Comparison of the effect of 8-methoxypsoralen (8-MOP) plus UVA (PUVA) on human melanocytes in vitiligo vulgaris and in vitro.

In this study, we examined the various effects of PUVA treatment on cultured human melanocytes, and it revealed that 1) the higher the dose of PUVA treatment, the more significant the inhibition of cell DNA and protein synthesis; 2) the higher the dose of PUVA treatment, the more significant the depletion of epidermal growth factor receptor (EGFR) expression; 3) PUVA treatment at 124 mJoule/cm2 depleted the vitiligo-associated melanocyte antigens (VAMA) immediately after irradiation, and both the VAMA and EGFR expression progressively recovered at 24 or 72 h after PUVA; 4) PUVA treatment stimulated tyrosinase activity, but not in a dose-dependent fashion. In vitiligo vulgaris, PUVA treatment may stimulate the regrowth of melanocytes from hair follicles, but deplete the epidermal Langerhans cells in depigmented lesion of patients with stable vitiligo. Comparing the above results obtained from in vivo and in vitro studies, it reveals significantly different biologic responses. Although the precise therapeutic mechanism of PUVA treatment in vitiligo is still not well known, it is proposed that 1) PUVA treatment may stimulate the other components of skin, such as keratinocytes, to release inflammatory mediators and some of them may act as melanocyte growth-stimulatory factors (MGSF), which further enhance the proliferation of remaining melanocytes in hair follicle; and 2) PUVA treatment may deplete the VAMA expression on cell membrane of melanocytes and also deplete epidermal Langerhans cells, which may result in blocking the progressing of antibody-dependent cell-mediated cytotoxicity to melanocytes in vitiligo.     

Correlation between bathing time and photosensitivity in 8-methoxypsoralen (8-MOP) bath PUVA

Bath PUVA (psoralen plus ultraviolet A) using 8-methoxypsoralen has become increasingly popular in recent years as an effective treatment option for a continuously expanding range of skin disorders. Among the various variables of bath PUVA treatment, the impact of bathing time on photosensitivity has never been investigated in detail. We therefore determined the threshold UVA dose for erythema induction after different bathing periods. A marked influence of bathing time on photosensitivity was found. Increasing the soaking period from 5 min to 30 min resulted in a greater than 60% reduction of the minimal phototoxic and minimal perceptible phototoxic dose. Our results demonstrate that the duration of the psoralen bath is a critical parameter in bath PUVA treatment and has a major influence on UVA dose requirements.     

Effect of 8-methoxypsoralen plus UVA (PUVA) on lymphocyte transformation and T cells in psoriatic patients

The peripheral blood lympochytes of the psoriatic patients studied initially showed a normal response to phytohaemagglutinin (PHA) and to purified protein derivative of turberculin (PPD) in a microculture using whole blood, but a lower than normal response to a high concentration of concanavalin A (Con A). The initial level of E-rosette-forming T cells in psoriatic patients (51.3%) was significantly lower than that in healthy controls (66.7%). A single exposure to 8-methoxypsoralen (8-MOP) and UVA light (PUVA) did not suppress the lymphocyte responses to PHA, Con A or PPD, rather the responses showed a tendency to be slightly increased. Similarly, no changes in the mitogen responses of peripheral blood lymphocytes were recorded during or after 12 weeks PUVA therapy for psoriasis. The lymphocytes still showed a weaker than normal response to a high concentration of Con A. However, the percentage of E-rosette-forming T cells in the peripheral blood increased from 51.3% to 62.8% after 12 weeks PUVA therapy. The low initial level of E-rosette-forming T cells was found to correlate more closely with the activity than with the extent of the disease. The increase found in the E-rosette-forming cells during PUVA therapy did not correlate with the improvement of the psoriatic lesions. The low response of peripheral blood lymphocytes of psoriatic patients to a high concentration of Con A correlated with the age of the patients but not with the activity or extent of the disease.     

Systemic suppression of contact hypersensitivity in mice by psoralen plus UVA radiation (PUVA)

Treatment of mice with 8-methoxypsoralen plus longwave UV radiation (UVA, 320-400 nm) decreased their response to contact sensitizers applied subsequently to unirradiated skin. This decreased reactivity exhibited a delayed time course, it affected the afferent but not the efferent phase of the reaction, and it was associated with the development of splenic suppressor cells. These suppressor cells were antigen-specific T lymphocytes, and they prevented the induction, but not the elicitation, of contact hypersensitivity in recipient mice. In all of these characteristics, the decreased reactivity induced by treatment with psoralen plus UVA radiation (PUVA) resembled that produced by UV radiation of shorter wavelengths (less than 320 nm). These studies suggest that PUVA treatment may initiate the same sequence of cellular events as does exposure to sunlamp (UVB, 280-320 nm) radiation, leading to preferential activation of the suppressor cell pathway.     

