Delayed-type hypersensitivity (DTH) immune response related with EBV-DNA in nasopharyngeal carcinoma treated with autologous dendritic cell vaccination after radiotherapy.

The aim of this work was to investigate the outcome of an autologous dendritic cell (DC) vaccination in patients with stage II/III nasopharyngeal carcinomas (NPC). From 38 patients with stage II/III Epstein-Barr virus (EBV)-associated NPCs after a radiotherapy, 16 human leukocyte antigen-A2 (HLA-A2)-positive patients were enrolled and medicated with autologous DCs, which were pulsed with HLA-A2-restricted EBV-encoded latent membrane protein 2A (LMP2A) peptides. The lymphocyte subsets, serum cytokines, and EBV-DNA levels as well as the delayed-type hypersensitivity (DTH) responses were determined after vaccination combined with a radiotherapy/chemotherapy. The serum levels of interleukin-2 and interferon-γ (P<0.05) as well as the percentage of natural killer and CD4+T cells increased significantly (P<0.05) after the vaccination. Nine of 16 (56.25%) patients showed a positive skin response to the HLA-A2 restricted EBV LMP2A peptides in a DTH test. The serum EBV-DNA level decreased significantly from 1519 ± 384 to 1214 ± 211 copies/mL in the 9 DTH-positive patients (P=0.0310). No unanticipated or serious toxicity was observed and the vaccine was well tolerated. In conclusion, in NPC patients vaccinated after radiotherapy with autologous DCs, which were pulsed with EBV LMP2A peptides, Th1-specific immune responses were elicited particularly in DTH test positive individuals. The clinical results obtained are encouraging and the EBV-specific HLA-A2-restricted DC vaccination is a promising treatment for EBV-related NPCs.