Circulating T-regulatory cells in PNET: A prospective study

Purpose Bone marrow regulatory T-cells (Tregs) have been evaluated in patients with peripheral neuroectodermal tumor (PNET); data on peripheral blood circulating Tregs are lacking. The objective of our study was to determine baseline Tregs (both Treg frequency and absolute number) in patients with PNET and correlate with patient characteristics, and observe their change with treatment and relapse. Methods Five milliliters blood was evaluated in de novo patients with PNET at diagnosis, post-neoadjuvant chemotherapy and at relapse/progression, along with nine healthy controls using flow-cytometric analysis for Treg cells (CD4+ CD25+ FoxP3+). Results Thirty-seven patients with median age 17 years; male/female ratio 5.1:1 had significantly higher baseline absolute Tregs than controls (mean 338.95 ± 264.63/mm3 vs. 34.83 ± 24.90/mm3; P