A new US study suggests that adding antibiotics to current medication for treating multiple sclerosis could slow down the disease.

The study is published in the early online issue of the Archives of Neurology and is the work of Dr Alireza Minagar, of the Louisiana State University Health Sciences Center, Shreveport, and colleagues.

Multiple sclerosis (MS) is triggered by unidentified antigens or other disease-causing agents in the environment and affects people who are genetically predisposed to the disease.

MS causes inflammation that destroys parts of the brain and results in progressive degeneration of brain tissue, wrote the authors. The most common type of MS is called relapsing-remitting MS where patients get muscle weakness and spasms after periods with no symptoms.

Interferon, a drug that boosts the immune system and fights viruses, and is taken by many patients with relapsing-remitting MS, does not prevent relapses and does not stop the brain forming new lesions which can be seen using MRI scans (magnetic resonance imaging).

Minagar and colleagues carried out a single-center trial with 15 patients (average age 44.5 years) who had relapsing-remitting MS, had been taking interferon for at least six months and were having symptoms and showing new brain lesions.

Every day for four months the patients took a 100 mg dose of the antibiotic doxycycline. This was in addition to the continuing interferon therapy.

Every month the patients had a neurological exam and MRI scan as well blood tests to check safety.

After four months the patients’ brains showed fewer lesions on the MRI scan. 60 per cent of the patients showed more than 25 per cent reduction in the number of lesions that were present at the start of the study.

The patients also demonstrated lower scores on a disability test.

One patient relapsed; the adverse events were described as “mild” and not a result of the combination therapy, they were known effects of the individual drugs.

The authors wrote that doxycycline, and other antibiotics in the tetracycline family, may help combat MS and other inflammatory diseases by slowing down enzymes that attack certain cells of the nervous system. This protects the brain and boosts the immune system, they suggested.

“There is growing interest in combination therapy in patients with MS to stabilize the clinical course, reduce the rate of clinical relapses and decelerate the progressive course of the underlying pathologic mechanism,” wrote the investigators.

The researchers concluded that:

“Overall, data from this cohort suggest that the treatment combination of oral doxycycline and interferon beta-1a may be safe and effective in some patients with MS.”

But they also cautioned that further controlled studies are needed to make sure the treatment is safe and works with a larger group of patients.

According to a report earlier today in the BBC News Health section, scientists are also looking at the possibility that a bacteria called Chlamydia pneumoniae, more usually linked to respiratory disease, might infect the brain and trigger MS.

“Combination Therapy With Interferon Beta-1a and Doxycycline in Multiple Sclerosis: An Open-Label Trial.”
Alireza Minagar; J. Steven Alexander; Robert N. Schwendimann; Roger E. Kelley; Eduardo Gonzalez-Toledo; Joaquim J. Jimenez; Lucia Mauro; Wenche Jy; Stacy J. Smith.
Arch Neurol 2007 0: 2007.41
Early Release Article, posted December 10, 2007
Printed issue: Arch Neurol. 2008;65(2)

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Written by: Catharine Paddock