Remission associated with human herpesvirus infection in west syndrome.

Generally, West syndrome is an intractable epileptic syndrome in infancy, although spontaneous remission has been reported in some cases. An immunologic response to infection might be one of the factors involved in the remission of West syndrome, but the mechanisms remain unknown. On the other hand, exanthema subitum is a common disease occurring in infancy with the characteristics of fever and rash. Two kinds of human herpesvirus, 6 and 7, have been isolated as causal agents of exanthema subitum. We experienced one symptomatic case and three cryptogenic cases of West syndrome that showed spontaneous remission. In the symptomatic case, the subject showed a temporary remission; however, in the other cases, the remissions were long term. In the present study, we report the patients' improvement and electroencephalographic (EEG) findings. In all of our cases, hypsarrythmia disappeared on the EEG findings, the human herpesvirus 6 IgG antibodies increased in all four cases, and the herpesvirus 7 IgG antibodies increased in two cases. We postulate that the remission of the four cases proceeded from infection by exanthema subitum. The changes in serum antibody values suggest that the spontaneous remission of West syndrome was related to human herpesvirus 6 and 7 infections.