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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Betz, S. A. Articles by Willman, C. L. Search for Related Content PubMed PubMed Citation Articles by Betz, S. A. Articles by Willman, C. L. Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  False-positive flow cytometric platelet glycoprotein IIb/IIIa expression in myeloid leukemias secondary to platelet adherence to blasts SA Betz, K Foucar, DR Head, IM Chen and CL Willman Department of Pathology, University of New Mexico School of Medicine, Albuquerque. Because neither morphologic nor routine cytochemical features are pathognomonic, the diagnosis of acute megakaryoblastic leukemia (AML- M7) is difficult, requiring either specialized ultrastructural or immunologic techniques. Because the ultrastructural techniques are cumbersome, immunologic assays for expression of several platelet- specific antigens, such as CD41a (platelet glycoprotein IIb/IIIa), have become the primary method used to detect megakaryoblastic differentiation. In our flow cytometric analysis of the immunophenotypes of over 1,000 cases of AML from patients registered to Southwest Oncology Group (SWOG) Treatment Protocols, we found that 38% of cases demonstrated CD41a reactivity. Because this frequency of CD41a expression by flow cytometry greatly exceeded the number of morphologically defined cases of AML-M7, we postulated that the reaction may be caused by platelets adherent to leukemic blasts. To investigate this hypothesis, we performed a side-by-side comparison of flow cytometric and cytospin immunofluorescence studies on 37 cases of adult de novo AML that demonstrated a wide range of CD41a expression by flow cytometric analyses. We found that the expression of CD41a detected by flow cytometric techniques was secondary to adherent platelets or platelet fragments in 85% of cases. Many of these cases also expressed the lineage-specific carbohydrate, LNF III (CD15), which may mediate platelet adhesion to mature monocytes and neutrophils. Only 15% of the CD41a flow cytometrically positive cases demonstrated true diffuse membrane and cytoplasmic positivity on cytospin slides indicative of megakaryoblastic differentiation. Cytospin immunofluorescence for CD41a should be performed on all cases of suspected AML-M7. If only flow cytometric techniques are used, adherent platelets may result in the erroneous diagnosis of this AML subtype. Volume 79, Issue 9, pp. 2399-2403, 05/01/1992 Copyright © 1992 by The American Society of Hematology CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: C. D. Jennings and K. A. Foon Recent Advances in Flow Cytometry: Application to the Diagnosis of Hematologic Malignancy Blood, October 15, 1997; 90(8): 2863 - 2892. [Full Text] [PDF]

	Copyright © 1992 by American Society of Hematology         Online ISSN: 1528-0020