Assertion: rheumatoid arthritis's system | /r/Causes | joint pain
Facets:
Source sentences:
text: What it is: RA happens when the immune system attacks your own tissues and causes joint pain, swelling, and stiffness.
text: It’s an autoimmune disease: The body’s immune system mistakenly attacks the joints, causing inflammation, joint pain and swelling, the American College of Rheumatology explains.