Which of the following is an example of an autoimmune disease, in which the immune system mistakenly attacks the body’s own tissues?

Introduction / Context:
Autoimmune diseases occur when the immune system, which normally protects the body against infections, mistakenly targets and damages its own cells and tissues. This question asks you to identify which listed condition is a classic autoimmune disease. Understanding this concept is important for immunology and general health awareness.

Given Data / Assumptions:

• Several disease conditions are listed as options.

• Only one of these is primarily caused by an autoimmune reaction.

• The options include allergic reactions, occupational lung disease, cardiovascular events, and common infections.

• We assume basic knowledge of what autoimmune means in contrast to allergy or infection.

Concept / Approach:
In autoimmune diseases, the body produces antibodies or T cells that react against self antigens. Systemic lupus erythematosus is a well known autoimmune disease that can affect skin, joints, kidneys, and other organs. By contrast, acute anaphylaxis is a severe allergic reaction to external antigens, farmers lung is a hypersensitivity reaction to inhaled organic dust, a heart attack is caused by blocked coronary arteries, and the common cold is due to viral infection. Recognizing which disease involves immune attack on self tissues allows us to identify the correct answer.

Step-by-Step Solution:
Step 1: Recall that systemic lupus erythematosus involves the production of autoantibodies against components of cell nuclei and other self antigens. Step 2: Understand that these autoantibodies form immune complexes that can deposit in tissues such as kidneys, joints, and skin, leading to inflammation and damage. Step 3: Compare this with acute anaphylaxis, which is a rapid, severe allergic reaction mediated by immunoglobulin E antibodies against foreign substances like drugs or insect venom. Step 4: Farmers lung is a hypersensitivity pneumonitis due to inhaled organic dusts from moldy hay and is primarily an allergic reaction, not an autoimmune attack on normal tissues. Step 5: A heart attack results from reduced blood flow to heart muscle due to blocked coronary arteries and is not an immune mediated self attack in the classical autoimmune sense. Step 6: The common cold is a viral infection of the upper respiratory tract. Step 7: Therefore, systemic lupus erythematosus is the only option that clearly represents an autoimmune disease.

Verification / Alternative check:
Lists of major autoimmune diseases in medical sources routinely include systemic lupus erythematosus alongside conditions like rheumatoid arthritis and type 1 diabetes. Acute anaphylaxis appears in sections on allergies and hypersensitivity, not autoimmunity. Farmers lung is grouped with occupational lung disorders and hypersensitivity pneumonitis. Heart attack is discussed in cardiovascular disease chapters, and the common cold is discussed under viral infections. This classification confirms that systemic lupus erythematosus is the autoimmune disease among the options.

Why Other Options Are Wrong:

Acute anaphylaxis: A severe immediate allergic reaction to external antigens, not self antigens.

Farmers lung: A hypersensitivity reaction to inhaled organic dusts, more allergic than autoimmune.

Heart attack myocardial infarction: Caused by blocked coronary arteries and ischemia, not by the immune system attacking healthy tissues as a primary mechanism.

Common cold: A viral infection caused by rhinoviruses and other respiratory viruses, not an autoimmune condition.

Common Pitfalls:
Students may confuse allergy and autoimmunity because both involve the immune system. However, in allergy the immune system reacts to non self substances like pollen or dust, whereas in autoimmunity the target is self tissue. Another pitfall is assuming that any chronic disease with inflammation is autoimmune, when it may have other causes. Carefully distinguishing between self and non self targets helps avoid these mistakes.

Final Answer:
The autoimmune disease listed is Systemic lupus erythematosus.