Combination treatment with methotrexate and cyclosporin for severe recalcitrant psoriasis

An increasingly important approach to the management of patients with severe psoriasis is the concurrent use of two systemic treatments. Previous guidelines have advised against the use of methotrexate and cyclosporin in combination. We report the successful use of a combination of methotrexate and cyclosporin in the treatment of 19 patients with severe, recalcitrant psoriasis, 15 of whom had psoriatic arthropathy. Most patients had previously received two or more systemic treatments. Before combination treatment was started nine of the patients were taking methotrexate and 10 were taking cyclosporin at the maximum tolerated doses. The duration of combination treatment was bimodally distributed, with seven patients having short-term treatment (mean +/- SD duration 18. 9 +/- 15.7 weeks) and 12 patients having long-term treatment (mean +/- SD duration 193.2 +/- 160.6 weeks). Those patients who received short-term treatment did not develop any evidence of toxicity from either agent. Of those patients on long-term treatment, three developed mild impairment of renal function that returned to normal following a reduction in dose of cyclosporin, and three had impairment of renal function (following long-term cyclosporin monotherapy) that improved, but did not normalize, following a reduction in dose of cyclosporin. In each case, combination treatment for psoriasis resulted in good control of both skin and joint problems using lower doses of each agent than would have been used for monotherapy. We conclude that the combination of methotrexate and cyclosporin is an effective treatment for this group of patients.

Bullous pemphigoid developing during systemic therapy with chloroquine

Bullous pemphigoid has been reported to be induced or precipitated by systemic therapy with several drugs, including penicillamine, captopril, frusemide and ampicillin. We report an African male patient with sarcoidosis who was prescribed chloroquine for progressive dyspnoea. After 3 months he developed generalized pruritus which evolved into a widespread bullous eruption with acral targetoid lesions resembling erythema multiforme. The histological and immunofluorescence findings were diagnostic of bullous pemphigoid. The atypical clinical features of this case resemble the phenotype that has been noted in previous reports of drug-induced bullous pemphigoid.

Increased T-cell receptor vbeta2 chain expression in skin homing lymphocytes in psoriasis

Studies have shown over-representation of certain T-cell receptor (TCR) Vbeta chains in lesional psoriatic skin, implying selection or expansion, possibly by bacterial superantigen. We investigated the pattern of TCR Vbeta chain usage in peripheral blood lymphocytes (PBL) bearing the skin homing receptor cutaneous lymphocyte associated antigen (CLA) in psoriasis patients. Results showed increased expression of TCR Vbeta2 in CLA-positive PBL in psoriasis patients (n = 15) compared with normals (n = 10); P < 0.002. As Vbeta2 is preferentially expressed by lymphocytes responding to certain bacterial superantigens, this study could possibly indicate a role for superantigens in the pathogenesis of psoriasis.

In vivo UVA-1 and UVB irradiation differentially perturbs the antigen-presenting function of human epidermal Langerhans cells

Ultraviolet B (UVB, 290-320 nm) radiation is known to suppress the immune function of epidermal Langerhans cells. We have recently described that in vitro UVB irradiation perturbs the antigen-presenting cell function of Langerhans cells by inhibiting their expression of functional B7 costimulatory molecules (B7-1, B7-2). The aim of this study was to determine wavelength-specific UV effects on Langerhans cells function in vivo, specifically UVB and UVA-1. To address this issue, volunteers were irradiated on the sun protected volar aspects of their forearms with 3 x minimal erythema dose of UVB (Philips TL-12) and UVA-1 (UVASUN 5000 Mutzhaas). Langerhans cells were isolated from suction blister roofs immediately following irradiation. Langerhans cells isolated from UVB- but not from UVA-1-irradiated skin failed to activate naïve resting allogeneic T cells (mixed epidermal cell leukocyte reaction) or primed tetanus toxoid reactive autologous T cells. Langerhans cells isolated from sham-irradiated or UVA-1-irradiated skin strongly upregulated B7-2 molecules during short-term tissue culture. By contrast, Langerhans cells from UVB-irradiated skin did not upregulate B7-2 molecules. Furthermore, exogenous stimulation of the B7 pathway by anti-CD28 stimulatory monoclonal antibodies restored the capacity of UVB-irradiated Langerhans cells to activate both alloreactive and tetanus toxoid-reactive T cells, implying suppressed antigen-presenting cell activities and perturbed B7 expression of Langerhans cells isolated from UVB-irradiated skin are related. Those studies demonstrate that in vivo UVB, but not UVA-1, interferes with the activation-dependent upregulation of B7 molecules on Langerhans cells, which in turn is of functional relevance for the perturbed antigen-presenting cell function of Langerhans cells within UVB- but not UVA-1-irradiated skin.

Ultraviolet B induced suppression of induction of contact sensitivity in human skin is not associated with tumour necrosis factor-alpha-308 or interleukin-10 genetic polymorphisms

Low doses of ultraviolet B (UVB) can induce localized immunosuppression in skin. This effect may be important in the induction of skin cancers and is thought to be mediated by tumour necrosis factor (TNF) alpha and interleukin (IL) 10 in conjunction with other factors. In humans a transition polymorphism in the TNF-alpha gene may affect TNF-alpha secretion and the promoter region of the IL-10 gene contains a CA repeat polymorphism which may affect gene function. We have therefore investigated the association of these polymorphisms with UVB-induced immunosuppression in humans. Volunteers (n = 42) were irradiated with UVB then sensitized on irradiated skin with diphenylcyclopropanone (DPCP) and subsequently antigen challenged with DPCP. DNA was extracted from blood samples and volunteers genotyped for the TNF-alpha polymorphism by polymerase chain reaction (PCR) and restriction digestion. The CA repeat polymorphism was amplified by PCR and sized by gel electrophoresis. Twenty-four volunteers were susceptible to UVB-induced immunosuppression and 18 were resistant. The association of allele frequencies and phenotype was statistically tested using a chi2-test. For both the TNF-alpha and IL-10 polymorphisms, there was no statistically significant association between allele types and response to UVB. These results indicate that variation in the immune response to UVB in humans is not associated with the TNF-alpha-308 transition or IL-10 CA repeat polymorphisms, although other as yet undetected DNA sequence variants of these genes may be involved.

