Decreased risk of melanoma and nonmelanoma skin cancer in patients with vitiligo: a survey among 1307 patients and their partners.

BACKGROUND: Vitiligo is a common skin disease characterized by autoimmune melanocyte destruction. Recent genetic studies suggest a lower susceptibility to melanoma in patients with vitiligo; however, lifetime melanoma prevalence in patients with vitiligo has not previously been studied. Nonmelanoma skin cancer (NMSC) prevalence has been studied, but only in small studies and with contradictory results. OBJECTIVES: This retrospective, comparative cohort survey was designed to assess lifetime prevalences of melanoma and NMSC in patients with vitiligo compared with nonvitiligo controls. METHODS: Patients with nonsegmental vitiligo, who visited our clinic between January 1995 and September 2010, and were aged 50 years or older at the time of the study, were invited to participate in a postal survey. The questions regarded demographics, vitiligo characteristics, phototherapy history, skin cancer risk factors and the number of skin cancers experienced during the patient's lifetime. Patients were asked to have their partner fill in a control questionnaire. All skin cancers were validated by a pathology report. In total 2635 invitations were sent and 1307 eligible questionnaires were returned (50%). Multivariate logistic regression models were used to quantify adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for associations between vitiligo and lifetime prevalences of melanoma and NMSC. RESULTS: Adjusted for confounders, patients with vitiligo had a threefold lower probability of developing melanoma (adjusted OR 0·32; 95% CI 0·12-0·88) and NMSC (adjusted OR 0·28; 95% CI 0·16-0·50). Subgroup analyses of patients treated with narrowband ultraviolet (UV) B, and psoralen and UVA did not show dose-related trends of increased age-adjusted lifetime prevalence of melanoma or NMSC. CONCLUSIONS: Our findings suggest that patients with vitiligo have a decreased risk of both melanoma and NMSC.

A randomized comparison of excimer laser versus narrow-band ultraviolet B phototherapy after punch grafting in stable vitiligo patients.

Background Ultraviolet radiation following punch grafting may stimulate the migration of melanocytes from the grafts into the vitiliginous skin, thereby increasing the rate of repigmentation. We compared the effects of the 308-nm xenon chloride excimer laser (EL) vs. narrow-band ultraviolet B (NB-UVB) after punch grafting in patients with vitiligo. Objectives The aims of this study were to evaluate (i) repigmentation (%); (ii) treatment satisfaction; and (iii) patient preferences for EL vs. NB-UVB therapy after punch grafting in vitiligo. Methods Fourteen patients were treated with the punch-grafting technique on two symmetrical vitiligo patches. Starting 1 week after the punch grafting, the vitiligo patches were treated twice a week during 3 months, with EL on one side and with NB-UVB on the other side. Repigmentation (%) was measured by a digital image analysis system. Patients' satisfaction and preference for treatment were also assessed. Results Whereas both treatment modalities induced repigmentation, no statistically significant difference was found in grade of repigmentation after 3 months. With EL, 71.4% lower cumulative dose was reached. Patients were significantly more satisfied with NB-UVB and preferred it over EL. Conclusions The choice between EL and NB-UVB cannot solely be based on repigmentation, but rather on other factors, such as patients' preferences. However, given the lower UV dose of EL, we recommend its use in vulnerable populations, such as in small children and patients with sun-damaged skin with a history of long-term UVB treatment.

Laser and intense pulsed light therapy for the treatment of hypertrophic scars: a systematic review.

Hypertrophic scars are difficult to improve and remain a therapeutic challenge. Several lasers and light sources have been evaluated in the past decades and have been shown to improve hypertrophic scars. However, a systematic review is not available. To assess current evidence of efficacy of all laser and intense pulsed light therapies used in the treatment of hypertrophic scars, we performed a systematic review searching electronic databases MEDLINE, EMBASE and CENTRAL. The quality of the controlled clinical trials was evaluated according to the Cochrane Collaboration's tool for assessing risk of bias. Thirteen articles involving seven different lasers met the inclusion criteria. Most evidence was found for the pulsed dye laser (PDL) 585 nm (eight studies), followed by the PDL 595 nm (two studies), whereas limited evidence (one trial per laser) was available for the fractional nonablative laser 1540 nm, CO2 laser 10,600 nm, low-level laser therapy, Nd:YAG laser 532 nm and Erbium:YAG laser 2940 nm. Treatment recommendations should be formulated with caution as current evidence is insufficient for comparing the efficacy of different laser therapies. The PDL 585 nm showed a low efficacy for the treatment of hypertrophic scars. With moderate efficacy, the PDL 595 nm is promising, although more research is necessary. Little evidence was found for the efficacy of other lasers. Future research, with a low risk of bias, well-defined scar characteristics, validated outcome measures, standardized measurement methods, follow-up periods of at least 6 months and well-defined laser settings, is needed.

