Basophil-derived amphiregulin is essential for UVB irradiation-induced immune suppression.

UVB irradiation (290-320 nm) is used to treat skin diseases like psoriasis and atopic dermatitis, and is known to suppress contact hypersensitivity (CHS) reactions in mouse models. Regulatory T cells (Treg cells) have been shown to be responsible for this UVB-induced suppression of CHS. The epidermal growth factor (EGF)-like growth factor amphiregulin (AREG) engages EGFR on Treg cells and, in different disease models, it was shown that mast cell-derived AREG is essential for optimal Treg cell function in vivo. Here we determined whether AREG has a role in UVB-induced, Treg cell-mediated suppression of CHS reactions in the skin. Our data show that AREG is essential for UVB-induced CHS suppression. In contrast to the general assumption, however, mast cells were dispensable for UVB-induced immune suppression, whereas basophil-derived AREG was essential. These data reveal, to our knowledge, a previously unreported function for basophils in the homeostasis of immune responses in the skin. Basophils thus fulfill a dual function: they contribute to the initiation of effective type 2 immune responses and, by enhancing the suppressive capacity of local Treg cell populations, also to local immune regulation in the skin.

Assessment of cyclobutane pyrimidine dimers by digital photography in human skin.

UV-mediated DNA damage and repair are important mechanisms in research on UV-induced carcinogenesis. UV-induced DNA-damage and repair can be determined by immunohistochemical staining of photoproduct positive nuclei of keratinocytes in the epidermis. We developed a new method of analysing and quantifying thymine dimer (TT-CPD) positive cells in the epidermis. Normal skin of healthy controls was exposed to UVB ex vivo and in vivo. Skin samples were immunohistochemically stained for TT-CPDs. Digital images of the epidermis were quantified for TT-CPDs both visually and digitally. There was a UVB-dose dependent induction of TT-CPDs present in the ex vivo UVB-irradiated skin samples. The linear measurement range of the digital quantification was increased compared to the manual counting. The average 24-hour repair rate of the initiated TT-CPDs elicited by the UVB irradiation at T=0 of the 8 HCs showed a 34% decrease of TT-CPD photoproducts by the manual counting method and a 51% decrease determined by digital counting. The digital quantification method improves immunohistochemical quantification of DNA photo damage. It is more sensitive in measuring the extent of DNA-damage per nucleus.

Photosensitivity testing in children.

BACKGROUND: Phototesting is an important diagnostic tool to objectify light-related symptoms. Data on phototesting procedures in children are scarce. OBJECTIVE: The aim of this study was to evaluate phototest results in photosensitivity disorders in children. METHODS: The phototest procedures are described. All children phototested in our department between 1995 and 2007 were included in this retrospective study. Children given the diagnosis of polymorphic light eruption (PLE) were selected for follow-up. RESULTS: A total of 92 children (39 boys and 53 girls, age range 4-16 years) were successfully phototested. A photosensitivity disorder was confirmed in 56 children (61%, 24 boys and 32 girls). PLE was diagnosed in 39%, photosensitivity associated with atopic dermatitis in 23%, and erythropoietic protoporphyria in 23%. Other diagnoses were less common. Ten children with PLE were followed up for at least 5 years. Seven reported their photosensitivity had not changed over time, in two cases it had diminished, and in one patient the photosensitivity had disappeared. LIMITATIONS: Retrospective study design is a limitation. CONCLUSION: Phototesting in children is feasible when performed in a case- and child-dependent manner. PLE was the most prevalent diagnosis in our series followed by photosensitivity in atopic dermatitis.

Cost effectiveness of home ultraviolet B phototherapy for psoriasis: economic evaluation of a randomised controlled trial (PLUTO study).

