Cytoplasmic Expression of CD3ε Heterodimers by Flow Cytometry Rapidly Distinguishes Between Mature T-Cell and Natural Killer–Cell Neoplasms

• Published in: American journal of clinical pathology Vol. 154; no. 5; pp. 683 - 691
• Main Authors: Shi, Min, Nguyen, Phuong, Timm, Michael M, Otteson, Gregory E, Horna, Pedro, Olteanu, Horatiu, Jevremovic, Dragan
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01-11-2020
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; CD16 antigen; CD3 antigen; CD3 Complex - metabolism; CD4 antigen; CD45 antigen; CD5 antigen; CD56 antigen; CD57 antigen; CD7 antigen; CD8 antigen; Cell lineage; Diagnosis, Differential; Female; Flow Cytometry; Gene rearrangement; Humans; Immunohistochemistry; Immunophenotyping; Killer Cells, Natural - metabolism; Leukemia, Large Granular Lymphocytic - diagnosis; Leukemia, Large Granular Lymphocytic - metabolism; Leukemia, Large Granular Lymphocytic - pathology; Lymphocytes T; Lymphoma, T-Cell - diagnosis; Lymphoma, T-Cell - metabolism; Lymphoma, T-Cell - pathology; Male; Middle Aged; Natural killer cells; T cell receptors; T-Lymphocytes - metabolism; Tumors; Flow cytometry; T-cell neoplasm; Cytoplasmic CD3; NK-cell neoplasm
• ISSN: 0002-9173; 1943-7722
• DOI: 10.1093/ajcp/aqaa086

Abstract
Objectives
Distinguishing between T-cell and natural killer (NK)–cell neoplasms could be difficult given their overlapping immunophenotype. In this study, we investigated whether a flow cytometry assay with cytoplasmic staining for CD3 could be used for this purpose.
Methods
Flow cytometry immunophenotyping was performed on 19 surface CD3 (sCD3)–negative mature T-cell neoplasms, 10 sCD3-positive mature T-cell neoplasms, 13 mature NK-cell neoplasms, and 19 normal controls. In addition to routine antibody panels (CD2, sCD3, CD4, CD5, CD7, CD8, CD16, CD45, CD56, CD57, CD94, CD158a, CD158b, CD158e, NKG2A TCRγ/δ), cytoplasmic staining for a monoclonal CD3 antibody (clone SK7/Leu-4) was assessed in all cases. A molecular study for T-cell receptor (TCR) gene rearrangement and an immunohistochemical study for TCRβ were performed.
Results
Our data showed all T-cell neoplasms were uniformly positive for cytoplasmic CD3 (cCD3) regardless of sCD3 expression, whereas 85% of NK-cell neoplasms completely lacked cCD3 expression. The 2 cases with classic NK-cell immunophenotype but partial cCD3 expression showed no molecular genetic features of T-cell lineage by TCR gene rearrangement studies.
Conclusions
Uniform cCD3 positivity and homogeneous cCD3 negativity highly suggest T-cell and NK lineage, respectively. When partial cCD3 expression is encountered, additional confirmatory studies should be pursued for the most accurate lineage assignment.