Question

Which immune system fails to discriminate between self and non-self? A. Insulin-dependent diabetes ($\beta$-cell antibodies) B. Asthma (antibodies against lung cells) C. Myasthenia gravis (acetylcholine receptor autoantibodies) D. Hepatitis (antibody against hepatic cells) E. Rheumatoid arthritis (antibodies against joint protein) Choose the correct answer from the options given below:

• A. A and E only \
• B. D and B only \
• C. A, C and E only \
• D. B and C only

Hint:

Type 1 Diabetes, Myasthenia Gravis, and Rheumatoid Arthritis are textbook examples of autoimmune diseases where the body mistakenly attacks its own cells.

Answer 1

The Correct Option is C

Step 1: Concept Autoimmunity occurs when the immune system loses immunological tolerance, failing to distinguish between the body's own self-antigens and foreign non-self targets. This leads to immune-mediated damage to healthy tissues.

Step 2: Meaning Classic autoimmune diseases are defined by the abnormal production of autoantibodies that directly target specific self-proteins or receptors.

Step 3: Analysis * Condition A (Insulin-dependent diabetes): A classic organ-specific autoimmune disease where the immune system generates autoantibodies that destroy the insulin-producing $\beta$ cells in the pancreas $\rightarrow$ Autoimmune. * Condition B (Asthma): Primarily a chronic inflammatory disease driven by hypersensitivity reactions to environmental allergens, rather than an autoimmune attack targeting lung cell antibodies. * Condition C (Myasthenia gravis): A classic neuromuscular autoimmune disease caused by autoantibodies that block or destroy acetylcholine receptors at the neuromuscular junction $\rightarrow$ Autoimmune. * Condition D (Hepatitis): Most commonly caused by viral infections (like HBV or HCV) or environmental toxins, rather than behaving primarily as a hallmark autoimmune disorder. * Condition E (Rheumatoid arthritis): A systemic autoimmune disease where autoantibodies target joint tissue proteins, leading to chronic joint inflammation and destruction $\rightarrow$ Autoimmune.

Step 4: Conclusion The classic autoimmune conditions listed are A, C, and E, matching option C. Final Answer: (C)