The prostate is composed of many elements, including the epithelium, which secretes a component of the seminal fluid, and the stroma, which acts as the supporting scaffolding upon which the rest is built. Each is associated with specific and common illness: The epithelium gives rise to prostate adenocarcinoma and the stroma gives rise to benign enlargement that can cause urinary obstruction.
Mixed in with the other elements are muscle, nerves, and blood vessels, which carry nutrients to the prostate. The blood vessels also carry cells that fight disease, including infectious agents, such as bacteria, and respond to trauma; they also carry medications, such as antibiotics.
The cells that fight disease are interchangeably known as white blood cells, leukocytes, and inflammatory cells. This class of cells is then subdivided into sub-classes, including neutrophils, eosinophils, monocytes, and lymphocytes, each with somewhat separable roles in the response to illness.
In many cases, clinical symptoms are tightly correlated with the presence in organs of inflammatory cells. For example, gingivitis, which can be an intensely painful condition, is associated with a concentration of inflammatory cells in the gums. Accordingly, it was for a long time thought that symptomatic prostatitis is associated with an inflammatory response in the prostate. This is apparently false.
The opportunity to examine the relationship of prostate inflammation to clinical symptoms came up in the context of a study about prostate cancer prevention using a 5-alpha reductase inhibitor known as dutasteride. This is because every patient who entered the study had to first have a prostate biopsy, from which pathologists could determine the degree of inflammation (and cancer, which if present disqualified the patient from the cancer prevention trial). These patients then also completed a questionnaire that measured their clinical prostatitis symptoms using the NIH Chronic Prostatitis Symptom Index (CPSI). Overall, the study found no "substantive links" between CPSI and inflammation.