Prolactin: does it have a role in the pathogenesis of psoriasis?

BACKGROUND

The aetiopathogenesis of psoriasis is still not fully understood. Recently, it has been reported that prolactin (PRL) exerts a proliferative effect on human keratinocytes in vitro. PRL may, therefore, play an important role in the pathogenesis of psoriasis.

OBJECTIVE

To assess the serum PRL level in patients with psoriasis vulgaris (PV).

METHODS

Serum levels of PRL were estimated in 12 patients with PV (age: 11-45 years with mean +/- SD 30.4 +/- 10.2 years; sex: 7 males, 5 females) and the results were compared with those in 9 patients with atopic dermatitis (age: 15-47 years with mean +/- SD 28.1 +/- 11.9 years; sex: 4 males, 5 females) and 20 normal control subjects (age: 16-45 years with mean +/- SD 36.1 +/- 11.9 years; sex: 15 males, 5 females).

RESULTS

Serum PRL in PV (mean +/- SD 25.8 +/- 16.1 ng/ml) was significantly higher compared to those in atopic dermatitis (mean +/- SD 9.1 +/- 4.7 ng/ml) and normal control subjects (mean +/- SD 10.3 +/- 5.3 ng/ml; ANOVA --> p = 0.0008). Three patients with PV (2 males and 1 female with ages of 35, 40 and 11 years, respectively) had the highest serum levels well above the normal range but they were <100 ng/ml, the minimum limit for the diagnosis of prolactinoma (chi2 test --> p <0.025).

CONCLUSION

Since PRL belongs to the growth hormone family, its raised serum level may have a role in the hyperproliferation of kerationocytes in vivo, the hallmark of the psoriasis disease process.