A 35-year-old presents with cystic lesion in the liver on ultrasound. Serological tests (ELISA) are positive for Echinococcus antigen. Casoni's skin test shows immediate-type hypersensitivity. Which cell type is responsible for the eosinophilia seen in this patient?
- A Th2 cells via IL-5 ✓
- B Th1 cells via IFN-γ
- C Tc cells via perforin
- D NK cells via ADCC
Explanation
Helminthic infections including hydatid disease (Echinococcus granulosus) drive a Th2 immune response characterised by release of IL-4, IL-5, and IL-13. IL-5 is the principal cytokine responsible for eosinophilia — it promotes eosinophil production, maturation, and release from bone marrow, as well as eosinophil survival in tissues. IgE-mediated mast cell degranulation (also Th2-driven) underlies the anaphylactic risk if a cyst ruptures. IFN-γ (Th1) and perforin (cytotoxic T cells) are more relevant to intracellular pathogen clearance, not helminth-driven eosinophilia.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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