OBJECTIVE: To assess the costs and cost effectiveness of phototherapy with ultraviolet B light provided at home compared with outpatient ultraviolet B phototherapy for psoriasis. DESIGN: Cost utility, cost effectiveness, and cost minimisation analyses performed alongside a pragmatic randomised clinical trial (the PLUTO study) at the end of phototherapy (mean 17.6 weeks) and at one year after the end of phototherapy (mean 68.4 weeks). SETTING: Secondary care, provided by a dermatologist in the Netherlands. PARTICIPANTS: 196 adults with psoriasis who were clinically eligible for narrowband (TL-01) ultraviolet B phototherapy were recruited from the dermatology departments of 14 hospitals and were followed until the end of phototherapy. From the end of phototherapy onwards, follow-up was continued for an unselected, consecutive group of 105 patients for one year after end of phototherapy. INTERVENTIONS: Ultraviolet B phototherapy provided at home (intervention) and conventional outpatient ultraviolet B phototherapy (control) in a setting reflecting routine practice in the Netherlands. Both treatments used narrowband ultraviolet B lamps (TL-01). MAIN OUTCOME MEASURES: Total costs to society, quality adjusted life years (QALYs) as calculated using utilities measured by the EQ-5D questionnaire, and the number of days with a relevant treatment effect (>/=50% improvement of the baseline self administered psoriasis area and severity index (SAPASI)). RESULTS: Home phototherapy is at least as effective and safe as outpatient phototherapy, therefore allowing cost minimisation analyses (simply comparing costs). The average total costs by the end of phototherapy were euro800 for home treatment and euro752 for outpatient treatment, showing an incremental cost per patient of euro48 (95% CI euro-77 to euro174). The average total costs by one year after the end of phototherapy were euro1272 and euro1148 respectively (difference euro124, 95% CI euro-155 to euro403). Cost utility analyses revealed that patients experienced equal health benefits-that is, a gain of 0.296 versus 0.291 QALY (home v outpatient) by the end of phototherapy (difference 0.0052, -0.0244 to 0.0348) and 1.153 versus 1.126 QALY by one year after the end of phototherapy (difference 0.0267, -0.024 to 0.078). Incremental costs per QALY gained were euro9276 and euro4646 respectively, both amounts well below the normally accepted standard of euro20 000 per QALY. Cost effectiveness analyses indicated that the mean number of days with a relevant treatment effect was 42.4 versus 55.3 by the end of phototherapy (difference -12.9, -23.4 to -2.4). By one year after the end of phototherapy the number of days with a relevant treatment effect were 216.5 and 210.4 respectively (6.1, -41.1 to 53.2), yielding an incremental cost of euro20 per additional day with a relevant treatment effect. CONCLUSIONS: Home ultraviolet B phototherapy for psoriasis is not more expensive than phototherapy in an outpatient setting and proved to be cost effective. As both treatments are at least equally effective and patients express a preference for home treatment, the authors conclude that home phototherapy should be the primary treatment option for patients who are eligible for phototherapy with ultraviolet B light. TRIAL REGISTRATION: Current Controlled Trials ISRCTN83025173 and Clinicaltrials.gov NCT00150930.

Home versus outpatient ultraviolet B phototherapy for mild to severe psoriasis: pragmatic multicentre randomised controlled non-inferiority trial (PLUTO study).

OBJECTIVE: To determine whether ultraviolet B phototherapy at home is equally safe and equally effective as ultraviolet B phototherapy in an outpatient setting for patients with psoriasis. DESIGN: Pragmatic multicentre single blind randomised clinical trial (PLUTO study). SETTING: Dermatology departments of 14 hospitals in the Netherlands. PARTICIPANTS: 196 patients with psoriasis who were clinically eligible for narrowband (TL-01) ultraviolet B phototherapy. The first 105 consecutive patients were also followed for one year after therapy. INTERVENTION: Ultraviolet B phototherapy at home using a TL-01 home phototherapy unit compared with standard narrowband ultraviolet B phototherapy in an outpatient setting. Both therapies were done in a setting reflecting routine daily practice in the Netherlands. MAIN OUTCOME MEASURES: The main outcome measure was effectiveness as measured by the proportion of patients with a 50% or more reduction of the baseline psoriasis area and severity index (PASI) or self administered psoriasis area and severity index (SAPASI), called the PASI 50 and SAPASI 50 (relevant treatment effect). Another outcome of effectiveness was the percentage reduction in median scores on the PASI as well as SAPASI. Also the proportions of patients reaching the PASI 75 and SAPASI 75 (successful treatment effect), and the PASI 90 and SAPASI 90 (almost complete clearance) were calculated. Other secondary outcomes were quality of life (SF-36, psoriasis disability index), burden of treatment (questionnaire), patients' preferences and satisfaction (questionnaire), and dosimetry and short term side effects (diary). RESULTS: 82% of the patients treated at home compared with 79% of the patients treated in an outpatient setting reached the SAPASI 50 (difference 2.8%, 95% confidence interval -8.6% to 14.2%), and 70% compared with 73% reached the PASI 50 (-2.3%, -15.7% to 11.1%). For patients treated at home the median SAPASI score decreased 82% (from 6.7 to 1.2) and the median PASI score decreased 74% (from 8.4 to 2.2), compared with 79% (from 7.0 to 1.4) and 70% (from 7.0 to 2.1) for patients treated in an outpatient setting. Treatment effect as defined by the mean decline in PASI and SAPASI scores was significant (P<0.001) and similar across groups (P>0.3). Total cumulative doses of ultraviolet B light were similar (51.5 v 46.1 J/cm(2), difference 5.4, 95% confidence interval -5.2 to 16.0), and the occurrence of short term side effects did not differ. The burden of undergoing ultraviolet B phototherapy was significantly lower for patients treated at home (differences 1.23 to 3.01, all P

