Original Articlesα-Hemoglobin-stabilizing Protein Is a Sensitive and Specific Marker of Erythroid PrecursorsRaess, Philipp W. MD, PhD*; Paessler, Michelle E. DO*,†; Bagg, Adam MD*; Weiss, Mitchell J. MD, PhD‡; Choi, John Kim MD, PhD§ Author Information *Department of Pathology and Laboratory Medicine, University of Pennsylvania †Department of Pathology ‡Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, PA §Department of Pathology, St Jude Children’s Research Hospital, Memphis, TN Conflicts of Interest and Source of Funding: Supported in part by the National Institutes of Health (NIH) under grants R01 DK061692, R01 HL087427, and P30DK090969 (M.J.W.). The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: John Kim Choi, MD, PhD, Department of Pathology, St Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 250, Memphis, TN 38105 (e-mail: [email protected];[email protected]). The American Journal of Surgical Pathology 36(10):p 1538-1547, October 2012. | DOI: 10.1097/PAS.0b013e31825fa501 Buy Metrics Abstract α-Hemoglobin-stabilizing protein (AHSP) is an abundant erythroid-specific chaperone protein that facilitates incorporation of nascent α-globin into hemoglobin A. We characterized AHSP expression by immunohistochemistry in a panel of 100 neoplastic and reactive bone marrow biopsies and splenic tissue with extramedullary hematopoiesis and compared it with established erythroid markers CD71 and CD235a. In all cases, AHSP expression was limited to physiological nucleated erythroid precursors (EPs) and blasts in erythroid leukemias. Although CD71 also stained EPs, it additionally stained nonerythroid malignant cells to varying extents in acute leukemia, diffuse large B-cell lymphoma, metastatic carcinomas, and small round blue cell tumors. In contrast, CD235a staining was erythroid-specific but stained non-nucleated red blood cells in all specimens, limiting its utility. We conclude that AHSP is superior to CD71 and CD235a for detecting normal and neoplastic nucleated EPs. © 2012 Lippincott Williams & Wilkins, Inc.