Excimer laser vs. clobetasol propionate 0·05% ointment in prurigo form of atopic dermatitis: a randomized controlled trial, a pilot.

BACKGROUND: Recent findings have established the 308-nm xenon chloride excimer laser (EL) as a new option in the area of ultraviolet (UV) B phototherapy. As this laser enables high radiant exposure of narrowband UVB and precise targeting of affected skin, it appears to be a promising treatment for the prurigo form of atopic dermatitis (AD). OBJECTIVES: To investigate the efficacy and safety of the EL compared with clobetasol propionate (CP) in the prurigo form of AD. METHODS: In a prospective randomized within-patient controlled study, 13 patients with a prurigo form of AD were randomized to receive EL on one side and topical CP on the other side. Laser treatment was performed twice a week for 10 weeks. Clinical responses were evaluated using Physician Assessment of Individual Signs, Physician Global Assessment, Patient Global Assessment and photographic documentation. Histopathological changes were evaluated and duration of remission was monitored during a 6-month follow-up period. RESULTS: Both treatments resulted in a significant improvement of all outcome measures after 10 weeks of treatment. During follow up, the EL showed more improvement compared with CP. Histopathology demonstrated marked decrease of epidermal thickness and inflammatory infiltrate at the EL-treated sites. No significant side-effects occurred. CONCLUSIONS: This study suggests that the EL can safely and effectively be used in the treatment of the prurigo form of AD. For the long term, the EL might be a good alternative to topical corticosteroids and an option in case of therapy-resistant patients.

European S3-guidelines on the systemic treatment of psoriasis vulgaris.

Of the 131 studies on monotherapy or combination therapy assessed, 56 studies on the different forms of phototherapy fulfilled the criteria for inclusion in the guidelines. Approximately three-quarters of all patients treated with phototherapy attained at least a PASI 75 response after 4 to 6 weeks, and clearance was frequently achieved (levels of evidence 2 and 3). Phototherapy represents a safe and very effective treatment option for moderate to severe forms of psoriasis vulgaris. The onset of clinical effects occurs within 2 weeks. Of the unwanted side effects, UV erythema from overexposure is by far the most common and is observed frequently. With repeated or long-term use, the consequences of high, cumulative UV doses (such as premature aging of the skin) must be taken into consideration. In addition, carcinogenic risk is associated with oral PUVA and is probable for local PUVA and UVB. The practicability of the therapy is limited by spatial, financial, human, and time constraints on the part of the physician, as well as by the amount of time required by the patient. From the perspective of the cost-bearing institution, phototherapy has a good cost-benefit ratio. However, the potentially significant costs for, and time required of, the patient must be considered.

Treatment of vitiligo vulgaris with narrow-band UVB and oral Polypodium leucotomos extract: a randomized double-blind placebo-controlled study.

BACKGROUND: The first choice treatment for vitiligo vulgaris is narrow-band UVB (NB-UVB), but no satisfactory treatment exists. OBJECTIVES: To investigate if Polypodium leucotomos, an antioxidative and immunomodulatory plant extract, improves NB-UVB-induced repigmentation. METHODS: Fifty patients with vitiligo vulgaris randomly received 250 mg oral P. leucotomos or placebo three times daily, combined with NB-UVB twice weekly for 25-26 weeks. RESULTS: Repigmentation was higher in the P. leucotomos group vs. placebo in the head and neck area (44% vs. 27%, P = 0.06). Small repigmentation increases (P = n.s.) were observed for the trunk (6% increased repigmentation), extremities (4%), and hands and feet (5%) in the P. leucotomos group vs. placebo. Patients attending more than 80% of required NB-UVB sessions showed increased repigmentation in the head and neck area in the P. leucotomos group vs. placebo (50% vs. 19%, P < 0.002); no significant differences were seen in the other body areas. Patients with skin types 2 and 3 showed more repigmentation in the head and neck area in the P. leucotomos group vs. placebo (47% vs. 21%, P = 0.01), and no significant differences were seen in the other body areas. No conclusions could be drawn on skin types 4 and 5 due to low patient numbers. CONCLUSION: There is a clear trend towards an increase in repigmentation of vitiligo vulgaris affecting the head and neck area when NB-UVB phototherapy is combined with oral P. leucotomos. This effect may be more pronounced in light skin types.

