A CASE OF HUMAN HERPESVIRUS 6 ENCEPHALOPATHY AND ITS CEREBROSPINAL FLUID CYTOKINE LEVEL

Objectives: We report a case of human herpesvirus 6 (HHV-6) encephalopathy that revealed recurrent seizures at the eruptive stage. We present the cerebrospinal fluid (CSF) cytokine level in the early stage of HHV- 6 encephalopathy.

Methods: A case is an 11 month-old Japanese male infant. He was admitted to our hospital due to high fever and two episodes of generalized tonic-clonic seizure in one hour. A diazepam suppository controled these seizures. Next day of admission, high fever had subsided and roseola was developed. After about 36 hours of the rash eruption, he had another recurrent seizures. Intravenous diazepam, continuous intravenous midazolam, nor intramuscular injection of phenobarbital was effective. Seizures were controlled by phenytoin. In MRI, no abnormalities were found in the T1, T2 weighted images and FLAIR images. DWI showed an increased signal area in the subcortical white matter of bilateral frontal lobes. We obtained a CSF sample on admission. We checked HHV-6 DNA by PCR and examined concentration of interleukin-6 (IL-6) and interleukin-1â (IL-1â) in the CSF sample.

Results: White blood cell count and biochemical analysis in the CSF sample was normal. HHV-6 DNA was detected. The IL-6 concentration was 17.4ñg/ml and IL-1â was less than 10ñg/ml.

Conclusion: Yoshikawa et al. reported cytokine synthesis using HHV-6 infected astrocytoma cell line (U251). They reported that protein levels of IL-6 in HHV-6 infected U251 supernatant was increased, but IL-1â was not detected. These findings were consistent with our case. We conclude pro-inflammatory cytokine may play an important roles developing HHV-6 encephalopathy.