Which are the causes of Rheumatoid Arthritis?

The exact cause of Rheumatoid Arthritis remains unknown, though it is widely understood as an autoimmune condition where the body’s immune system mistakenly attacks the lining of the joints, known as the synovium.

The Pathophysiology of Rheumatoid Arthritis

In Rheumatoid Arthritis, the immune system loses its ability to distinguish "self" from "non-self." Think of the immune system as a security team: in a healthy person, it protects the body from invaders like bacteria. In Rheumatoid Arthritis, this team becomes hyper-alert and begins treating the healthy joint tissue as an intruder, leading to chronic inflammation, pain, and potential structural damage.

Genetic and Environmental Factors

Genetics play a significant role in determining susceptibility. The most well-studied genetic markers are the HLA-DRB1 genes, often referred to as the "shared epitope." While these genes increase the risk, they do not guarantee that an individual will develop the disease. Environmental triggers are the "second key" that may unlock this genetic predisposition. Smoking is the most strongly established environmental risk factor for Rheumatoid Arthritis, as it is known to trigger inflammatory processes in the lungs that can lead to the production of anti-citrullinated protein antibodies (ACPAs) years before joint symptoms appear.

Distinguishing Causes from Risk Factors

It is vital to distinguish between a cause and a risk factor. A cause is a direct catalyst, while a risk factor increases the probability of development. Currently, research is focused on the "multi-hit hypothesis," which suggests that a combination of genetic susceptibility, environmental triggers (such as smoking or gum disease), and hormonal factors must align to initiate the disease. Because the etiology is not fully understood, current clinical research is deeply invested in microbiome studies and epigenetic markers to better predict who might develop Rheumatoid Arthritis.

Medical Disclaimer: This information is for educational purposes and should not replace professional medical advice, diagnosis, or treatment. Always seek the advice of your rheumatologist or other qualified health provider with any questions regarding your medical condition.

References

• National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)


• NIH Genetic and Rare Diseases Information Center (GARD)


• Orphanet: The portal for rare diseases and orphan drugs


• Arthritis Foundation