Interleukin 8 and the male genital tract

Abstract

Interleukin 8 (IL-8) is a pro-inflammatory CXC chemokine involved in inflammatory reactions. IL-8 exerts its function in concert with other cytokines and chemokines causing chemoattraction of leukocytes to the inflammatory sites, recruitment and activation of neutrophils to phagocytosis and bacterial clearance. Furthermore, IL-8 is characterized by chemoattractant activity on basophils and T cells, and by a potent pro-angiogenic action. IL-8 is crucially involved in several inflammatory diseases. In particular, it has been suggested that IL8 might play a key role in male genital tract (MGT) infection/inflammation. In fact, IL-8 seems crucially involved in benign prostatic hyperplasia-related inflammation. In addition, among different cytokines and chemokines, seminal plasma IL-8 (sIL-8) appears to be the most reliable and predictive surrogate marker of prostatitis. Furthermore, evidence is emerging on sIL-8 involvement in inflammation not only of the prostate, but also of other organs of the MGT, in particular seminal vesicles and epididymis, but not the testis, and in male accessory gland infection (MAGI). Accordingly, an association between sIL-8 levels and color-Doppler ultrasound characteristics of the MGT suggestive of inflammation has been recently reported. sIL-8 is strongly related to leukocytospermia, and although the relationship between sIL-8 levels and sperm parameters has not been completely clarified, a tight inverse correlation with ejaculate volume has been demonstrated, suggesting an association with distal MGT sub-obstruction, corroborated by the correlation with ejaculatory duct and seminal vesicle abnormalities. Finally, recent studies have focused on the role of IL-8 in cancer biology, in particular in prostate cancer, thus increasing the interest in this pro-inflammatory chemokine.