 Abstract No: 1538 Presentation at ESCV 2015: Poster 1 The prevalence of viruses causing gastroenteritis in Ireland Z. Yandle National Virus Reference Laboratory, Dublin, Ireland Background: The National Virus Reference Laboratory (NVRL) in Dublin receives approximately 12 000 faecal samples a year requesting viral gastroenteritis investigation. Up until June 2014
Abstracts / Journal of Clinical Virology 70 (2015) S1–S126
Abstract No: 1536
Conclusion: TW/E-HIT assays using horse RBCs demonstrated the highest GMTs. Their specificity was comparable to that of standard HIT. Therefore, the TW/E-HIT assay represents a sensitive and specific alternative for the diagnosis of highly pathogenic influenza viruses. In order to evaluate this method for practicability in endemic regions, sensitivity and specificity tests should be repeated with a suitable Asian serum panel.
K. Skolimowska ∗ , I. Ramsay, C. Atkinson, S. Krichevskaya, G. Nebbia, T. Haque
http://dx.doi.org/10.1016/j.jcv.2015.07.091
Royal Free Hospital, London, UK
Abstract No: 1535
Background: Human herpes virus 6 (HHV-6) is a ubiquitous virus that infects the majority of the population by two years of age. It causes a wide spectrum of disease and has been associated with neurological dysfunction, particularly seizures and meningoencephalitis. HHV-6 is the only human herpes virus known to integrate within host cell chromosomes and is transmitted from parent to child, without causing disease. The prevalence of chromosomally integrated HHV-6 (ciHHV-6) is estimated at ∼1%. The differentiation between infection and chromosomal integration in patients presenting with neurological symptoms is paramount to correct diagnosis and appropriate management. Case: A six week old female was brought to A&E with a one day history of fever and irritability. On examination, the infant was pyrexial with a temperature of 38 ◦ C and had a blanching, erythematous maculopapular rash across the back. The rest of the examination was unremarkable. Routine bloods were normal. Lumbar puncture produced a clear cerebrospinal fluid (CSF) with a white cell count 241/cu mm (neutrophils 95%), red cell count 167/cu mm, protein 0.54 g/L, glucose 2.1 mmol/L. Gram stain did not yield any organisms. A clinical diagnosis of meningitis was made and intravenous ceftriaxone and amoxicillin were commenced. The patient remained pyrexial for 24 h, but was feeding well. Polymerase chain reaction (PCR) of CSF subsequently detected both enterovirus and HHV-6 (viral load 283,426 copies/ml). HHV-6 PCR detected a viral load of >2 million copies/ml in whole blood. PCR on cellular and plasma fractions gave HHV-6 viral load of 719,979 copies/ml and 5214 copies/ml, respectively. The patient was discharged with a diagnosis of enterovirus meningitis. Conclusion: This case illustrates the potential for misdiagnosis of active HHV-6 infection, in particular HHV-6 meningitis. In asymptomatic ciHHV-6, virus can be detected in a variety of cell types and compartments, such as CSF, and this case highlights that HHV-6 meningitis should not be diagnosed solely on the basis of a positive CSF result. It is well established that a viral load >1 million copies/ml in whole blood is highly suggestive of HHV-6 chromosomal integration, rather than active infection, given that every nucleated cell contains at least one viral genome. By additionally testing peripheral blood and its cellular and plasma fractions for HHV-6, we were able to demonstrate that these positive findings were consistent with ciHHV-6 with the conclusion that this was a bystander to enterovirus meningitis. An awareness of chromosomal integration is critical to accurately interpreting HHV-6 results.
Presentation at ESCV 2015: Poster 1 Utility of the AusDiagnostics HighPlex platform for diagnosis of respiratory viruses and atypical pneumonia pathogens E. Cunningham 1,∗ , P. Cliff 1 , S. O’Shea 1 , E. MacMahon 2 1
Viapath, United Kingdom Guy’s and St. Thomas’ NHS Foundation Trust, United Kingdom 2
Background: In our laboratory, diagnosis of respiratory viruses is carried out using the Luminex xTAG RVP Fast Version 2.0 assay, and causes of atypical pneumonia are identified using a mixture of urinary antigen testing, serology and molecular testing at a reference laboratory. An alternative approach to testing is provided by the AusDiagnostics High-Plex system. This is a high-throughput multiplex tandem PCR system that processes 24 samples using a 16plex panel within 3 h. We have conducted a comparative evaluation of the High-Plex system with our current in house assays. Methods: Extracted nucleic acid from 159 clinical specimens (136 retrospective and 23 prospective) and 69 EQA samples (QCMD) were tested with the Respiratory Virus panel, and results compared with those obtained using our routine Luminex xTAG RVP Fast Version 2.0 assay. A further 76 retrospective clinical specimens and 20 EQA samples were tested with the Atypical Pneumonia 16-plex assay, and results compared with those obtained using Legionella urinary antigen testing and referral laboratory molecular tests. Positive samples were confirmed by an external laboratory. Results: The High-Plex system was simple to use and produced results from nucleic acid extracts within a 3-h timeframe. There was evidence of improved sensitivity with the Respiratory virus panel compared to the Luminex xTAG RVP Fast version 2.0 assay for Influenza A, Influenza B, Respiratory Syncitial virus (RSV), Parainfluenza type 3, Adenovirus and human metapneumovirus. In addition, the High-Plex system demonstrated improved Influenza A subtyping. The Atypical Pneumonia panel performed well, demonstrating concordance with reference laboratory results for L. pneumophila, L. longbeachae, M. pneumoniae and C. psittaci. Conclusion: Overall, both the AusDiagnostics Respiratory Virus and Atypical Pneumonia panels demonstrated improved or equivalent sensitivity to the existing methods used in our laboratory. These results together with significantly improved workflow make the AusDiagnostics High-Plex system a suitable platform for respiratory diagnostics. http://dx.doi.org/10.1016/j.jcv.2015.07.092
Presentation at ESCV 2015: Poster 1 Chromosomal integration of HHV-6 – A diagnostic quandary
http://dx.doi.org/10.1016/j.jcv.2015.07.093 Abstract No: 1538 Presentation at ESCV 2015: Poster 1 The prevalence of viruses causing gastroenteritis in Ireland Z. Yandle National Virus Reference Laboratory, Dublin, Ireland Background: The National Virus Reference Laboratory (NVRL) in Dublin receives approximately 12 000 faecal samples a year requesting viral gastroenteritis investigation. Up until June 2014