ANCA Associated with Behçet's Disease

Behçcet's disease is a multisystem disorder affecting primarily mucocutaneous and ocular sites although the gastrointestinal, cardiovascular, central nervous and respiratory systems may also be involved. Hulusi Behçet, a Turkish dermatologist, first described Behçet's disease in 1937 and suggested a possible infectious aetiology1. The pathogenesis of this condition still remains unclear although it is likely that infection acts as a trigger in genetically susceptible individuals.

We report a patient with unusual cutaneous manifestations of Behçet's disease and antineutrophil cytoplasmic antibodies (ANCA) directed against the cytotoxic protein, bactericidal/permeability-increasing protein (BPI). This is the first report of Behçet's disease associated with this autoantibody.

Home phototherapy: report on a workshop of the British Photodermatology Group, December 1996

Phototherapy is a popular and effective treatment for many patients with skin diseases. However, repeated journeys to hospital for phototherapy can be inconvenient and expensive. If it were available, many patients might prefer home-based phototherapy as long as it was safe and effective. Indeed, many psoriasis patients already self-treat with ultraviolet A sunbeds at home. This report represents a consensus view from a British Photodermatology Group workshop held in December 1996, the purpose of which was to examine the potential role of home-based phototherapy in dermatological practice. We conclude that home-based therapy represents a suboptimal treatment with greater attendant risks than phototherapy in a hospital environment. The level of medical supervision of the home treatment is crucial to its safety and effectiveness. Until further studies are forthcoming, home phototherapy should be largely restricted to those with overwhelming difficulties in attending hospital.

Treatment of psoriasis with intermittent short course cyclosporin (Neoral). A multicentre study

A 1 year, prospective multicentre study was performed to investigate the efficacy and safety of intermittent treatment with cyclosporin in psoriasis vulgaris. Subjects received cyclosporin (Neoral) 5 mg/kg per day until achieving 90% reduction in area affected, or for a maximum of 12 weeks. Those failing to demonstrate a satisfactory response were withdrawn. When further treatment was required, cyclosporin was recommenced. This cycle was repeated up to three times. Psoriasis activity was recorded using the area affected and sign scores for erythema, scaling and infiltration. Overall assessments of response and tolerability were recorded. Forty-one subjects, mean age 36, mean PASI 12.8, entered the first treatment period. Thirty-three received a second period of treatment and 16 a third. Eighteen failed to complete the study as planned: five were withdrawn due to adverse events, four due to treatment failure and nine due to protocol violations. At the end of each treatment period, significant improvements were seen in all efficacy parameters. Overall response was graded as 'considerable improvement' or 'minimal or no symptoms', by over 80% of subjects and investigators. Median intervals to relapse for subjects remaining in the study were 72 days (range 28-329) and 53 days (range 14-141) after periods 1 and 2, respectively. There were significant increases in mean serum creatinine and blood pressure during each treatment period. However, there were no significant differences in either parameter between baseline and the final follow-up visit. At the end of each treatment period, overall tolerability of the treatment was considered 'good' or 'very good' by over 80% of subjects and investigators.

Eosinophil infiltration into human skin is antigen-dependent in the late-phase reaction

Eosinophils play a critical role in late-phase reaction allergic inflammatory responses, although the factors responsible for selective tissue eosinophilia are currently ill-defined. To determine whether recruitment of eosinophils is allergen-specific, or a feature of inflammation in allergic individuals, we have examined cutaneous cell infiltrates and endothelial cell adhesion molecule expression in atopic subjects 6 h (n = 8) and 24 h (n = 7) following ultraviolet-B (UVB) irradiation, or intradermal injection of late-phase reaction allergens or diluent control, using standard immunohistochemical techniques. The numbers of eosinophils were increased significantly, when compared to controls, at both 6 h (P < 0.01) and 24 h (P < 0.05), following intradermal allergen challenge, whereas no significant increase in eosinophils was observed following UVB irradiation. UVB and allergen both induced significant increases in neutrophils, monocytes and T cells at 24 h compared to control sites. An increased expression of endothelial cell adhesion molecules, E-selectin and intercellular adhesion molecule-1 (ICAM-1), was observed in both models of inflammation. Vascular cell adhesion molecule-1 (VCAM-1) was induced weakly on some biopsies following allergen, and not at all following UVB. These data indicate that eosinophil infiltration in susceptible individuals is a specific property of allergen. Although this study would support the postulated role of VCAM-1 in selective eosinophil recruitment, given its variable and weak expression, additional factors are likely to be involved.

