Prolactin and vitiligo: proposed autocrine/paracrine actions

Abstract

Background The exact cause of vitiligo remains unclear. Several theories have been proposed, including autoimmune and neuroendocrine theories. Prolactin has been studied as an immunomodulatory factor in several autoimmune diseases. Regarding vitiligo, previous studies revealed contradictory results. This is the first study to assess tissue prolactin and prolactin receptor (PRLR) expression in vitiligo. Objective To measure the level of serum prolactin, tissue prolactin, as well as PRLR in patients with vitiligo vulgaris and controls to verify their possible role in vitiligo pathogenesis. Patients and methods A case–control study was conducted on 40 participants: 20 patients with vitiligo and 20 age-matched and sex-matched healthy controls. Blood samples were taken to determine the serum prolactin level (ng/ml). Skin biopsies were obtained from the lesional skin of patients and normal skin of controls to determine the level of tissue prolactin (ng/mg) and PRLR (ng/g) by enzyme-linked immunosorbent assay. Results Serum and tissue prolactin and PRLR levels were significantly higher in patients than in controls (P<0.001). Tissue prolactin level had a positive correlation with PRLR level (r=0.739, P<0.001). Conclusion Prolactin plays a role in the pathogenesis of vitiligo, mainly from an intracutaneous position where an autocrine/paracrine loop could have a larger share.

Keywords

• autocrine
• paracrine
• pathogenesis
• prolactin
• receptor
• vitiligo