HHV-6: clinical and laboratory investigations and correlations with encephalitis in liver transplant recipients

Human herpesvirus (HHV) 6 infections and reactivation are emerging factors in neurology. This study aimed to verify the presence of encephalitis associated with HHV-6 positivity by antigenemia or polymerase chain reaction (PCR) in liver transplant recipients.

We analyzed the medical records and laboratory results of 20 recipients with antigenemia or a positive PCR for HHV-6. The range of the transplantation dates was September 2006 to March 2010; the period of the medical records was from the date of transplantation to 1 year thereafter. Encephalitis was diagnosed by these symptoms: fever, mening, signs, seizures, dysphasia, visual and hearing impairment, or sensory and motion alterations. "Possible encephalitis" was considered when the patients had at least 2 of the symptoms. PCR or antigenemia for HHV-6 was not performed with central nervous fluid. The correlation between HHV-6 infection and encephalitis was evaluated with the use of descriptive statistical tests.

Symptoms associated with encephalitis occurred in 7/20, patients (35%): 5/20 with fever and 4/20 with mental confusion. Involuntary movements were present in 1 case. The symptoms appeared with in the first 10 days in 6/20 patients and lasted for 1 year.

This study showed that symptoms associated with encephalitis occurred in a considerable number of patients with positive PCR and/or antigenemia for HHV-6 after liver transplantation. This correlation needs retrospectie and prospective studies to determine the specific association.