Eosinophilia with increased serum creatinine kinase
A 33-year-old man presents with 5-week history of calf pain, swelling, and low-grade fever. Serum levels of creatinine kinase are elevated. A muscle biopsy reveals numerous eosinophils. Her peripheral blood smear shows eosinophilia. Which of the following interleukins is primarily responsible for the increase in eosinophils?