O'Brien's actinic granuloma: response to isotretinoin

We describe a 75-year-old man demonstrating the florid clinical features of actinic granuloma of O'Brien. This rare disfiguring condition is believed to result from a granulomatous reaction of the dermis to solar-induced elastosis and is poorly responsive to topical steroids. Twelve weeks' treatment with isotretinoin prevented the development of new granulomata and produced almost complete resolution of established lesions.

Contact and photocontact sensitization in chronic actinic dermatitis: sesquiterpene lactone mix is an important allergen

Eighty-nine patients with chronic actinic dermatitis (CAD) were retrospectively studied: 69 (78%) male and 20 (22%) female, with mean ages of 66 and 64 years, respectively; nine (10%) were dark skinned. Eight (9%) were abnormally sensitive to UVB wavelengths alone, 74 (83%) to UVB and UVA, and seven (8%) to UVB, UVA and visible radiation. Eighty-six patients were patch tested to an extended standard European series of contact allergens, including in 80 cases a 0.1% mix of three sesquiterpene lactones, and photopatch tested to a standard photopatch series. Sixty-four of these 86 patients (74%) had positive patch or photopatch tests; 36% (29 of 80) were sensitive to the sesquiterpene lactone mix, 21% (18 of 86) to fragrance compounds, 20% (17 of 86) to colophony, and 14% (12 of 86) to rubber chemicals. Ten (12%) had positive photopatch tests; five (6%) to musk ambrette, six (7%) to sunscreens and one to both. Fourteen of the eighty-nine patients with CAD (16%) had preceding endogenous eczema. In 18 of 86 patients (21%), CAD occurred alone, with neither detectable contact nor photocontact allergy, nor a preceding history of endogenous eczema. This study confirms the association between Compositae (sesquiterpene lactone) dermatitis and CAD.

The practice of ultraviolet phototherapy in the United Kingdom

A survey, using a postal questionnaire, was carried out to examine the current practice of UVB phototherapy in dermatology centres in the U.K. The questionnaire was sent to 115 dermatology departments, and sought information regarding the type and age of each machine used for ultraviolet B (UVB) phototherapy, methods of prescribing, recording and terminating patient exposure, and the skin conditions treated. Completed questionnaires were received from 87 of the 115 centres, giving a response rate of 76%. The survey showed that an appreciable number of U.K. phototherapy centres are using equipment which is both old, and suboptimal in producing a therapeutic response. There appeared to be a wide variation in the approach to phototherapy, both in terms of prescribing initial and incremental exposure, and in terminating treatment. The findings suggest that effectiveness and efficiency might be improved, and the risk/benefit ratio of phototherapy further reduced, by some rationalization of treatment protocols.

Multiple lentigines confined to psoriatic plaques

The development of naevus spilus-like hyperpigmentation at sites of resolving plaques of psoriasis has been reported previously. Although the mechanism is not understood, PUVA therapy has been implicated in most cases. We report an additional case in which lentigines, confined to sites of resolving psoriasis, occurred following oral PUVA. We also describe similar clinical features in two patients who had not received PUVA, which strengthens the observation that this treatment is not a prerequisite for development of this unusual pattern of pigmentation.

Cutaneous photosensitivity in dermatomyositis

The incidence and nature of cutaneous photosensitivity were studied in 10 patients suffering from dermatomyositis. Five reported an abnormality, which consisted of photoaggravation of preexisting cutaneous lesions in three, and abnormal transient erythemal responses in two. Monochromatic irradiation testing of all 10 patients demonstrated reduced minimal erythemal doses in two, at 307.5 nm, and at 340 and 360 nm, respectively; only the latter individual had clinical light sensitivity. Exposure to low-dose, solar-simulated radiation of the unaffected skin of the former patient, and five others who agreed to the procedure, three of whom complained of light sensitivity, induced a lesion with the clinical and immunofluorescence characteristics of dermatomyositis in only the first one. Four other patients replied to a mailed questionnaire, and three of these reported aggravation of their rash and provocation of new lesions by sunlight. Photosensitivity may thus be an important cutaneous feature of dermatomyositis.

