Rheumatoid arthritis (RA) is caused by white blood cells attacking healthy cells, even though they are not supposed to.1
Some of these healthy cells getting hit are the cells lining the surfaces of joints.1
I thought white blood cells are supposed to protect us from things like bacteria and viruses, right?
Right you are!
But sometimes, white blood cells get seriously confused. And in their wild confusion, they become over-reactive and can attack cells that they really shouldn’t.2
In RA, they happen to attack cells in-between the joints, causing uncontrolled inflammation which then leads to pain, joint damage and other symptoms.1,2
Why would white blood cells attack healthy cells?
The short answer is we don’t know, and more research is needed.
Because we don’t know what causes white blood cells to over-react, treatments for RA are only designed to suppress white blood cells.1,3
But even in RA, white blood cells are important for fighting off infections, which leads to a shared side effect across all RA treatments: Risk of serious infections.1,3
To learn more:
References: 1. Smolen JS, et al. Lancet 2016. Published online: May 3, 2016. 2. Janeway CA, et al. Immunobiology, 5th edition. Garland Science, New York, 2001. 3. UpToDate. Patients information: Rheumatoid arthritis treatment (beyond the basics). Available at http://www.uptodate.com. Accessed on May 05, 2016.
Last updated: September 17, 2016.
Photo adapted from original by DoveMed.