Interferon-gamma in cerebrospinal fluid without pleocytosis in scrub typhus.

We detected immunoreactive interferon-gamma (IFN-gamma) both in cerebrospinal fluid (CSF) and in serum of 5 patients with scrub typhus, one with meningitis and 4 other cases with neither CSF pleocytosis nor blood-CSF barrier dysfunction. Our data suggest intrathecal synthesis of IFN-gamma without pleocytosis which implies occult cerebral involvement in scrub typhus.