The Journal of Immunology, 2007, 178: 49.18.
Copyright © 2007 by The American Association of Immunologists, Inc.
Increased Levels of Circulating CD4+CD25+ T cells (T-regs) Correlate with Clinical Cancer Stage And Inversely Correlate with CD8+ T cell Frequency
Amir Al-Khami1,
Alberto J. Montero2,
Mohamed L. Salem1,
Kristi Vissage2,
David J. Cole1 and
C. Marcela Diaz-Montero1
1 Department of Surgery,
2 Department of Medicine, Medical University of South Carolina, 86 Jonathan Lucas St. Room 506, Charleston, SC, 29425
Abstract
Regulatory T cells inhibit immune responses mediated by T cells. Increased circulating levels of T-regs in patients (pts) have been reported in some solid tumors. Moreover, increased apoptosis among circulating CD8+ T cells has been reported in cancer pts. The goal of our study was therefore to determine how levels of circulating T-regs and CD8+T cells correlate with clinical cancer stage in a diverse cohort of pts. Flow cytometry analyses were performed on whole blood from 14 normal healthy controls and 35 cancer pts with newly diagnosed tumors prior to any therapy (stages: I/II, n=12; III/IV n=23). Although no significant difference was observed in T-regs between normal and stage I/II cancer pts (4.36% vs. 4.92%), levels were significantly increased in stage III/IV pts (7.26%; p=0.039). Moreover, there was an inverse correlation between CD8+T cell frequencies and clinical cancer stage, with stage III/IV pts having the lowest levels relative to normal (3.97% vs. 7.01%; p=0.036). In conclusion, T-regs were increased only in pts with advanced stage III/IV cancer and percentage of total CD8+T cells inversely correlated with clinical tumor stage. Thus, increased levels of T-regs and decreased levels of CD8+ T cells might contribute to cancer-mediated immunosupression.
