OBJECTIVETo investigate the clinical significance of interleukin-17 (IL-17) level in patients with extranodal NK/T-cell lymphoma(ENKTL).

METHODSEighty patients with nasal ENKTL who received radiotherapy, chemotherapy or radiotherapy combined with chemotherapy from January 2011 to January 2012 were enrolled in the study. Eighty healthy volunteers were selected as the controls (control group). About 5 ml of peripheral blood was collected from all patients and controls. IL-17 level was determined by ELISA. The age, sex, ECOG score, B symptoms, LDH level, lymph node involvment, Ann Arbor stage, IPI, KPI, peripheral blood lymphocyte and lymph node metastasis, number of lymphocytes and monocytes in peripheral blood were recorded. All patients were followed up for 3 year progression-free survival (PFS) and overall survival (OS).

RESULTSThe average IL-17 level in patients with ENKTL was 6.48 pg/ml and the average concentration of IL-17 in control group was 0.56 pg/ml (P<0.01). The level of IL-17 in patients with B-symptoms and lymph node involvement was significantly higher than that in the control group. The differences in IL-17 level were not statistically significant among patients with different age, sex, ECOG, LDH, Ann Arbor stage, IPI, KPI, lymphocyte count and monocyte cell count. The sensitivity and specificity of IL-17 were 74.5% and 73.7% respectively, and the optimal threshold was 3.49 pg/ml and AUC was 0.799 (95% CI: 0.688-0.909) (P<0.01). The PFS and OS were longer in the patients with IL-17≤3.49 pg/ml and longer in the patients without lymph node involvement and Ann Arbor I. Multivariate analysis showed that independent predictors of PFS and OS in patients with ENKTL were plasma IL-17 levels and age (P<0.05).

CONCLUSIONENKTL patients with different clinical characteristics have different levels of IL-17, the different level of IL-17 has different effects on prognosis of patients with ENKTL.