A patient with thymoma develops pure red cell aplasia. The autoantibody responsible targets which erythroid precursor surface molecule?

• A Glycophorin A on mature erythrocytes
• B Erythropoietin receptor on BFU-E and CFU-E ✓
• C Band 3 protein on reticulocytes
• D CD20 on early B-lymphoid progenitors

Explanation

Thymoma-associated pure red cell aplasia is mediated by autoantibodies that target the erythropoietin receptor on erythroid progenitors (BFU-E and CFU-E), blocking EPO signalling and ablating erythropoiesis while leaving white cell and platelet production intact. Glycophorin A and Band 3 are mature red cell antigens not involved in this mechanism. CD20 is a B-cell marker unrelated to erythroid development.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.