Alopecia areata treatment with a phototoxic dose of UVA and topical 8-methoxypsoralen

Twenty-five patients with alopecia totalis (AT) or alopecia universalis and 124 patients with alopecia areata (AA) were treated with photochemotherapy, combining topical 8-methoxypsoralen (8-MOP) with UV irradiation of the scalp at a phototoxic dose. The mean energy required was 15 J/cm2 for AA and 42 J/cm2 for AT. Ninety-four patients had multiple bald patches and 12 with AT had complete or > 50% hair regrowth. Positive treatment results did not seem to depend on the age of onset or the duration of the disease. Few side-effects of topical psoralens plus UVA (PUVA) treatment were noted, except a for few days of slight erythema caused by the high dose of UV.     

Dark effect of 8-methoxypsoralen (8-MOP) on lymphocytes

Summary A new technique based on liquid phase ion exchange chromatography on short column is proposed for quantitative determination of tyrosine and Dopa.-Amino, -guanidinopropionic acid is used as an internal standard of coloration. The role of H₂O₂ and ascorbic acid on tyrosine and Dopa was checked. Ascorbic acid prevents the auto-oxidation of Dopa, H₂O₂ has no effect on tyrosine but oxidizes Dopa even in the presence of excess ascorbic acid. This method was tested in mushroom tyrosinase, with and without ascorbic acid. Assays performed with tyrosinase from rabbit occular extracts clearly showed that they do oxidize tyrosine.Reliability of the method is comparable to radioassay.This work was supported in part by INSERM grant ATP 78-99     

Effect of cutaneous hypoxia upon erythema and pigment responses to UVA, UVB, and PUVA (8-MOP + UVA) in human skin

The effect of oxygen deprivation upon UVA-, UVB-, and PUVA-induced pigment and erythema responses in normal human skin was examined. Before exposure, varying degrees of hypoxia in the skin of the forearm were achieved by inflating a sphygmomanometer cuff applied to the upper arm. After the transcutaneously measured pO2 had stabilized, sites on the inner forearm were exposed to UVA, UVB, or 8-MOP + UVA radiation, to determine dose thresholds for the induction of erythema and pigmentation at different cuff pressures. Inflation of the cuff to greater than systolic pressure completely inhibited immediate and delayed pigment responses (IPD, DT) to UVA doses greater than 10 times the normal pigmentation threshold dose. UVA-induced delayed erythema responses were partially inhibited by cuff inflation: 2.7 times the minimal erythema dose of UVA was necessary to cause an erythema response when exposure occurred during vascular occlusion. In contrast, erythema and pigment responses to UVB and PUVA were unaltered by cuff pressures exceeding systolic pressure during exposure. Inhibition of UVA-induced erythema and pigment responses by vascular occlusion were reversed by the transcutaneous diffusion of 100% O2. These findings indicate that the cutaneous responses to UVA and UVB occur by separate pathways differing with respect to O2 dependence. Our findings agree with those of other studies which indicate that PUVA-induced phototoxicity and melanogenesis are not O2-dependent.     

Long-term stability of 8-methoxypsoralen in ointments for topical PUVA therapy ('Cream-PUVA').

8-Methoxypsoralen (8-MOP) is an established photochemotherapeutic agent for PUVA therapy. Recently, a so-called 'cream-PUVA' modality was introduced into therapy of psoriasis and other dermatoses. Little is known, however, about the stability of 8-MOP in ointments used for the topical application of this compound. Therefore, we investigated the long-term stability of 8-MOP in three different ointments, Unguentum Cordes(TM), Cold Cream Naturel(TM) and a water-containing gel on the basis of Carbopol 940. All three ointments were prepared with 8-MOP concentrations of 0.05 and 0.005%, and stored over 12 weeks at room temperature (19-20 degrees C) and at 5 degrees C. 8-MOP concentrations were measured at days 1, 8, 15, 29, 57 and 88 after preparation by thin-layer chromatography (TLC). The ointments were dissolved in an organic solvent, 10 microl were transferred onto the TLC plate and the chromatograms were developed first in toluene and then in toluene/ethyl acetate 2:1 v/v to resolve 8-MOP from the ointment constituents. The peak heights of 8-MOP were used for quantitation. The intraday variabilities are <3% for Unguentum Cordes and Cold Cream Naturel and <6% for the Carbopol 940 gel. The interday variabilities were <6.3% in all cases. In Unguentum Cordes and Cold Cream Naturel the concentrations of 8-MOP remain stable, but in Unguentum Cordes the emulsion began to break up after 8 weeks. In the Carbopol gel, only about 40% of the nominal concentrations of 8-MOP were found and they decrease significantly at storage at 5 degrees C. We conclude that the Carbopol gel seems to be unsuitable for PUVA therapy, whereas Cold Cream Naturel shows the best results.     