Patients with moderate-to-severe plaque psoriasis preferred oral therapies to phototherapies: a preference assessment based on clinical scenarios with trade-off questions.

OBJECTIVE: The importance of validly identifying and incorporating patients' views for improving health care is generally acknowledged. Common approaches to assess patients' preferences are based on the quality adjusted life year (QALY) framework, but this ignores a number of aspects that may be relevant. As an alternative, we assessed patients' treatment preferences and trade-offs for five common systemic therapies for psoriasis. STUDY DESIGN AND SETTING: Twenty-nine patients with moderate-to-severe psoriasis expressed treatment preferences for five oral and phototherapies and indicated the relative importance of various treatment attributes, such as adverse effects, discomforts, and safety measures. In a structured interview, they were presented with clinical scenarios that contained descriptions of process and outcome characteristics and illustrations of the anticipated treatment benefit. RESULTS: Over all paired comparisons, methotrexate (33%), cyclosporin (30%), acitretin (15%), UV-B (14%), and PUVA (8%) were preferred to the other treatment. Patients were willing to trade-off their initial preference for more improvement of psoriasis. CONCLUSIONS: Psoriasis patients generally prefer oral to phototherapies and consider most adverse effects and several discomforts important for selecting treatment. Our scenario-based structured interview approach to treatment preferences allowed us to incorporate a broad spectrum of potentially relevant decision components in a clinically meaningful way.

Biological therapies in the systemic management of psoriasis: International Consensus Conference.

Psoriasis is a chronic, immune-mediated disorder that usually requires long-term treatment for control. Approximately 25% of patients have moderate to severe disease and require phototherapy, systemic therapy or both. Despite the availability of numerous therapeutic options, the long-term management of psoriasis can be complicated by treatment-related limitations. With advances in molecular research and technology, several biological therapies are in various stages of development and approval for psoriasis. Biological therapies are designed to modulate key steps in the pathogenesis of psoriasis. Collectively, biologicals have been evaluated in thousands of patients with psoriasis and have demonstrated significant benefit with favourable safety and tolerability profiles. The limitations of current psoriasis therapies, the value of biological therapies for psoriasis, and guidance regarding the incorporation of biological therapies into clinical practice are discussed.

Evaluation of medium-dose UVA1 phototherapy in localized scleroderma with the cutometer and fast Fourier transform method.

PURPOSE: To evaluate the efficacy of medium-dose UVA1 phototherapy in patients with localized scleroderma. METHOD: A controlled pilot study with medium-dose UVA1 (48 J/cm2) was performed. The results were evaluated by means of a skin score and two objective methods for quantifying sclerosis (cutometer and fast Fourier transform method). Patients were treated 4 times a week for 5 weeks. The follow-up period was 12 weeks. RESULTS: All patients responded to therapy. Skin score and cutometer results showed improvement of skin elasticity of treated skin compared to control skin. Fast Fourier transform measurements showed no change in bundle orientation ratio and spacing. CONCLUSION: We concluded that treatment for 12 weeks 4 times a week with medium-dose UVA1 may be a beneficial therapy and a well-tolerated treatment modality for localized scleroderma (morphea). After 12 weeks, improvement of skin sclerosis can be detected by skin score and cutometer measurements but not by the fast Fourier transform method.

Calcipotriol ointment and cream or their vehicles applied immediately before irradiation inhibit ultraviolet B-induced erythema.