Effect of granulocyte macrophage-colony stimulating factor on Langerhans cells in normal and healthy atopic subjects

Granulocyte macrophage-colony stimulating factor (GM-CSF) is a multipotent cytokine produced by many cutaneous cell types including keratinocytes. Langerhans cells (LC) represent the major antigen-presenting cells in skin, and in vitro studies demonstrate that GM-CSF is of pivotal importance in LC. Healthy volunteers (n = 3 non-atopic, n = 3 with atopy) received recombinant human GM-CSF (0. 05 microg/mL) by intradermal injection for 3 days to the same site. Diluent was injected in a similar manner as control. Biopsies were taken 24 h after the final injection and examined immunohistochemically for LC and inflammatory cell markers. Compared with control sites, intradermal GM-CSF resulted in shortening of dendritic cell processes and redistribution of LC in the epidermis; numbers of CD1a + cells in the epidermis were significantly decreased (P < 0.005), while those in the dermis were significantly increased (P < 0.05) following intradermal GM-CSF when compared with controls. Double labelling studies on epidermal CD1a + cells indicated de novo expression of intercellular adhesion molecule (ICAM)-1 and increased expression of HLA-DR following GM-CSF (P < 0. 005, P < 0.005, respectively). Additional findings included a marked mixed inflammatory cell infiltrate in the dermis and increased expression of the endothelial cell adhesion molecules E-selectin and ICAM-1. These data indicate that in normal human skin, GM-CSF induces changes in the phenotype and distribution of CD1a + cells consistent with LC functional maturation and exit from the epidermis to the dermis. As these events are central to the initiation of cutaneous inflammation, GM-CSF may potentially play a critical role in the pathogenesis of inflammatory dermatoses.

Psoriasis as a T cell-mediated autoimmune disease

Psoriasis is a common chronic skin disease in which T lymphocytes are thought to play a vital pathogenic role. Evidence shows that these are activated memory skin-homing T cells which induce characteristic disease features via cytokine production. Understanding the mechanisms of T cell accumulation in skin and mediation of psoriasis is critical to designing immunotherapy for this distressing disease.

Susceptibility to effects of UVB irradiation on induction of contact sensitivity, relevance of number and function of Langerhans cells and epidermal macrophages

Sensitization on skin exposed to acute low-dose UVB irradiation separates normal humans into two phenotypically distinct groups: One group, following sensitization on UVB-irradiated skin, develops contact sensitivity, designated UVB resistant (UVB-R) and the second group, following sensitization on UVB-irradiated skin, fails to develop contact sensitivity, designated UVB susceptible (UVB-S). To investigate whether UVB susceptibility in humans in related to antigen-presenting activity in the skin we studied the effect of UVB irradiation on the number and function of the epidermal antigen-presenting cells in volunteers identified as UVB-R and UVB-S. Single cell suspensions of epidermal cells from control skin and skin exposed to 3 minimal erythema doses (MED) of UVB 3 days previously were stained for Langerhans cells (CD1a+HLA-DR+) and epidermal macrophages (CD1a-HLA-DR+). The UVB exposure of the skin significantly decreased the percentage of Langerhans cells (UVB-R: n = 7, P < 0.02, UVB-S: n = 6, P < 0.03) and increased the percentage of epidermal macrophages (UVB-R: n = 7, P < 0.03, UVB-S: n = 6, P < 0.03) however to the same degree in both the UVB-R and the UVB-S group. To study the effect on Langerhans cell alloreactivity, epidermal cells were harvested immediately after UVB irradiation. However, in both UVB-R and UVB-S subjects the Langerhans cell alloreactivity was blocked to the same degree immediately after UVB irradiation compared to nonirradiated epidermal cells. To determine the effect of UVB irradiation on epidermal macrophages, epidermal cells were harvested 3 days after UVB irradiation. Irradiated epidermal cells from both UVB-R and UVB-S subjects demonstrated a strong antigen-presenting capacity compared to epidermal cells from control skin leading to activation of T cells that mainly secrete interferon (IFN)-gamma and not interleukin (IL)-4. In conclusion we found that UVB susceptibility was not correlated with the number of Langerhans cells or epidermal macrophages in the skin at the same time of sensitization. Neither was it correlated with the capacity of Langerhans cells nor UVB-induced epidermal macrophages to activate T cells in vitro.

Contrasting effects of ultraviolet A1 and ultraviolet B exposure on the induction of tumour necrosis factor-alpha in human skin

Ultraviolet B (UVB) irradiation of the skin causes immunosuppression which is relevant to the induction of skin cancer. The mechanism of this immunomodulation is unclear but various regulatory molecules have been implicated, including cis-urocanic acid (cis-UCA) and the cytokines tumour necrosis factor-alpha (TNF-alpha) and interleukin 10 (IL-10). Whether ultraviolet A (UVA) induces similar changes has not been investigated fully. We studied the effect of in vivo UVB and long-wave UVA (UVA1) exposure on the induction of TNF-alpha, IL-10 and cis-UCA in human skin. Volunteers were irradiated with three minimal erythema doses (MED) of UVB or UVA1. At different times after irradiation, suction blisters were raised from irradiated and from non-irradiated (control) skin. The TNF-alpha and IL-10 protein concentration, and the percentage of cis-UCA in the blister fluid, were then determined. UVB irradiation of human skin led to a rapid and significant increase in TNF-alpha concentration in suction-blister fluid, with maximal values 6 h after irradiation (n = 6, P < 0.05). In contrast, UVA1 irradiation led to a decrease in TNF-alpha concentration in the suction-blister fluid compared with non-irradiated skin, with the lowest values 6 h after irradiation (n = 6, P < 0.05). Both UVB and UVA1 exposure of the skin induced a slight increase in IL-10 concentration. However, the increase in IL-10 was only significant after UVB irradiation (UVB, n = 6, P < 0.05; UVA, n = 7, P < 0.1). As previously shown, both UVB and UVA1 result in the photo-isomerization of trans-UCA and an increased percentage of cis-UCA was found in the suction-blister fluid. Thus the results show differential effects of UVB and UVA1 irradiation on the induction of immunoregulatory molecules, which may help to explain the variation in immune responses after UVB and UVA1 exposure of human skin.

