Tegafur-induced photosensitivity — evaluation of provocation by UVB irradiation

Dermatology, A 75-year-old Japanese man with photodistributed erythematous lichen planus like eruptions visited the dermatology clinic of Kobe University in November 1994. He had had an operation for gastric cancer in July 1992, and thereafter he had been taking 600 mg/d of tegafur. In July 1994, he was exposed to the sun for 2 h and the following day noticed an itchy rash in the areas exposed to the sun. He consulted his surgeon and stopped i taking the tegafur In October. Thereafter his eruption gradually improved. A biopsy J specimen taken on the initial visit to our hospital, 22 days after the cessation of tegafur, revealed perivascular collections of mononuclear cells in the upper dermis and slight liquefaction degeneration of the epidermal basal cells with some civatte bodies. Immunofluorescent staining showed no deposits of immunoglobulins or complements. Photosensitivity studies were performed with a bank of 7 fluorescent sunlamps (Toshiba FL20SE) emitting 280–370 nm (nnainly UVB energy, peaKing at 305 nm) and a bank ot 14 fluorescent black lights (Toshiba FL32SBL) emitting 300–420 nm (mainly UVA energy peaking at 365 nm). His minimal erythema doses (MEDs) of 58.5 mJ/cm² in UVB and of large dose of UVA over 12.6 J/cm² were in the normal range. Patch tests and two sets of photopatch tests were made with 5% tegafur and 5-fluorouracil (5-FU) in white petrolatum using Finn chambers. One set was exposed to 6.3 J/cm² of UVA, and a second set to a suberythemal dose of UVB, 40 mJ/cm², after 24 h of closed patch tests. Twenty four hours after UV irradiation for photopatch tests, and 48 h after the initial patch for patch tests, the reaction was evaluated. No abnormal reactions in patch and photopatch tests were detected. Tegafur was readministered at a dose of 200 mg every eight hours. After a total dose of 2400 mg (day 4), the skin of the back was exposed to UVB (6–120 mJ/cm²) and UVA (2–12.6 J/cm²) two hours after the last oral intake of tegafur. No decrease in MED or any abnormal reaction was observed. After a total of 3600 mg (day 6), a new skin site on the back was exposed to 3 MED of UVB. The next day (day 7, after a total dose of 4200 mg), 3 MED of UVB was irradiated on the same site and 5 MED of UVB was irradiated at a new site. Lastly, after a total dose of 4800 mg (day 8), 3 MED and 5 MED of UVB was again irradiated on the same sites that were irradiated on the previous day, and 10 MED UVB and 21 J/cm² UVA were irradiated at new individual sites. Eight days after the last irradiation (day 16, after 9600 mg of drug intake) the 10 MED UVB irradiated site revealed miliar-sized papules with a faint red hue after sunburn reaction. Simultaneously, an edematous erythema recurred on the face, neck, upper back, and hands, where the rash had previously been, without exposure to UVB or UVA. These tests were conducted while the patient was hospitalized and he was very careful not to be exposed to the sun, even through glass. The biopsy specimens of 10 MED irradiated sites and the flare-up lesion of his upper back revealed liquefaction degeneration of the epidermal basal cells with civatte bodies. Immunofluorescent staining study showed IgM, IgA, and C4 deposition of the civatte bodies in the flare-up lesion which had not been exposed to any UV irradiation.     

Acute effects of UVB radiation on the proliferation and differentiation of keratinocytes

PURPOSE: The effects of UVB radiation on the proliferation and differentiation of epidermal keratinocytes were investigated with respect to timing, dosage, and repeated exposures. METHODS: Nine healthy volunteers were placed into three subgroups and exposed to UVB radiation on buttock skin using a Waldmann UV 800 unit fitted with Philips TL-20W/12 fluorescent lamps. Three volunteers were given 2 MED of UVB and biopsied at: pre-exposure, 24, 48 and 72 h after UVB exposure. For three volunteers, 1 MED, 2 MED, 3 MED of UVB were applied. After 48 h, biopsies were taken from non-irradiated and irradiated sites. Finally, three volunteers received 1 MED of UVB daily for 5 days, and the non-irradiated and irradiated sites were biopsied 48 h after the final exposure. The expression of proliferation and differentiation markers by keratinocytes were detected by immunohistochemical staining, and the results were analysed quantitatively by image analysis. RESULTS: The expression of proliferation and differentiation markers was observed prominently 48 h after irradiation. Higher doses of UVB caused an increase in proliferation and differentiation marker expression. Repeated exposures potentiated the effect of UVB radiation. CONCLUSION: UVB irradiation concomitantly promotes epidermal proliferation and differentiation. Responses were maximal 48 h after irradiation. This effect of UVB increases linearly according to dose and repetition.     

