Can a chlamydial cause for MS be proved in an individual patient by serology?
Not at the moment. This because Chl pneumoniae is a common organism and infections with the bacterium are common. Antibody levels tend to rise during life, even in people who are asymptomatic. Patients with extracerebral infections of some duration (particularly reactive arthritis) can show high titres in the microimmunofluorescence test; it is generally reckoned that a titre of 1:512 or above, in the presence of appropriate clinical findings, supports a diagnosis of Chl pneumoniae disease. MS is different; the pathology is at the blood-brain barrier. One would not expect an elevation of circulating antibodies unless an extracerebral component to the infection were also present. This may be the case in progressive disease; there is a statistical elevation of antibodies in a group of such patients. This supports the idea of a chlamydial cause for MS, but makes no prediction in an individual. That is why treatment must at the moment be empirical. Antibiotics have been around for more tha