CD44 variant expression in cutaneous T-cell lymphoma

Expression of the lymphocyte homing receptor CD44 and its splice variants have been linked to tumour dissemination and poor prognosis in non-Hodgkin's lymphoma. Specifically, the in vitro expression of variant exon V6 confers metastatic potential in rat pancreatic carcinoma cell lines. In this study, we investigated the expression of CD44 splice variants in cutaneous T-cell lymphomas, including patients with mycosis fungoides (MF), Sezary syndrome (SS), large-cell anaplastic lymphoma (LCAL) and HTLV1-associated cutaneous lymphoma. In addition, 4 involved lymph nodes from 2 patients with MF and 1 patient with SS were examined. Inflammatory dermatoses, lichen planus and psoriasis, and normal skin were also studied. Immunohistochemistry was performed using a panel of monoclonal antibodies, including those with specificity for CD44H (standard isoform) and variant exons V3, V6 and V8-9. Normal epidermal keratinocytes were consistently CD44H and CD44 V3, V6 and V8-9 positive. In all the different clinicopathological subtypes and stages of cutaneous T-cell lymphomas, including involved lymph nodes, tumour cells consistently expressed CD44H, but were CD44 V3 and V6 negative. CD44 V8-9 was expressed on a majority of tumour cells in 2/5 LCAL and on occasional tumour cells in 2/5 LCAL. Occasional V8-9 positive tumour cells were also identified in 6/13 MF, 1/4 SS and 3/4 HTLV1. In 2/3 lymph node samples from 2 patients with tumour-stage MF, CD44 V8-9 expression was found on a small percentage of atypical mononuclear cells. Scattered V8-9 positive dermal mononuclear cells were present in sections of lichen planus and psoriasis. We have found no evidence to suggest that the metastasis-associated CD44 variant exon (V6) is expressed in cutaneous T-cell lymphoma, or that CD44H expression is associated with an adverse prognostic group. It is not clear whether the strong expression of CD44 V8-9 in 2 patients with CD30 positive LCAL reflects activation status or metastatic potential.

Localization of endothelial proliferation and microvascular expansion in active plaque psoriasis

Expansion of the dermal microvasculature is a prominent feature of psoriasis. Although the pathogenetic process resulting in vascular morphological changes remains unclear, considerable evidence suggests the involvement of angiogenesis. To assess the degree and site of psoriatic microvascular expansion, immunohistochemical studies were performed on paired lesional and non-lesional specimens from 10 patients with active, untreated plaque psoriasis. Five-micron thick sections were labelled with monoclonal antibody JC/70A specific for the endothelial marker CD31, and vascular quantification was achieved using hue-saturation-intensity image analysis. Assessment of vasculature in the papillary dermis (superficial plexus) demonstrated a fourfold increase in endothelial surface area of lesional compared with non-lesional skin (P < 0.01), while there was no significant increase in vasculature of the upper reticular dermis. Subsequently, 18-micron thick sections were double-labelled with MIB-1 antibody to the nuclear proliferation marker Ki-67 and JC/70A. Endothelial cell proliferation was identified in the vertical limbs of capillary loops in eight out of 10 lesional biopsies and in no non-lesional biopsies. The endothelial MIB-1 labelling index was 3.1% of total endothelial cells of the superficial plexus. These findings confirm endothelial proliferation underlying psoriatic microvascular expansion, and indicate that this process is limited to a specific site in the dermal capillary bed.

Identification of a major susceptibility locus on chromosome 6p and evidence for further disease loci revealed by a two stage genome-wide search in psoriasis

Psoriasis is a common chronic inflammatory disorder of the skin. To further understand the pathogenesis of psoriasis we have chosen to investigate the molecular genetic basis of the disorder. We have used a two-stage approach to search the human genome for the location of genes conferring susceptibility to psoriasis, using a total of 106 affected sibling pairs identified from 68 independent families. As over a third of the extended kindreds included affected relatives besides siblings, in addition to an analysis of allele sharing between affected sibling pairs, a novel linkage strategy was applied that extracts full non-parametric information. Four principal regions of possible linkage were identified on chromosomes 2, 8, 20 (p <0.005) and markers from the MHC region at 6p21 (p <0.0000006) for which significant evidence of linkage disequilibrium was also observed (p <0.00002). Whilst data from limited case control associations exist to implicate the MHC, the results of this genome wide analysis demonstrate that, at least in the population studied, a gene or genes located within the MHC and close to the class 1 HLA loci, represent the major determinant of the genetic basis of psoriasis.

Progress in psoriasis. Psoriasis: from gene to clinic. London, UK, 5-7 December 1996

In a meeting dedicated to a single common complex disease such as psoriasis, it is not surprising that many unanswered questions were raised. However, the meeting highlighted the impressive progress being made in psoriasis research at both the investigative and the therapeutic levels. A follow-up meeting is to take place in 1999, when further characterization of susceptibility gene loci should be available, together with data concerning the selective nature of disease-causing T cells and the antigens that trigger the disease. Identification of these critical factors should allow development of highly specific therapeutic agents, some of which are beginning to find their way into clinical development.

Ramipril-associated lichen planus pemphigoides

We report the first case of lichen planus pemphigoides (LPP) secondary to ingestion of ramipril, an angiotensin-converting enzyme inhibitor. Clinical, histological and immunofluorescent findings were all consistent with a diagnosis of LPP. Linear basement membrane zone (BMZ) staining with IgG and C3 was only seen at the roof of split-skin preparations and circulating autoantibody to the BMZ was present at a titre of 1/100. Controlled immunoblotting of epidermal extracts detected the bullous pemphigoid antigens of 230 and 180 kDa.