Throwing a light on photosensitivity in atopic dermatitis: a retrospective study.

BACKGROUND: Photosensitivity in atopic dermatitis (AD) is a well known but ill-defined phenomenon. OBJECTIVES: To determine the prevalence of photosensitivity in patients with AD, define its clinical characteristics, and analyze the photo provocation test (phototest) results. METHODS: A retrospective study of patients with AD who were phototested because of suspected photosensitivity at our department during the period 1994-2004. RESULTS: The total number of patients with AD seen in our department between 1994 and 2004 was 3804, of whom 145 patients (45 men and 100 women) were phototested. Photosensitivity was confirmed in 108 (74%) of these 145 patients (33 men and 75 women). The minimal erythema dose (MED) for UVB was decreased in eight of these 108 patients (7%) and the MED for UVA in five patients (5%). Two major clinical reaction patterns were observed: a polymorphic light eruption-type reaction in 51 patients (47%) and an eczematous reaction in 44 patients (41%). Seventy-two of the 108 patients (67%) had a pathologic reaction to UVA and UVB, 18 patients (17%) were only UVB sensitive, and 18 patients (17%) were only UVA sensitive. Photopatch tests were performed in 125 patients (86%). Twenty-nine patients (23%) had a positive photocontact reaction to one or more substances. CONCLUSION: Photosensitivity is found in approximately 3% of patients with AD and the majority are female. Photosensitivity in patients with AD consists of two clinical reaction patterns distinguishable by phototesting. Patients were diagnosed with either AD and co-existing polymorphic light eruption or photosensitive AD.

Narrowband ultraviolet B and medium-dose ultraviolet A1 are equally effective in the treatment of moderate to severe atopic dermatitis.

BACKGROUND: Phototherapy may be effective in atopic dermatitis (AD). Medium-dose (MD) ultraviolet (UV) A1 was introduced for the treatment of AD. Few immunohistochemical data are available pertaining to phototherapy in AD. Regulatory T cells may play a role in clearing AD. OBJECTIVES: We sought to compare the clinical and immunohistochemical effects of narrowband (NB) UVB and MD UVA1 treatment in patients with AD. METHODS: Thirteen adult patients with AD were included in this randomized investigator-blinded half-sided comparison study between NB UVB and MD UVA1. Disease activity was measured using the Leicester sign score. Skin biopsy specimens were taken before and after phototherapy. Regulatory T cells were stained with the forkhead box protein P3 (FoxP3). RESULTS: NB UVB and MD UVA1 both significantly decreased AD severity (P < .01) and the dermal cellular infiltrate. The percentage of FoxP3(+)CD3(+) T cells did not change after NB UVB or MD UVA1 treatment. LIMITATION: MD UVA1 therapy was given 3 times per week instead of the preferred regimen of 5 times per week. This was necessary to achieve good blinding of the study. CONCLUSIONS: NB UVB and MD UVA1 seem equally effective in the treatment of patients with moderate to severe AD. Neither MD UVA1 nor NB UVB had an effect on the percentage of FoxP3(+)CD3(+) T cells.

In vivo nonlinear spectral imaging microscopy of visible and ultraviolet irradiated hairless mouse skin tissues.

