What is the prevalence of sarcoidosis in Ireland?

Correct Answer: B

Rationale: The correct answer is B: Among the highest globally. Sarcoidosis prevalence in Ireland is relatively high compared to other regions. This is due to genetic factors, environmental influences, and possibly healthcare practices. Sarcoidosis rates vary worldwide, with Ireland being noted for its higher prevalence. Choices A, C, and D are incorrect because Ireland's sarcoidosis prevalence is not among the lowest globally, similar to the global average, or extremely rare.

Correct Answer: E

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: B

Rationale: The correct answer is B: AIRE. APECED (Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy) is caused by mutations in the AIRE gene. AIRE is responsible for regulating the expression of self-antigens in the thymus, crucial for the development of immune tolerance. Deficiency in AIRE leads to the production of autoantibodies and autoimmune manifestations. Incorrect options: A: CTLA-4 is involved in downregulating immune responses but is not directly linked to APECED. C: Tregs (regulatory T cells) play a role in immune tolerance, but APECED is not directly caused by their deficiency. D: TGF-β is a cytokine involved in immune regulation, but its deficiency does not lead to APECED.

Correct Answer: D

Rationale: Step 1: Viral antigenic shift involves major changes in the surface proteins of the virus, particularly the hemagglutinin (HA) protein. Step 2: These changes result in the emergence of new variants that are not recognized by preexisting antibodies. Step 3: This process is distinct from antigenic drift, which involves minor changes due to random mutations. Step 4: Choice D correctly states that viral antigenic shift refers to the appearance of new HA variants not recognized by preexisting antibodies. Summary: Choice A is incorrect because viral antigenic shift is not caused by multiple random mutations. Choice B is incorrect as antigenic shift involves major changes, not a single mutation. Choice C is incorrect as it affects surface proteins like HA, not just internal proteins.

Correct Answer: A

Rationale: Defensins are cationic antimicrobial peptides that play a crucial role in the innate immune system by disrupting the microbial cell membrane. This property allows them to kill a wide range of pathogens. Option A is correct because it accurately describes the primary function of defensins. Option B, opsonins, are proteins that enhance phagocytosis but are not specific to defensins. Option C, DAMPs, are damage-associated molecular patterns released by damaged cells and are not related to defensins. Option D, fatty acids, are not directly related to the antimicrobial properties of defensins.