Contrasting effects of ultraviolet-A and ultraviolet-B exposure on induction of contact sensitivity in human skin

Ultraviolet-B (UVB), in addition to direct effects on DNA, induces immunological changes in the skin that predispose to the development of skin cancer. Whether ultraviolet-A (UVA) induces similar changes is unknown. This effect can be investigated in humans in vivo using epicutaneous antigens as a model of tumour antigens. Volunteers (n = 46) were randomly assigned to received no sensitization, sensitization with the allergen diphenylcyclopropenone (DPCP) on non-UV-exposed normal skin, or sensitization with DPCP on skin exposed to three minimal erythema doses (MED) of either UVA or UVB radiation 3 days before sensitization. Three weeks after sensitization all volunteers were challenged with five different concentrations of DPCP. The challenge reactions were scored clinically and the increase in skin thickness was measured using a micrometer. Sensitization on UVB-exposed skin reduced the immunization rate compared with sensitization on non-irradiated skin (P < 0.03) as previously described. In contrast, sensitization on skin exposed to three MED UVA radiation did not result in a decreased immunization rate compared with non-irradiated skin. These results indicate that in humans erythemagenic doses of UVA radiation do not reduce the immunization rates to epicutaneous allergens. Thus UVB and UVA irradiation have contrasting effects on cell-mediated immunity in humans. These findings may at least in part explain the less carcinogenic effect of UVA irradiation.

E-selectin binds to squamous cell carcinoma and keratinocyte cell lines

E-selectin is an endothelial adhesion molecule that binds carbohydrate epitopes on leukocytes and has been implicated in a potential pathway of tumor metastasis. Keratinocyte cell lines express similar carbohydrate epitopes, one of which, sialyl Lewis X (SL-X) is a ligand for E-selectin and is also expressed by squamous cell carcinomas (SCC) in situ. The functional role of keratinocyte selectin ligands was investigated using a soluble E-selectin chimaeric protein (pE-sel-Ig) containing pig lectin-like and epidermal growth factor-like domains fused to human IgG. After incubation of keratinocyte cell lines (A431 and SVK14) and normal keratinocytes with pE-sel Ig, binding was quantified by flow cytometry. Frozen sections of SCC were overlaid with pE-sel Ig and binding was visualized immunoenzymatically. Immunolabeling was undertaken using monoclonal antibodies (CSLEX-1 and HECA-452), which label E-selectin ligands including sialyl Lewis X. E-selectin bound strongly to A431 and SVK14 cells; the degree of binding paralleled staining intensity with CSLEX-1 antibody. HECA-452 antibody stained A431 cells strongly but SVK14 cells only weakly. Normal keratinocytes and normal epidermis did not express CSLEX-1 or HECA-452 antigens or bind E-selectin. Serial sections of SCC revealed close correlation between fusion protein binding and antibody staining. Antibody pretreatment of tumor sections with CSLEX-1 blocked fusion protein binding, whereas HECA-452 antibody only slightly reduced fusion protein binding. pE-sel Ig pretreated with YT11.1 antibody failed to bind to A431 or SVK14 cells or to SCC. These studies provide functional evidence that SL-X/E-selectin pathways may be important in SCC metastasis and that A431 and SVK14 cells provide a good model to investigate these mechanisms.

Expression of E-cadherin in human epidermal non-melanoma cutaneous tumours

E-cadherin is a calcium-sensitive, cell-to-cell, adhesion molecule that is expressed widely in normal human epithelial tissue. Abnormal expression has been described in colorectal, breast and nasopharyngeal squamous cell carcinomas, where loss of E-cadherin is associated with an increased metastatic potential. We have examined, by standard immunohistochemical techniques using the monoclonal antibody HECD-1 (E-cadherin monoclonal antibody), the distribution of E-cadherin in normal human skin and in non-melanoma neoplastic lesions. In the normal epidermis, E-cadherin was strongly expressed on the surface of keratinocytes and specialized epithelial structures. Staining was absent from the lower pole of basal keratinocytes in contact with the basement membrane. Weak cytoplasmic staining was also noted in basal keratinocytes. No reactivity was demonstrated in dermal structures. The assessment of cutaneous tumours demonstrated an altered pattern of staining in most cases. Cell surface expression was reduced in 28 of 30 cases of basal cell carcinomas (BCC). Twenty showed an additional feature of positive staining on the dermal aspect of peripheral cells of tumour lobules. In squamous cell carcinomas (SCC) (n = 16), surface expression was attenuated in eight and absent in a further four. Strong surface expression, similar to normal skin was seen in all examples of Bowen's disease (n = 6), viral wart (n = 3), seborrhoeic keratosis (n = 3) and actinic keratosis (n = 4). This study demonstrates that, in BCC and SCC, but not in premalignant lesions, cell-surface expression of E-cadherin is reduced, consistent with the observation that the loss of E-cadherin is associated with tumour invasion.

Generalized endemic Kaposi's sarcoma

Kaposi's sarcoma (KS) is a multicentric neoplasm thought to arise from both vascular and lymphatic endothelium. It is subdivided into four main categories on the basis of clinical features, course and prognosis. We report a 54-year-old Afro-Caribbean male, living in the UK for the past 26 years, with classic features of generalized endemic KS. Because he has never lived on the African continent, the role of genetic rather than environmental factors is favoured in the aetiology of KS in this individual. This disorder is rarely seen in Afro-Caribbeans living in the UK, who have never actually lived in Africa.

Tumour necrosis factor alpha is pro-inflammatory in normal human skin and modulates cutaneous adhesion molecule expression

Tumour necrosis factor alpha (TNF-alpha) is a potent immunoregulatory cytokine produced by many cutaneous cells, including keratinocytes, mast cells and Langerhans cells. To explore its potential role in inflammatory skin disease, we have studied immunohistochemically the effects of intradermal recombinant human TNF-alpha (rHuTNF-alpha) on cutaneous inflammatory cells, adhesion molecules and Langerhans cells in normal human skin. Volunteers receive rHuTNF-alpha 100 U (group A), 5000 U (group B), or 100 U daily for 5 days (group C), and biopsies were taken at 6 h (groups A and B), or 6 h after the final injection (group C). An inflammatory cell infiltrate developed in all cases: following single injections of either 100 or 5000 U rHuTNF-alpha this was predominantly neutrophilic, whereas following multiple injections of 100 U few neutrophils were seen, although many lymphocytes (CD3+, CD4+) were present. In all groups there was an increase in cells of monocyte/macrophage lineage (CD36+). TNF-alpha induced a dose- and time-dependent decrease in CD1a+ epidermal Langerhans cell numbers and an increase in dermal CD1a+ cells, suggesting migration of Langerhans cells away from the epidermis. TNF-alpha induced endothelial E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in all groups, and adhesion molecule expression by interstitial dermal dendritic cells (ICAM-1 and VCAM-1) and keratinocytes (ICAM-1) was observed. These findings indicate that TNF-alpha is a potent modulator of cutaneous immune function in vivo, and this central role in the cutaneous immune response suggests that TNF-alpha may be an attractive target for therapeutic inhibition.

