Flow cytometric immunophenotyping of regulatory T cells in chronic lymphocytic leukemia: comparative assessment of various markers and use of novel antibody panel with CD127 as alternative to transcription factor FoxP3

Abstract

This study analyzed the frequency of regulatory T cells (Tregs) in chronic lymphocytic leukemia (CLL) by multiparameter flow cytometric immunophenotyping. Patients showed significantly increased frequencies of Tregs as compared to controls, a significantly higher percentage than that identified by previous studies, possibly indicating a different prognosis of CLL in different parts of the world and, more precisely, a worse prognosis of CLL in the Indian population. A higher frequency of Tregs was also seen in advanced stage of disease with significantly reduced frequencies of Tregs in patients with CLL after chemotherapy. A significant proportion of CD127low/−FoxP3+ Tregs expressed only low levels of CD25. Thus, CD127 appears to be a better marker than CD25 for the identification of CD4+FoxP3+ T cells as potential Tregs. Our results suggest that the specificity and sensitivity of CD4+CD127low/− cells are comparable to those of CD4+FoxP3+, which is the gold standard, and can be used as an alternative. This novel flow cytometric antibody panel with fewer number of antibodies is cost-effective and can be used to enumerate Tregs in resource-limited settings.

Keywords::

• Chronic lymphocytic leukemia
• regulatory T cell
• FoxP3
• CD4
• CD127low/−
• CD25high
• novel
• limited antibody panel

Acknowledgements

Financial support for this work was obtained from the Ministry of Science and Technology (Department of Science and Technology), Government of India (No. SR/FT/LS-151/2008).

Potential conflict of interest

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