Complex Mechanisms in Prostatic Inflammatory Response

Context: The immunology of the prostate has developed into a new field of research in urology. The leukocyte population increases are not yet fully understood, but it has been demonstrated that most resected prostate tissue shows signs of inflammatory response. Objective: This article reviews recent findings and discusses the complex mechanisms involved in the prostatic inflammatory response and the immunologic functions of the prostate, and the roles the prostatic inflammatory response in the cause of prostate disease such as benign prostatic hyperplasia (BPH). Evidence acquisition: We performed a search of the medical literature with PubMed, using keywords such as prostate cancer, inflammation of the prostate, leukocytes, estrogen, and cytokine and genetic expression of inflammation. Articles and data were reviewed as to their relevance, and inclusion and exclusion criteria were determined prospectively. Evidence synthesis: Evidence showing that inflammation of the prostate plays a role in prostate cancer (PCa) is mounting. Different types of inflammation exist and are distinguished according to the distribution and location of leukocytes and the histology of the surrounding tissue. Most resected prostate tissue shows signs of inflammatory response, and a relationship between T-cell infiltration and stromal proliferation can be found. Evidence for the importance of estrogen and proinflammatory cytokine interleukin (IL; IL-6, IL-8, IL-15, IL-17) also can be found. Early stages of investigation of the immunologic function of the prostate show that both prostatic epithelial and stromal cells express members of the toll-like receptor family and are therefore capable of recognizing foreign incoming antigens. Conclusions: Although this area of study is new, the immunology and inflammatory responses of the prostate are seen as important components of further study of prostate diseases such as PCa and BPH. Data supporting the role of immunology and activated leukocytes in malignant cells are also an important finding and can possibly lead to new knowledge about malignant cells.