Diffuse plane xanthomatosis and acquired palmoplantar keratoderma in association with myeloma

We report a patient with diffuse plane xanthomatosis, acquired palmoplantar keratoderma, and myeloma. Although diffuse plane xanthomatosis is a recognized manifestation of paraproteinaemia, keratoderma is not. However, successful treatment of the myeloma in our patient coincided with a dramatic improvement in the keratoderma, suggesting a genuine association between the two disorders.

Vascular proliferation and angiogenic factors in psoriasis

Psoriasis is a common, chronic skin disorder characterized by hyperproliferation of the epidermis, inflammatory cell accumulation and increased tortuosity and dilatation of dermal papillary blood vessels. Research into the pathogenesis of psoriasis has concentrated mainly on the interplay between inflammatory cells and epidermal proliferation. Central to the proposed pathogenetic pathway are cytokines produced by activated keratinocytes, which are thought to induce both keratinocyte proliferation and lymphocyte migration. Cytokines also mediate upregulation of adhesion molecules on vascular endothelium which in turn permits lymphocyte recruitment. The close spatial relationship between altered microvasculature and epidermis is clearly important in psoriasis. Consequently, understanding the mechanisms underlying vascular changes is fundamental to an elucidation of pathogenetic mechanisms in psoriasis.

Detection of circulating adhesion molecules in erythrodermic skin disease

BACKGROUND

Diagnosis of the underlying dermatosis in erythroderma is often difficult. The cause of increased mortality in erythroderma, particularly in relation to infection, is incompletely understood.

OBJECTIVE

We investigated the potential diagnostic use of circulating intercellular adhesion molecule-1 (cICAM-1), vascular cell adhesion molecule-1 (cVCAM-1), and E-selectin (cE-selectin) levels in erythroderma.

METHODS

cICAM-1, cVCAM-1, and cE-selectin were measured by enzyme-linked immunosorbent assay in 14 patients with erythroderma of known cause and in 17 control subjects. Levels were correlated with other markers of the inflammatory response.

RESULTS

In erythroderma median cICAM-1, cVCAM-1, and cE-selectin levels were significantly elevated, but no difference was found between values in patients with eczema and values in those with psoriasis. Circulating adhesion molecule levels did not correlate with erythrocyte sedimentation rate or total white blood cell count.

CONCLUSION

cICAM-1, cVCAM-1, and cE-selectin were detectable in patients with erythroderma but were not differential diagnostic use in this study. Because in vitro these molecules may interfere with normal cell adhesion mechanisms, we speculate that they may contribute to the immunosuppressive state in these patients.

An association between psoriasis and hereditary multiple exostoses. A clue for the mapping of a psoriasis susceptibility gene?

Chronic plaque psoriasis affects approximately 1.6% of the U.K. population. Population, family and twin studies all strongly suggest an important genetic component in the pathogenesis of the disease, although genetic linkage studies have, so far, failed to identify susceptibility genes. We describe a family in which psoriasis cosegregates through three generations with a known autosomal dominant disorder, hereditary multiple exostoses (HME). A major locus for HME has recently been mapped to chromosome 8q. Observations in this family may provide a mapping clue for a psoriasis susceptibility gene.

The immunopathology of psoriasis

Psoriasis is a common chronic skin disorder affecting 2% of the general population. Present evidence strongly suggests that it is an immunologically mediated disease; the evidence includes the results of disease association studies linking psoriasis to certain MHC antigens and immunohistochemical studies revealing early influx into lesions of activated T lymphocytes. Accumulation of these cells in skin is mediated by upregulated expression of leukocyte adhesion molecules on vascular endothelium and epidermal keratinocytes and by production of proinflammatory and chemotactic cytokines. Activation of cell-mediated immune mechanisms in lesional skin is highlighted by the increased antigen-presenting capacity of Langerhans cells isolated from psoriatic skin compared to normal skin. The nature of the antigens precipitating psoriasis, however, remains unknown although a role for streptococcal superantigens has been postulated. These studies have led to the belief that immunotherapy may hold great promise for the treatment of psoriasis. Indeed both cyclosporin A and FK506 are effective therapies and evidence suggests that anti-CD4 antibodies may be of great value.

Langerhans' cell expression of the selectin ligand, sialyl Lewis x

Cellular adhesion molecules play a central role in leucocyte migration through peripheral blood and tissues. A crucial stage in these events in selectin-mediated adhesion involving E-selectin expressed on activated endothelium interacting with a range of carbohydrate ligands expressed by specific subpopulations of leucocytes. As such mechanisms may be relevant to bone marrow-derived dendritic epidermal Langerhans' cell (LC) migration, expression of these carbohydrate ligands was assessed immunocytochemically in whole skin biopsies and in epidermal cell suspensions obtained from adult humans. Double-labelling experiments revealed that sialyl Lewis x, recognized by the monoclonal antibody CSLEX1, was expressed on epidermal LC (n = 9). Furthermore, expression was enhanced at 24 hr following epicutaneous application of antigen and in the inflammatory disorder psoriasis (n = 10). E-selectin was concomitantly strongly expressed on dermal endothelium in psoriasis and allergic contact dermatitis. Intradermal injection of the T-cell-derived cytokine interferon-gamma (IFN-gamma) led to increased LC expression of sialyl Lewis x. In epidermal cell suspensions, in contrast to keratinocytes, CD1a+ cells expressed sialyl Lewis x, intensity of which was enhanced after 4 days in culture. CSLEX1 staining could be abolished and CD15 (non-sialated Lewis x) expression induced by saponification and treatment with neuraminidase. Expression of other selectin ligands was also examined. While the cutaneous lymphocyte antigen defined by the monoclonal antibody HECA-452 reacted with a small minority of LC, sialyl Lewis a and sulphatide were not expressed under any experimental conditions. These studies indicate that E-selectin-sialyl Lewis x interactions are potentially important in LC migration, both into and out of skin.

