title: Analysis of immunohistochemical markers in bone marrow sections to evaluate for myelodysplastic syndromes and acute myeloid leukemias.
abstract: BACKGROUND
  Accurate bone marrow (BM) blast counts (BCs) are essential for diagnosis (dx) of myelodysplasia (MDS), MDS/myeloproliferative (MDS/MPD) disease, or acute myeloid leukemia (AML), and may be difficult in hemodiluted bone marrow aspirates (BMAs). Erythroid precursors (EPs) may be indistinguishable from myeloblasts in BM sections (aspirate clots/cores). We compare the usefulness of immunohistochemistry (IHC) [ie, CD34, CD117, myeloperoxidase (MPO), Hemoglobin A1 (HbA1), and terminal deoxynucleotidyl transferase (TdT)] of BM sections (IHC-BM) with BMA, bone marrow touch preparation (BMTP), and flow cytometry (FC) BCs.
  
  
  METHODS
  The initial BC (48), percentage (%) of Eps (38) (both based on initial 100 to 600-cell counts), and FC expressions of CD34, CD117, Glycophorin A(GLY A), and TdT (44) were tabulated from 50 BMs (MDS, MDS/MPD, or AML). BMAs (48) and BMTPs (25) subsequently received 500-cell counts. IHC-BM was performed (45:formalin, 5:B5-fixed) [CD34 (46), CD117 (45), HbA1 (45), TdT (42), and MPO (45)].
  
  
  RESULTS
  Retrospective BMA BCs revealed a 31% (15/48) discrepant rate between the original/retrospective BMA BCs; 80% revealed an underestimated initial BC. There was a 28% discordance rate between the retrospective BMA and BMTP reviews; 77% showed a higher BMTP BC. IHC showed significantly higher BCs in 19% (9/47), resulting in a different dx (5). However, CD34 and CD117 IHCS revealed lower BCs in 38% and 48%, respectively. The CD34 IHC results were primarily due to CD34-negative blasts by FC. The CD117 IHC results were largely unexplained. EPs were CD34 and CD117-negative.
  
  
  CONCLUSIONS
  (1) Evaluation for MDS/AML requires 500-cell counts of BMAs and/or BMTPs. (2) CD34 and/or CD117 blasts by FC indicate IHC-BM may increase BC accuracy. (3) CD34 is more reliable than CD117 by IHC; however, in combination, they are most reliable and should be performed on BM clots/cores due to variable reactivity.
authors.affiliation: Divisions of Hematopathology, Departments of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525, USA. cdunphy@unch.unc.edu
authors.forename: Cherie H
authors.initials: CH
authors.lastname: Dunphy
authors.forename: Dennis P
authors.initials: DP
authors.lastname: O'Malley
authors.forename: Sherrie L
authors.initials: SL
authors.lastname: Perkins
authors.forename: Chung-Che
authors.initials: CC
authors.lastname: Chang
mesh_terms: D018952:Antigens, CD34 / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D001772:Blood Cell Count; D001853:Bone Marrow / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D004253:DNA Nucleotidylexotransferase / Q000032:analysis; D005434:Flow Cytometry; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D015470:Leukemia, Myeloid, Acute / Q000201:enzymology / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D009190:Myelodysplastic Syndromes / Q000201:enzymology / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D009195:Peroxidase / Q000032:analysis; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis; D012189:Retrospective Studies
chemical_list: D018952:Antigens, CD34; D015415:Biomarkers; D004253:DNA Nucleotidylexotransferase; D006442:Glycated Hemoglobin; D009195:Peroxidase; D019009:Proto-Oncogene Proteins c-kit