CD1 gene expression in human skin

In human epidermis, expression of CD1a is confined to Langerhans cells (LC), whereas CD1c expression has been observed in dendritic cells of the dermis, as well as the epidermis. In transfected fibroblasts, expression of CD1c at the cell surface appears to exclude expression of either CD1b or CD1a, despite continued transcription of the latter genes. In order to determine whether this mechanism might be operative in human skin, we have compared the expression of CD1a and CD1c on the surface of dermal and epidermal dendritic cells to their expression at the level of mRNA using a combination of dual-label immunofluorescence microscopy, northern blot hybridization, and reverse transcriptase-polymerase chain reaction (RT-PCR). By both immunofluorescence and Northern blotting, CD1c expression was observed in both dermal and epidermal cells, whereas expression of CD1a was confined largely to the epidermis. Moreover, as shown by immunomagnetic bead selection and RT-PCR, CD1a and CD1c were both expressed on epidermal LC, but were absent from other epidermal cell types. These results argue against cell surface exclusion as a mechanism for selective expression of CD1c in human dermis.

Differential expression of protein kinase C isoenzymes in normal and psoriatic adult human skin: reduced expression of protein kinase C-beta II in psoriasis

Psoriatic lesions contain elevated levels of 1,2-diacylglycerol, the physiologic activator of protein kinase C (PKC), suggesting that PKC activation may be aberrant in psoriasis. We therefore have investigated the expression and properties of PKC isozymes in normal and psoriatic skin and in human skin cells. Chromatographic and immunoblot analyses revealed the presence of the calcium-dependent PKC isozymes PKC-alpha and -beta, but not -gamma, in normal human epidermis. PKC-beta was more prominent, constituting two thirds of the total calcium-dependent PKC activity. In psoriatic lesions, expression of both PKC-alpha and -beta was decreased, with preferential reduction (80%) of PKC-beta. Northern analysis and semi-quantitative polymerase chain reaction (PCR) indicated no change in the mRNA levels of PKC-alpha and -beta between normal and psoriatic epidermis. In normal epidermis, PKC-alpha was expressed mainly in the lower epidermis, whereas PKC-beta was localized to the upper cell layers, with very intense staining of CD1a+ Langerhans cells. In psoriasis, PKC-alpha staining was present in the lower epidermis, whereas PKC-beta staining was essentially absent, with the exception of some positive inflammatory cells. In addition to PKC-alpha and beta, immunoblot and Northern/PCR analysis revealed expression of four calcium-independent PKC isozymes, delta, epsilon, zeta, and eta, in both normal and psoriatic skin. There were no significant differences in mRNA levels among any of these PKC isozymes, between normal and psoriatic skin. Soluble PKC-zeta protein was modestly increased (twofold) in psoriatic, compared to normal, skin, whereas the levels of PKC-delta, epsilon, and eta were unchanged. Analysis of PKC isozyme expression in the three major cell types of human epidermis revealed that Langerhans cells and keratinocytes were the major sources of PKC-beta and PKC-zeta, respectively. These data demonstrate the diversity of PKC isozyme expression in human skin, and suggest that alterations of PKC-beta and -zeta may participate in the aberrant regulation of growth and differentiation observed in psoriasis.

An in vivo experimental model for effects of topical retinoic acid in human skin

An occlusive patch-test assay has been developed for assessment of topical retinoid action in human epidermis. Previous work with this assay has demonstrated marked epidermal hyperplasia in skin treated with topical all-trans-retinoic acid for 4 days and similar effects with the local irritant, sodium lauryl sulphate. To investigate the capabilities of this assay further, a time-course and dose-response were performed with all-trans-retinoic acid, and a comparison made with sodium lauryl sulphate. At no time, between 1 and 4 days, could the clinical or histological effects of 0.1% and 0.025% cream formulations of all-trans-retinoic acid be distinguished from each other. Epidermal hyperplasia was used to generate a 4-day dose-response for all-trans-retinoic acid at concentrations from 0.001 to 0.025% dissolved in a 70% ethanol/30% propylene glycol vehicle. All-trans-retinoic acid could be successfully differentiated from sodium lauryl sulphate at 2 days by virtue of its greater ability to increase epidermal thickness, spongiosis and glycosaminoglycan deposition. It appears that although all-trans-retinoic acid and sodium lauryl sulphate produce similar epidermal histological changes at 4 days, significant differences at earlier time-points suggest differing mechanisms of action. In addition, this in vivo human assay is able to provide potency ranking for doses of all-trans-retinoic acid, and may predict clinical efficacy of retinoids in improvement of acne and/or photodamage.

