Guidelines for topical PUVA: a report of a workshop of the British photodermatology group

Psoralen photochemotherapy [psoralen ultraviolet A (PUVA)] plays an important part in dermatological therapeutics, being an effective and generally safe treatment for psoriasis and other dermatoses. In order to maintain optimal efficacy and safety, guidelines concerning best practice should be available to operators and supervisors. The British Photodermatology Group (BPG) have previously published recommendations on PUVA, including UVA dosimetry and calibration, patient pretreatment assessment, indications and contraindications, and the management of adverse reactions.1 While most current knowledge relates to oral PUVA, the use of topical PUVA regimens is also popular and presents a number of questions peculiar to this modality, including the choice of psoralen, formulation, method of application, optimal timing of treatment, UVA regimens and relative benefits or risks as compared with oral PUVA. Bath PUVA, i.e. generalized immersion, is the most frequently used modality of topical treatment, practised by about 100 centres in the U.K., while other topical preparations tend to be used for localized diseases such as those affecting the hands and feet. This paper is the product of a recent workshop of the BPG and includes guidelines for bath, local immersion and other topical PUVA. These recommendations are based, where possible, on the results of controlled studies, or otherwise on the consensus view on current practice.

Characterization of photosensitivity in the Smith-Lemli-Opitz syndrome: a new congenital photosensitivity syndrome

Photosensitivity has recently been reported as a feature of the Smith-Lemli-Opitz syndrome (SLO). The aim of this study was to establish the photobiological features of this disorder and to examine the hypothesis that the photosensitivity is caused by the high levels of 7-dehydrocholesterol found in SLO. All known cases of SLO in the U.K. were reviewed and clinical details of photosensitivity were recorded in detail. The action spectrum of the photosensitive eruption was defined by monochromator light testing. Thirteen of the 23 subjects (57%) had severe photosensitivity, and in 10 there was no photosensitivity. No correlation was identified between levels of 7-dehydrocholesterol and severity of photosensitivity, suggesting that the photosensitivity in SLO is not caused by a direct phototoxic effect mediated by 7-dehydrocholesterol. A novel pattern of photosensitivity was observed, with onset of a sunburn-like erythema on sun-exposed skin within minutes of sun exposure, which persisted in most cases for up to 24-48 h before fading. Monochromator light testing in three subjects showed an ultraviolet (UV) A-mediated photosensitivity eruption with greatest photosensitivity at 350 nm. Photosensitivity is a common and prominent feature of SLO and appears to be UVA-mediated. Elucidation of its biochemical basis may provide insight into normal cutaneous protective mechanisms against UVA-induced photodamage, and also sun sensitivity in general.

Photosensitivity in the Smith-Lemli-Opitz syndrome: the US experience of a new congenital photosensitivity syndrome

Photosensitivity has been briefly mentioned in several publications on the Smith-Lemli-Opitz (SLO) syndrome, an autosomal recessive mental retardation syndrome. We conducted a questionnaire-based survey to determine the incidence and main features of photosensitivity in SLO. We confirmed a high incidence, and initial evidence suggests that SLO may be the first example of an inherited photosensitivity disorder in which sensitivity to UVA is common.

Demographic study of port wine stain patients attending a laser clinic: family history, prevalence of naevus anaemicus and results of prior treatment

All patients with port wine stains (PWS) attending a tunable dye laser clinic were examined by one author (SWL), forming a large group which has allowed study of the demographic data of such patients. Two hundred and eighty-three patients, 217 females (median age 24 years, range 0.5-73) and 66 males (median age 20 years, range 0.75-72), were examined. The PWS were on the face in 226, neck in 69, trunk in 36, upper limb in 35 and lower limb in 29. The commonest lesional colour was purple (63 patients), while 39 naevi were pink/red, 35 pink/ purple and 35 pink. The naevus was flat in 255 patients, cobblestoned in 28, associated with hypertrophy in 31 and with scarring in 22. Seventy-two patients (25.4%) had a positive family history of birthmarks, 20 strawberry haemangiomas and 22 PWS, the family history of PWS being higher than expected for the prevalence of this naevus in the population. One hundred and forty-six patients were also examined for naevus anaemicus which was noted in 12 (8.2%), confirming an association between these two naevi. Ninety-four patients had received previous treatment, most commonly with the argon laser (56 patients), of whom only five reported a good result, and 17 of 22 patients with treatment-related scarring had been treated with this laser. Cosmetic camouflage was used in 109 (38.5%) of patients, who usually had PWS on the face (94%), of whom only 46 (16%) had received advice of its use.

