Expression of human β-defensin-2 in psoriatic epidermis models treated with balneophototherapy

The molecular mechanisms of action of salt water soaks combined with ultraviolet (UV) irradiation--balneophototherapy (BPT)--are unknown.

We aimed to investigate the effect of BPT on the expression of human β-defensin-2 (hBD2) using a psoriatic epidermis model (PEM).

Using real-time RT-PCR and ELISA, we studied the expression patterns of hBD2 in PEM which were treated over three consecutive days with differently concentrated salt water solutions [(3% NaCl; 30% NaCl, 30% Dead Sea salt (DSS)] and consecutive narrowband UVB exposure.

mRNA of hBD2 was significantly reduced in irradiated 3% NaCl, 30% NaCl and 30% DSS soaked PEM when compared with non-irradiated PEM. ELISA for hBD2 revealed significantly reduced protein expression in irradiated 3% NaCl, 30% NaCl and 30% DSS soaked PEM when compared with non-irradiated PEM. Compared with irradiated controls and 3% NaCl soaked and irradiated PEM, BPT using 30% NaCl and 30% DSS revealed significantly decreased hBD2 protein levels.

Both mono-treatment with salt water soaks and BPT of PEM result in altered expression of hBD2, whereas the effects observed are most prominent after BPT. hBD2 gene and protein expression is predominantly down-regulated following BPT indicating that this combined phototherapeutic regimen is superior to mono-UVB or salt water soaks alone with respect to normalization of hBD2 expression in psoriatic epidermis.