IL-2 therapy promotes suppressive ICOS+ Treg expansion in melanoma patients
Geok Choo Sim, … , Patrick Hwu, Laszlo Radvanyi
Geok Choo Sim, … , Patrick Hwu, Laszlo Radvanyi
Published December 2, 2013
Citation Information: J Clin Invest. 2014;124(1):99-110. https://doi.org/10.1172/JCI46266.
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Research Article Immunology

IL-2 therapy promotes suppressive ICOS+ Treg expansion in melanoma patients

Abstract

High-dose (HD) IL-2 therapy in patients with cancer increases the general population of Tregs, which are positive for CD4, CD25, and the Treg-specific marker Foxp3. It is unknown whether specific subsets of Tregs are activated and expanded during HD IL-2 therapy or whether activation of any particular Treg subset correlates with clinical outcome. Here, we evaluated Treg population subsets that were induced in patients with melanoma following HD IL-2 therapy. We identified a Treg population that was positive for CD4, CD25, Foxp3, and the inducible T cell costimulator (ICOS). This Treg population increased more than any other lymphocyte subset during HD IL-2 therapy and had an activated Treg phenotype, as indicated by high levels of CD39, CD73, and TGF-β. ICOS+ Tregs were the most proliferative lymphocyte population in the blood after IL-2 therapy. Patients with melanoma with enhanced expansion of ICOS+ Tregs in blood following the first cycle of HD IL-2 therapy had worse clinical outcomes than patients with fewer ICOS+ Tregs. However, there was no difference in total Treg expansion between HD IL-2 responders and nonresponders. These data suggest that increased expansion of the ICOS+ Treg population following the first cycle of HD IL-2 therapy may be predictive of clinical outcome.

Authors

Geok Choo Sim, Natalia Martin-Orozco, Lei Jin, Yan Yang, Sheng Wu, Edwina Washington, Deborah Sanders, Carol Lacey, Yijun Wang, Luis Vence, Patrick Hwu, Laszlo Radvanyi

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Figure 3

ICOS+ Tregs (CD4+CD25+Foxp3+) are more highly activated and more highly cycling than ICOS– Tregs or other lymphocyte subsets before and after HD IL-2 therapy.

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ICOS+ Tregs (CD4+CD25+Foxp3+) are more highly activated and more highly ...
(A) Flow cytometry staining for Ki67 expression using intracellular flow cytometry staining in ICOS+ and ICOS– Treg subsets before and after cycle 1 of HD IL-2 therapy. Frequencies of Ki67+ cells are as indicated in dot plots. (B) Summary results from 10 patients are shown in scatter plots. (C) PBMCs from 5 patients were stained for the indicated subsets together with intracellular staining for Ki67 before therapy (day 0), shortly after therapy (day 6), and 3 weeks after therapy (day 21) (see Methods section). Percentages of Ki67+ cells in each lymphocyte subset were determined and then arcsine transformed for 1-way ANOVA and Tukey’s multiple comparison analysis. Arcsine-transformed values were plotted for the indicated subsets. Horizontal bars represent median values. (D) Fresh PBMCs from 3 patients shortly after HD IL-2 therapy (day 6) were isolated and stained with eFluor 670 dye for the dye dilution proliferation assay. Cells were cultured for 5 days in the presence of HD IL-2 (3,000 IU/ml). After 5 days, cells were harvested and stained for Treg markers. The gating strategy and frequencies of indicated cell subsets are as shown in dot plots. Frequencies of proliferative cells in ICOS+ and ICOS– Treg subsets are as indicated in histograms (***P < 0.001, **0.001 < P < 0.01, *0.01 < P < 0.05).