Human herpesvirus-6 antigenemia after liver transplantation.
BACKGROUND
Human herpesvirus (HHV)-6 has recently been reported in liver transplant patients. It infects and causes dysfunction in hepatic transplants, which provides serious differential diagnostic problems between allograft rejection and viral infection. The diagnosis of posttransplantation HHV-6 infection is usually based on serology or on polymerase chain reaction detection of viral DNA in peripheral blood specimens. However, serology does not tell the exact time of the infection, and detection of viral DNA by polymerase chain reaction may also indicate a latent infection in seropositive patients. Here we report the diagnostic use of frequent monitoring of HHV-6 antigenemia after liver transplantation.


METHODS
Altogether 622 blood specimens from 51 consecutive adult liver transplant patients were analyzed. The diagnosis was based on demonstration of HHV-6-specific antigens in peripheral blood mononuclear cells using immunoperoxidase staining and monoclonal antibodies and on serology.


RESULTS
During the first year (7-280 days) after transplantation, HHV-6 infection was diagnosed in 11 (22%) of 51 patients. HHV-6 early antigens, as well as HHV-6 variant B antigens, were detected in all 11 patients. HHV-6 diagnosis was confirmed by serology. The episode of HHV-6 antigenemia usually lasted for several weeks together with mild, if any, clinical signs of the infection. A significant graft dysfunction was associated with HHV-6 antigenemia in 8 of 11 patients, and viral antigens were also detected in the liver biopsy specimens of 3 of these patients.


CONCLUSIONS
An active HHV-6 infection can be diagnosed from peripheral blood by detection of virus-specific antigens in mononuclear cells. HHV-6 antigenemia correlated with seroresponse.
Department of Virology, Helsinki University Central Hospital and University of Helsinki, Finland. Irmeli.Lautenschlager@huch.fi
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I
Lautenschlager
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K
Linnavuori
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K
Höckerstedt
D000328:Adult; D000956:Antigens, Viral / Q000097:blood*; D003586:Cytomegalovirus Infections / Q000175:diagnosis; D015774:Ganciclovir / Q000627:therapeutic use; D006566:Herpesviridae Infections / Q000175:diagnosis* / Q000188:drug therapy; D015654:Herpesvirus 6, Human / Q000276:immunology*; D006801:Humans; D016031:Liver Transplantation / Q000009:adverse effects*
D000956:Antigens, Viral; D015774:Ganciclovir