A comparison of psoralen plus ultraviolet A (PUVA) monotherapy,tacalcitol plus PUVA and tazarotene plus PUVA in patients with chronic plaque-type psoriasis

BACKGROUND: Numerous studies have shown that the additional administration of topical or systemic antipsoriatic agents might serve as an effective means to increase the efficacy of photochemotherapy [psoralen plus ultraviolet (UV) A (PUVA)] for psoriasis. OBJECTIVES: To compare the therapeutic response to tacalcitol plus PUVA, tazarotene plus PUVA and PUVA monotherapy in patients with chronic plaque-type psoriasis. In addition, we also assessed the duration of remission induced by each regimen and the tolerability of the two combination treatments. METHODS: Thirty-one patients with chronic plaque-type psoriasis were included in this observer-blinded, intrapatient comparison trial. PUVA treatment was given four times weekly. Additionally, tacalcitol ointment and 0.1% tazarotene gel were applied separately on two target areas once daily in the evening. At the onset of therapy and every 2 weeks thereafter the response to treatment was determined by the Psoriasis Severity Index score, which assesses the degree of erythema, infiltration and scaling of the psoriatic lesions. After complete or near complete clearing patients were followed-up until relapse. RESULTS: Twenty-four patients completed the study. The treatment requirements to induce complete or near complete clearing were significantly lower for both combination treatments than for PUVA monotherapy (P < 0.01). The median cumulative UVA dose and number of exposures were 30.6 J cm-2 (95% confidence interval, CI 22.5-71.2) and 14 (95% CI 11-16) for tacalcitol plus PUVA, 32.3 J cm-2 (95% CI 22.5-73.8) and 14 (95% CI 11-19) for tazarotene plus PUVA, and 37.0 J cm-2 (95% CI 29.5-83.9) and 16 (95% CI 14-22) for PUVA monotherapy. No difference between the three regimens was observed with regard to duration of remission. Adverse reactions occurred more often with 0.1% tazarotene than with tacalcitol but were in general mild and completely reversible upon using a lower concentration of 0.05% tazarotene. CONCLUSIONS: Tacalcitol ointment and tazarotene gel are both comparably effective in improving the therapeutic result of PUVA therapy in patients with chronic plaque-type psoriasis. Besides accelerating the treatment response, both agents, by virtue of their UVA dose-sparing effect, might also help to reduce possible long-term hazards of PUVA treatment.     

Paired comparison of bathwater versus oral delivery of 8-methoxypsoralen in psoralen plus ultraviolet: A therapy for chronic palmoplantar psoriasis

BACKGROUND: Both bath psoralen plus ultraviolet A (PUVA) and oral PUVA with 8-methoxypsoralen (8-MOP) have been successfully used for the treatment of recalcitrant palmoplantar psoriasis. This trial was designed to assess the efficacy and side effects of the different treatment modalities in a randomized half-side comparison. Methods: Eight patients with moderate-to-severe psoriasis on soles (n = 6) and/or palms (n = 8) were randomly assigned to receive bath PUVA treatment on one side and oral PUVA on the other. Initial treatment dose was 50% of the minimal phototoxic dose evaluated for bath PUVA and oral PUVA. Treatment was given three times a week for 4 weeks. Before treatment and every week a severity index (SI) was assessed by summing the scores of erythema, infiltration, scaling and vesicles evaluated on a scale from 0 to 4. After 4 weeks of treatment the half-side trial was finished and the treatment was continued on both sides with the more effective treatment regimen. RESULTS: Both bath PUVA and oral PUVA achieved a reduction of the mean initial SI from 5.9 (95% confidence intervals (CI) 4.5-8.0) to 3.3 (1.8-6.0) (44% SI reduction, P < 0.005, Student's paired t-test) and 6.0 (5.0-7.8) to 2.9 (1.8-4.0) (52% SI reduction; P < 0.005), respectively. The statistical comparison of the entire 4-week study period revealed a significant better effect in lesions treated with oral PUVA compared with bath PUVA (P = 0.033). However, at 4 weeks, there was no significant difference between the achieved SI reduction of oral PUVA and bath PUVA. Systemic side effects (nausea and/or dizziness) were only observed after oral PUVA. CONCLUSION: This study gives evidence that in the first 4 treatment weeks oral PUVA is slightly more effective than bath PUVA but the former has more systemic side effects.     

