Question:hard
A 33-year-old man presents with a 5-week history of calf pain, swelling, and low-grade fever. Serum creatine kinase is elevated. A muscle biopsy reveals numerous eosinophils, and he also has peripheral blood eosinophilia. Which of the following interleukins is primarily responsible for the increase in eosinophils in this patient?
A 33-year-old man presents with a 5-week history of calf pain, swelling, and low-grade fever. Serum creatine kinase is elevated. A muscle biopsy reveals numerous eosinophils, and he also has peripheral blood eosinophilia. Which of the following interleukins is primarily responsible for the increase in eosinophils in this patient?
Show Hint
Eosinophils are a Th2 story; pick the Th2 master cytokine from the options offered.
Updated On: Jun 23, 2026
- IL-2
- IL-4
- IL-1
- IL-6
Show Solution
The Correct Option is B
Solution and Explanation
Think Th2: wherever you see eosinophils plus IgE plus allergy, the cytokine family at work is IL-4, IL-5, and IL-13 from Th2 cells.
Cross out the rest: IL-2 is the T-cell growth factor, it expands lymphocytes not eosinophils. IL-1 and IL-6 are classic macrophage-derived pyrogens that cause fever and acute-phase response but have no specific eosinophil role.
Pick within the list: the most specific eosinophil cytokine is IL-5, yet it is absent from the options. IL-4 is the master switch that commits naive T cells to the Th2 lineage, so it sits at the top of the pathway that produces eosinophilia. Therefore IL-4 is the best available answer.
Pearl: remember IL-4 starts Th2, IL-5 grows eosinophils; when only IL-4 is offered, choose it.
Reference: basic immunology, T-helper subsets.
Cross out the rest: IL-2 is the T-cell growth factor, it expands lymphocytes not eosinophils. IL-1 and IL-6 are classic macrophage-derived pyrogens that cause fever and acute-phase response but have no specific eosinophil role.
Pick within the list: the most specific eosinophil cytokine is IL-5, yet it is absent from the options. IL-4 is the master switch that commits naive T cells to the Th2 lineage, so it sits at the top of the pathway that produces eosinophilia. Therefore IL-4 is the best available answer.
Pearl: remember IL-4 starts Th2, IL-5 grows eosinophils; when only IL-4 is offered, choose it.
Reference: basic immunology, T-helper subsets.
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