Pustular eruptions after chlorpromazine

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Heat shock protein 65 immunoreactivity in experimentally induced polymorphic light eruption

The expression of 65 kiloDalton heat shock protein (HSP65) immunoreactivity of skin biopsies from experimentally induced polymorphic light eruption (PLE) lesions was studied, to investigate its possible role as a photo-induced antigen responsible for precipitating lesions. In each subject the 24-h minimal erythema dose of solar simulated radiation was determined and an area of skin previously affected by PLE subjected to 70% of the minimal erythema dose in order to induce PLE lesions. The irradiated areas were sequentially biopsied between 0 and 6 days. ML-30, a monoclonal antibody which recognises heat shock protein 65, was used to label the sections by means of an indirect immunoperoxidase technique. In PLE patients clinical inflammation was noted by 5 h post-irradiation, with subsequent evolution of PLE-like lesions; these were still present at 6 days. Increased ML-30 antibody labelling in epidermal keratinocyte and endothelial cell cytoplasm was recognisable from 1 h post-irradiation, and in dermal dendritic cells from 5 h sustained through to 6 days. In normal subjects neither clinical nor histological features of inflammation were noted after irradiation, nor any increase in HSP65 labelling.

Polymorphic light eruption: prevalence in Australia and England

The prevalence and clinical characteristics of polymorphic light eruption were assessed by a questionnaire survey of 172, 196 and 182 subjects in Perth, Ballarat and London, respectively. The prevalence was 5.2% in Perth (latitude 32 degrees), 3.6% in Ballarat (37.5 degrees) and 14.8% in London (51.5 degrees). The age distribution (mostly first three decades) and male:female ratio (1:3) was similar for affected individuals in all three areas. Development of tolerance during the summer was more common in Perth (66.7%) and Ballarat (71.4%) than in London (40.7%).

Penicillamine-induced elastosis perforans serpiginosa treated successfully with isotretinoin

Elastosis perforans serpiginosa (EPS) and the elastotic changes of pseudoxanthoma elasticum (PXE) are rare but well-recognized side-effects of long-term penicillamine therapy. A 42-year old female patient who developed both of these cutaneous side-effects following treatment with high-dose penicillamine for Wilson's disease is described; near-complete resolution of the EPS, but not the PXE was achieved by treatment with isotretinoin (0.5 mg/kg/day) for 6 weeks, despite continuation of the penicillamine.

Low-dose ultraviolet-B irradiation depletes human epidermal Langerhans cells

We have examined the effects of low-dose monochromatic UVB irradiation (295 +/- 5 nm), biologically equivalent to that generally incident on the skin during a 12-session sun-bed course, on the expression of the CD1a epidermal Langerhans cell surface marker in human skin in vivo. In five subjects, 1.5 minimal erythema doses (MEDs) at 295 nm depleted its expression by 50%. In five further subjects, a single 1.5 MED dose, 1.5 MEDs in 10 equal fractions on alternate days, and a single 1.5 MED dose at one-tenth the previously used irradiance, delivered to separate sites, also led to variable but significant depletion of CD1a expression of around 30-50%. Thus, low-dose UVB irradiation, whether received rapidly or slowly, appears significantly and approximately equally to deplete human epidermal Langerhans cell numbers as measured by CD1a expression.

p53 immunoreactivity in cutaneous PUVA tumors is similar to that in other non-melanoma skin neoplasms

Expression of the p53 tumor suppressor gene product was determined in keratoses and skin cancers associated with psoralen photochemotherapy (PUVA). An immunocytochemical study was employed using CM-1 (polyclonal) and Do-1 (monoclonal) antibodies to human wild-type p53. Thirty-two cutaneous lesions and 20 perilesional PUVA-irradiated skin biopsies were examined from 7 patients, all of whom had received more than 200 PUVA treatments and/or a cumulative UVA dose of greater than 1000J/cm2 as treatment for widespread plaque psoriasis. p53 immunoreactivity was seen in 7 of 15 squamous cell carcinomas (46.7%), 5 of 8 dysplastic keratoses (62.5%) and in no basal cell carcinomas or benign keratoses. The overall prevalence of p53 immunoreactivity in 46.2% of malignant or dysplastic PUVA-associated skin tumors is similar to that previously found by our group in comparable skin tumors from the general population. Most patients with lesions showing positive p53 immunoreactivity had, however, been exposed to additional risk factors before receiving PUVA therapy. p53 gene sequencing of PUVA-associated non-melanoma skin cancer (NMSC) may clarify whether p53 mutation contributes to the development of these tumors and whether this relates to PUVA therapy or prior carcinogen exposure.