Topical tretinoin (retinoic acid) improves melasma. A vehicle-controlled, clinical trial

Melasma is a common disorder of cutaneous hyperpigmentation predominantly affecting the faces of women. Little is known about the aetiology of melasma, and treatment is frequently disappointing. Topical tretinoin is of benefit in treating other forms of hyperpigmentation, for example liver spots, and we therefore investigated its effectiveness in melasma. Thirty-eight women completed a randomized, vehicle-controlled study, in which they applied 0.1% tretinoin (n = 19) or vehicle cream (n = 19) once daily to the face for 40 weeks. At the end of treatment 13 (68%) of 19 tretinoin-treated patients were clinically rated as improved or much improved, compared with 1 (5%) of 19 in the vehicle group (P = 0.0006). Significant improvement first occurred after 24 weeks of tretinoin treatment. Colorimetry (an objective measure of skin colour) demonstrated a 0.9 unit lightening of tretinoin-treated melasma and a 0.3 unit darkening with vehicle (P = 0.01); these results correlated with clinical lightening (r = 0.55, P = 0.0005). Histologically, epidermal pigment was reduced 36% following tretinoin treatment, compared with a 50% increase with vehicle (P = 0.002). Reduction in epidermal pigment also correlated with clinical lightening (r = -0.41, P = 0.01). Moderate cutaneous side-effects of erythema and desquamation occurred in 88% of tretinoin-treated and 29% of vehicle-treated patients. Topical 0.1% tretinoin produces significant clinical improvement of melasma, mainly due to reduction in epidermal pigment, but improvement is slow.

Comparison of CD271 (adapalene) and all-trans retinoic acid in human skin: dissociation of epidermal effects and CRABP-II mRNA expression

A new synthetic retinoid analogue, adapalene (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid, CD271), which is relatively selective for retinoic acid receptor beta, was noted to be an effective comedolytic agent in the rhino mouse model and to have clinical efficacy against acne. In pursuit of this observation, we studied the effects of CD271 on the development of erythema, spongiosis, and epidermal hyperplasia as well as other well-characterized markers of in vivo retinoid action after 4 d of occluded topical treatment. The objective of the study was to elucidate further those parameters associated with potential clinical efficacy. Twenty-five subjects were treated with 0.1% all-trans retinoic acid cream, all-trans retinoic acid vehicle, 0.1% CD271 gel, or CD271 vehicle under occlusion for 4 d. Only all-trans retinoic acid induced erythema (p < 0.01 versus all other treatments). Similarly, histologic analysis revealed that epidermal hyperplasia and spongiosis were induced only by all-trans retinoic acid (p < 0.01 versus all other treatments). By immunohistochemical analysis: all-trans retinoic acid increased expression of epidermal transglutaminase, involucrin, and calgranulin (p < 0.05 versus all other treatments). In contrast to these data, both CD271 and all-trans retinoic acid caused marked and significant (p < 0.05) elevation of cellular retinoic acid-binding protein-II (CRABP-II) messenger ribonucleic acid steady-state levels as judged by quantitative RNA blot analysis. Although CD271 treatment did not lead to erythema or affect epidermal morphology, its ability to induce a marker of retinoid action (i.e., CRABP-II) was 70% the potency of all-trans retinoic acid. This study suggests that CRABP-II gene expression may be a more sensitive indicator of retinoid biologic activity in skin than are erythema or changes in epidermal morphology and differentiation.

Retinoic acid metabolites exhibit biological activity in human keratinocytes, mouse melanoma cells and hairless mouse skin in vivo

Topical all-trans retinoic acid (RA) modulates growth and differentiation of skin and is used in the treatment of various dermatological disorders. RA is metabolized to 4-hydroxy RA, 4-oxo RA and 5,6-epoxy RA, which are believed to be markedly less active than RA. 3,4-didehydroretinoic acid (ddRA) is a metabolite of 3,4-didehydroretinol which is present in skin. ddRA is biologically active and acts as a morphogen. We have determined the relative biological activity of ddRA, 4-hydroxy RA, 4-oxo RA and 5,6-epoxy RA as assessed by three retinoid responsive systems relevant to skin. RA, ddRA, 4-hydroxy RA, 4-oxo RA and 5,6-epoxy RA (10-100 nM) reduced epidermal transglutaminase activity in human keratinocytes to similar extents, and inhibited alpha-melanocyte-stimulating hormone-isobutylmethylxanthine-inducible tyrosinase activity in Cloudman S-91 mouse melanoma cells by 67, 39, 48, 51 and 19%, respectively, at 100 nM. Daily topical application of the retinoids to hairless mouse skin for 4 days resulted in dose-dependent changes in epidermal thickness and global histological score. The relative potencies of RA, ddRA, 4-hydroxy RA, 4-oxo RA and 5,6-epoxy RA, as calculated by parallel line assay, were 1.0, 0.60, 0.34, 0.29 and 0.18, respectively, for epidermal hyperplasia and 1.0, 0.78, 0.23, 0.14 and 0.08, respectively, for global histological score. Interestingly, the compounds exhibited a similar rank order of potency with respect to induction of cellular retinoic acid binding protein-II mRNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Inflammatory breast carcinoma (carcinoma erysipeloides): an easily overlooked diagnosis

A 70-year-old woman developed erythema and induration of the right chest wall, and swelling of her right arm. The provisional diagnosis was deep venous thrombosis and/or cellulitis of the right arm. Skin biopsy showed a poorly differentiated adenocarcinoma within lymphatic vessels, and immunohistochemical staining revealed this to be of breast origin. Inflammatory carcinoma or carcinoma erysipeloides represents < 1% of all cases of breast carcinoma. Our case illustrates the importance of considering this entity in the differential diagnosis of unilateral chest wall erythema and induration.