A comparison of systemic photochemotherapy with 8-methoxypsoralen (8-MOP) and with trimethylpsoralen (TMP) in vitiligo

Oral 8-MOP and TMP were compared in the PUVA therapy for vitiligo. Group A (25 cases) was initiated on 0.3 mg/kg of 8-MOP with 1/2 Joule/cm2 of UVA and weekly increments of 1/2 Joule/ cm2 and Group B was started on 0.6 mg/kg of TMP with 1 Joule/cm2 of UVA and weekly increments of 1 Joule/cm2. Therapy was given thrice a week. Repigmentation was evaluated by using a 0-6 scale. At the end of 60 sittings, on acceptable cosmetic response was seen over the face, neck and upper extremities in both groups, while trunk and lower extremities showed lesser response. 8-MOP gave earlier response, needing a lower cumulative UVA dose i.e. 75 J/cm2 as compared to TMP i.e. 106 J/cm2. Phototoxicity was seen more often with 8-MOP. In conclusion, in Indians, 8-MOP is the drug of choice in PUVA therapy of vitiligo provided precautions against phototoxicity are adequate.     

Effects of 8-Methoxypsoralen (8-MOP) and UVA on human lymphocytes

Summary Peripheral lymphocytes of 37 psoriatic patients are tested before and under PUVA treatment using as parameter the non specific stimulation effect of HgCl₂ (10 µg/ml) in culture, measuring the³H-thymidine incorporation after the last 16 h of a 5-days culture. Oral 8-MOP in therapeutic doses is decreasing the lymphocyte stimulation as well as 8-MOP together with UVA irradiation during the first week of treatment. After 1 week, the stimulation is, on the contrary, significantly enhanced after irradiation. Lymphocytes isolated by centrifugation over Lymphoprep are submitted to PUVA conditions in petri dishes (Hank's solution 8-MOP 1 µg/ml, irradiation with 350 nm, 93-372 mJ/cm²). The total cell number, the E-rosette formation (as marker for T-Lymphocytes) and the EAC-rosette formation (as marker for B-Lymphocytes) are determined. PUVA conditions have an energy dependent decreasing effect on the cell number, while the T- and B-cell proportions remain constant. UVA irradiation alone has such an effect only with high energies. 8-MOP without UVA has no significant influence on the cell number.Offprint requests to: Dr. G. Lischka (address see above)     

Phototesting in bath-PUVA: marked reduction of 8-methoxypsoralen (8-MOP) activity within one hour after an 8-MOP bath

It is not known how long after 8-MOP bath-PUVA administration erythema can be induced. Therefore, after determination of dose-dependence and kinetics of bath-PUVA erythema, we investigated the development of erythema using an erythematogenic UVA-dose (3 J/cm²) in time course experiments. Our results show that there is a loss of biological 8-MOP activity already 1 h after 8-MOP bath. This has important consequences for clinical practice with bath-PUVA, concerning the optimum time interval between the 8-MOP bath and irradiation as well as the persistence of photosensitivity in normal skin after bath-PUVA.     

NB-UVB联合8-MOP PUVA治疗小腿斑块状银屑病疗效评价

目的: 评价NB-UVB联合8-甲氧补骨脂素（8-MOP） PUVA治疗斑块状银屑病的疗效。方法: 分别对16例银屑病患者双侧小腿进行PASI评分,一侧给予NB-UVB照射,另一侧给予NB-UVB联合8-MOP PUVA,每周3次,共治疗20次。结果: NB-UVB治疗侧治疗前后PASI评分分别为8.21±2.97和2.31±1.01,差异有统计学意义(P＜0.05);NBUVB联合8-MOP PUVA治疗侧分别为8.33±2.54和1.20±0.93,差异有统计学意义(P＜0.05)。治疗后NBUVB联合8-MOP 治疗侧较NB-UVB治疗侧PASI更低,差异有统计学意义(P＜0.05)。结论：NB-UVB联合8-MOP PUVA可明显促进小腿顽固部位皮损的消退。     

Reduction in 8-methoxypsoralen immersion time alters the erythemal response to bath PUVA