Cockayne's syndrome: correlation of clinical features with cellular sensitivity of RNA synthesis to UV irradiation

Cockayne's syndrome (CS) is a rare autosomal recessive disorder with dwarfism, mental retardation, and otherwise clinically heterogeneous features. In cultured CS fibroblasts, the failure of RNA synthesis to recover to normal rates after UV-C irradiation provides a useful and relatively simple diagnostic test. We have measured post-UV-C RNA synthesis in 52 patients for whom a clinical diagnosis of CS was considered a possibility. Twenty-nine patients showed the defect characteristic of CS cells, and 23 had a normal response. We have attempted to correlate the cellular diagnosis with the different clinical features of the disorder. Clinical details of the patients were obtained from referring clinicians in the form of a questionnaire. Our results show that, apart from the cardinal features of dwarfism and mental retardation, sun sensitivity correlated best with a positive cellular diagnosis. Pigmentary retinopathy, gait defects, and dental caries were also good positive indicators, although several patients with a positive cellular diagnosis did not have these features.

The efficacy of psoralen photochemotherapy in the treatment of aquagenic pruritus

Psoralen photochemotherapy (PUVA) was effective in the treatment of five patients with aquagenic pruritus, associated in one with polycythaemia rubra vera and in another with the myelodysplastic syndrome. Relapse occurred within 2-24 weeks when treatment was discontinued. Maintenance therapy or a further course of PUVA was necessary to maintain remission. This requirement may limit the value of the therapy.

Adhesion molecule expression in polymorphic light eruption

Endothelial leukocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) are cytokine-regulated cell-surface leukocyte adhesion molecules. We have investigated the in vivo kinetics and pattern of expression of these adhesion molecules in relation to tissue accumulation of leukocytes in the photodermatosis, polymorphic light eruption (PMLE), which is characterized by dense perivascular leukocytic infiltration. Immunohistology was performed on biopsies taken at varying time points from PMLE lesions induced in 11 subjects by suberythemal solar simulated irradiation. Vascular endothelial ELAM-1 expression was first observed at 5 h, maximal at 24 to 72 h, and remained elevated at 6 d. VCAM-1, minimally expressed in control skin, was induced above background levels on endothelium and some perivascular cells after 24 h and maintained at 6 d. Endothelial cell ICAM-1 expression was increased above control levels at 72 h and 6 d. Keratinocyte ICAM-1 expression, most marked overlying areas of dermal leukocytic infiltration, began at 5 h and was strong at 72 h and 6 d. In addition to lymphocytes, significant numbers of neutrophils but not eosinophils were detected in the dermal leukocytic infiltrate that appeared at 5 h and persisted at 6 d. The pattern of adhesion molecule expression that we have observed is similar to that seen in normal skin during a delayed hypersensitivity reaction. These observations support an immunologic basis for PMLE.

Elevated hprt mutant frequency in circulating T-lymphocytes of xeroderma pigmentosum patients

The mutant frequency to 6-thioguanine resistance in circulating T-lymphocytes from 10 xeroderma pigmentosum patients (including complementation groups D and G and XP variants) has been determined. A highly significantly elevated frequency was observed, compared to age-matched, non-smoking control donors (x 2.1-fold higher than the mutant frequency in normal control donors, adjusted for age and cloning efficiency, p less than 0.001). The mutant frequency of 5 XP heterozygotes was in the normal range, when age, smoking habit and log cloning efficiency were taken into account. A number of possible factors which may account for the elevated mutant frequency seen in the XP donors (including an elevated spontaneous mutation rate, UV mutagenesis of the T-cells as they pass through the skin, an effect of environmental mutagens such as tobacco smoke, or as a consequence of immune deficiency) are discussed.

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.

Abnormal erythemal response and elevated T lymphocyte HRPT mutant frequency in Cockayne's syndrome

In three children with Cockayne's syndrome (CS), skin exposed to ultraviolet radiation responded transiently either with erythematous papules or an exaggerated sunburn-like response, without chronic actinic damage. Irradiation monochromator tests demonstrated an abnormal delay or reduction in the threshold to ultraviolet (UVB) irradiation-induced erythema similar to that of xeroderma pigmentosum (XP). As with XP there was an elevated frequency of mutants resistant to 6-thioguanine in circulating T lymphocytes. The mutant frequency in a single obligate heterozygote was normal. In contrast to XP, in the two CS individuals studied, adaptive cell-mediated immunity and natural killer cell function were normal. Because the risk of skin cancer is very high in XP but not in CS, the normal immune function in CS provides evidence that immune surveillance may be important in UV tumorigenesis.