Restoration of collagen formation in photodamaged human skin by tretinoin (retinoic acid)

BACKGROUND

Topical tretinoin (retinoic acid) modifies fine wrinkles and certain other features of human skin damaged by exposure to the sun (photodamage), but histologic changes do not account for this improvement. In mice with photodamage induced by ultraviolet light, effacement of fine wrinkles by tretinoin is correlated with dermal collagen synthesis but not with histologic changes. We investigated whether collagen synthesis was reduced in photodamaged human skin and, if so, whether it could be restored by treatment with topical tretinoin.

METHODS

Biopsies of photodamaged skin from the extensor aspect of the forearm and skin from the buttocks, which had been protected from the sun, were performed on 26 healthy subjects. In addition, 29 patients with photodamaged skin were treated for 10 to 12 months with a daily application of 0.1 percent tretinoin cream (15 patients) or vehicle cream (14 patients). Skin-biopsy specimens obtained at base line and after treatment were assessed immunohistologically for evidence of dermal collagen I formation (collagen synthesis).

RESULTS

Collagen I formation was 56 percent less in the papillary dermis of photodamaged skin than in skin protected from the sun (P < 0.001) and was correlated with the clinical severity of photodamage (r = -0.58, P = 0.002). Treatment of photodamaged skin with tretinoin produced an 80 percent increase in collagen I formation, as compared with a 14 percent decrease in collagen formation with the use of vehicle alone (P = 0.006).

CONCLUSIONS

The formation of collagen I is significantly decreased in photodamaged human skin, and this process is partly restored by treatment with tretinoin.

Paraneoplastic pemphigus presenting as a lichen planus pemphigoides-like eruption

BACKGROUND

Paraneoplastic pemphigus refers to a specific disease entity in which neoplasia is associated with severe mucosal ulceration and polymorphous cutaneous eruptions, sometimes resembling erythema multiforme. Direct immunofluorescence and indirect immunofluorescence on standard substrates are similar to pemphigus vulgaris; however, paraneoplastic pemphigus serum uniquely binds to all epithelia and has distinctive immunoprecipitation characteristics.

OBSERVATIONS

A 63-year-old woman with chronic lymphocytic leukemia developed a severe, mucocutaneous, vesiculobullous eruption with the clinical and histopathologic characteristics of lichen planus pemphigoides evolving into a Stevens-Johnson-like presentation and the immunofluorescence findings of pemphigus vulgaris. Evaluation of her serum confirmed the presence of autoantibodies specific for paraneoplastic pemphigus by indirect immunofluorescence and immunoprecipitation criteria.

CONCLUSION

The spectrum of paraneoplastic pemphigus must now be expanded to include cases that present clinically and histologically as a lichen planus pemphigoides-like eruption.

Differential regulation of tyrosinase activity in skin of white and black individuals in vivo by topical retinoic acid

Tyrosinase activity is a key determinant of melanin production in skin. Because retinoic acid regulates tyrosinase activity in melanoma cells, we analyzed modulation of pigmentation in vivo by retinoic acid. Black and white subjects were either not treated, or treated topically for 4 d under occlusion with vehicle, retinoic acid (0.1%), or the irritant sodium lauryl sulfate (2%). In untreated skin, tyrosinase activity and melanin content were significantly greater (2.3 times, and 3.2 times, respectively) in blacks versus whites. Four days of treatment with topical retinoic acid did not alter tyrosinase activity or melanin content in black skin. In contrast, retinoic acid treatment significantly induced (2.7 times, n = 8) tyrosinase activity, compared to vehicle treatment, in white skin. Melanin content, however, remained unchanged at 4 d. In separate experiments, tyrosinase activity in white subjects (n = 25) was increased 16% (p = 0.01) in sodium lauryl sulfate-treated skin, and 77% (p = 0.0005) in retinoic acid-treated skin, compared to vehicle-treated skin. The effect of retinoic acid on tyrosinase activity could be differentiated from non-specific irritation, because tyrosinase activity in retinoic acid-treated skin was significantly greater (52%, p = 0.004) than sodium lauryl sulfate-treated skin. Similar results were obtained with the dihydroxyphenylalanine reaction done on vehicle, sodium lauryl sulfate-, and retinoic acid-treated white skin. Northern analysis (n = 6) and semi-quantitative polymerase chain reaction (n = 6) demonstrated that retinoic acid treatment did not alter tyrosinase mRNA levels in white skin. Western analysis revealed that induction of tyrosinase activity by retinoic acid also was not associated with increased tyrosinase protein content (n = 9), indicating that regulation of tyrosinase activity by retinoic acid occurs through a post-translational mechanism. These data demonstrate that low tyrosinase activity in white skin in vivo is retinoic acid inducible and high tyrosinase activity in black skin in vivo is neither further induced nor reduced by retinoic acid.