Adhesion molecules in allergic inflammation

Allergic inflammation is characterized by recruitment of specific leukocyte subpopulations from blood into tissue and requires a series of cell adhesion-molecule-mediated interactions between postcapillary vascular endothelium and the leukocyte cell surface. Three major groups are involved: selectins, integrins, and the immunoglobulin gene superfamily. P- and E-selectin mediate initial leukocyte adhesion, whereas beta 2-integrin/ICAM-1 and VLA-4/VCAM-1 pathways mediate leukocyte arrest and transendothelial migration. Because VLA-4 expression is restricted to eosinophils and lymphocytes, VCAM-1 has been implicated in selective eosinophil recruitment characterizing allergic inflammation. However, additional factors such as profile of cytokine release are likely to operate since tissue eosinophilia has been observed in the absence of VCAM-1 expression. Recent use of monoclonal antibodies against functional epitopes on various cell adhesion molecules in animal models of extrinsic allergic asthma offers new possibilities in management of allergic disease.

Expression of selectin ligands by cutaneous squamous cell carcinoma

Recent evidence suggests that interactions between endothelial selectins and tumor surface selectin ligands may be of importance in cancer metastasis. To investigate the role of such mechanisms in cutaneous tumors, whole skin biopsies were examined immunohistochemically for a variety of selectin ligands including sialyl-Lewis-X, sialyl-Lewis-A (S-Le(a)), sulfatides, and CD15. In 12 of 12 squamous cell carcinomas (SCCs), there was expression of sialyl-Lewis-X and CD15, but no tumor expressed S-Le(a). Occasional keratinocytes in eight of 12 SCCs expressed sulfatides. All selectin ligands were absent on keratinocytes in basal cell carcinomas (BCCs, n = 8) and normal skin (n = 8), with the exception of one BCC that expressed S-Le(a). E-selectin was not present in normal skin, but was strongly expressed by dermal endothelium in both SCC and BCC. Keratinocyte cell lines A431, HaCaT, and SVK14 were investigated by flow cytometry, which demonstrated sialyl-Lewis-X and S-Le(a) expression by all three, whereas normal human keratinocytes did not express these molecules. These findings suggest a potential role for selectin-mediated events in early and late metastasis, and differential expression of these ligands by BCC and SCC may explain the relatively low metastatic potential of the former.

Neuropeptides induce rapid expression of endothelial cell adhesion molecules and elicit granulocytic infiltration in human skin

Inflammatory cell infiltrates and cell adhesion molecule expression have been examined in normal human skin after intradermal injection of sensory neuropeptides substance P (n = 6), vasoactive intestinal polypeptide (n = 6), and calcitonin gene-related peptide (n = 6) together with PBS as control (n = 4). Each neuropeptide induced rapid, time-dependent neutrophil influx into dermis, which was initially observed at 15 min and persisted for 8 h after injection. Increases in numbers of neutrophils with time after substance P, vasoactive intestinal polypeptide and calcitonin gene-related peptide were highly significant when compared with controls p &lt; 0.005, p &lt; 0.005, p &lt; 0.005, respectively (analysis of variance). Substance P additionally induced marked eosinophilic accumulation at 4 and 8 h in four of six subjects. These changes paralleled rapid translocation of P-selectin from cytoplasmic Weibel-Palade granules to luminal membranes by 15 min, and significant up-regulation of E-selectin expression at 4 and 8 h. Increases in percentage of E-selectin positive vessels with respect to time after each neuropeptide were highly significant when compared with controls, p &lt; 0.005, p &lt; 0.005, p &lt; 0.005 (ANOVA), respectively, and were significantly correlated with neutrophil infiltrates, r = 0.55, p &lt; 0.001. VCAM-1 was not expressed, and constitutive ICAM-1 expression on dermal endothelium was unchanged at all time points examined (0-8 h). Induction of endothelial adhesion molecule expression by neuropeptides provides a mechanism for neutrophil accumulation in neurogenic inflammation. Substance P-induced eosinophil accumulation in the absence of VCAM-1 expression suggests that mechanisms distinct from VCAM-1/very late antigen-4 binding mediate selective tissue eosinophilia.

Neuropeptides induce rapid expression of endothelial cell adhesion molecules and elicit granulocytic infiltration in human skin

Inflammatory cell infiltrates and cell adhesion molecule expression have been examined in normal human skin after intradermal injection of sensory neuropeptides substance P (n = 6), vasoactive intestinal polypeptide (n = 6), and calcitonin gene-related peptide (n = 6) together with PBS as control (n = 4). Each neuropeptide induced rapid, time-dependent neutrophil influx into dermis, which was initially observed at 15 min and persisted for 8 h after injection. Increases in numbers of neutrophils with time after substance P, vasoactive intestinal polypeptide and calcitonin gene-related peptide were highly significant when compared with controls p < 0.005, p < 0.005, p < 0.005, respectively (analysis of variance). Substance P additionally induced marked eosinophilic accumulation at 4 and 8 h in four of six subjects. These changes paralleled rapid translocation of P-selectin from cytoplasmic Weibel-Palade granules to luminal membranes by 15 min, and significant up-regulation of E-selectin expression at 4 and 8 h. Increases in percentage of E-selectin positive vessels with respect to time after each neuropeptide were highly significant when compared with controls, p < 0.005, p < 0.005, p < 0.005 (ANOVA), respectively, and were significantly correlated with neutrophil infiltrates, r = 0.55, p < 0.001. VCAM-1 was not expressed, and constitutive ICAM-1 expression on dermal endothelium was unchanged at all time points examined (0-8 h). Induction of endothelial adhesion molecule expression by neuropeptides provides a mechanism for neutrophil accumulation in neurogenic inflammation. Substance P-induced eosinophil accumulation in the absence of VCAM-1 expression suggests that mechanisms distinct from VCAM-1/very late antigen-4 binding mediate selective tissue eosinophilia.

Vascular cell adhesion molecule-1: expression in normal and diseased skin and regulation in vivo by interferon gamma

BACKGROUND

Vascular cell adhesion molecule-1 (VCAM-1) is an endothelial protein with adhesive properties for inflammatory cells including lymphocytes. Its role in skin disease and regulation in vivo are uncertain.

OBJECTIVE

Our purpose was to determine expression of VCAM-1 in normal and inflamed skin and the effect on this of the T-cell-derived cytokine interferon gamma (IFN-gamma).