Acute skin alterations following ultraviolet radiation investigated by optical coherence tomography and histology

Optical coherence tomography (OCT) appears to be a promising technique to study skin in vivo. As part of an exploratory study to investigate UV induced effects non-invasively we aimed to evaluate the kinetics of acute UVB- as well as UVA1 induced skin alterations by means of OCT, and to correlate the results obtained with routine histology. Twelve healthy subjects received daily 60 J/cm² of UVA1 and 1.5 minimal erythema doses of UVB on their upper back over three consecutive days. One day (24 h) after the last UV exposure, OCT measurements and skin biopsies were performed in four subjects (day 1) on the centre of the irradiated sites and an adjacent non-irradiated control site. The same procedure was performed in four subjects 3 days and 6 days after irradiation, respectively. Prior to OCT assessment two waterproof marks were drawn on the centre of UVB and UVA1 exposed sites and the control site. The OCT scanner, SkinDex 300, was used in the RI1D measurement modus in order to investigate morphological features, epidermal thickness, and scattering coefficients. Immediately after OCT assessment, 4 mm punch biopsies were taken from the previously marked sites. OCT as well as histological examinations performed on day 1, 3, and 6, revealed markedly higher values for epidermal thickness on UVB exposed skin sites, and slightly increased epidermal thickening in UVA1 exposed sites. UVB exposed sites showed disruption of the entrance signal in the B-scan of OCT resulting in a thickened layer with a signal-poor centre corresponding to hyperkeratosis and parakeratosis as confirmed by routine histology. Surprisingly, the mean scattering coefficients of the epidermis were slightly lower on UVA1 exposed sites, as compared to non-irradiated skin. By contrast, the scattering coefficient of the upper dermis of UVA1 irradiated skin was hardly altered. Moreover, the scattering coefficient of the upper dermis assessed on UVB exposed skin on day 1 was clearly smaller than the scattering coefficient observed on non-irradiated and UVA1 exposed skin. Conclusively, it was possible to demonstrate by means of OCT differences of epidermal thickness and pathological features of the stratum corneum following UV exposure. UVA1 induced epidermal pigmentation as well as UVB induced dermal inflammation may affect the light attenuation in the tissue indicated by a decrease of the scattering coefficient. OCT seems to be a useful tool to monitor UV induced effects in vivo.     

Increased expression of Fas on human epidermal cells after in vivo exposure to single-dose ultraviolet (UV) B or long-wave UVA radiation

BACKGROUND: Apoptosis has been proposed to act as an important mechanism for eliminating keratinocytes that have been irreversibly damaged by ultraviolet (UV) irradiation. One way to induce apoptosis in keratinocytes is through activation of the cell surface receptor Fas (CD95), either with the ligand (FasL) or directly with UV radiation. OBJECTIVES: To investigate the regulation of Fas and FasL expression in human skin and the formation of apoptotic cells after in vivo exposure to UVB or long-wave UVA radiation. METHODS: Volunteers were irradiated with either 3 minimal erythema doses (MED) of UVB (n = 6) or 3 MED of long-wave UVA (n = 6) on buttock skin 12, 24 and 72 h before skin punch biopsies were taken. Expression of Fas and FasL was demonstrated by immunohistochemistry on cryostat sections. Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated fluorescein-deoxyuridine triphosphate nick-end labelling reaction. RESULTS: In five of six subjects, exposure to UVB radiation resulted in increased homogeneous expression of Fas on epidermal cells, with greatest expression at 24 and 72 h after irradiation. In all subjects, exposure to long-wave UVA resulted in increased homogeneous expression of Fas on epidermal cells, with greatest expression at 12 h after irradiation. In five of six subjects, exposure to UVB radiation resulted in temporarily decreased expression of FasL, but after 72 h the expression of FasL had returned to the preirradiation level. The expression of FasL on epidermal cells after exposure to long-wave UVA showed considerable variation. UVB irradiation was a stronger inducer of epidermal apoptosis than was UVA irradiation. The number of apoptotic epidermal cells did not correlate with expression of Fas or FasL. CONCLUSIONS: In human skin the expression of Fas on epidermal cells increases after in vivo exposure to UVB or long-wave UVA. Exposure to UVB causes a temporary decrease in the expression of FasL on epidermal cells.     

