Persistent peripheral blood EBV-DNA positive with high expression of PD-L1 and upregulation of CD4 + CD25 + T cell ratio in early stage NK/T cell lymphoma patients may predict worse outcome

Although gemcitabine, oxaliplatin and L-asparaginase/pegylated asparaginase (P-GEMOX) treatment for early-stage extranodal natural killer/T cell lymphoma (ENKTL) is effective, some patients die within 1 year of diagnosis. We attempted to determine an optimal biomarker for identifying such patients. We enrolled 71 patients with ENKTL who received P-GEMOX between January 2011 and January 2014. We classified the patients according to the outcome into worse (died within 1 year) or better groups (survival time ≥ 3, 4 or 5 years). The area under the curve (AUC) was determined to identify the optimal biomarker for differentiating the groups. The AUC was highest in patients who were plasma Epstein–Barr virus (EBV) DNA-positive post-treatment. The AUC was 0.82, 0.86 and 0.86 when the worse group was compared to the better group, respectively. Among the post-treatment EBV DNA-positive patients, as compared to EBV DNA-negative patients, pre-treatment EBV DNA-positive patients had a higher proportion of CD4 + CD25 + T cells. There was higher programmed cell death protein ligand-1(PD-L1) expression in post-treatment EBV DNA-positive patients. Post-treatment positive EBV DNA status maybe a useful biomarker of worse outcomes in early stage ENKTL.