“Here you have two inflammatory diseases, one affects the intestine and the other affects the joints, and both share the same genetic defect and treated with the same drugs. Do they have a common trigger? That was the question we raised and set out to investigate,” Naser said.
Bég recruited 100 of her patients for the study. Subjects volunteered clinical samples for testing. Of the patients with rheumatoid arthritis 78 percent were found to have a mutation in the PTPN2/22 gene, the same genetic mutation found in Crohn’s patients, and 40 percent of that number tested positive for MAP.
“We believe that individuals born with this genetic mutation and who are later exposed to MAP through consuming contaminated milk or meat from infected cattle are at a higher risk of developing rheumatoid arthritis,” Naser said.
Researchers said that further study is needed.
“We don’t know the cause of rheumatoid arthritis, so we’re excited that we have found this association,” Bég said. “But there is still a long way to go. We need to find out why MAP is more predominant in these patients — whether it’s present because they have RA, or whether it caused RA in these patients. If we find that out, then we can target treatment toward the MAP bacteria.”