METHODS

VCAM-1 was detected immunohistochemically in frozen-section biopsy specimens of inflammatory dermatoses and skin tumors. Volunteers received intradermal IFN-gamma and underwent biopsy 2 hours to 6 days later.

RESULTS

In normal skin, VCAM-1 was present on perivascular dendritic cells and some follicular keratinocytes. In allergic contact dermatitis, atopic dermatitis, and psoriasis, VCAM-1 was variably upregulated on dermal endothelium and dendritic cells, but was most pronounced in lichen planus. IFN-gamma led to marked upregulation of endothelial and dermal dendritic cell VCAM-1.

CONCLUSION

VCAM-1 may be involved in the pathogenesis of various skin diseases and in vivo, IFN-gamma is a potent modulator of its expression.

Increased epidermal cell proliferation in normal human skin in vivo following local administration of interferon-gamma

Recombinant human interferon-gamma was administered intradermally (10 micrograms in 0.1 ml) to healthy adult human volunteers from day 1 to day 3, and epidermal cell proliferation was measured on whole skin biopsies at day 6. Three independent parameters were assessed, namely, a) epidermal keratin-16 expression, b) keratinocyte proliferating cell nuclear antigen expression, and c) keratinocyte silver nucleolar organizer region counts. Significantly increased scores for each parameter were observed after interferon-gamma injection (P < 0.01 in each case) compared to site-matched controls. Keratin-16 expression was confined to suprabasal epidermis, whereas proliferating cell nuclear antigen and silver nucleolar organizer region counts were particularly elevated in the basal epidermis. Taken together with previous findings, these studies indicate both proinflammatory and growth regulatory roles for interferon-gamma in human skin. These data are likely to be of particular importance to pathophysiological mechanisms of psoriasis and related cutaneous inflammatory diseases.

A case of chromoblastomycosis responding to treatment with itraconazole

Chromoblastomycosis is a rare, chronic, cutaneous infection caused by a group of dematiacaeous fungi. We report a case which, in addition to characteristic clinical and histopathological features of chromoblastomycosis, displayed atypical, deep dermal/subcutaneous involvement, and showed a good response to itraconazole.

The tissue distribution of factor XIIIa positive cells

Factor XIIIa has previously been used to identify a subgroup of dermal dendritic cells which co-express class II MHC antigens, intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function associated antigen-1 (LFA-1), leading to the suggestion that they play a central role in skin immune responses. To examine whether these cells may also be important constituents of other organs we have performed an immunohistochemical survey of normal tissue to identify the distribution of this factor XIIIa positive subgroup of dendritic cells in humans. Routine tissue sections from a range of organs were assayed for factor XIIIa expression using a standard peroxidase-antiperoxidase (PAP) immunolabelling technique. Dendritic, factor XIIIa positive cells were observed in all tissues studied, but were most numerous in skin and mucosal tissues (gastrointestinal tract, bladder). They were also observed associated with epithelial structures in lung and kidney, but were only rarely observed in liver, thyroid, testis and spleen. The distinctive distribution of these cells is consistent with an important role for them in immune responses at those sites.

Excess melanocytic nevi in children with renal allografts

BACKGROUND

Renal allograft transplantation is associated with an increased incidence of malignant melanoma. The development of excess melanocytic nevi may be an indicator of this risk.

OBJECTIVE

This study determines the prevalence of melanocytic nevi in children who have received renal allografts.

METHODS

Total and regional melanocytic nevi counts were made in 38 children (27 boys, 11 girls) with a renal allograft and in 38 individually age- and sex-matched healthy controls; counts were related to age, sex, skin type, and duration of immunosuppression.

RESULTS

There was a significant increase in the total number of nevi in the renal transplant group compared with the control group (p < 0.05), with most marked increases occurring on the back and at acral sites. A strong positive correlation between nevi count and duration of immunosuppression independent of age was observed (p < 0.005).

CONCLUSION

Excess numbers of melanocytic nevi occur in children with renal allografts. These patients constitute a risk group for malignant melanoma and require continued assessment.

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.

Preferential adherence of T lymphocytes and neutrophils to psoriatic epidermis

T lymphocytes and neutrophils accumulate in psoriatic epidermis. To determine whether the epidermis plays an active role in this process through the production of cellular adhesion factors, leucocyte adherence to lesional psoriasis was compared with normal skin in a modified frozen-section adhesion assay. Lymphocyte and neutrophil suspensions were prepared by standard Ficoll-Hypaque techniques from peripheral blood of normal volunteers and overlaid on to glutaraldehyde-fixed 8-microns cryostat sections of skin. Adhesion of phorbol ester-activated T lymphocytes to the epidermis was significantly greater in psoriasis compared with normal skin (P < 0.01). Adhesion was absent (a) at 7 degrees C, (b) in the presence of EDTA and (c) in the absence of lymphocyte activation. Immunostaining demonstrated that all adherent lymphocytes were CD3+ve (i.e. T cells). Likewise, neutrophils adhered more prominently to psoriatic epidermis. Adhesion was most prominent at the tips of dermal papillae, corresponding to areas of maximal intercellular adhesion molecule-1 (ICAM-1) expression. Both neutrophils and lymphocytes adhered to dermal papillary vascular endothelium. These studies provide functional data that psoriatic epidermal cells are actively involved in leucocyte adherence. The distribution of adhesion suggests that both ICAM-1-dependent and independent mechanisms are involved.

Epidermal dendritic cells in psoriasis possess a phenotype associated with antigen presentation: in situ expression of beta 2-integrins

BACKGROUND

Epidermal dendritic cells (DCs) isolated from psoriasis possess greatly enhanced T lymphocyte-activating properties compared with DCs from normal skin, suggesting that DCs in psoriasis express surface antigens crucial for antigen presentation. These include beta 2-integrins and intercellular adhesion molecule (ICAM)-1.

OBJECTIVE

Our purpose was to determine DC phenotype in psoriatic compared with normal epidermis with respect to these molecules.

METHODS

Tissue sections were single labeled with a peroxidase antiperoxidase (PAP) immunohistochemical technique and double labeled where necessary with a combination of a PAP and an alkaline phosphatase-anti-alkaline phosphatase technique.

