Diagnostic relevance of screening clinical specimens from patients attending infectious diseases and haematology units for HHV6 DNA: a two-year experience
Abstract number: o61
Parruti G., Manna A., Di Girolamo A., Ciotti M., Racciatti D., D'Amico G., Favalli C., Pizzigallo E., D'Antonio D.
HHV6 (Human Herpes Virus 6) is a member of the bherpesvirinae subfamily in the Herpesviridae family. It has a yet incompletely defined cell tropism and its clinical spectrum is currently being clarified, both in the immunocompetent and in the immunocompromised host. We introduced the use of tools for molecular diagnosis of HHV6 active replication into routine clinical practice at our Institutions late in 2003. Here we summarize the preliminary results of our 2-year experience in terms of diagnostic efficiency.
Sample preparation for DNA isolation, commercially available kits were used, according to manufacturers' instructions. DNA extraction from large clinical samples (such as plasma, serum, cerebrospinal fluid, urine, sputum, broncoalveolar lavage fluid) was mainly performed using the QIAamp DNA Mini Kit (QIAgen GmbH, Hilden, Germany). Detection of positive samples for HHV6:
Clinical specimens were scored as positive for HHV6 when they tested as positive for the Herpesvirus-Consensus PCR (Argene Biosoft) amplification product, again positive for the HHV6 amplification product and negative for HSV type 1, HSV type 2, Varicella-Zoster virus, Epstein-Barr virus and Cytomegalovirus amplifications. Quantisation of HHV-6 DNA. Quantisation of HHV6 DNA was performed using standard curves generated by TaqMan probes and primers in an ABI 7000 machine (Q-HHV-6 Real Time System -Amplimedical Bioline).
During 2004 and 2005 (January through October), 1207 samples were processed at our Institutions, 987 of which (81.7%) collected at Haematological Units. Thirty-two samples (2.7%) from 19 patients turned out to be positive: 16 of them were from immunocompetent patients (8 patients), the remaining 16 were from immunocompromised patients (11 patients, 1 of whom was HIV positive). Among immunocompetent patients, 2 had persistent fever with rash; one had persistent fever only, while the remaining 5 had recurrent or persistent stomatitis. Among immunocompromised patients, 9 had a diagnosis of haematological malignancy.
Molecular diagnosis of HHV6 active replication seems to be an interesting tool to diagnose a wide range of persistent or recurring clinical conditions. It seems to be particularly promising when used to screen previously unrecognized conditions in the immunocompetent host, as in the case of recurrent stomatitis or persistent fever with rash.
|Session name:||XXIst ISTH Congress|
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