UVA1 and UVB irradiated skin investigated by optical coherence tomography in vivo: a preliminary study

In histological studies, it has frequently been demonstrated that ultraviolet (UV) exposure, in particular UVB, can induce significant thickening of the viable epidermis and/or stratum corneum. Since skin biopsy alters the original skin morphology and always requires an iatrogenic trauma, we aimed to introduce optical coherence tomography (OCT) in vivo for the investigation of changes of epidermal thickness (ET) following UVA1 and UVB irradiation. Twelve healthy subjects received daily 60 J/cm2 of UVA1 and 1.5 minimal erythema doses UVB on their upper back over 3 consecutive days. Twenty-four hours after the last irradiation, OCT assessments were performed on UV exposed and adjacent nonirradiated control sites. Data of ET as expressed by comparison of the averaged A-scans differed significantly between nonirradiated (94.2 +/- 15.7 microm), UVA1 (105.4 +/- 12.8 microm) and UVB (125.7 +/- 22.1 microm) exposed sites. In comparison to the nonirradiated sites, UVA1 exposed skin showed significant (P = 0.022) increase of ET of 11% and UVB exposed sites a significant (P < 0.001) increase of 25%. ET of UVA1 and UVB exposed skin sites differed significantly (P =0.005). Our results obtained from OCT in vivo measurements confirm data of previous histological studies indicating that not only erythemogenic doses of UVB, but also suberythemogenic doses of UVA1 may have a significant impact on ET. OCT appears to be a promising bioengineering technique for photobiological studies. However, further studies are needed to establish its measurement precision and validity, and to investigate in vivo spectral dependence on UV induced skin changes such as skin thickening.     

广州地区102例正常人紫外线最小红斑量测定

目的:测定广州地区正常人紫外线最小红斑量(MED)的正常值范围,探讨其与性别、年龄、皮肤日光类型的关系。方法:以SUV1000型日光紫外模拟器作为照射光源,测定102名健康志愿者腹部正常皮肤的MED值(Ⅲ型、Ⅳ型皮肤)。结果:102名受试者MED均值:UVA为50.0 J/cm2,UVB为43.0 m J/cm2。不同皮肤类型间,Ⅲ型皮肤MED均值:UVA为38.5 J/cm2,UVB为36.1 m J/cm2;Ⅳ型皮肤MED均值:UVA为50.0 J/cm2,UVB为47.0 m J/cm2,Ⅳ皮肤MED均值均明显大于Ⅲ型皮肤(P值均<0.01)。不同性别间,男性MED均值:UVA为50.0 J/cm2,UVB为43.0 m J/cm2;女性:UVA为50.0 J/cm2,UVB为43.0 m J/cm2,不同性别间差异均无统计学意义(P值均>0.05)。不同性别的不同年龄阶段间UVA、UVB MED均值差异均无统计学意义(P值均>0.05);UVA-MED的正常值范围为≥30 J/cm2,UVBMED的正常值范围为≥29.1 m J/cm2。结论:紫外线MED的影响因素与皮肤日光反应类型有关,Ⅲ型皮肤UVA-MED、UVB-MED均明显低于Ⅳ型皮肤(P<0.01)。本组受试者MED与性别和年龄无直接关系。     

118例志愿者紫外线最小红斑量值测定

目的 测定118例志愿者长波紫外线(UVA)和中波紫外线(UVB)的最小红斑量(MED)正常值。方法 以SUV1000型日光紫外模拟仪为光源,测定118例健康志愿者和非炎症性皮肤病患者UVA-MED和UVB-MED正常值。结果 UVA-MED均值男性为55J/cm²(18-95J/cm²),女性40J/cm²(15-100J/cm²);UVB-MED均值男性31mJ/cm²(12-95mJ/cm²),女性29mJ/cm²(8-95mJ/cm²)。男性UVA-MED显著高于女性(P<0.05),UVB-MED两性间差异无统计学意义(P>0.05)。皮肤光反应类型为Ⅲ型的受试者UVA-MED和UVB-MED均显著低于Ⅳ型(两种类型皮肤UVA-MED:在男性、女性均P<0.05;UVB-MED:在男性P<0.05,女性P<0.01)。女性的年龄与MED值无关;30-49岁男性UVB-MED低于其他年龄组,UVA-MED与年龄无关。遮光部位测得的UVA-MED和UVB-MED与户外停留时间长短无关。结论 皮肤光反应类型是决定MED的重要因素。     

