P1-153 - Prognositc Inpact of Tumor-Infiltrating FOXP3+ Regulatory T Cells in Dlbcl Treated with R-CHOP

Abstract

ABSTRACT Background Tumor-infiltrating immune cells perform important functions in host immune reaction against diffuse large B cell lymphoma (DLBCL). We assessed the distribution and prognostic significance of FOXP3+ regulatory T-cells (Treg) in DLBCL. Patients and methods We examined samples from 94 patients (54 men and 40 women; median age, 70 years) at diagnosis who were prospectively enrolled between 2002 and 2008. All patients treated with R-CHOP. The pattern of FOXP3 protein expression was evaluated using immunehistochemistry in paraffin-embeded tissue samples. In addition, these samples were stained with antibodies for CD10, bcl-6 and MUM-1 via the tissue microarray to classify into subgroups. Results The median percentage of FOXP3+ cells was 91/mm2 (range 4–2100/mm2). Patients with poor performance status (PS) and high serum lactate dehydrogenase (LDH) showed lower numbers of FOXP3+ cells (PS, P = 0.014; LDH, P = 0.0048). Patients with high counts of FOXP3+ cells (>90/mm2) have better prognosis than those of low counts [5-year (5-y) overall survival (OS); 72.1 and 49.7% P = 0.024, respectively]. Although no prognostic difference was observed between the GCB type and the non-GCB type (5-y OS: GCB 71.2%, non-GCB 53.1%, P = 0.12), low counts of the FOXP3+ cell and the non-GCB type patient were poorer prognosis than high counts and the non-GCB type (low 5-y OS, 31.2%; high 5-y OS, 69.8%; P = 0.02). Conclusion An increased count of the FOXP3+ tumor-infiltrating cell might predict better prognosis of DLBCL.