Changes in plasma EBV-DNA and immune status in patients with nasopharyngeal carcinoma after treatment with intensity-modulated radiotherapy

BackgroundPrevious studies reported the early diagnostic values of plasma Epstein-Barr virus (EBV)-DNA. The present study aimed to assess the relationship between the concentration of plasma EBV-DNA and the number of CD8(+)PD-1(+)(programmed cell death-1,PD-1) and regulatory T (Treg) cells in patients with nasopharyngeal carcinoma (NPC) who were treated with intensity-modulated radiotherapy (IMRT).MethodsThis study included 37 patients treated with IMRT. Peripheral blood samples were collected two times for each patient, before radiation therapy and 1week after the treatment. Further, the numbers of CD4(+), Treg, CD8(+), and CD8(+)PD1(+) cells were determined by flow cytometry.ResultsThe changes after IMRT were determined by comparing the numbers of neutrophils, lymphocytes, CD4(+), Treg, CD8(+), CD8(+)PD1(+) cells, and the concentration of plasma EBV-DNA between pretreatment and post-treatment groups. IMRT could reduce the expression level of PD-1 and the number of Treg cells. The concentration of plasma EBV-DNA and the expression level of CD8(+)PD-1(+) were closely associated with the occurrence and development of NPC. Thus, EBV-DNA can be used as an important marker for early diagnosis, and IMRT can strongly reduce the copies of EBV-DNA.ConclusionsThis study showed that IMRT could reverse T-cell exhaustion and reduce the copies of EBV-DNA. In clinical practice, plasma EBV-DNA is a sensitive biomarker for diagnosis, prognosis, and evaluation of clinical efficacy.