Impact of etanercept treatment on ultraviolet B-induced inflammation, cell cycle regulation and DNA damage

Background Current studies indicate that treatment with tumour necrosis factor (TNF)‐α blockers plus ultraviolet (UV) B phototherapy results in higher relative Psoriasis Area and Severity Index reduction as compared with TNF‐α monotherapy. Objectives This study aimed to investigate the acute impact of etanercept on UVB‐induced inflammation, cell cycle regulation and DNA damage. Methods Eleven subjects diagnosed with psoriasis who fulfilled the indication criteria for etanercept treatment were studied. A healthy skin site on the upper back was treated with UVB at 2 minimal erythema doses (MED). After 1, 24 and 72 h punch biopsies were taken from this site. Following the 72 h biopsy etanercept 50 mg was administered subcutaneously. After 48 h, 2 MED was given on healthy skin adjacent to previously treated skin sites. Again, after 1, 24 and 72 h punch biopsies were taken from this site. UVB‐ as well as UVB plus etanercept‐treated skin was assessed by means of colorimetry and immunohistochemical studies for caspase 3, cyclin D₁, interleukin‐12, Ki‐67, p16, p53, survivin, thymine dimers and TNF‐α. Results Erythema formation did not differ significantly between UVB‐ and UVB plus etanercept‐treated sites. Comparisons between UVB‐ and UVB plus etanercept‐treated sites at a given time (1, 24, 72 h) did not result in significant differences in immunoreactivity of the markers investigated, except for cyclin D₁, p53 and survivin. Immunoreactivity of cyclin D₁ and p53 was significantly decreased in UVB plus etanercept‐treated sites at 24 h. Survivin expression was significantly higher in UVB plus etanercept‐treated skin as compared with UVB monotherapy. Conclusions Our data indicate that combined treatment with broadband UVB and TNF‐α blockers might increase the risk of photocarcinogenesis by influencing apoptotic as well as antiapoptotic pathways.     

The Relationship among Minimal Erythema Dose,Minimal Delayed Tanning Dose,and Skin Color

The relationship among minimal erythema dose (MED), minimal delayed tanning dose (MDTD), and skin color was examined in 16 healthy volunteers using three different spectra. The subjects were exposed to UVB, UVA+B, and UV+Visible light (UV+Visible) with a xenon arc solar simulator as a light source. The MEDs for UVB and UVA+B were less than the MDTDs, whereas the MED for UV+Visible was higher than the MDTD. There was no significant correlation between the MED and the MDTD for UVB or UVA+B. The MED for UV+Visible was significantly correlated to the MDTD (p<0.01). Skin color significantly correlated with MEDs for UVB and UVA+B (p<0.01), but not for UV+Visible. There was no significant correlation between skin color and the MDTD for any spectra. From these results, it is suggested that the relationship between erythemal and melanogenic responses is dependent on spectral bands of the light source and that skin color is a predictor of UV-induced erythema.     

Human epidermal basal cell responses to ultraviolet-B differ according to their location in the undulating epidermis

BACKGROUND: Exposure of skin to excessive ultraviolet-B (UVB) radiation causes epidermal hyperproliferation that leads to epidermal hyperplasia, however, it is not yet clear exactly how these responses progress. OBJECTIVES: We attempted to clarify the response patterns involved with epidermal hyperproliferation following UVB radiation. METHODS: UVB was irradiated at 2 minimal erythema doses (MED) to human back skin and epidermal morphologic changes were evaluated using in vivo confocal laser microscopy. Skin biopsy specimens were collected from exposed and from non-exposed regions, and were subjected to histochemical and immunohistochemical analysis. RESULTS: The in vivo confocal laser microscopic analysis showed that UVB-induced epidermal hyperplasia was prominent at the epidermal rete ridges. Further, 3 days after UVB exposure, numerous Ki67-positive epidermal cells were observed in the epidermal rete ridges, but not in the epidermis at the top of the dermal papilla. These results suggest that cells highly responsive to UVB exist in the epidermal rete ridges and that their hyperproliferation leads to elongation of the epidermal rete ridges. In contrast, the number of keratin 10-positive basal cells, known as transitional cells, was increased throughout the epidermis, suggesting that an upward migration of keratinocytes from the epidermal basal layer occurred regardless of their location. However, diffusion of melanin to the suprabasal layers was markedly observed in epidermal regions above the dermal papillae, suggesting the occurrence of strong upper cell movement at this position. CONCLUSION: Based on our results, we conclude that differences in keratinocyte responses to UVB radiation exist in cells located in the undulating epidermal basal layer.     

