Alemtuzumab was used in B-cell chronic lymphocytic leukemia. Its target antigen and the clinically important consequence of that choice are:
- A CD38, expressed on plasma cells, causing loss of serum immunoglobulin only
- B CD20, restricted to pre-B and mature B cells, causing isolated humoral deficiency
- C CD52, expressed on both B and T cells, causing profound and prolonged combined immunosuppression ✓
- D CD33, expressed on myeloid precursors, causing neutropenia with preserved lymphocyte function
Correct answer: C. CD52, expressed on both B and T cells, causing profound and prolonged combined immunosuppression
Explanation
Alemtuzumab targets CD52, a surface antigen present on virtually all mature B and T lymphocytes, monocytes, and macrophages but not on hematopoietic stem cells. Depletion therefore affects cellular and humoral immunity together, and lymphopenia persists for many months, creating a marked risk of opportunistic infections including CMV, Pneumocystis, and fungal disease, so prophylaxis is required. Rituximab's CD20 restriction spares T cells, which is why its infection profile is milder.
Reference: Katzung Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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