E Du, Lin Wang, Chang-ying Li, Chang-wen Zhang, Yan-chun Qu, Ran-lu Liu, Yong Xu, Kuo Yang, Zhi-hong Zhang

Permanent prostate brachytherapy (PPB) is an effective treatment choice for low and intermediate risk prostate cancer (PCa). However, the impact of PPB on tumor immune status is still poorly understood. This study aimed to assess the immune status in PCa patients before and at different time points after PPB (1, 3, 6, and 12 months). Blood was collected from 32 patients with low and intermediate risk PCa and 12 healthy volunteers. The frequency of immunocompetent cells was identified by flow cytometry. The concentration of immunoglobulins and complements was detected by ELISA. Various immunocompetent cells were dysregulated in PCa patients compared with healthy volunteers. Peripheral serum prostate-specific antigen (PSA) decreased rapidly at the first month after PPB treatment, and the peripheral serum PSA became very low at 6 months after PPB treatment. CD3+ T cells, CD4+ T cells, CD3-CD16+/56+ natural killer (NK) cells were increased significantly at certain time points after PPB. Although the percentage of the CD8+ T cells did not change markedly, the ratio of CD4/CD8 increased significantly at 3 months after PPB (P=0.0196). There was no influence of PPB on B cells number, but the concentration of immunoglobulins IgM, IgG, and IgA, and complements C3 and C4 in patients increased at some time points after PPB. The immunocompetent cells are dysregulated in PCa patients. PPB treatment could effectively kill tumor cells and then stimulate cellular immunity and humoral immunity in PCa patients.