Borrelia burgdorferi in the central nervous system: experimental and clinical evidence for early invasion.

Intravenous injection into adult Lewis rats of live Borrelia burgdorferi, the spirochetal agent of Lyme disease, was followed by increased permeability of the blood-brain barrier. Permeability was measured by the ratio of 125I-labeled albumin in cerebrospinal fluid to that in blood. Permeability changes were dose-dependent, began 12 h after inoculation, and reversed within 1 week. Only live, intravenously inoculated organisms produced impairment of the blood-brain barrier. A spirochetal strain-dependent effect was noted in that changes were more marked with a recent isolate than with a strain in long-term in vitro culture. Mild pleocytosis and spirochetes were noted in the cerebrospinal fluid of rats with increased blood-brain barrier permeability. This experimental evidence for early central nervous system invasion was pursued in studies of the human disease. Specific B. burgdorferi antigens could be detected in the cerebrospinal fluid of patients with early Lyme disease by use of murine monoclonal antibodies as probes.