We demonstrate the capability of nonlinear spectral imaging microscopy (NSIM) in investigating ultraviolet and visible light induced effects on albino Skh:HR-1 hairless mouse skin non-invasively.

Neutrophil infiltration in normal human skin after exposure to different ultraviolet radiation sources.

Exposure of the skin to UV radiation can lead to a local infiltration of neutrophils. Not much is known on whether the infiltration of neutrophils in the irradiated skin is UV source dependent. In this study we compared different UV sources (solar-simulated radiation [SSR], narrowband [NB]-UVB, broadband [BB]-UVB and UVA1) in their potency to induce neutrophil infiltration in normal human skin after exposure to two times the minimal erythema dose of UV radiation. Biopsies were collected from irradiated buttock skin 6 and 24 h after irradiation and from nonirradiated skin. The presence, distribution and amount of skin-infiltrated neutrophils were determined using immunohistochemical staining. Analysis revealed that SSR was most effective in inducing neutrophil infiltration. NB-UVB gave a neutrophil influx pattern similar to that seen with SSR but in smaller numbers. BB-UVB and UVA1 were far less potent in inducing neutrophil infiltration compared with SSR or NB-UVB. Our findings indicate that neutrophil infiltration in the UV-irradiated skin is UV source dependent. When the spectra emitted by the different UV sources were compared UVB seemed to be more effective than UVA in inducing neutrophil infiltration. Furthermore, our results suggest that longer wavelengths within the UVB range are mostly responsible for the infiltration of neutrophils in the UV-irradiated skin.

Erythropoietic protoporphyria without skin symptoms-you do not always see what they feel.

Erythropoietic protoporphyria (EPP) is an inherited disorder of the porphyrin metabolism that often remains undiagnosed in children. We report on a 4-year-old girl who had been suffering for 1 year from recurrent painful crises affecting her hands, feet, and nose following sun exposure. Objective skin lesions were absent until the age of 6. Porphyrin analysis revealed elevated free erythrocyte protoporphyrin (FEP) levels confirming the diagnosis of EPP. This illustrates that skin lesions might be completely absent in children affected with EPP, a fact that has only been reported once previously. Because EPP can manifest with few and unspecific cutaneous symptoms or no skin lesions at all, like in this patient, the diagnosis of EPP might be delayed or missed. EPP should be excluded in all photosensitive children, especially when discomfort is disproportionate to the extent of the cutaneous lesions. The clinic, pathophysiology, diagnosis, complications, and therapy of EPP are discussed.

UVB phototherapy in an outpatient setting or at home: a pragmatic randomised single-blind trial designed to settle the discussion. The PLUTO study.

BACKGROUND: Home ultraviolet B (UVB) treatment is a much-debated treatment, especially with regard to effectiveness, safety and side effects. However, it is increasingly being prescribed, especially in the Netherlands. Despite ongoing discussions, no randomised research has been performed, and only two studies actually compare two groups of patients. Thus, firm evidence to support or discourage the use of home UVB phototherapy has not yet been obtained. This is the goal of the present study, the PLUTO study (Dutch acronym for "national trial on home UVB phototherapy for psoriasis"). METHODS: We designed a pragmatic randomised single-blind multi-centre trial. This trial is designed to evaluate the impact of home UVB treatment versus UVB phototherapy in a hospital outpatient clinic as to effectiveness, quality of life and cost-effectiveness. In total 196 patients with psoriasis who were clinically eligible for UVB phototherapy were included. Normally 85% of the patients treated with UVB show a relevant clinical response. With a power of 80% and a 0.05 significance level it will be possible to detect a reduction in effectiveness of 15%. Effectiveness will be determined by calculating differences in the Psoriasis Area and Severity Index (PASI) and the Self Administered PASI (SAPASI) scores. Quality of life is measured using several validated generic questionnaires and a disease-specific questionnaire. Other outcome measures include costs, side effects, dosimetry, concomitant use of medication and patient satisfaction. Patients are followed throughout the therapy and for 12 months thereafter. The study is no longer recruiting patients, and is expected to report in 2006. DISCUSSION: In the field of home UVB phototherapy this trial is the first randomised parallel group study. As such, this trial addresses the weaknesses encountered in previous studies. The pragmatic design ensures that the results can be well generalised to the target population. Because, in addition to effectiveness, aspects such as quality of life and cost-effectiveness are also taken into consideration, this study will produce valuable evidence to either support or discourage prescription of home UVB phototherapy. TRIAL REGISTRATION: Current controlled trials/Nederlands Trial register: ISRCTN83025173. Clinicaltrials.gov: NCT00150930.

