A study for proposal of use of regulatory T cells as a prognostic marker and establishing an optimal threshold level for their expression in chronic lymphocytic leukemia

Abstract

Although regulatory T cells (Tregs) have been extensively studied in chronic lymphocytic leukemia, there is no uniform guideline or consensus regarding their use as a prognostic marker. This study describes the methodology used to develop an optimal threshold level for Tregs in these patients. Treg levels were assessed in the peripheral blood of 130 patients and 150 controls. Treg frequencies were linked to established prognostic markers as well as overall survival and time to first treatment. The cut-offs for Treg positivity were assessed by receiver operating characteristic (ROC) analysis. A cut-off of 5.7% for Treg cell percentage and of 35 cells/μL for absolute Treg cell count were determined as optimal in patients with CLL along with a median Treg percentage of 15.5% used to separate patients with low- and high-risk disease. The experiments presented here will possibly aid in the use of Treg frequencies as a potential prognostic marker in CLL.

Keywords::

• Chronic lymphocytic leukemia
• regulatory T cell
• prognostic marker
• optimal cut-off
• receiver operating characteristic analysis
• Kaplan–Meier estimates
• overall survival
• time to first treatment

Acknowledgements

The authors would like to thank all patients who agreed to be involved in this study.

Potential conflict of interest

Disclosure forms provided by the authors are available with the full text of this article at www.informahealthcare.com/lal.

This work was supported by a grant obtained from the Ministry of Science and Technology (Department of Science and Technology, No. SR/FT/LS-151/2008) to Dr. Alakananda Dasgupta.

Supplementary material available online

Supplementary Tables showing ROC analysis results.