title: Psoralen-ultraviolet A-induced erythema: sensitivity correlates with the concentrations of psoralen in suction blister fluid.
abstract: Since the advent of psoralen-ultraviolet A (PUVA) therapy, the value of plasma 8-methoxypsoralen (8-MOP) concentrations to predict PUVA-induced erythema has been widely investigated. Plasma 8-MOP concentrations have not been proportional to, and cannot alone predict, the degree of PUVA-induced erythema. We assumed that PUVA-induced erythema was related more closely to psoralen concentrations in the skin tissue rather than those within blood vessels. This study was designed to investigate the correlations between the 8-MOP concentrations in suction blister fluid (SBF) and in plasma, with the degree of PUVA-induced erythema. 8-MOP concentrations in plasma and SBF were measured in 15 vitiligo patients and 11 volunteers. Blood and SBF samples were collected 2 h after taking 8-MOP, and 8-MOP concentrations in plasma and SBF were quantified using reverse-phase high-performance liquid chromatography. Eleven volunteers were phototested using a series of doses of ultraviolet A at the time of sampling. The erythema responses were estimated visually to determine the minimal phototoxic dose (MPD). SBF 8-MOP concentrations showed a weak positive correlation with plasma 8-MOP concentrations, which means that we could not predict the exact SBF 8-MOP concentrations using the plasma 8-MOP concentrations. The MPD showed a better correlation with the log of the SBF 8-MOP concentration than with that of the plasma 8-MOP concentration. These results show that plasma 8-MOP concentration cannot represent the exact SBF 8-MOP concentration, and that SBF 8-MOP concentrations, which are representative of the skin tissue 8-MOP level, are more closely related to the erythemal sensitivity during PUVA therapy.
authors.affiliation: Department of Dermatology, Sungkyunkwan University School of Medicine, Samsung Medical Center, 50 Ilwon-Dong, Kangnam-Ku, Seoul 135-710, Korea. yeouc@smc.samsung.co.kr
authors.forename: U C
authors.initials: UC
authors.lastname: Yeo
authors.forename: J H
authors.initials: JH
authors.lastname: Shin
authors.forename: J M
authors.initials: JM
authors.lastname: Yang
authors.forename: K B
authors.initials: KB
authors.lastname: Park
authors.forename: M M
authors.initials: MM
authors.lastname: Kim
authors.forename: H S
authors.initials: HS
authors.lastname: Bok
authors.forename: E S
authors.initials: ES
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D001768:Blister / Q000378:metabolism / Q000601:surgery; D004890:Erythema / Q000097:blood / Q000209:etiology* / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008730:Methoxsalen / Q000097:blood / Q000493:pharmacokinetics; D008875:Middle Aged; D011701:PUVA Therapy / Q000009:adverse effects*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D008730:Methoxsalen