Serum prolactin levels in psoriasis and correlation with cutaneous disease activity

BACKGROUND: Prolactin (PRL), a neuropeptide secreted by the anterior pituitary gland, possesses a variety of physiological actions. It has been implicated as an important immunomodulator and exerts a proliferative effect in cultured human keratinocytes via specific receptors. Some studies have indicated an increase in serum PRL levels in psoriasis and exacerbation of psoriasis when a prolactinoma is present. AIM: To evaluate the correlation between serum PRL levels and Psoriasis Area and Severity Index (PASI). METHODS: Serum PRL levels were measured in 20 patients (10 mean, 10 women, age range 18-88 years) with plaque-type psoriasis before and after a 6-week period of topical treatment with tacalcitol ointment. Results were compared with a group of 20 healthy volunteers. RESULTS: Serum PRL levels were significantly increased in the psoriatic group compared with the control group (P < 0.001) and were significantly reduced after treatment (P = 0.001). There was a correlation between pretreatment serum PRL levels and PASI (r = 0.33; P = 0.02). CONCLUSIONS: These results indicate that serum PRL levels may serve as a biological marker of psoriatic disease activity.