Results of ultraviolet (UV) B phototherapy can be improved by the application of calcipotriol, but studies are needed to decide how the two treatments should be combined. We studied the effect of UVB after application of calcipotriol ointment (50 microg g-1) and calcipotriol cream (50 microg g-1) and determined the optimal time of application of calcipotriol when combined with UVB phototherapy (280-350 nm), in a single-blinded randomized vehicle-controlled study of 37 healthy adult volunteers. Calcipotriol ointment or cream was applied randomly on five areas on the back at different time intervals from UVB irradiation. One area was left untreated as the control. Application times were the evening before, the morning before, 2 h before, immediately before, and immediately after irradiation. UVB irradiation was administered by TL20W/12 fluorescent tube lamps at increasing doses (20, 25, 32, 40, 50 and 64 mJ cm-2) to six subunits of each test area. Clinical assessment was performed 24 h after UVB irradiation by a blinded investigator. Calcipotriol ointment and cream were applied in 19 and 18 subjects, respectively, and erythema was measured for each application time quantified. We found that erythemal reactions were significantly smaller when calcipotriol ointment or cream was applied immediately before irradiation compared with all other application times. To explain these findings, a vehicle control study was performed. No difference in erythema was seen between calcipotriol medication and the vehicle controls. Spectrophotometric analysis of the calcipotriol cream and ointment showed no UV absorbance in the UVB range. No signs of photosensitization were noted. In conclusion, the vehicles of the calcipotriol ointment and cream inhibit the induction of erythema by UVB irradiation if applied immediately before phototherapy. Consequently, calcipotriol ointment and cream should not be applied directly before UVB irradiation; however, they may be applied at any time up to 2 h prior to or immediately after UVB irradiation. Possible explanations for this sunscreen activity are discussed.

No additional effect of calcipotriol ointment on low-dose narrow-band UVB phototherapy in psoriasis.

BACKGROUND: Broad-band UVB phototherapy has appeared to be effective in clearing psoriatic lesions. After the advent of calcipotriol ointment, promising results have been obtained by combining these two therapeutic modalities. Also, an additional effect of narrow-band UVB phototherapy on treatment with calcipotriol ointment has been demonstrated. OBJECTIVE: Our purpose was to compare treatment with low-dose narrow-band UVB phototherapy both with and without calcipotriol ointment. METHODS: We included 53 patients suffering from plaque-type psoriasis. All patients underwent low-dose narrow-band UVB phototherapy. Nearly half of the patients were randomized to apply calcipotriol ointment (50 microg/g) twice daily on the affected skin. The Psoriasis Area and Severity Index (PASI) was used to evaluate psoriatic lesions. RESULTS: In this study we showed that low-dose narrow-band UVB phototherapy is effective in the treatment of psoriasis and that calcipotriol ointment does not improve treatment outcome. CONCLUSION: Calcipotriol ointment does not improve treatment with low-dose narrow-band UVB phototherapy.

Low-dose narrow-band UVB phototherapy combined with topical therapy is effective in psoriasis and does not inhibit systemic T-cell activation.

BACKGROUND: Psoriasis is a chronic T-cell-mediated inflammatory skin disease which can be treated with topical medication, phototherapy or systemic medication. A subgroup of psoriatic patients does not respond to monotherapy and needs combination therapy. We used low-dose narrow-band UVB phototherapy, combined with balneotherapy, short-contact anthralin, liquor carbonis detergens and calcipotriol for treatment of psoriatic patients in our day care centre. OBJECTIVE: Our purpose was to study the efficacy, induction of erythema and effect on systemic T-cell activation of this combination therapy. METHODS: Skin reflectance spectrophotometry was used to measure skin erythema. The Psoriasis Area and Severity Index (PASI) was used to evaluate psoriatic patients. Serum soluble IL-2 receptor (sIL2-R) levels were measured by an ELISA. RESULTS: The possible erythematogenic effect of low-dose narrow-band UVB irradiation was studied (skin reflectance spectrophotometer) in a control group of psoriatic patients (n = 11). No induction of skin erythema was seen. Subsequently, this low-dose irradiation regimen was used in combination with topical medication in 26 psoriatic patients. A 90% decrease in the PASI was seen after a mean number of 35 treatment sessions. Seventeen patients (65%) remained in remission during the following 6 months. Serum sIL-2R levels were elevated in all patients (mean 913 U/ml) and did not change during treatment. CONCLUSION: Our data indicate that low-dose narrow-band UVB can be used successfully, in combination with topical treatment, in a day care setting to treat psoriatic patients. Since sIL-2R serum levels were not decreased, it can be speculated that this treatment does not induce systemic immunosuppression.

Prolonged increase of cis-urocanic acid levels in human skin and urine after single total-body ultraviolet exposures.

