Serum 5-S-cysteinyldopa levels in patients with psoriasis undergoing narrowband ultraviolet B phototherapy

• Published in: Clinical and experimental dermatology Vol. 33; no. 6; pp. 750 - 753
• Main Authors: Kikuchi, K., Wakamatsu, K., Tada, Y., Komine, M., Ito, S., Tamaki, K.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.11.2008; Blackwell
• Subjects: Adult; Aged; Aged, 80 and over; Biological and medical sciences; Biomarkers - blood; Cysteinyldopa - blood; Dermatology; Female; Humans; Male; Medical sciences; Middle Aged; Prospective Studies; Psoriasis - blood; Psoriasis - radiotherapy; Psoriasis. Parapsoriasis. Lichen; Skin - radiation effects; Statistics, Nonparametric; Time; Treatment Outcome; Ultraviolet Therapy - adverse effects; Human; Skin disease; Treatment; Psoriasis; Dermatology; UVB radiation; Serum; Phototherapy
• ISSN: 0307-6938; 1365-2230; 1365-2230
• DOI: 10.1111/j.1365-2230.2008.02792.x

Summary Background.  Ultraviolet (UV) B radiation from sunlight can result in tanning or burning of the skin. Narrowband UVB (NB‐UVB), a relatively new light source that is not yet widely available, is effective for treating generalized psoriasis without the use of psoralens. Aims.  The melanin‐related metabolite 5‐S‐cysteinyldopa (5‐S‐CD), which reflects pheomelanin production, has been used as a biological marker of melanoma progression, but there are no studies available on therapeutic UVB effects on serum 5‐S‐CD of human subjects. In the present study, we measured the time course of changes in serum levels of 5‐S‐CD in patients with psoriasis undergoing NB‐UVB phototherapy. Methods.  In total, 11 Japanese patients with generalized psoriasis vulgaris received NB‐UVB treatment five times per week, at an initial dose of 0.1 J/cm2. The dose was increased by 10–20% per treatment for > 20 treatments. Serum samples were taken before and 3, 7, 10, 14 and 28 days after phototherapy. Results.  After 4 weeks of NB‐UVB treatment, 9 of 11 patients were in remission, confirming the effectiveness of NB‐UVB for treating Japanese patients with psoriasis. Two patients withdrew before day 28 because of other complications. Mean level of 5‐S‐CD in serum was significantly increased on day 7, 10 14 and 28 compared with the level before phototherapy and it peaked on day 10. Conclusions.  Serum 5‐S‐CD levels were significantly increased by therapeutic UVB exposure. Sustained levels of 5‐S‐CD in serum appear to reflect the degree of skin injury during NB‐UVB phototherapy.