Immune System Failure: Self vs. Non-Self Discrimination

The immune system's primary role is to distinguish between the body's own components (self) and foreign invaders (non-self). When this discrimination fails, the immune system mistakenly attacks the body's own tissues, leading to autoimmune diseases.

Analyzing Autoimmune Conditions

We need to identify the conditions listed where the immune system attacks 'self' components:

• A. Insulin-dependent diabetes: Characterized by antibodies attacking the pancreas's beta cells, which produce insulin. This is a clear failure of self-recognition.
• C. Myasthenia gravis: Involves autoantibodies targeting acetylcholine receptors, crucial for nerve-muscle communication. This is an autoimmune attack on self.
• E. Rheumatoid arthritis: An autoimmune disorder where the immune system attacks proteins and tissues in the joints, causing inflammation and damage. This targets self-components.

Evaluating Other Options

Options B and D are less direct examples or potentially ambiguous in the context of pure autoimmune failure:

• B. Asthma: Primarily an inflammatory and allergic condition of the airways, not typically classified as a direct autoimmune attack on lung cells by antibodies.
• D. Hepatitis: While autoimmune hepatitis exists, the term 'Hepatitis' broadly includes viral causes (non-self). Without specification, it's less definitively an example of self vs. non-self failure compared to A, C, and E.

Conclusion on Immune Discrimination Failure

Conditions A (Insulin-dependent diabetes), C (Myasthenia gravis), and E (Rheumatoid arthritis) clearly represent instances where the immune system fails to discriminate between self and non-self, attacking the body's own tissues.