Pathophysiology of photoaging of human skin: focus on neutrophils.

UV-induced skin damage is the result of a complex cascade of events. Many studies have focused on the skin effects induced by UV-B or UV-A separately. Recently a UV-source that emits UV-B and UV-A together in a ratio comparable to daily sunlight has been introduced: i.e. solar simulated radiation (SSR). By exposing human skin type I-III to erythematogenic doses of UV (> or =1 MED) emitted by a SSR source we have noticed that: (a) neutrophils are initially the main infiltrating cell type in the dermis and (b) these infiltrating cells are the a key source of in vivo enzymatically [corrected] active enzymes such as elastase, [corrected] matrix metallo proteinases-1 and -9 (MMPs-1 and -9). These enzymes are relevant to the process of photoaging, as they break down the extracellular matrix. Keratinocytes and fibroblasts also produce matrix degrading enzymes, but to a lesser extent. Our results indicate a primary role for infiltrating neutrophils in the initial steps of photoaging. This is further supported by the observation that after exposure of skin type VI to physical doses of SSR, equivalent to those used for skin types I-III, no neutrophils and neutrophil-derived enzymatic activity were observed, explaining why skin type VI is [corrected] less susceptible to photoaging than skin types [corrected] I-III. Statement: Although most of the data, referred to, have been published, the current perspective in which they are put together is completely novel and has not been published elsewhere.

UV hardening therapy: a novel intervention in patients with photosensitive cutaneous lupus erythematosus.

BACKGROUND: Patients with cutaneous lupus erythematosus (LE) and a history of disease- related photoaggravation, confirmed by phototesting, may not respond to photoprotection and/or medical intervention. Ultraviolet B-hardening therapy may improve tolerance for environmental ultraviolet radiation (UVR) in photosensitive disorders. OBJECTIVE: We studied the effect of UVB hardening on the cutaneous manifestations of patients with LE and their tolerance for UVR. PATIENTS AND METHODS: A retrospective study of continuous, home-based, UVB-hardening therapy in 44 patients with cutaneous LE (systemic LE: 9 patients; chronic LE: 21 patients; subacute cutaneous LE: 10 patients; cutaneous LE not specified: 4 patients) who had confirmed photosensitivity. Exposure to the UVB source was performed year-round, 3 times weekly, with increasing doses to a maximum of 10 minutes per session. Tolerance for environmental UVR was established through questionnaires, phototesting, and assessment of disease activity by physician and patient. RESULTS: Of 44 patients, 35 were able to gradually increase their monthly UVB doses. Nine patients dropped out because of insufficient efficacy or skin irritation, or were unable to adhere to the hardening regimen. Of the 35 patients who succeeded in hardening their skin with UVB, 28 patients reported an improved tolerance for environmental UVR. This outcome was confirmed by repeat phototesting in a subgroup. In only 5 patients, an improvement of cutaneous LE symptoms was noted by either physician or patient. No serious adverse events were encountered. LIMITATIONS: This was a retrospective study and no control group was used. CONCLUSION: This is the first report that describes UVB hardening as a potential therapy in patients with cutaneous LE and confirmed photosensitivity. This intervention may lead to improved tolerance for environmental UVR and, in a minority of patients, even to decreased cutaneous activity of LE.

Responses of black and white skin to solar-simulating radiation: differences in DNA photodamage, infiltrating neutrophils, proteolytic enzymes induced, keratinocyte activation, and IL-10 expression.