Lack of photoprotection against UVB-induced erythema by immediate pigmentation induced by 382 nm radiation

Immediate pigment darkening (IPD) was induced on the backs of 11 human volunteers of skin types III and IV by exposing the skin to UVA radiation (382 nm). The minimum erythema dose (MED) of UVB radiation was also determined by exposing sites to graduated doses of 304 nm radiation. The order of exposure of distinct anatomic areas was as follow: UVB followed by IPD induction; IPD induction followed by UVB; IPD induction followed 3 h later by UVB; and UVB only. Erythema responses induced by UVB were graded by inspection 24 h later and the MEDs in the 4 areas were compared. The induction of IPD before UVB exposure caused no significant change in the MED compared to sites receiving UVB only, or receiving UVA radiation after UVB, confirming that the IPD reaction does not protect against UVB-induced erythema. There was also no evidence of photorecovery, i.e., an increase in the MED of UVB resulting from exposure to longer wavelength, UV or visible radiation following UVB exposure.     

Long-term evaluation of erythema and pigmentation induced by ultraviolet radiations of different wavelengths

BACKGROUNDS/AIMS: Although multiple studies have been reported about the biological effects of ultraviolet (UV) radiations, the comparative and long-term reactions of human skin by several different UV-wavebands were not reported. The aim of this study was to investigate a time course of erythema and pigmentation induced by UVA 1, broad-band UVA (BBUVA), narrow-band UVB (NBUVB) and broad-band UVB (BBUVB). METHODS: Ten volunteers participated in this study for 6 months. Four skin areas, from the back of each subject, were irradiated with two minimal erythema dose (MED) of four different UV wavelengths corresponding to UVA 1, BBUVA, NBUVB and BBUVB. Skin color changes were evaluated by visual scoring and values were converted into the L*a*b color system. RESULTS: For both UVA 1 and BBUVA, erythema and pigmentation were most pronounced immediately and 1 h after exposure. Thereafter, erythema rapidly diminished but pigmentation persisted throughout the study. For both NBUVB and BBUVB, test areas reacted with erythema of maximum intensity at 1 and 2 days, respectively. A maximum tanning was reached at 3-6 days for NBUVB and 4-7 days for BBUVB, and the return toward the original color point was at 1 and 3 months, respectively. No significant difference was found in visual and colorimetric evaluation for the time course of skin color changes. CONCLUSION: Two MED of UVA produced far prolonged erythema and pigmentation than UVB. For UVA, UVA 1 and BBUVA showed similar intensity and time course of skin reaction. For UVB, erythema and pigmentation produced by NBUVB were milder in intensity and shorter in time course than those by BBUVB. These results would provide standard data on time courses and intensity of skin color changes by different UV wavelengths.     

A long-term evaluation of erythema and pigmentation induced by ultraviolet radiations of different wavelengths

BACKGROUND/AIMS: The long-term reactions of human skin by different ultraviolet (UV)-wavebands were not reported. This study was to investigate a time course of erythema and pigmentation induced by UVA-1, broadband UVA (BBUVA), narrowband UVB (NBUVB) and broadband UVB (BBUVB). METHODS: Ten volunteers participated in this study for 6 months. Four skin areas, from the back of each subject, were irradiated with two minimal erythema dose (MED) of four different UV wavelengths corresponding to UVA-1, BBUVA, NBUVB and BBUVB. RESULTS: For both UVA-1 and BBUVA, erythema and pigmentation were most pronounced immediately and 1 h after exposure. Erythema rapidly diminished but pigmentation persisted throughout the study. For both NBUVB and BBUVB, test areas reacted with erythema of maximum intensity at 1 and 2 days, respectively. A maximum tanning was reached at 3-6 days for NBUVB and 4-7 days for BBUVB, and the return toward the original point was at 1 and 3 months, respectively. CONCLUSION: Two MED of UVA produced far prolonged erythema and pigmentation than UVB. For UVA, UVA-1 and BBUVA showed similar intensity and time course of skin reaction. For UVB, erythema and pigmentation produced by NBUVB were milder in intensity and shorter in a time course than those by BBUVB.     

