The bacterium Chlamydia pneumoniae, a common cause of "walk-in pneumonia," is found in the nervous systems of most patients with multiple sclerosis (MS), according to a report presented at the American Neurological Association's 125th annual meeting, October 15 through 18 in Boston.

    Employing more sensitive methods than used previously to address this controversial question, researchers from the University of Heidelberg in Germany found signs of the bacterium in 66% of MS patients, versus only 21% of patients suffering from other neurological illnesses.

    "If these results can be confirmed by others and if further evidence can be collected that confirms an association between C. pneumoniae and MS, clinical trials are required that attempt to treat MS patients with antibiotics effective against C. pneumoniae," said Armin Grau, MD, senior author of the report.

    Multiple sclerosis is a disorder of the nerve fibers of the brain and spinal cord. In MS patients, scarring (sclerosis) replaces myelin, a substance that normally insulates the nerves and speeds electrical conduction through the fibers.

    Depending on which nerve fibers are hindered, patients can experience problems ranging from weakness and clumsiness to numbness, visual disturbances, and even emotional and intellectual changes. Some patients experience MS as cycles of relapse and remission; others progress to severe debilitation and may die from the disease.

    Though the cause of MS is not known, circumstantial evidence has suggested that it is an autoimmune disorder wherein the immune system's defense mechanisms mistakenly destroy the myelin. Research has therefore been focused on finding the process that corrupts the immune system, and physicians have attempted, with limited success, to treat the disease with drugs that suppress the immune system.

    On the other hand, a number of studies have suggested that an environmental agent, perhaps an infectious organism such as a virus, may be involved in the disease. However, attempts to isolate such an organism have failed.

    Several recent studies have produced conflicting evidence about the presence of the C. pneumoniae bacterium in the nervous systems of MS patients. Researchers have debated whether the various assays used were correctly applied or sufficiently sensitive. In this study, Grau and his colleagues used a particularly sensitive form of a process called polymerase chain reaction to look for evidence that C. pneumoniae genes were present in the cerebrospinal fluid of patients.

    They found that 12 of 18 MS patients, but only 4 of 19 patients with other neurological diseases, tested positive for the presence of C. pneumoniae. Already in progress is a study by the same researchers involving much larger groups of patients, as well as attempts to replicate the data with other methods of detection.

    In using patients with other neurological diseases as the controls, the researchers provided evidence to counteract the argument that people with any neurological disease, whose immune systems may be compromised, are more likely to have the bacterium in their nervous systems.

    If these results continue to be reproduced with other detection methods, a clinical trial with antibiotics may be able to answer the question of whether the bacteria cause the disease or whether patients who already have MS are simply more susceptible to C. pneumoniae.



    ©American Neurological Association (ANA)

    17 October 00