Cis-urocanic acid (cis-UCA), a mediator of immunosuppression, is formed from trans-UCA upon UV-exposure of the skin. This study describes a liquid chromatographic method for the simultaneous quantification of cis- and trans-UCA in skin, urine and plasma of nonirradiated volunteers. It also describes cis- and trans-UCA kinetics in UV-irradiated volunteers. New procedures to remove interfering substances from urine and plasma are reported. Normal levels of cis-UCA in skin, urine and plasma of nonirradiated volunteers were 0.5 nmol/cm2, 0.03 mumol/mmol creatinine (median 0.00) and undetectable and those of trans-UCA were 17.1 nmol/cm2, 1.36 mumol/ mmol creatinine and 0.5 microM, respectively. Upon single total body UVB (290-320 nm) exposures of 250 J/m2, epidermal cis-UCA levels immediately reached a maximum and returned to basic levels 3 weeks later. The cis-UCA levels in urine reached a maximum in 5-12 h postirradiation and reached baseline values in 8-12 days. Additionally, a single total body UVA (320-400 nm) irradiation of 200 kJ/m2 yielded a similar pattern. The kinetics of cis-UCA in plasma could not be followed due to low concentrations; however, that of skin and urine was informative in relation to solar exposures and phototherapy.

Extracorporeal photochemotherapy (photopheresis) induces apoptosis in lymphocytes: a possible mechanism of action of PUVA therapy.

The mechanism of action of psoralen plus UVA (PUVA) and photopheresis is not entirely understood. These therapies are assumed to be immunomodulating partly by gradually decreasing leukocyte viability. We investigated whether this delayed form of cell death was due to apoptosis. Untreated and treated (PUVA exposed) leukocytes obtained from six patients with systemic sclerosis and (untreated) leukocytes from healthy control individuals were studied. Qualitative gel electrophoresis and quantitative in situ nick translation analysis of DNA fragmentation was performed. Apoptosis of the treated cells did occur (gel electrophoresis) after 24 h. At t = 0 h, immediately after exposure to PUVA, there was no evidence of DNA fragmentation in the treated cells. The percentage of treated cells undergoing apoptosis was 20-55% at t = 24 h (in situ nick translation). The untreated leukocytes of the patients and the healthy individuals showed no distinctive rise in apoptotic cells. Apoptosis of the leukocytes after PUVA or photopheresis treatment might be a mechanism of action and might explain the therapeutic response.

A systematic review of five systemic treatments for severe psoriasis.

We systematically reviewed the evidence concerning the ability of five systemic treatments to induce remission in patients with severe psoriasis: ultraviolet B (UVB), photochemotherapy (PUVA), methotrexate (MTX), retinoids (RET) and cyclosporin A (CYA). An elaborate literature search was performed, the validity of studies was assessed, and data were analysed. In total, 89, 193, 101, 155 and 127 studies (n = 665) concerning UVB, PUVA, MTX, RET and CYA were found. The exclusion rate was high, mainly because of concomitant antipsoriatic therapy, outdated dosages or inadequate documentation. No study on MTX could be included. A total of 129 patient series was included in the analysis, reporting on 13,677 patients. Study size-weighted averages of the proportions of patients with clearance and good, moderate and poor response (defined, respectively, as 95-100%, 75-100%, 50-75% and < 50% reduction in the outcome measurements as compared with baseline) were calculated. PUVA therapy was associated with the highest average proportion of patients with clearance (70%), and the highest proportion of patients with good response (83%), followed by UVB (68%) and CYA (64%). Incidence of side-effects per week was highest in the RET group and lowest in the phototherapy groups. This review may provide a basis for the development of guidelines for the treatment of psoriasis. Trials comparing oral modalities applied according to currently accepted standards should also be carried out.

Methotrexate osteopathy in long-term, low-dose methotrexate treatment for psoriasis and rheumatoid arthritis.

BACKGROUND: In dermatology and rheumatology, methotrexate is frequently prescribed in low dosages per week; in oncology, high dosages per week are prescribed. Methotrexate osteopathy was first reported in children with leukemia treated with high doses of methotrexate. In animal studies, low doses of methotrexate proved to have an adverse effect on bone metabolism, especially on osteoblast activity. OBSERVATIONS: Methotrexate osteopathy is a relatively unknown complication of low-dose methotrexate treatment. We describe three patients treated with low-dose oral methotrexate in whom signs and symptoms were present that were similar to those found in children treated with high doses of methotrexate. All three patients had a triad of severe pain localized in the distal tibiae, osteoporosis, and compression fractures of the distal tibia, which could be identified with radiographs, technetium Tc 99m scanning, and magnetic resonance imaging. CONCLUSIONS: Methotrexate osteopathy can occur in patients treated with low doses of methotrexate, even over a short period of time. As pain is localized in the distal tibia, it is easily misdiagnosed as psoriatic arthritis of the ankle, but the diagnosis can be correctly made by careful investigation and use of imaging techniques. The only therapy is withdrawal of methotrexate. It is important that more physicians become aware of this side effect of methotrexate therapy, which can occur along with arthritic symptoms.

