Utility of CD26 in flow cytometric immunophenotyping of T‐cell lymphomas in tissue and body fluid specimens

DM Pierson, D Jones, T Muzzafar… - Cytometry Part B …, 2008 - Wiley Online Library
DM Pierson, D Jones, T Muzzafar, MJ Kersh, P Challagundla, LJ Medeiros, JL Jorgensen
Cytometry Part B: Clinical Cytometry: The Journal of the …, 2008Wiley Online Library
Background CD26 is expressed by most CD4+ T cells in normal peripheral blood
specimens. Neoplastic T cells are frequently CD26− in mycosis fungoides/Sezary syndrome
involving the peripheral blood. However, CD26 expression by reactive and neoplastic T
cells in solid tissues and body fluids has not been fully characterized by flow cytometry (FC).
Methods Solid tissue and body fluid specimens were assayed for CD26 expression using
four‐color FC immunophenotyping, by qualitative assessment of population clusters, and by …
Background
CD26 is expressed by most CD4+ T cells in normal peripheral blood specimens. Neoplastic T cells are frequently CD26− in mycosis fungoides/Sezary syndrome involving the peripheral blood. However, CD26 expression by reactive and neoplastic T cells in solid tissues and body fluids has not been fully characterized by flow cytometry (FC).
Methods
Solid tissue and body fluid specimens were assayed for CD26 expression using four‐color FC immunophenotyping, by qualitative assessment of population clusters, and by quantitation with comparison with isotype controls. Benign T cells were studied in reactive tissues and in the background of other malignancies.
Results
Many T‐cell lymphomas were dim or negative for CD26, whereas a few were brightly positive. In the majority of T‐cell lymphomas, CD26 expression could potentially help identify aberrant population clusters. T cells in reactive tissue specimens and tumor‐infiltrating T cells were commonly dim to negative for CD26.
Conclusions
Both T‐cell lymphomas and reactive T cells in tissue and body fluid specimens often show low levels of CD26 expression. Therefore, quantitative methods may not reliably distinguish benign from neoplastic T cells in these specimens. However, CD26, in combination with other T‐cell markers, can be helpful for identifying aberrant population clusters in T‐cell lymphomas. © 2008 Clinical Cytometry Society
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