Example of Immune complex-mediated (type III) hypersensitivity is
The question is asking for an example of this type. The correct answer options might include SLE, post-streptococcal glomerulonephritis, or maybe something like rheumatoid arthritis. Wait, rheumatoid arthritis is type II, I think. Or is it type III? Hmm, need to be careful here. Let me double-check. Type II is antibody-mediated against cell surface antigens, like in Goodpasture's. Type III is immune complexes, so SLE, SLE has anti-nuclear antibodies forming complexes that deposit in organs. Serum sickness is another example, which is a reaction to foreign serum proteins. Post-streptococcal glomerulonephritis is also type III because of immune complexes from strep antigens and antibodies.
Now, the options given in the original question are A to D, but they're not listed here. The user probably had a specific set of options, but since they're missing, I need to infer based on common distractors. Common incorrect answers might include type I (allergic reactions like hay fever), type II (like hemolytic anemia), type IV (delayed hypersensitivity like contact dermatitis). So, if the options included something like "Hay fever" for type I, that's a wrong answer. Similarly, "Anaphylaxis" is type I. "Contact dermatitis" is type IV. "Goodpasture's disease" is type II.
The core concept here is understanding the classification of hypersensitivity reactions. The correct answer is an example where immune complexes cause tissue damage. The clinical pearl would be to remember that type III involves immune complex deposition leading to inflammation and complement activation. High-yield facts often tested are the classic examples of each type. So SLE is a key example for type III. Another example is serum sickness, which occurs after exposure to certain drugs or sera. The student should know that type III is about immune complexes, not just antibodies or T cells.
I need to structure the explanation with the required sections. Start with Core Concept, then explain why the correct answer is right (using SLE as an example), then go through each wrong option. The clinical pearl should highlight the key examples. Finally, the correct answer line. Make sure to use bold for section headers and key terms, keep it concise, and within the character limit. Check for any possible errors in the examples, like confusing type II and III. Also, ensure that the explanations are clear and not too technical, but still precise for a postgraduate student.
**Core Concept**
Type III hypersensitivity involves immune complex deposition (antigen-antibody complexes) in tissues, triggering complement activation and neutrophil-mediated inflammation. It differs from other hypersensitivity types by the presence of circulating immune complexes causing vascular injury and organ damage.
**Why the Correct Answer is Right**
Systemic lupus erythematosus (SLE) is a prototypical type