Vitamin D Receptor Expression in Chronic Plaque Psoriasis Before and After Narrowband Ultraviolet B Phototherapy.

BACKGROUND/PURPOSE: Psoriasis is a multifactorial disease. It is a combination of genetic, immunological, and environmental factors. Vitamin D receptor (VDR) is a nuclear receptor that regulates epidermal cell growth through the inhibition of proliferation and induction of keratinocytes terminal differentiation. Aim of the study was to investigate the effect of Narrow-band UVB (NB-UVB) therapy on VDR expression in the skin of psoriasis patients.

MATERIALS AND

METHODS

Forty patients with different severities of psoriasis were assessed using the psoriasis area and severity index (PASI) score. Lesional and non-lesional skin biopsies were obtained from each patient before NB-UVB therapy, and then a third lesional biopsy was performed after completing 24 sessions of NB-UVB. Immunohistochemistry for VDR was performed on all specimens.

RESULTS

There was a significant decrease in VDR expression in psoriatic lesions compared to that in non-lesional skin before treatment. A statistically negative correlation was detected between the degree of VDR expression before treatment and PASI score, family history, and duration of psoriasis. There was a significant increase in VDR expression at the sites of psoriasis lesions post-NB-UVB therapy compared to pretreatment lesional skin.

CONCLUSION

VDR expression was down-regulated in psoriatic lesions compared to non-lesional skin, and NB-UVB therapy improved VDR expression in psoriasis skin lesions.