A patient with pemphigus vulgaris refractory to prednisolone 1 mg/kg/day is considered for rituximab. Which of the following best describes the mechanism by which rituximab achieves remission in pemphigus?
- A Inhibits IL-4 and IL-13 signaling, reducing IgE-mediated blistering
- B Blocks TNF-alpha-mediated acantholysis in the spinous layer
- C Activates regulatory T cells to suppress the humoral immune response
- D Depletes CD20+ B cells, reducing production of pathogenic anti-desmoglein antibodies ✓
Explanation
Rituximab is a chimeric anti-CD20 monoclonal antibody that selectively depletes B lymphocytes. In pemphigus, pathogenic IgG anti-desmoglein antibodies are produced by B cells and plasma cells. Rituximab (375 mg/m² weekly x4 or 1000 mg x2 doses 2 weeks apart) produces prolonged remission by depleting the B-cell pool responsible for anti-Dsg antibody production. It is now first-line therapy for moderate-to-severe pemphigus per recent guidelines. IL-4/IL-13 inhibition (dupilumab) is used for atopic dermatitis; TNF-alpha blockade is used in psoriasis and hidradenitis suppurativa.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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