Stomach ulcer bug H. pylori may reduce risk of developing multiple sclerosis

Jan 21 2015

A West Australian team has found evidence that the stomach ulcer bacterium, Helicobacter pylori, is associated with a lower risk of multiple sclerosis (MS), bolstering evidence for the role of the ‘hygiene hypothesis’ in autoimmune disorders.

In research published this week in the Journal of Neurology, Neurosurgery and Psychiatry, researchers, led by Clinical Professor Allan Kermode and Dr Marzena Fabis Pedrini at the Western Australian Neuroscience Research Institute (WANRI), in collaboration with Nobel Laureate, Professor Barry J Marshall AC, have revealed that prior infection with the ‘stomach ulcer bug’ Helicobacter Pylori (H. pylori) is associated with a lower risk of developing MS.

This work was supported by MS Research Australia, via Vacation Scholarships to students Kirsten Bennett and Alexander Wood of The University of Western Australia at WANRI and the Sir Charles Gairdner Hospital.

Dr Matthew Miles, Chief Executive Officer of MS Research Australia said ‘This is an outstanding example of the kind of research funded by MS Research Australia that can lead to designing new ways to treat or prevent MS.’

C/Professor Kermode said:

The results from this research may indicate that H. pylori has a protective effect against MS and also bolsters evidence for the role of the hygiene hypothesis in autoimmune diseases.

The hygiene hypothesis suggests that exposure to infections in early life may be required to prime the immune system and suppress the development of allergic and autoimmune conditions in later life. Increasing sanitation and use of anti-bacterial products has been put forward as a potential explanation for the growing incidence of allergies and autoimmune conditions in Western societies.

H. pylori is known to infect around half the world’s population, and in the majority of people causes no symptoms. However, the bacterium was famously revealed as a cause of stomach ulcers by Australian Nobel Laureates, Professor Barry J Marshall and Professor Robin Warren.

Previous studies have looked for possible links between H. pylori and MS, but have included relatively small numbers of patients and produced conflicting results.

This is the largest study to date of the relationship between H. pylori and MS. It was enabled by the Perth Demyelinating Disease Database created by C/Professor Kermode and C/Professor Bill Carroll over eighteen years ago. This comprehensive database contains clinical and DNA information from over 80% of individuals registered with MS in Western Australia.

Dr David Blacker WANRI’s Medical Director said:

The scale of patient data captured by this database is an incredible asset to national and international researchers looking for answers in the field of demyelinating diseases like MS.

The team looked for evidence of prior infection with H. pylori in blood samples taken from 550 people with MS and compared this to samples from 299 age and sex matched healthy individuals from the Busselton Community Health Study.

Their study showed that H. pylori infection is more common in women who do not have MS and less common in women with MS, indicating that the presence of an H. pylori infection may reduce the risk of developing MS. The same association was not seen in men.

The authors speculate that infections such as H. pylori may shift the balance of the immune system to a less inflammatory state, therefore reducing the risk of immune hypersensitivity and lowering the likelihood of developing autoimmune disorders such as MS. However, why this effect is stronger in women than men requires further investigation.

Understanding exactly how past infections such as H. pylori influence the immune system could pave the way for designing new drugs that mimic this effect, to treat or prevent MS and other autoimmune diseases.

‘It is encouraging to see that Australian researchers are at the forefront of research discoveries and actively collaborate to ensure that progress can be made faster. This research gives hope to the people living with MS and their families. Congratulations to this outstanding group of West Australian researchers’ said Mr Marcus Stafford, CEO of the MS Society of WA.