Topical tretinoin (retinoic acid) therapy for hyperpigmented lesions caused by inflammation of the skin in black patients

BACKGROUND AND METHODS

Irregular disfiguring skin hyperpigmentation due to inflammation may develop in black persons. We investigated the treatment of this hyperpigmentation with topical tretinoin (0.1 percent retinoic acid cream). Fifty-four subjects completed a 40-week randomized, double-blind, vehicle-controlled study. Twenty-four subjects applied tretinoin daily to the face, arms, or both areas, and 30 subjects applied vehicle cream. At base line and after 40 weeks of treatment, each subject's post-inflammatory hyperpigmented lesions and normal skin were assessed by clinical and colorimetric evaluations and by analysis of biopsy specimens.

RESULTS

The facial post-inflammatory hyperpigmented lesions of the tretinoin-treated subjects were significantly lighter after the 40 weeks of therapy than those of the vehicle-treated subjects (P < 0.001); overall improvement was first noted after four weeks of tretinoin treatment. At the end of treatment, colorimetry demonstrated a 40 percent lightening of the lesions toward normal skin color in the tretinoin-treated lesions, as compared with an 18 percent lightening in vehicle-treated lesions (P = 0.05). The epidermal melanin content in the lesions decreased by 23 percent with tretinoin and by 3 percent with vehicle (P = 0.24). Normal skin was minimally lightened by tretinoin as compared with vehicle, according to both clinical evaluation (0.1 vs. -0.1 unit change on an 8-point scale; P = 0.055) and colorimetry (P < 0.001). Retinoid dermatitis developed in 12 of the 24 tretinoin-treated subjects who completed the study (50 percent) and in 1 tretinoin-treated subject who withdrew from the study, but diminished as the study progressed.

CONCLUSIONS

Topical application of tretinoin significantly lightens post-inflammatory hyperpigmentation and, to a clinically minimal but statistically significant degree, lightens normal skin in black persons.

Stimulus-selective induction of CRABP-II mRNA: a marker for retinoic acid action in human skin

Acute topical treatment of human skin with retinoic acid (RA) results in a pleiotropic response, some aspects of which are mimicked by non-specific irritants. To identify reliable cutaneous markers of retinoid action, it is important to determine which aspects of this response are specifically due to the presence of RA. We have previously demonstrated a rapid and pronounced increase in steady-state cellular RA-binding protein II (CRABP-II)mRNA levels after topical RA treatment. Here we characterize the dose dependence and kinetics of this response, and compare the effects of a well-known irritant, sodium dodecylsulfate (SDS), to those of RA and its vehicle. The induction of CRABP-II mRNA in response to 0.1% RA cream was maximal by 16 h (elevenfold relative to untreated skin), and persisted at near-maximal levels (eight-fold) for up to 4 d. RA was potent in eliciting this response, as approximately half-maximal stimulation was observed after 16 h of treatment with 0.001% RA. Treatment for 4 d with 0.1% RA cream versus 2% SDS in RA vehicle resulted in nearly identical levels of cutaneous erythema, spongiosis, and epidermal thickening. However, the CRABP-II mRNA response to 2% SDS was no greater than that observed in response to vehicle alone (2.9 times relative to occluded skin control at 4 d). SDS also had no effect upon either CRABP-II or RAR-beta mRNA levels in quiescent human dermal fibroblasts in vitro, whereas RA elicited both responses at 1000-times lower concentrations than SDS. Taken together, these data identify the CRABP-II mRNA response as a reliable, rapid, and selective marker for retinoid activity in human skin.

Effects of all-trans retinoic acid and Ca++ on human skin in organ culture

In this study, we have established an organ culture model of human skin and examined the effects of both all-trans retinoic acid (RA) and extracellular Ca++ on the epidermal and dermal components of the organ-cultured skin. Our data show that while organ cultures maintained in serum-free, growth factor-free culture medium containing 0.15 mM Ca++ degenerated rapidly, those treated with concentrations of RA that have been shown previously to stimulate fibroblast and keratinocyte proliferation in monolayer culture (J Invest Dermatol 1989, 93:449; 1990, 94:717; Am J Pathol 1990, 136:1275) demonstrated a healthy appearance for up to 12 days. Degeneration of the control cultures was characterized by separation of the epidermis from the underlying dermis, progressive cell necrosis leading to a complete absence of viable cells from both the dermal and epidermal compartments, disintegration and fibrillation of the dermal connective tissue, and a cessation of protein synthesis. RA-treated organ cultures contained large numbers of healthy-appearing cells in both the epidermal and dermal compartments. One or several layers of viable basal cells in the epidermis could be seen at least through day 12. However, the upper layers of the epidermis frequently separated from the cells in the basal layer. The dermal connective tissue was histologically well-preserved. Furthermore, the level of protein synthesis was higher in the RA-treated cultures than in the control cultures. In addition to treating organ cultures with RA, other cultures were exposed to serum-free, growth factor-free culture medium containing 1.4 mM Ca++. The presence of the elevated Ca++ concentration also preserved cellular and connective tissue structures in the dermal and epidermal compartments. In comparison to RA there was better preservation of the overall epidermal structure. The upper layers of epidermal cells did not separate from the basal cells, and the various stages of epithelial differentiation could be seen. Histologically, the dermis was well-preserved in the presence of elevated extracellular Ca++. Specimens treated with a combination of Ca++ and RA demonstrated features consistent with the features induced by each treatment separately. This included an expanded basal layer of epithelial cells and a prominent keratotic layer with a fairly orderly pattern of differentiation. The tendency of the upper epidermis to separate from the basal cells was partially mitigated. Taken together, these data indicate that both RA and extracellular Ca++ act to prevent the degeneration of human skin in organ culture but probably do so through different mechanisms.

