Serological diagnosis of Borrelia meningitis.

The antibody response against a Borrelia strain isolated from Swedish Ixodes ricinus ticks was determined by enzyme linked immunosorbent assay (ELISA) and indirect immunofluorescence assay (IFA) of cerebrospinal fluid (CSF) and serum specimens from 45 patients with chronic meningitis. Probable Borrelia etiology could be demonstrated in 41 of 45 (91%) patients with clinical symptoms of chronic meningitis. Approximately 25% of the patients had significantly elevated titer of antibody to the spirochete in CSF but not in serum. Patients with short duration of disease were especially prone to be antibody negative in serum but positive in CSF. Significant rise in serum antibody titers was seldom demonstrated in patients treated with antibiotics.