Chlamydia pneumoniae in multiple sclerosis: humoral immune responses in serum and cerebrospinal fluid and correlation with disease activity marker

Humoral immune responses to Chlamydia pneumoniae (C. pneumoniae) were studi ed in paired sera and cerebrospinal fluid (CSF) of patients with definite m ultiple sclerosis (MS) and other inflammatory and non-inflammatory neurolog ical diseases. Seropositivity was not significantly different between these groups. However, C. pneumoniae-specific IgG titers were significantly high er in CSF of MS than in controls. Sixteen out of 52 seropositive MS patient s (30.8%) showed intrathecal synthesis of C, pneumoniae-specific IgG but on ly one of 43 seropositive controls (2.3%). In MS, this was strongly associa ted with intrathecal synthesis of polyclonal IgG in 13/16 patients. However , these elevated C. pneumoniae antibody titers in CSF did not significantly correlate with disease duration, disease course, clinical or MRI disease a ctivity disability or presence of oligoclonal IgG in MS.