CD8+ T Lymphocyte Subsets in Bladder Tumor Draining Lymph Nodes

Abstract

Background: Cytotoxic CD8+ T cells, as essential parts of the adaptive immune system, play pivotal roles in anti-tumor immune responses. It is well documented that cytokine expression profiles and activation status of these cells during anti-tumor immune responses affect the outcome of host-tumor interaction. Objective: To investigate the percentages of CD8+ lymphocytes and their subsets in tumor draining lymph nodes of patients with bladder cancer. Methods: Forty-five patients with bladder cancer, candidate for radical cystectomy, were recruited. Mononuclear cells were isolated from draining lymph nodes using Ficoll-Hypaque gradient centrifugation, and were activated by PMA/Ionomycin in the presence of Golgi inhibitors. The cells were then permeabilized and stained with appropriate flourochrome conjugated antibodies against CD3, CD8, IFN-γ, IL-17 and IL-4 molecules. Data were collected on a fourcolor flow cytometer and analyzed by CellQuestPro software. Results: Despite no difference in the frequency of IL-17 producing CD8+ (Tc17) lymphocytes, the mean expression of IL-17 in this subset was significantly elevated in high-grade patients (p=0.011). The percentage of double positive IFN-γ/IL-17 CD8+ lymphocytes was also significantly increased in node positive patients compared to node negative ones (p=0.046). Our results also demonstrated that the percentage of IFN-γ producing CD8+ (Tc1) lymphocytes was significantly increased in the patients with higher histological grade compared to those with lower ones (p=0.038). Conclusion: IFN-γ and IL-17 producing CD8+ T cells may increase in advanced stages of bladder cancer, but their correlation with tumor prognosis remains to be investigated.