How does autoimmunity contribute to disease mechanism?

• A. The immune system mistakenly targets self-antigens, leading to tissue damage and chronic inflammation (e.g., lupus, rheumatoid arthritis)
• B. The immune system only targets pathogens and ignores self-antigens
• C. Autoimmune processes strengthen tissues against inflammation
• D. Autoimmunity is caused by external infections only

Answer: (C)

Autoimmune involvement in disease comes from a breakdown of immune tolerance, causing the immune system to mistakenly attack the body’s own tissues. When autoreactive B and T cells are activated, autoantibodies and inflammatory cytokines target self-antigens, leading to tissue injury and chronic inflammation. This is why autoimmune diseases like lupus and rheumatoid arthritis cause ongoing tissue damage rather than strengthening tissues.

Infections can sometimes act as triggers for autoimmunity (through mechanisms like molecular mimicry or bystander activation), but they are not the sole cause, and autoimmunity is not simply the immune system’s attack on pathogens while ignoring self. The idea that autoimmunity strengthens tissues is inconsistent with the typical destructive inflammatory processes seen in autoimmune diseases.