Black skin is more resistant to the deleterious effects of ultraviolet radiation than white skin. A higher melanin content and a different melanosomal dispersion pattern in the epidermis are thought to be responsible for this. Our purpose was to compare skin responses in black and white skin following exposure to solar-simulating radiation (SSR) to further investigate the photoprotective properties of black skin. Six volunteers of skin phototype I-III (white) were exposed to (doses measured directly with a Waldmann UV detector device) 12,000-18,000 mJ per cm2 (2 MED) of SSR and compared with six volunteers of skin phototype VI (black) exposed to 18,000 mJ per cm2 (<1 MED) of SSR. The presence and distribution of skin pigment, DNA photodamage, infiltrating neutrophils, photoaging associated proteolytic enzymes, keratinocyte activation, and the source of interleukin 10 (IL-10) in skin biopsies taken before and after exposure were studied. In all white skinned subjects, 12,000-18,000 mJ per cm2 of SSR induced DNA damage in epidermal and dermal cells, an influx of neutrophils, active proteolytic enzymes, and diffuse keratinocyte activation. Additionally, in three of the white skinned volunteers IL-10 positive neutrophils were found to infiltrate the epidermis. Except for DNA damage in the supra basal epidermis, none of these changes was found in black skinned subjects. Increased skin pigmentation appears to be primarily responsible for the observed differences in skin responses. Our data could provide an explanation as to why black skin is less susceptible to sunburn, photoaging, and skin carcinogenesis.

Differential expression of cytokines in UV-B-exposed skin of patients with polymorphous light eruption: correlation with Langerhans cell migration and immunosuppression.

BACKGROUND: Disturbances in UV-induced Langerhans cell migration and T helper (T(H)) 2 cell responses could be early steps in the pathogenesis of PLE. OBJECTIVE: To establish whether UV-B exposure induces aberrant cytokine expression in the uninvolved skin of patients with polymorphous light eruption (PLE). DESIGN: Immunohistochemical staining and comparison of microscopic sections of skin irradiated with 6 times the minimal dose of UV-B causing erythema and the unirradiated skin of patients with PLE and of healthy individuals. SETTING: University Medical Center (Dutch National Center for Photodermatoses). Patients Patients with PLE (n = 6) with clinically proven pathological responses to UV-B exposure and normal erythemal sensitivity. Healthy volunteers (n = 5) were recruited among students and hospital staff. MAIN OUTCOME MEASURES: Expression of cytokines related to Langerhans cell migration (interleukin [IL] 1, IL-18,and tumor necrosis factor [TNF] alpha); T(H)2 responses (IL-4 and IL-10); and T(H)1 responses (IL-6, IL-12, and interferon gamma). Double staining was performed for elastase (neutrophils), tryptase (mast cells), and CD36 (macrophages). RESULTS: The number of cells expressing IL-1beta and TNF-alpha was reduced in the UV-B-exposed skin of patients with PLE compared with the skin of healthy individuals (P<.05 for TNF-alpha). No differences were observed in the expression of T(H)1-related cytokines but fewer cells expressing IL-4 infiltrated the epidermis of patients with PLE 24 hours after irradiation (P =.03). After UV exposure TNF-alpha, IL-4, and, to a lesser extent, IL-10 were predominantly expressed by neutrophils. CONCLUSIONS: The reduced expression of TNF-alpha, IL-4, and IL-10 in the UV-B-irradiated skin of patients with PLE appears largely attributable to a lack of neutrophils, and is indicative of reduced Langerhans cell migration and reduced T(H)2 skewing. An impairment of these mechanisms underlying UV-B-induced immunosuppression may be important in the pathogenesis of PLE.

Photodynamic treatment and H2O2-induced oxidative stress result in different patterns of cellular protein oxidation.