Juvenile spring eruption of the ears: a probable variant of polymorphic light eruption

We report 18 cases in which a pruritic, erythematous, papular and vesicular eruption developed on the ears following sun exposure. Four of these patients had, on other occasions, suffered from typical polymorphic light eruption. The clinical features, histological changes, and results of phototesting suggest that juvenile spring eruption of the ears is a localized form of polymorphic light eruption.

Polymorphic light eruption

Polymorphic light eruption (PLE) describes a broad clinical spectrum including a number of different yet overlapping clinical subgroups. In the absence of an understanding of pathogenic mechanisms it remains unclear whether these subdivisions are appropriate. The action spectrum for PLE usually includes the ultraviolet A (UVA) spectrum, but a proportion of patients respond principally to UVB. This diversity in action spectra remains unexplained, as does the difficulty in artificial induction of lesions, particularly when physiologically relevant doses of UV radiation are employed. Models for the pathogenesis of PLE must explain several characteristic features of the condition, including nonuniform susceptibility of exposed skin areas, higher incidence in temperature climates, particularly in spring, and progressive tolerance during the summer months in some patients. Although unproven, an immunological mechanism is consistent with such features and is supported by immunohistological changes and keratinocyte ICAM-1 expression, similar to known type IV hypersensitivity reactions, and clinical response of severe cases to immunosuppression with azathioprine. Other recently proposed mechanisms include an abnormality in cutaneous arachidonic acid metabolism in response to UV irradiation, and excessive leukotriene B4 release by circulating leukocytes following UVA irradiation.

Genetic heterogeneity in erythropoietic protoporphyria: a study of the enzymatic defect in nine affected families

Erythropoietic protoporphyria (EPP) is associated with a deficiency of protohaem ferrolyase. We have used a novel assay for this enzyme based on its ability to utilize zinc as a substrate to investigate the inheritance of EPP in nine affected families. Zinc chelatase activity was markedly reduced in peripheral blood mononuclear cells from 14 EPP patients (mean, 3.3 nmol Zn protohaem/h/mg protein; range, 0.3-8.0) when compared with 41 controls (16.8 +/- 3.6) p less than 0.01. In three families with parent-to-child transmission of disease, the asymptomatic parent had an enzymatic activity within the normal range. In three pedigrees where the parents were asymptomatic, enzymatic activities were below the 95% confidence limits in both. Zinc chelatase activity was below the mean control value in 17 of the 18 parents in nine affected pedigrees, and six of seven asymptomatic offspring of patients with protoporphyria. The findings suggest that EPP is not transmitted as a simple dominant trait and that inheritance of more than one gene may be required for disease expression.

The acute idiopathic photodermatoses

The acute idiopathic photodermatoses are more common in females and comprise polymorphic light eruption, actinic prurigo, hydroa vacciniforme, and solar urticaria. Polymorphic light eruption occurs considerably more frequently than the others and while precise pathogenic mechanisms are still unclear, increasing evidence suggests an immunological basis for this condition. Although clinically distinct, actinic prurigo may be a variant of polymorphic light eruption, whereas solar urticaria and possibly hydroa vacciniforme are distinct entities, the former representing a type I hypersensitivity response. Polymorphic light eruption is characterized by a recurrent cutaneous reaction to ultraviolet (UV) exposure occurring after a delay of several hours that consists of pruritic erythematous papules, vesicles, or plaques on usually only some exposed sites and resolves without scarring over about a week. Actinic prurigo is differentiated from polymorphic light eruption by childhood onset and more persistent and excoriated lesions present both on sun-exposed and, to a lesser extent, non-exposed sites. Hydroa vacciniform is a rare disorder that also begins in childhood, and is characterized by recurrent crops of vesicles on sun-exposed skin and subsequent vacciniforme scarring. Solar urticaria is an uncommon condition that usually begins in the third or fourth decade and is differentiated from the other acute idiopathic photodermatoses by rapid onset of urticarial lesions within minutes of UV exposure and resolution within 1 to 2 hours.

