PERSISTENT INTRATHECAL IMMUNE ACTIVATION IN PATIENTS WITH HERPES-SIMPLEX ENCEPHALITIS

Neopterin and beta2-microglobulin (beta2M) levels were analyzed in seq uential cerebrospinal fluid (CSF) and serum samples from 20 patients w ith herpes simplex encephalitis (HSE) and 30 patients with acute febri le encephalopathy of other cause (non-HSE). Markedly elevated acutepha se CSF levels of neopterin and beta2M were found in 19 HSE patients, b ut the levels were only moderately increased in most of those with non -HSE. Neopterin levels were analyzed in an additional 15 HSE patients who died within a month of the onset of neurologic symptoms and correl ated with the clinical severity of the HSE. After HSE, but not after n on-HSE, increased levels of neopterin and beta2M persisted for a long time (greater-than-or-equal-to 13 years). Specific intrathecal IgG act ivity persisted in all but 2 HSE patients. These findings indicate tha t there is a vigorous acute inflammatory response and a long-term pers istence of intrathecal cellular and humoral immune activity in HSE.