Topical retinoic acid for photoaging: clinical response and underlying mechanisms

Photoaging is primarily composed of wrinkling, mottled hyperpigmentation and a tactile roughness of the skin, all three of these parameters improve following use of topical retinoids. It appears that smoothening of the skin results from a combination of epidermal changes including thickening, stratum corneum compaction and glycosaminoglycan deposition. Lightening of actinic lentigines and mottled hyperpigmentation correlates with a reduction in epidermal melanin content maybe resulting from inhibition of tyrosinase activity. Effacement of wrinkling in mice correlates with new collagen synthesis, and there is evidence that this is also the case in humans. An irritant dermatitis is a feature of retinoid-treated skin but this diminishes in severity during treatment despite continued improvement in photoaging. Thus it is unlikely that irritation per se is responsible for clinical improvement.

Failure of reticular erythematous mucinosis to respond to cyclosporine

We describe a 48-year-old woman who had worsening psoriasis, photosensitive reticular erythematous mucinosis (REM), and acne rosacea. The psoriasis was unresponsive to etretinate, and the REM was unsuccessfully treated with hydroxychloroquine. Cyclosporine (6 mg/kg/day) successfully cleared the psoriasis in 8 weeks but did not improve the REM and acne rosacea. Possible causes for the lack of response of the REM to cyclosporine are discussed.

Human skin levels of retinoic acid and cytochrome P-450-derived 4-hydroxyretinoic acid after topical application of retinoic acid in vivo compared to concentrations required to stimulate retinoic acid receptor-mediated transcription in vitro

Metabolism of retinoic acid to a less active metabolite, 4-hydroxyretinoic acid, occurs via cytochrome P-450 isozyme(s). Effect of a pharmacological dose of retinoic acid on the level of retinoic acid in skin and on cytochrome P-450 activity was investigated. A cream containing 0.1% retinoic acid or cream alone was applied topically to adult human skin for four days under occlusion. Treated areas were removed by a keratome and a microsomal fraction was isolated from each biopsy. In vitro incubation of 3H-retinoic acid with microsomes from in vivo retinoic acid treated sites resulted in a 4.5-fold increase (P = 0.0001, n = 13) in its transformation to 4-hydroxyretinoic acid in comparison to in vitro incubations with microsomes from in vivo cream alone treated sites. This cytochrome P-450 mediated activity was oxygen- and NADPH-dependent and was inhibited 68% by 5 microM ketoconazole (P = 0.0035, n = 8) and 51% by carbon monoxide (P = 0.02, n = 6). Cotransfection of individual retinoic acid receptors (RARs) or retinoid X receptor-alpha (RXR-alpha) and a chloramphenicol acetyl transferase (CAT) reporter plasmid containing a retinoic acid responsive element into CV-1 cells was used to determine the ED50 values for stimulation of CAT activity by retinoic acid and its metabolites. Levels of all trans and 13-cis RA in RA-treated tissues were greater than the ED50 values determined for all three RARs with these compounds. Furthermore, the level of all trans RA was greater than the ED50 for RXR-alpha whereas the 4-OH RA level was greater than the ED50 for RAR-beta and RAR-gamma but less than for RAR-alpha and RXR-alpha. These data suggest that there are sufficient amounts of retinoic acid in treated skin to activate gene transcription over both RARs and RXR-alpha.

Short-term retinoic acid treatment increases in vivo, but decreases in vitro, epidermal transglutaminase-K enzyme activity and immunoreactivity

