BackgroundDuring the course of multiple sclerosis (MS) intrathecal oligoclonal IgGs are present in the cerebrospinal fluid (CSF). The intracellular human pathogenChlamydia pneumoniaemay play a role either as a causative pathogenetic agent in the disease, orC. pneumoniae-infected MS patients could be immunologically less able to clear the agent from the central nervous system (CNS).MethodsCSF samples were studied in 100 individuals – 70 MS patients and 30 age-matched controls with other neurological diseases. CSF was taken by lumbal puncture; cell cultures were performed by the cell vial technique, followed by a 4-day incubation at 37°C. A nested PCR was performed.ResultsC. pneumoniaewas detectable in the CSF of only 2.9% of the MS patients and none of control patients (with no significant difference between the MS patients and controls). IgG antibodies were positive in only 1.43% of the MS patients and 3.33% of the controls. IgA antibodies were positive in 6.66% of the control patients and none of the patients were positive for IgM antibodies. There was no statistically significant difference between the two groups of patients with respect to the three antibody classes.ConclusionsThe results confirm the high leave of controversy surrounding a possible link betweenC. pneumoniaeand MS, and the matter requires further thorough investigation.