Photoisomerization spectrum of urocanic acid in human skin and in vitro: effects of simulated solar and artificial ultraviolet radiation.

Ultraviolet (UV) irradiation of trans-urocanic acid (UCA), a major UV absorbing component of the epidermis, leads to the formation of cis-UCA, which mediates immunosuppressive effects. In this study, the net yield of cis-UCA was measured after the photoisomerization of urocanic acid by narrow UV wavebands (spectral range 295-405 nm), with the irradiation doses related to solar irradiance at sea level. The formation of cis-UCA in Caucasian skin (in vivo), as well as in aqueous solution (in vitro), was determined by HPLC analysis. The same irradiation conditions were met in both components of the study. The in vivo experiments showed high efficiency of cis-UCA formation in the spectral region of 305-341 nm, whereas high efficiency in vitro was found at 305 and 326 nm. At 350 and 363 nm, cis-UCA was formed in vivo, but not in vitro. At longer test wavelengths up to 405 nm, no significant formation of cis-UCA was detectable. The established partition between UVB and UVA at 320 nm is not relevant for the isomerization pattern of UCA. Additional studies revealed substantial cis-UCA formation in human skin by UVA phototherapy lamps. Furthermore, raised levels of 295 nm irradiation doses, a possible effect of stratospheric ozone depletion, were found to increase the cis-UCA yield. Our results demonstrate that the formation of cis-UCA in the skin with common exposures takes place over a broad spectrum range of UVB and UVA, up to at least 363 nm. These findings emphasize the potency of UVA to isomerize UCA, and they may contribute to further elucidation of the effects of phototherapy and sunbathing.

A new psoralen-containing gel for topical PUVA therapy: development, and treatment results in patients with palmoplantar and plaque-type psoriasis, and hyperkeratotic eczema.

Topical photochemotherapy with psoralen and its derivatives 4,5',8-trimethylpsoralen (TMP) and 8-methoxypsoralen (8-MOP), with UVA irradiation, was evaluated with regard to minimum phototoxic dose, concentration, timing of UVA irradiation and systemic and local side-effects, in healthy volunteers. Psoralen (0.005%) in aqueous gel was found to be superior to TMP and 8-MOP in aqueous gel. No hyperpigmentation was seen after topical PUVA treatment with psoralen in aqueous gel. Patients with plaque-type psoriasis (n = 7), palmoplantar psoriasis (n = 7) and hyperkeratotic eczema (n = 2) were treated. Topical PUVA therapy was effective in most psoriasis patients, without the occurrence of local or systemic side-effects. Moreover, hyperkeratotic eczema patients who did not respond to conventional therapy showed partial remission. These results indicate that topical PUVA therapy with psoralen in aqueous gel is a useful therapeutic modality for treatment of psoriasis patients, and patients with recalcitrant dermatoses such as palmoplantar psoriasis and hyperkeratotic eczema.

Effect of low-dose ultraviolet-B radiation on the function of human T lymphocytes in vitro.

Purified peripheral blood human T lymphocytes, derived from normal individuals, were assayed for their susceptibility to low doses of ultraviolet B (UVB) in vitro. Exposure of T cells to graded single doses (range 0-8 mJ/cm2) of UVB resulted in a dose-dependent reduction of viability. This phototoxic effect was not immediately apparent, however, but became manifest 48-72 h subsequent to irradiation. A dose as little as 0.5-1 mJ/cm2 was sufficient to cause 50% mortality. Irradiated T cells showed a reduced ability to proliferate, irrespective of the stimulus used, and a reduced ability to produce cytokines IL-2, IL-4, IL-5, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha). This decreased ability was UVB-dose related and, remarkably, was exactly correlated to phototoxicity. UVB had no effect on CD4 and CD8 expression or their ratio, whereas the expression of IL-2R (CD25) was only slightly reduced. Our data suggest that UVB radiation neither selectively affects Th1 or Th2 nor CD4 or CD8 T cell subsets. The high susceptibility of T cells to UVB might explain, at least in part, the beneficial effect of phototherapy during treatment of certain immunodermatological diseases.