Epidermal transglutaminase-K is believed to catalyze the covalent linking of loricrin and involucrin to form cross-linked (CE) envelopes. In normal skin, transglutaminase-K is expressed as a band immediately below the stratum corneum, whereas in psoriasis and healing skin its expression is considerably expanded throughout the suprabasal layers. We have investigated whether the hyperproliferative state induced by short-term application of topical retinoic acid is similarly characterized by an increase in transglutaminase-K enzyme activity and immunoreactivity. Retinoic acid (0.1% cream) or vehicle were applied to human skin and occluded for 4 d. Skin biopsies were obtained for measurement of transglutaminase-K and transglutaminase-C activity and immunoreactivity. For comparison, cultured normal human keratinocytes were incubated for 4 d in the presence of 1 microM retinoic acid and the subsequent transglutaminase-K activity and immunoreactivity measured. Transglutaminase-K activity was increased 2.8 times in retinoic acid compared to vehicle-treated skin (p less than 0.005, n = 12) whereas there was no significant difference in transglutaminase-C activity. However, transglutaminase-K mRNA levels were not significantly different between retinoic acid- and vehicle-treated skin. In vehicle-treated skin, transglutaminase-K immunoreactivity was limited to a narrow, substratum corneal band, but was considerably expanded in a diffuse suprabasal pattern in retinoic acid-treated epidermis. In contrast, transglutaminase-K immunostaining was decreased and its enzymatic activity reduced sixfold in retinoic acid-treated keratinocytes (p less than 0.01, n = 4). These results demonstrate that retinoic acid treatment in vivo, in contrast to in vitro, leads to not only increased transglutaminase-K protein expression but also increased enzymatic activity in the absence of detectable increases in mRNA levels. These data, taken with the previously reported lack of in vivo modulation of the differentiation markers keratins 1 and 10 by retinoic acid, indicate that certain aspects of keratinocyte terminal differentiation that are altered in vitro by retinoic acid do not occur in vivo in human skin.

Mechanisms of action of retinoic acid in skin repair

The ability of topically applied retinoic acid to improve photoaged skin has stimulated research interest into its mechanism of action. Currently available assay systems are either in-vitro or mouse models, neither of which are truly representative of the in-vivo situation in man. Another drawback is that skin biopsies available from studies using retinoic acid to treat photoageing are of insufficient size to accomplish biochemical and molecular assays. In order to address these problems, a 4-day in-vivo retinoid assay has been developed which serves as a good predictive model for the chronic effects of retinoic acid on skin and helps to characterize the mechanism of action of retinoic acid.

The clinical identification and quantification of photodamage

The distinction between intrinsic and extrinsic ageing can be made on both histological and clinical grounds. Clinical criteria associated with the diagnosis of extrinsic ageing are coarse wrinkles, actinic lentigines, elastotic conditions, purpura, telangiectasia and cutaneous neoplasms. These parameters are always superimposed on changes associated with intrinsic ageing: namely, fine wrinkles and benign growths. There is heightened interest in extrinsic ageing as a result of studies demonstrating the efficacy of topical tretinoin in improving this condition. As a consequence, systems for grading extrinsic ageing have been developed, including a photographic standard scale which removes some of the subjectivity inherent to current methodology.

Expression of growth hormone receptor, insulin-like growth factor 1 (IGF-1) and IGF-1 receptor mRNA and proteins in human skin

A cDNA corresponding to the membrane receptor for growth hormone (GH) was amplified by polymerase chain reaction (PCR) directly from human skin. The cDNA was cloned and found to have complete sequence homology to the extracellular domain of human liver GH receptor (GH-R). Northern analysis, using the cloned GH-R as probe, revealed relatively higher levels of GH-R transcripts in cultured human dermal fibroblasts compared to cultured keratinocytes or keratome biopsies. Semi-quantitative PCR analysis indicated that the level of GH-R mRNA in cultured melanocytes was similar to that in fibroblasts. The receptor protein encoded by GH-R mRNA in fibroblasts was shown by affinity cross-linking to have an apparent M(r) of 115-120 kDa, similar to that of 3T3-F442A fibroblasts used as a control. mRNA transcripts for the major mediator of GH actions, insulin-like growth factor 1 (IGF-1), were detected by PCR in fibroblasts, melanocytes, and keratome biopsies, but not in keratinocytes. In contrast, IGF-1 receptor mRNA were abundant in cultured keratinocytes and skin biopsies, as determined by Northern analysis. IGF-1 but not GH (5-50 ng/ml) promoted clonal proliferation of cultured keratinocytes. In contrast, GH (10 ng/ml) after 5 d markedly increased fibroblast cell numbers (70%, p less than 0.009) over 0.2% serum control. These data indicate that human skin cells possess the molecular elements necessary to respond to GH and raise the possibility that GH may influence skin growth in vivo.

Cellular localization of mRNA for cellular retinoic acid-binding protein II and nuclear retinoic acid receptor-gamma 1 in retinoic acid-treated human skin

We have previously shown that cellular retinoic acid-binding protein II (CRABP-II), but not cellular retinoic acid-binding protein I (CRABP-I), mRNA expression is markedly induced in human skin by topical retinoic acid. In the present study, we have investigated the pattern of expression of CRABP-II transcripts in 4-d RA-treated human skin by non-radioactive in situ hybridization (n = 5) and Northern analysis (n = 4). RA induced accumulation of CRABP-II transcripts throughout the epidermis, dermal fibroblasts, and endothelial cells as determined by in situ hybridization. In skin treated with vehicle, a faint hybridization signal was observed only in basal layers of the epidermis consistent with low-level expression of CRABP-II mRNA. RA-mediated accumulation of CRABP-II transcripts in skin was also confirmed by Northern analysis. Neither RA nor vehicle induced significant changes in nuclear RA receptor-gamma 1 or keratin 5 gene expression in skin as determined by in situ or Northern hybridization. These results indicate that RA-induced CRABP-II mRNA accumulation is primarily localized to spinous and granular layers in epidermis, and in superficial dermis.