Photodynamic treatment (PDT) is an emerging therapeutic procedure for the management of cancer, based on the use of photosensitizers, compounds that generate highly reactive oxygen species (ROS) on irradiation with visible light. The ROS generated may oxidize a variety of biomolecules within the cell, loaded with a photosensitizer. The high reactivity of these ROS restricts their radius of action to 5-20 nm from the site of their generation. We studied oxidation of intracellular proteins during PDT using the ROS-sensitive probe acetyl-tyramine-fluorescein (acetylTyr-Fluo). This probe labels cellular proteins, which become oxidized at tyrosine residues under the conditions of oxidative stress in a reaction similar to dityrosine formation. The fluorescein-labeled proteins can be visualized after gel electrophoresis and subsequent Western blotting using the antibody against fluorescein. We found that PDT of rat or human fibroblasts, loaded with the photosensitizer Hypocrellin A, resulted in labeling of a set of intracellular proteins that was different from that observed on treatment of the cells with H2O2. This difference in labeling patterns was confirmed by 2D electrophoresis, showing that a limited, yet distinctly different, set of proteins is oxidized under either condition of oxidative stress. By matching the Western blot with the silver-stained protein map, we infer that alpha-tubulin and beta-tubulin are targets of PDT-induced protein oxidation. H2O2 treatment resulted in labeling of endoplasmic reticulum proteins. Under conditions in which the extent of protein oxidation was comparable, PDT caused massive apoptosis, whereas H2O2 treatment had no effect on cell survival. This suggests that the oxidative stress generated by PDT with Hypocrellin A activates apoptotic pathways, which are insensitive to H2O2 treatment. We hypothesize that the pattern of protein oxidation observed with Hypocrellin A reflects the intracellular localization of the photosensitizer. The application of acetylTyr-Fluo may be useful for characterizing protein targets of oxidation by PDT with various photosensitizers.

Narrowband UVB and psoralen-UVA in the treatment of early-stage mycosis fungoides: a retrospective study.

BACKGROUND: Treatment of early-stage mycosis fungoides (MF) consists of topical steroids, phototherapy (UVB), photochemotherapy (psoralen plus UVA [PUVA]), topical nitrogen mustard, or total skin electron-beam irradiation. It has been reported that the same effective UVB dose is safer than PUVA regarding carcinogenicity and produces fewer side effects. Narrowband UVB (311 nm) results in less irritation and erythema and is more effective compared with broadband UVB. OBJECTIVE: Our purpose in this retrospective study was to analyze the response to treatment, relapse-free interval, and irradiation dose in 56 patients with early-stage MF (stage Ia and Ib). A total of 21 patients were treated with narrowband UVB (311 nm); 35 patients were treated with PUVA. RESULTS: Narrowband UVB treatment led to complete remission in 17 of 21 patients (81%), partial remission in 4 of 21 (19%), and none showed progressive disease. PUVA treatment led to complete remission in 25 of 35 patients (71%), partial remission in 10 of 35 (29%), and none showed progressive disease. The mean relapse-free interval for patients treated with UVB was 24.5 months (range, 2-66 months) and for patients treated with PUVA, 22.8 months (range, 1-43 months). CONCLUSION: Narrowband UVB therapy for patients with early-stage MF is an effective treatment modality. It has several advantages over treatment with broadband UVB and PUVA. When treating patients with early-stage MF it may be beneficial to start with narrowband UVB therapy and, if there is progression or no response, switch to PUVA therapy.

Epidermal langerhans cell depletion after artificial ultraviolet B irradiation of human skin in vivo: apoptosis versus migration.

Ultraviolet B radiation can suppress cellular immunity. One of the mechanisms related to this immunosuppression is the disappearance of Langerhans cells from the epidermis. The aim of this study was to establish the mechanism of ultraviolet B-induced Langerhans cell disappearance in healthy individuals. The two most likely mechanisms for Langerhans cell disappearance are apoptosis and migration. Apoptosis was assessed in vivo by exposing buttock skin of 10 healthy volunteers to six minimal erythema doses of ultraviolet B. Only very few apoptotic Langerhans cells could be observed in sections from the ultraviolet B-exposed skin. Migration of Langerhans cells cannot be established in skin sections and suction blisters were therefore raised in an attempt to trap migrating Langerhans cells in the sub-basal membrane blister fluid. Blisters were raised on the flexor side of the lower arm of 30 healthy volunteers at several time points after exposure of the skin to six minimal erythema doses of ultraviolet B. Blister fluid was collected and blister roofs were removed to check for Langerhans cell disappearance. Langerhans cells were detected in the blister fluid of the ultraviolet B-exposed skin and not of the unexposed skin. The number of Langerhans cells in the blister fluid peaked at about 18 h after ultraviolet exposure, which coincided with the largest depletion of Langerhans cells in the blister roof. A fraction (20-30%) of the Langerhans cells in the blister fluid stained positive for DNA damage (cyclobutyl pyrimidine dimers), showing that they originated from the epidermis. Ultraviolet B-induced Langerhans cell disappearance appears to be mainly attributable to migration.