A 42-year-old with moderate-to-severe plaque psoriasis (PASI 18, DLQI 14) fails two conventional systemic agents. You initiate a biologic. Secukinumab acts specifically by blocking which cytokine that is the primary downstream effector in psoriasis pathogenesis?
- A IL-17A ✓
- B TNF-alpha
- C IL-12/23 (p40 subunit)
- D IL-23 (p19 subunit)
Correct answer: A. IL-17A
Explanation
Secukinumab is a fully human monoclonal antibody that specifically neutralises IL-17A, the key effector cytokine produced by Th17 cells that drives keratinocyte hyperproliferation, neutrophil recruitment, and epidermal barrier dysfunction in plaque psoriasis. TNF-alpha is targeted by adalimumab/etanercept; p40 subunit of IL-12/23 is targeted by ustekinumab; IL-23 p19 is targeted by guselkumab and risankizumab. IL-17A blockade also includes ixekizumab.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.