Intralesional cyclosporine for psoriasis. Relationship of dose, tissue levels, and efficacy

BACKGROUND AND DESIGN--To avoid systemic side effects, topical and intralesional administration of cyclosporine has been used; however, only intralesional administration has been successful. To understand more about the dosing requirements and resultant tissue levels of intralesional cyclosporine, we injected psoriasis plaques in a double-blind fashion with three different concentrations of cyclosporine (17 mg/mL in seven patients, 10 mg/mL in 13 patients, and 2.5 mg/mL in 11 patients) or matching vehicle three times weekly for 4 weeks. RESULTS--Statistically significant improvement was observed in plaques treated with 17 mg/mL (P = .003) compared with vehicle-treated plaques; the improvements in plaques treated with 10 mg/mL (P = .078) and 2.5 mg/mL (P = .054) achieved marginal statistical significance compared with vehicle treatment. Four weeks after discontinuation of therapy, the change from pretherapy in plaques that had received 17 mg/mL of cyclosporine was statistically significantly better (P less than .0001) than that with vehicle treatment. A similar finding but of marginal statistical significance (P = .059) occurred in the plaques that had received 10 mg/mL of cyclosporine. Throughout the study, untreated psoriasis plaques did not improve. Transient pain was the most common side effect noted with both cyclosporine and vehicle injections. Tissue levels of cyclosporine tended to be highest in plaques receiving the 17-mg/mL concentration; blood levels of cyclosporine were low throughout the study.

CONCLUSIONS

--Intralesional cyclosporine requires a sufficient dosage to improve psoriasis, apparently by a local mechanism of action. Improvement may persist for 4 weeks or longer.

Differential regulation of retinoic acid receptors and binding proteins in human skin

Many of the pleiotropic effects of retinoids are likely to be mediated by nuclear retinoic acid receptors (RAR) acting as ligand-dependent enhancer factors. However, in previous studies we have been unable to document altered RAR expression at the RNA level in response to retinoic acid (RA) treatment or in psoriatic lesions, conditions characterized by marked alterations in keratinocyte proliferation and differentiation, which are either caused by or responsive to RA. In an attempt to identify other potential regulators of RA responsiveness, we have used RNA blot hybridization to study the expression of the cellular retinoic acid binding proteins (CRABP) CRABP-I and CRABP-II, the RAR-gamma isoforms RAR-gamma 1 and RAR-gamma 2, and the low-affinity RAR homologue RXR in normal, RA-treated, and psoriatic human epidermis. CRABP-II is selectively and markedly induced by RA in adult human skin (J Biol Chem 266:17662-17666, 1991). However, in submerged, serum-free keratinocyte cultures, CRABP-II mRNA could not be induced by RA. Comparisons of intact human skin, submerged keratinocyte cultures, and human skin equivalent cultures indicated that induction of CRABP-II by RA requires epidermal stratification, dermal-epidermal interactions, or both. CRABP-II transcripts were also expressed in heat-separated human dermis at levels similar to those found in epidermal keratome biopsies, whereas CRABP-I transcripts were undetectable in dermal RNA. CRABP-II transcripts were markedly elevated in psoriatic lesions, as they were in RA-treated skin. In contrast, CRABP-I mRNA was undetectable and not increased in psoriatic lesions. Expression of RAR-gamma isoforms and RXR was not detectably altered in either psoriatic lesions or in RA-treated skin. Thus, altered expression of CRABP-II appears more likely to regulate the cutaneous actions of RA than does altered expression of CRABP-I, RXR, or RAR-gamma isoforms. From these and other results, a model for regulation of RA action involving sequestration of RA by CRABP-II is proposed.

Acute or Chronic Topical Retinoic Acid Treatment of Human Skin In Vivo Alters the Expression of Epidermal Transglutaminase, Loricrin, Involucrin, Filaggrin, and Keratins 6 and 13 but not Keratins 1, 10, and 14

Histologic and immunocytochemical analyses were performed on cutaneous biopsies from 10 patients treated with retinoic acid under occlusion for 4 d compared to biopsies from 19 patients treated nightly for 16 weeks. Acute application of RA caused epidermal thickening (9 of 10 samples), stratum granulosum thickening (7 of 10), parakeratosis (4 of 10), a marked increase in the number of cell layers expressing epidermal transglutaminase (7 of 10), and focal expression of two non-epidermal keratins, K6 (8 of 10) and K13 (2 of 10), changes also observed with chronic treatment. Involucrin, filaggrin, and loricrin were also altered in samples from both acute and chronic treatment. An increased number of cell layers expressed both involucrin and filaggrin from both the acute (7 of 10) and chronic (14 of 19) treatment groups. In the acute group, loricrin expression was significantly reduced or absent in some regions of the epidermis (5 of 10), whereas most chronic samples showed an increased number of cell layers expressing loricrin (12 of 19). The pattern of expression of three major epidermal differentiation products, keratins K1, K10, and K14, was not significantly altered in any of the acute or chronic samples, although there was a slight reduction in the detection of K10 in two of the acute samples. Thus, acute topical RA treatment under occlusion caused substantial changes in the epidermis, and reproduced most, but not all of the effects of chronic treatment.

