Increased peripheral natural Tregs in prostate cancer patients is correlated with PSA (40.13)

Abstract

Abstract The aims of this study were to analyze peripheral natural regulatory T cells (Treg) in Prostate Cancer (PCa) patients, regarding density and correlation with serum Prostate Specific Antigen (PSA). Peripheral Tregs from 75 subjects undergoing diagnostic prostate biopsies were enumerated by two sets of markers, CD4+CD25highFoxp3+ and CD4+CD25+CD127low/-. Association between peripheral Treg and serum PSA values was first determined in the entire population, including people with no prostate pathology (healthy) , PCa and Benign Prostate Hyperplasia (BPH) patients, and second, in 9 PCa patients before and after curative prostatectomy. Peripheral Treg frequencies were significantly increased in PCa patients (n=30) compared with BPH patients (n=30) and healthy subjects (n=15) by both methods (p<0.01). The percentage of Treg in BPH patients was also slightly but significantly higher than that of healthy subjects. Importantly, the increase paralleled the elevation in total serum PSA levels, demonstrating a strong positive correlation (r =0.70 by both methods). Additionally, prostatectomy concomitantly restored both peripheral Treg numbers and serum PSA levels. In conclusion, peripheral Treg densities are not only increased in PCa and BPH patients but are also strongly correlated with PSA, suggesting that PSA may have a role in induction and/or maintenance of increased proportion of Tregs in these people.