Which of the following best describes the mechanism of action of belimumab in the treatment of SLE?
- A Depletes CD20+ B cells through complement-dependent cytotoxicity
- B Inhibits B-lymphocyte stimulator (BLyS/BAFF), reducing B-cell survival and autoantibody production ✓
- C Blocks interleukin-6 receptor signaling
- D Inhibits calcineurin, preventing T-cell activation
Correct answer: B. Inhibits B-lymphocyte stimulator (BLyS/BAFF), reducing B-cell survival and autoantibody production
Explanation
Belimumab is a monoclonal antibody that inhibits B-lymphocyte stimulator (BLyS, also called BAFF), a cytokine essential for B-cell survival, maturation, and differentiation into antibody-producing plasma cells. By blocking BLyS, belimumab reduces autoreactive B-cell populations and subsequent autoantibody (anti-dsDNA, anti-Smith) production. Rituximab (anti-CD20) depletes B cells directly. Tocilizumab blocks IL-6 receptor. Calcineurin inhibitors (tacrolimus, cyclosporine) block T-cell activation.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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