DNA repair deficient photodermatoses

Photosensitive genodermatoses associated with established defects of DNA repair currently include the autosomal recessive diseases xeroderma pigmentosum (XP), Cockayne's syndrome (CS), trichothiodystrophy (TTD), and Bloom's syndrome (BS). XP is a heterogeneous disorder associated with defective excision repair or daughter strand repair of ultraviolet (UV)-induced DNA damage. It is characterized by cutaneous and ocular abnormalities predominantly on sun-exposed sites and in some cases, neurological features resulting from progressive neuronal loss. Skin involvement includes easy sunburning, pigmentary abnormalities, telangiectasia, dryness, scarring, and susceptibility to multiple benign and malignant neoplasms. In CS, defective repair of actively transcribing DNA is clinically associated with acute photosensitivity, growth retardation, demyelinating neurological abnormalities, and pigmentary retinal degeneration, but without increased cancer susceptibility. TTD is characterized by sulphur-deficient brittle hair, variable growth delay, mental retardation, ichthyosis, and in some cases photosensitivity. Although in some patients there is a deficiency of DNA excision repair identical to that in certain xeroderma pigmentosum patients, no increased cancer risk is present in trichothiodystrophy. In BS, deficient cellular DNA ligase is associated with congenital telangiectasia, photosensitivity, growth retardation, immune deficiency, increased susceptibility to infection, and predominantly internal rather than cutaneous malignancy. Immunological factors may at least determine the varying susceptibility to malignancy of these conditions.

Homozygous variegate porphyria: a case report

Homozygous variegate porphyria is described in a 14-year-old girl with a unique clinical presentation of photosensitivity from the second year of life, mental retardation, clinodactyly, and normal growth rate. The erythrocyte protoporphyrin concentration was raised with the protoporphyrin being predominantly zinc-chelated, which appears to be characteristic for all homozygous hepatic porphyrias. Protoporphyrinogen oxidase activity in lymphoblasts was decreased in both patient and parents despite the latter having normal porphyrin excretion.

Immune function, mutant frequency, and cancer risk in the DNA repair defective genodermatoses xeroderma pigmentosum, Cockayne's syndrome, and trichothiodystrophy

There is evidence for defective DNA repair in xeroderma pigmentosum, Cockayne's syndrome, and trichothiodystrophy, but for increased cancer risk only in xeroderma pigmentosum. Natural and adaptive immune surveillance and mutant frequency to 6-thioguanine resistance in circulating T-lymphocytes were studied in five patients with xeroderma pigmentosum, two with Cockayne's syndrome, and one with trichothiodystrophy. Forty-eight-hour cutaneous hypersensitivity responses to recall antigens excluded anergy and circulating CD3+, CD4+, CD8+, and CD16+ cell numbers were within normal limits in all patients tested, as were proliferative lymphocyte responses to PHA, except in the trichothiodystrophy patient. Proliferative responses to recall antigens (PPD, SKSD, and Candida) showed that all patients responded to one or more antigens. Direct natural killer cytotoxicity measured against the human erythromyeloid leukaemia cell line K562 using a 4-h 51Cr release assay was significantly reduced in xeroderma pigmentosum (specific cytotoxicity less than mean +/- SD greater than 17.4 +/- 9.4 per cent, with effector:target cell ratio of 50:1) compared to normal controls (45.8 +/- 17.8), but normal in Cockayne's syndrome and trichothiodystrophy. Generation of lymphokine activated killer cell activity was normal in the two xeroderma pigmentosum lines tested. The mutant frequency in the xeroderma pigmentosum donors was significantly increased (p less than 0.01) and was elevated in the two Cockayne's syndrome donors, taking age into account. No mutants were observed from the single trichothiodystrophy donor. These findings suggest that reduced natural killer cell activity may contribute to the greatly increased susceptibility to skin cancer in xeroderma pigmentosum.

Chronic actinic dermatitis: an immunohistologic and photobiologic study

Photobiologic, histologic, and immunohistochemical findings in 14 patients with chronic actinic dermatitis were compared. Grading of routine histologic features of involved skin demonstrated a spectrum of abnormalities ranging from changes resembling chronic dermatitis to those of cutaneous T cell lymphoma. Immunohistochemical staining showed dermal infiltrates to consist predominantly of T lymphocytes, with a significant trend toward lower CD4+/CD8+ ratios in cases with more florid histologic findings. Circulating CD4+/CD8+ cell ratios were normal in five patients and reduced in one patient. Photosensitivity extending to wavelengths longer than 340 nm was detected in eight patients, but the spectrum of photobiologic abnormality did not appear to correlate with either grading of histologic severity or variation in T cell subsets in lesional skin.