Prognostic significance of plasma interleukin-6/-8 in pancreatic cancer patients receiving chemoimmunotherapy

AIM: To investigate the association of plasma levels of interleukin(IL)-6 and-8 with Wilms’ tumor 1(WT1)-specific immune responses and clinical outcomes in patients with pancreatic ductal adenocarcinoma(PDA) treated with dendritic cells(DCs) pulsed with three types of major histocompatibility complex classⅠand Ⅱ-restricted WT1 peptides combined with chemotherapy.METHODS: During the entire treatment period, plasma levels of IL-6 and-8 were analyzed by ELISA. The induction of WT1-specific immune responses was assessed using the WT1 peptide-specific delayed-type hypersensitivity(DTH) test.RESULTS: Three of 7 patients displayed strong WT1-DTH reactions throughout long-term vaccination with significantly decreased levels of IL-6/-8 after vaccinations compared with the levels prior to treatment. Moreover, overall survival(OS) was significantly longer in PDA patients with low plasma IL-6 levels(< 2 pg/m L) after 5 vaccinations than in patients with high plasma IL-6 levels(≥ 2 pg/m L)(P = 0.025). After disease progression, WT1-DTH reactions decreased severely and were ultimately negative at the terminal stage of cancer. The decreased levels of IL-6/-8 observed throughout long-term vaccination were associated with WT1-specific DTH reactions and long-term OS.CONCLUSION: Prolonged low levels of plasma IL-6/-8 in PDA patients may be a prognostic marker for the clinical outcomes of chemoimmunotherapy.