Upregulation of plasmacytoid dendritic cells in glioma.

The immune system fails to eradicate established tumors partly due to the induction of immune tolerance within tumor microenvironment. Plasmacytoid dendritic cells (pDCs) play critical roles in regulating immune system. In this study, we investigated pDC in the peripheral blood of glioma. CD4 + CD123 + BDCA2+ pDCs were tested from peripheral blood mononuclear cells in 40 glioma patients and 40 healthy controls by flow cytometry. The results revealed that proportion of pDCs was significantly increased in cases than in controls (0.52 ± 0.07 versus 0.21 ± 0.02 %, p < 0.001), whereas myeloid dendritic cells (mDCs) did not present any obvious difference between patients and healthy donors (0.25 ± 0.04 versus 0.18 ± 0.02 %, p = 0.217). We further studied pDCs in glioma patients with different clinical stages. Data showed that cases with smoking history had elevated level of pDCs than those non-smoker patients (0.91 ± 0.16 versus 0.48 ± 0.06 %, p = 0.004). Interestingly, we observed that patients with aphasia presented significantly elevated pDCs than those without aphasia (0.93 ± 0.12 versus 0.41 ± 0.07 %, p < 0.001). These data suggested that pDCs may be closely involved in the pathogenesis of glioma and may play roles in certain symptoms of the disease.