Comparative study of frequency of different lymphocytes subpopulation in peripheral blood of patients with prostate cancer and benign prostatic hyperplasia

PURPOSE: Benign prostatic hyperplasia (BPH) and prostate cancer (PC) are the most common urologic diseases among men over fifty and, until recently, they were considered to be caused by the impaired immune response. Despite many studies designed to investigate T-cell-based antitumor immunity, the role of innate immune cells in BPH and PC is still poorly understood. In this study the frequency of different leukocytes subpopulation in peripheral blood of BPH, PC patients and in healthy volunteers was analysed and compared. METHODS: In a cross-sectional study 60 subjects were enrolled (20 patients with BPH or with PC and 20 healthy volunteers). Peripheral blood mononuclear cells (PBMC) were isolated and the percentage of T lymphocytes, natural killer (NK) and NKT cells, as well as subsets of T lymphocytes [CD3(+)CD56(-)CD4(+), T-regs (CD4(+)CD25(+)FoxP3(+)) and CD3(+)CD56(-)CD8(+)] and NK cells (CD3(-)CD56(+dim) and CD3(-)CD56(+bright)) were analysed by flow cytometry. Intracellular content of interleukin-4 (IL-4) and interferon gamma (IFN gamma in T lymphocytes, NK and NKT cells were also detected. RESULTS: The percentage of T lymphocytes and their subsets in peripheral blood lymphocytes did not differ among investigated groups, while the frequency of Tregs was the highest in PC patients. The percentage of NK cell and their subsets did not differ among investigated groups. Negative correlation between PSA value, percentage of T lymphocytes and NK cells was observed only in PC patients. Highly positive correlation between the PSA value and the percentage of Tregs was found in PC patients. CONCLUSION: Different frequencies in distinctly lymphocyte subpopulation in peripheral blood of healthy men, BPH and PC patients could be responsible for occurrence and progression of prostatic hyperplasia or tumour. Due to the ability of tumours to suppress the cognate T cell immune response, the cells of innate immunity (NKT and Tregs) may be playing a key role in the immunopathogenesis of PC and BPH.