RESULTS

In psoriatic compared with normal skin, decreased numbers of DCs expressed CD1a (p less than 0.05), whereas increased numbers of DCs expressed class II major histocompatibility antigens (p less than 0.05). In normal skin positive staining for CD18 was not observed, whereas in psoriasis both CD1a+ and CD1a- DCs expressed beta 2-integrins, LFA-1 (CD11a/CD18), and gp 150/95 (CD11c/CD18). DCs in atopic dermatitis and lichen planus were also found to express beta 2-integrins. Neither MAC 1 (CD11b/CD18) nor ICAM-1 was observed on DCs.

CONCLUSION

These data are consistent with either migration of dendritic antigen-presenting cells into the epidermis or in situ cytokine modulation of Langerhans cell phenotype in inflamed skin. Furthermore, they indicate that epidermal DCs in psoriasis and other cutaneous inflammatory diseases express molecules that are known to be crucial for Langerhans cell-driven T-cell activation in vitro.

HUT 78 T cells bind to noncytokine-stimulated keratinocytes using a non-CD18-dependent adhesion pathway

The initial in vitro observation that cultured keratinocytes, when treated with cytokines such as gamma interferon, increased the binding of T lymphocytes, opened up a whole new avenue of research to understand epidermal trafficking patterns in inflammatory skin diseases. A growing body of data strongly supports the in vivo role of lymphocyte-function-associated antigen-1 (CD18) expression by T cells in the binding to intercellular adhesion molecule-1 (CD54) expressing keratinocytes. To further explore the molecular basis for other possible adhesive interactions involving T cells and skin-derived cellular constituents, the authors used 2 cell lines (HUT 78 cells and Jurkat cells) and added them to multipassaged human keratinocytes, fibroblasts, and melanocytes. The skin-derived cells were treated with cytokines alone, or in combination, with a phorbol ester. HUT cells were capable of binding to keratinocytes in the absence of pretreatment with cytokines at 25 degrees C, which was not inhibited by anti-CD18 antibodies, or sensitive to reducing the temperature of the adhesion assay to 7 degrees C. Fibroblasts and melanocytes also constitutively bound HUT cells, but the binding to fibroblasts was highly temperature-sensitive. When keratinocytes were pretreated for 48 hours with gamma interferon plus phorbol ester, a "superadhesive" state was induced, resulting in a synergistically increased binding ability of both HUT cells and Jurkat cells. This effect was related to quantitative increases in keratinocyte intercellular adhesion molecule-1 expression. Several other clear-cut qualitative and quantitative differences were detectable in the ability of HUT cells and JS cells to bind to nontreated and cytokine/phorbol ester-treated keratinocytes, fibroblasts, and melanocytes. These results emphasize the complexity of molecular associations underlying T-cell trafficking patterns, potentially operative in the dermal and epidermal compartments of the skin.

Effect of In Vivo Interleukin-1 on Adhesion Molecule Expression in Normal Human Skin

We have examined the expression of three endothelial adhesion molecules (intercellular adhesion molecule-1 [ICAM-1], endothelial leukocyte adhesion molecule-1 [ELAM-1], and vascular cell adhesion molecule-1 [VCAM-1]) in normal human skin following intradermal injection of stratum corneum-derived interleukin-1 alpha (SCIL-1 alpha). In control skin, constitutive expression of ICAM-1 was found on endothelial cells and at low levels on dermal dendritic cells but not on keratinocytes. ELAM-1 and VCAM-1 were present in low levels on endothelium and perivascular dendritic cells, respectively. SCIL-1 alpha injection produced marked endothelial ELAM-1 upregulation. Double staining with neutrophil elastase demonstrated that many ELAM-1-positive vessels contained marginating neutrophils and that interstitial neutrophils were clustered around ELAM-1-positive vessels. An increase in dermal dendritic cell ICAM-1 expression occurred and in two of three biopsies there was keratinocyte expression of ICAM-1 in the SCIL-1 alpha-injected tissue. Also, there was upregulation of VCAM-1 on vascular endothelium and an increase in the dermal dendritic cell expression of this molecule. These results give in vivo confirmation that SCIL-1 alpha modulated endothelial and dermal dendritic cell adhesion molecule expression, and show that endothelial VCAM-1 is regulated in vivo by SCIL-1 alpha, thus providing a regulatable ICAM-1-independent means of mononuclear cell recruitment.

Role of keratinocytes in allergic contact dermatitis

Although once thought to play a purely structural role, there is increasing evidence that keratinocytes are actively involved in epidermal immune responses, including allergic contact dermatitis (ACD). In vitro studies demonstrate that both urushiol and nickel sulphate induce cytokine production in cultured keratinocytes including molecules responsible for endothelial cell activation and lymphocyte chemotaxis and adhesion. In vivo, these same molecules are expressed in experimentally induced patch test reactions to a variety of allergens. Furthermore, such expression precedes the onset of the inflammatory phase of ACD. Taken together, these studies suggest a role complementary to that of Langerhans cells for keratinocytes in the initiation and propagation of ACD.

Antigenic profile of human acrosyringium

The demonstration of HLA-DR on human acrosyringium has led to the suggestion that eccrine epithelium, through its interaction with certain molecules, might play an active role in epidermal immune responses. An immunohistochemical study was undertaken to identify the antigenic profile of acrosyringium in normal skin and following the intradermal administration of a T-lymphocyte-derived cytokine, interferon gamma (IFN-gamma). Acrosyringium in normal skin, in contrast to interappendageal epidermis, was found to lack CD1a+ Langerhans cells. However, antigens CD36 (OKM5) and L1 (MAC387) were uniquely expressed by keratinocytes immediately adjacent to the distal portion of acrosyringium. Constitutive expression of each class II MHC antigen, namely HLA-DR, DP and DQ was observed on luminal acrosyringial cells. EMB11 antigen (CD68), a mononuclear cell determinant, was similarly expressed on acrosyringial epithelium in normal skin. Following intradermal administration of IFN-gamma, intercellular adhesion molecule-1 (ICAM-1) (CD54) was induced on acrosyringial epithelium and the expression of HLA-DR was intensified. A range of other markers including CD3, CD4, CD8, CD11a, CD11b and CD15 were not expressed by acrosyringium either in normal skin or after administration of IFN-gamma. Expression of antigens associated with cell-mediated immune mechanisms on acrosyringium is consistent with the hypothesis that it may have an immunological role in epidermal immune responses.