A team led by Dr Veena Taneja from the Mayo Clinic in the US found that billions of bacteria in the gut play a role in regulating the immune system.
But an overabundance of a certain kind of gut bacteria -- more than what is considered typical -- could actually lead to autoimmune diseases like painful rheumatoid arthritis in people who may be susceptible to the disease, they found.
"A lot of people suspected that gut flora played a role in rheumatoid arthritis, but no one had been able to prove it because they couldn't say which came first -- the bacteria or the genes," said Dr Taneja.
"Using genomic sequencing technologies, we have been able to show the gut microbiome may be used as a biomarker for predisposition," she was quoted as saying by the Daily Mail.
The findings from a study in mice could help scientists predict which people are more likely to develop the painful condition and stop it in its tracks, the researchers said.
They said that identifying new biomarkers in intestinal microbial populations and maintaining a balance in gut bugs could help stop rheumatoid arthritis, which affects nearly one per cent of the world's population, before it starts.
In the study, published in the journal PLoS ONE, Dr Taneja and team genetically engineered mice with a human gene that is a strong indicator of predisposition to rheumatoid arthritis.
A set of control mice were engineered with a different variant of the gene, known to promote resistance to rheumatoid arthritis.
The researchers used these mice to compare their immune responses to different bacteria and the effect on rheumatoid arthritis.
It was found that female mice had a tripled their risk of developing an autoimmune disease compared to male mice, which the researchers said is similar to how women are more likely to develop rheumatoid arthritis than men. (More)