Evidence for infection with Chlamydia pneumoniae in a subgroup of patients with multiple sclerosis.

In a pilot study, we identified Chlamydia pneumoniae in the cerebrospinal fluid by polymerase chain reaction in 5 of 10 patients with definite multiple sclerosis (MS). In a second series, 2 of 20 patients with definite MS and 3 of 17 patients with possible/probable MS or MS variants, but none of 56 patients with other neurological, diseases were polymerase chain reaction-positive. We confirm that C. pneumoniae can be found in the cerebrospinal fluid of MS patients, but our rate of positive results is lower than in a recent report.