A 38-year-old woman with plaque psoriasis is considered for ustekinumab therapy. The molecular target of ustekinumab is:

• A The p19 subunit unique to IL-23
• B The IL-17A cytokine directly
• C The shared p40 subunit of IL-12 and IL-23 ✓
• D The TNF-alpha receptor on keratinocytes

Explanation

Ustekinumab is a fully human monoclonal antibody against the p40 subunit shared by IL-12 and IL-23, preventing both cytokines from binding their common receptor chain IL-12R-beta1 on T cells and NK cells. Agents such as risankizumab target only the p19 subunit unique to IL-23, which distinguishes them mechanistically from ustekinumab.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.