Alterations in human epidermal Langerhans cells by ultraviolet radiation: quantitative and morphological study

BACKGROUND: Ultraviolet (UV) exposure of human skin induces local and systemic immune suppression. This phenomenon has been well documented when UVB radiation (290-320 nm) is used. The mechanism is thought to involve Langerhans cells (LCs), the epidermal dendritic cells that play a crucial role in antigen presentation. A variety of studies have clearly demonstrated that UVB radiation decreases LC density and alters their morphology and immunological function, but little is known about the effects of the entire UV spectrum (ultraviolet solar simulated radiation, UV-SSR or UVB + UVA) or UVA (320-400 nm) radiation alone. OBJECTIVES: The purpose of this study was to analyse and compare the effects of a single exposure of human volunteers to UV-SSR, total UVA or UVA1 (340-400 nm) in the human epidermal LC density and morphology. METHODS: Immunohistochemistry on epidermal sheets with various antibodies and transmission electron microscopy (TEM) were used. RESULTS: Immunostaining for class II antigen revealed that a single UV-SSR exposure, corresponding to twice the minimal erythemal dose (MED), induced a significant reduction in LC density with only slight morphological alterations of remaining cells. After a single UVA exposure, LC density showed a dose-dependent reduction with a significant effect at 60 J cm(-2) (well above the MED). Moreover, the reduction of LC dendricity was also dose-dependent and significant for doses exceeding 30 J cm(-2). UVA1 radiation was as effective as total UVA for the later endpoint. As demonstrated by TEM, the location of Birbeck granules containing epidermal cells was modified in UVA-exposed areas. They were located in the spinous rather than in the suprabasal layer. In addition, the morphology of these cells was altered. We observed a rounding up of the cell body with a reduction of dendricity. Alterations of mitochondrial membrane and ridges were also seen. CONCLUSIONS: A single exposure of human skin in vivo to UV-SSR, UVA or UVA1 radiation results in different alterations of density and/or morphology of LCs. All these alterations may impair the antigen-presenting function of LCs leading to an alteration of immune response.     

Quantitative assessment of UV-induced changes in microcirculatory flow by laser Doppler velocimetry

Objective measurements of blood flow changes following UV irradiation in the skin of human volunteers have been made with the noninvasive technique of laser Doppler velocimetry (LDV). This optical procedure allowed perfusion (number of red cells X velocity) alterations in the cutaneous microcirculation to be monitored after exposure of the skin to UVA and UVB + UVC radiation. Response curves were obtained in 6 subjects following irradiation at 4 times the minimal UVB + UVC erythema dose (MED). Measurements were made on control (untreated) skin and on skin pretreated with a sunscreen lotion. It was found that: (1) the lotion vehicle had no protective effect, (2) the active sunscreen constituent (2-ethylhexylcinnamate, 5%) was significantly protective, and (3) the presence of bergapten (5-methoxypsoralen, 30 ppm) did not enhance or diminish the cinnamate protective effect. LDV measurements in 5 subjects were also taken during and subsequent to 5 daily exposures to 1 MED of UVB + UVC radiation. Control and pretreated skin sites were again studied and similar protective effects were observed. However, on subsequent reexposure of these sites to 4 MED of UVB + UVC, 14 days after the first of the 5 single MED doses, no significant change in skin blood perfusion was detected at either control or pretreated sites. In a separate series of experiments, LDV data were collected after UVA radiation exposures up to 15 J/cm2. No changes in microcirculation perfusion were detected in any of the situations considered. All LDV measurements were made with 2 instruments of slightly different design and were compared to subjective assessments of erythema performed by a single observer. The results suggest that LDV has significant potential as a means to quantify (1) UV exposures in excess of the MED and (2) the inhibition of UV-induced changes in microcirculatory flow by chemical protectants.     