Topical psoralen plus ultraviolet A (PUVA) using 8-methoxypsoralen (8-MOP) bath solution is a well established and effective treatment in dermatology. The standard immersion time in the UK is 15 min, but a shorter bathing period could potentially increase treatment convenience. In order to examine the effect of reduction in immersion time on skin phototoxicity, we compared the erythemal response to UVA following 5 min and 15 min psoralen baths. The study was performed on the forearm skin of 7 healthy volunteers using an 8-MOP psoralen concentration of 2.6 mg/l. One forearm of each volunteer was soaked for 15 min and the other for 5 min, followed by immediate irradiation with a series of 10 doses of broadband UVA ranging from 0.1 J/cm2 to 6.9 J/cm2. At 72 h, the minimal phototoxic doses (MPDs) were noted and erythema readings (erythema index) were taken in triplicate with a reflectance instrument. The median MPD following 5 min immersion was 1.7 (range 0.7-2.7) J/cm2 compared with 1.0 (range 0.4-1.7) J/cm2 after 15 min treatment, with no significant difference. However, the mean slope of erythema dose-response on the 15-min treated side was significantly steeper than on the 5-min treated side, 0.036 and 0.021 respectively, P < 0.05. Hence, this preliminary work shows that reducing 8-MOP immersion time to 5 min reduces the erythemal response to UVA. It will clearly be necessary to examine the effect of a shortened immersion period on disease clearance before considering such a change to the topical PUVA regime.     

Calculation of 8-methoxypsoralen dose according to body surface area in PUVA treatment

In 41 patients about to start PUVA, the dose of 8-methoxypsoralen (8-MOP) was calculated conventionally according to body weight (0·6mg/kg), or according to body surface area (25mg/m²) predicted from height and weight measurements. The two different methods of dosing were used on consecutive treatment days and the plasma 8-MOP concentration was measured on each occasion 2b after ingestion of the crystalline form of 8-MOP, given to the nearest 10 mg. Body weight calculated doses ranged from 30 to 60 mg with a significant difference in the plasma 8-MOP concentration between the dose groups, indicating a systematic variation according to the weight of the patient. When calculated according to body surface area, only two doses were used (40 or 50 mg), and there was no significant difference in plasma H-MOP concentration between the groups. Calculation of the dose of 8-MOP using body surface area may be performed quickly and simply provided the height and weight of individual patients is known. We provide evidence that this method of dosing will improve the therapeutic effect of PUVA in psoriasis.     

Comparison of the efficacy of local narrowband ultraviolet B (NB-UVB) phototherapy versus psoralen plus ultraviolet A (PUVA) paint for palmoplantar psoriasis

Palmoplantar psoriasis is an idiopathic disabling condition, often resistant to conventional therapies. The purpose of this study was to evaluate the efficacy and safety of local narrowband ultraviolet B (NB-UVB) phototherapy and to compare it with local psoralen plus ultraviolet A (PUVA) paint in patients with palmoplantar psoriasis unresponsive to conventional therapies other than phototherapy. A cohort of 25 patients with palmoplantar psoriasis were included in this study, which was based on a left-to-right comparison pattern. The treatments were administered with local narrowband UVB irradiation on one side and local PUVA on the other side three times a week over 9 weeks. Clinical assessments were performed at baseline and every 3 weeks during the 9-week treatment. There was a statistically significant decrease in the mean clinical scores at the third, sixth and ninth week with both treatments. The difference in clinical response between the two treatment modalities was statistically significant at the end of the treatment period, with the percentage reduction in severity index scores with the PUVA-paint-treated side being 85.45% compared with 61.08% for the NB-UVB treated side (t = 5.379, P = 0.0001, Student's t-test for unpaired samples). Our results show that, although some clinical improvement was achieved with local NB-UVB phototherapy, the results were better with local PUVA, and such a treatment option may be reserved for patients with palmoplantar psoriasis who experience phototoxic reaction to psoralens.     

Cutaneous carcinoma and 8-methoxypsoralen and ultraviolet A (PUVA) lentigines in Japanese patients with psoriasis treated with topical PUVA: a follow-up study of 214 patients

A total of 214 Japanese patients with psoriasis, under treatment with topical 8-methoxypsoralen and ultraviolet A (PUVA), were examined for malignant skin tumors and pigmented lesions during a follow-up period of up to 17 years (mean 5.8 years). One patient had developed multiple superficial basal cell carcinomas, and the remaining 213 patients had neither cutaneous carcinomas nor actinic keratoses. PUVA lentigines were seen in 89 patients (42%) and the incidence of lentigines increased as the number of PUVA treatments and the cumulative UVA dose increased. Melanocytic atypia was not observed histologically in 24 pigmented lesions examined. This report suggests that this topical PUVA regimen may not be highly carcinogenic in the Asian population.