Gut Health & Auto Immune Disease

Enterococcus gallinarum

Fascinating research published in the magazine Science earlier this year suggests that gut bacteria may hold key to treating auto immune disease.   The research was conducted by by a team led by Dr Martin Kriegel at Yale School of Medicine in the USA.

What is Auto Immune Disease?

An autoimmune disease is a condition where your immune system mistakenly attacks your all or part of your own body.  Usually your immune system guards against germs like bacteria and viruses sending out an army of fighter cells to attack them.  It can tell the difference between these ‘foreign’ cells and your own cells.  However if you have an autoimmune disease the immune system cannot differentiate between parts of your body, like your joints or skin and the ‘baddies’. It releases proteins called auto antibodies that attack your healthy cells.

There are over 80 different auto immune diseases.  More common example include:

  • Type 1 diabetes
  • Rheumatoid arthritis (RA)
  • Psoriasis/psoriatic arthritis
  • Multiple sclerosis (MS)
  • Systemic lupus erythematosus (lupus)
  • Inflammatory bowel disease – Crohn’s disease  / Ulcerative colitis 
  • Pernicious anaemia
  • Coeliac disease

Some autoimmune diseases target only one organ, for example Type 1 diabetes damages the pancreas. Other diseases, like MS and lupus, affect the whole body.

Currently, there is no cure for autoimmune diseases and treatment can only improve symptoms, hence the significance of this research.

The Auto Immune Study

Dr Kriegel and his team of scientists looked carefully at an ordinarily harmless gut bacterium called Enterococcus gallinarum. In a series of experiments using mice genetically prone to autoimmune conditions, the researchers discovered that the bacteria could spontaneously move from one part of the body to another; moving from the gut to the liver, spleen, and lymph nodes.

Once in these tissues, the E. gallinarum bacteria then stimulated the production of  auto-antibodies and caused inflammation – hallmarks of an autoimmune response. The team then confirmed that the mechanism of inflammation occurred in experiments using liver cells of healthy humans.  Further tests showed that the E. gallinarum bacteria are present in the livers of patients with autoimmune liver disease and lupus but were not detected in livers from healthy controls.

Blocking The Auto Immune Response

A further set of experiments showed how the research team could suppress autoimmunity in mice with an antibiotic or a vaccine targeted specifically at the E. gallinarum bacteriaThe antibiotic / vaccine was injected directly into the muscle to avoid targeting other bacteria found in the gut.  Through both options the researchers could halt growth of the bacterium in the tissues and lessen its effects on the immune system.

When we blocked the pathway leading to inflammation, we could reverse the effect of this bug on auto immunity,” said senior author Martin Kriegel, M.D.

It is this specific bacteria that was important as vaccinations against other bacteria investigated did not prevent mortality and autoimmunity.

Relevance For Systemic Lupus & Auto Immune Liver Disease

This research is particularly good news for sufferers of systemic lupus and autoimmune liver disease, however the team plan to do further research based on this that they hope will also  improve the lives of patients with other auto immune diseases.

 

IMAGE: enterococcus gallinarum (orange dots) in liver tissue. Credit: Vieira et al.