Contrasting effects of an ultraviolet B and an ultraviolet A tanning lamp on interleukin-6, tumour necrosis factor-α and intercellular adhesion molecule-1 expression

BACKGROUND: Recent studies have demonstrated that a tanning lamp emitting predominantly ultraviolet (UV) A induces significant yields of the type of potentially mutagenic DNA damage that are associated with the onset of skin cancer (i.e. cyclobutane pyrimidine dimers). UV-induced immunosuppression is also an important event leading to skin cancer. OBJECTIVES: To the modulation of key immunological molecules following exposure to a broad-spectrum UVB lamp and a predominantly UVA-emitting tanning lamp using model in vitro systems. METHODS: We compared secretion and mRNA expression of interleukin (IL)-6 and tumour necrosis factor (TNF)-alpha in normal human epidermal keratinocytes, and interferon (IFN)-gamma-induced intracellular adhesion molecule (ICAM)-1 in normal human fibroblasts irradiated in vitro with a broad-spectrum UVB lamp or with a Philips 'Performance' tanning lamp. RESULTS: With broad-spectrum UVB irradiation, upregulation of IL-6 and TNF-alpha mRNA was detected 6 h after irradiation, and a dose-dependent increase of cytokines in the supernatants of irradiated cells was found 24 h after irradiation. In contrast, there was no cytokine secretion and little evidence for mRNA upregulation following exposure to a tanning lamp. When cells were exposed first to broad-spectrum UVB, then the tanning lamp, UVB-induced cytokine secretion was inhibited, although mRNA levels were upregulated to a level close to that observed with UVB alone. By using a Schott WG 320 nm filter to attenuate the level of UVB relative to UVA emitted by the tanning lamp, the inhibition of cytokine secretion was shown to be associated with UVA exposure. Both UV sources inhibited IFN-gamma-induced ICAM-1 mRNA expression in a dose-dependent fashion. By using a Schott WG 335 nm filter, inhibition of ICAM-1 mRNA expression by the tanning lamp was shown to be associated with UVB exposure. CONCLUSIONS: These results suggest that UV sources emitting different levels of UVA and UVB have differential effects on the modulation of different immunoregulatory molecules, and indicate that there are potential interactions between these wavelengths.     

Failure of physiologic doses of pure UVA or UVB to induce lesions in photosensitive cutaneous lupus erythematosus: implications for phototesting

BACKGROUND: Phototesting studies in cutaneous lupus erythematosus have yielded variable results, with most trials reporting photo-induction of lesions by both UVA and UVB in substantial numbers of patients. OBJECTIVES: To determine the minimal erythema dose in patients with subacute cutaneous lupus erythematosus (SCLE) and controls. PATIENTS/METHODS: We phototested nine patients with SCLE and 14 skin type-matched controls, using repetitive dosing of UVA1 and UVB, but with filters that removed most of the shorter UVC and longer infrared and visible light. In addition, DNA was isolated from anticoagulated blood to genotype the TNF-alpha 308 region in each patient and control. RESULTS: We were unable to demonstrate a difference in minimal erythema dose (MED) between patients and controls, or any correlation of MED with either TNF genotype or systemic drug therapy for SCLE. In addition, no SCLE skin lesions were induced in the nine patients with either UVA or UVB, and one patient cleared a skin lesion after low-dose UVA1 irradiation. CONCLUSIONS: The potential role of wavelengths outside the UVA and UVB range in the photo-induction of cutaneous lupus skin lesions needs to be investigated, and there is a need to standardize phototesting equipment and procedures for patients with cutaneous lupus erythematous.     

Chronic actinic dermatitis in Asian skin: a Singaporean experience

Background/purpose: To study the characteristics of chronic actinic dermatitis (CAD) in a heterogeneous group of Singaporean patients. Methods: The photobiologicial features of all patients phototested and diagnosed with CAD from January 2005 to December 2009 were examined retrospectively. Results: Fifty‐eight patients were diagnosed as having CAD. The mean age at diagnosis was 62 years (range 35–83). Forty‐one were (70.7%) Chinese, six (10.3%) Indians, eight (13.8%) Malays, and three (5.2%) Others. Forty‐seven were (81.0%) male and 11 (19.0%) were female. Forty‐nine (84.5%) had Fitzpatrick skin phototype IV and nine (15.5%) had phototype V. Three of 26 (11.5%) tested for human immunodeficiency virus were positive. The face, neck, and forearms were most commonly affected. Thirty‐two patients (55.2%) had reduced minimal erythema dose (MED) to both ultraviolet B (UVB)and ultraviolet A (UVA), 23 patients (39.7%) had lowered MED to UVB only, while three (5.1%) had reduced MED to UVA only. Patients were followed up for a mean of 16.8 months. All were treated with photoprotection and topical steroids; however, a few required oral immunosuppression with partial improvement. Conclusion: In Singapore, CAD was seen more commonly in elderly Chinese males of Fitzpatrick skin phototype IV. Reduced MED to both UVB and UVA was the most common phototest finding.