A comparison of the response of unstimulated and stimulated T-lymphocytes and fibroblasts from normal, xeroderma pigmentosum and trichothiodystrophy donors to the lethal action of UV-C

Unstimulated T-lymphocytes from normal donors are significantly more sensitive to the lethal effects of UV-C than either stimulated T-lymphocytes or fibroblasts as judged by colony-forming ability. Data from other studies suggest that excision repair is more effective in stimulated than unstimulated T-lymphocytes leading to the prediction that these differences in survival should be minimal in cells established from excision defective donors. The prediction was met with XP6BR, a donor of unknown complementation group. For 3 XP's from complementation group D, however, enhanced survival in stimulated T-cells was observed. With cells from an excision-defective TTD who was included in complementation group D of XP both fibroblasts and unstimulated T-lymphocytes were hypersensitive. For a second excision defective TTD patient who was excluded from complementation group D, the unstimulated T-lymphocytes were more resistant than those of normal donors although the fibroblasts were hypersensitive. These results suggest that the in vitro response of stimulated T-lymphocytes or fibroblasts may not reflect the in vivo response of cells, as measured by the response of unstimulated T-lymphocytes.

UV-C sensitivity of unstimulated and stimulated human lymphocytes from normal and xeroderma pigmentosum donors in the comet assay: A potential diagnostic technique

We have studied incision-break formation in unstimulated and stimulated populations of human T-lymphocytes using the comet (single-cell microgel electrophoresis) assay. The frequency of strand breaks 1 h after UV-irradiation appears to be far greater in unstimulated than in stimulated lymphocytes from normal donors and the excess of strand breaks was observed for a far longer time after irradiation. This result corroborates the greater sensitivity of UV-C irradiation observed in a colony-forming assay but suggests that the defect may relate to a defect in strand rejoining rather than a defect in incision. Few strand breaks were seen in either unstimulated or stimulated lymphocytes of four xeroderma pigmentosum donors, suggesting that the method may offer a rapid diagnostic assay for XP.

Long-term survival and preservation of natural killer cell activity in a xeroderma pigmentosum patient with spontaneous regression and multiple deposits of malignant melanoma

A 67-year-old man with xeroderma pigmentosum (XP) originally presented with malignant melanoma at the age of 28 years. This recurred 22 years later and subsequently numerous primary and secondary melanomas developed on the skin, several of which underwent spontaneous regression. Despite a marked lymphopenia, the proportion of natural killer cells was elevated and it is proposed that this led to the regression of the melanomas. Skin-derived fibroblasts from the patient were more sensitive to UVC (D10 approximately 3 J/m-2) than those from normal individuals (D10 approximately 15 J/m-2). The fibroblast culture was shown to be defective in excision repair with less than 10% of residual activity compared with controls. No assignment to a complementation group has yet been made. There was an elevated frequency of mutants resistant to 6-thioguanine in the circulating T lymphocytes.

Molecular characterization of a high A2 beta thalassemia by direct sequencing of single strand enriched amplified genomic DNA

Two families, one of Anglo-Saxon-Dutch descent, and the other, West Indian black, have an atypical beta thalassemia characterized by an unusually high level of Hb A2 in the heterozygous state. Restriction endonuclease mapping showed a deletion of about 1.35 kilobase (kb) in the 5' region of the beta globin gene. Direct sequencing of a specific region of genomic DNA amplified by a new modification of the polymerase chain reaction defined the deletion to be 1,393 base pairs (bp) and to be the same in both families. The deletion extends from 485 bp 5' to the mRNA CAP site to the middle of the second intervening sequence. This deletion, together with three others previously described that remove the 5' end of the beta gene but leave the delta gene intact, are all associated with unusually high levels of Hb A2 in the heterozygous state.