A photonumeric scale for the assessment of cutaneous photodamage

BACKGROUND AND DESIGN

The assessment of the severity of cutaneous photodamage and its response to treatment is an impractical consideration for most practitioners without extensive experience or recourse to high-quality, standardized, baseline photographs. To address this problem, a nine-point photonumeric standard scale was developed using photographs of subjects representing grades of photodamage from none to severe. This scale was formally tested in a side-by-side comparison with a conventional and widely used written descriptive scale. A panel of seven graders used both scales to score two sets of 25 photographs of photodamaged individuals, and the intergrader agreement and repeatability for the scales were calculated.

RESULTS

The photonumeric scale demonstrated significantly greater agreement between graders than did the descriptive scale (chance-corrected agreements of 0.31 and 0.11, respectively, P less than .0001) with no significant difference in repeatability between the two methods.

CONCLUSIONS

This study demonstrates that the photonumeric standard scale is superior to existing methodology in the accurate assessment of cutaneous photodamage and would be a useful adjunct to studies of the efficacy of skin repair agents for this indication.

Topical tretinoin (retinoic acid) treatment for liver spots associated with photodamage

BACKGROUND

The hyperpigmented lesions commonly called liver spots distress patients, in part because such lesions are associated with aging. We investigated their treatment with topical 0.1 percent tretinoin (retinoic acid).

METHODS

Fifty-eight patients completed a 10-month randomized, double-blind study in which they applied either 0.1 percent tretinoin (n = 28) or vehicle (n = 30) cream daily to the face, upper extremities, or both. Fifteen patients who responded well were than randomly assigned to continue tretinoin therapy or use vehicle alone for six more months. Patients were evaluated by physical examination every month and by analysis of biopsy specimens of lesions obtained at base line and at the end of the 10-month trial.

RESULTS

After one month of treatment the patients treated with tretinoin had significant lightening of hyperpigmented lesions as compared with the patients who received vehicle (P less than 0.002). After 10 months, 20 (83 percent) of the 24 patients with facial lesions who were treated with tretinoin had lightening of these lesions, as compared with 8 (29 percent) of the 28 patients with facial lesions who received vehicle. The results for lesions of the upper extremities were similar. As compared with vehicle, tretinoin caused a significant decrease in the degree of epidermal pigmentation and increases in the degree of compaction of stratum corneum, thickness of the granular cell layer, and epidermal thickness. Reductions in epidermal pigmentation evident on histologic analysis were significantly correlated with the degree of clinical lightening of lesions (r = -0.53, P less than 0.0001). During the 6-month follow-up study, specifically identified lesions that had disappeared during the first 10 months of tretinoin treatment did not return in any patient, and six of seven patients who continued to use tretinoin had further improvement.

CONCLUSIONS

Topical 0.1 percent tretinoin significantly improves both clinical and microscopical manifestations of liver spots; these lesions do not return for at least six months after therapy is discontinued.

Differential modulation of transforming growth factor-beta 1 expression and mucin deposition by retinoic acid and sodium lauryl sulfate in human skin

Immunohistochemical staining of skin sections with two polyclonal antibodies (anti-CC 1-30 and anti-LC 1-30), specific for transforming growth factor-beta 1, revealed increased extracellular and decreased intracellular expression of transforming growth factor-beta 1 in retinoic acid-treated, compared to vehicle-treated, skin. Transforming growth factor-beta 1 staining, with both antibodies, was most marked in the upper layers of the epidermis, although dermal staining was also evident. The modulation of transforming growth factor-beta 1 expression by retinoic acid occurred in the absence of any change in its mRNA level. Transforming growth factor-beta 1 protein, as detected by rabbit polyclonal antibody (anti-LC 50-75) and mRNA, were only minimally detected in either retinoic acid- or vehicle-treated skin. Similar changes in TGF-beta 1 and TGF-beta 2 immunoreactivity and mRNA levels, as observed in retinoic acid-treated skin, were observed in skin following topical application of the irritant sodium lauryl sulfate, indicating that the alterations induced by retinoic acid were not specific. In contrast, mucin deposition, which is induced by transforming growth factor-beta, was elevated in retinoic acid-treated but not sodium lauryl sulfate-treated skin. Cultured adult human keratinocytes also expressed predominantly transforming growth factor-beta 1 protein, as measured by ELISA, and mRNA. Treatment of keratinocytes with retinoic acid resulted in a 50% induction of transforming growth factor-beta 1 protein, without any detectable change in transforming growth factor-beta 2. These data demonstrate disassociation of modulation of transforming growth factor-beta 1 expression and mucin deposition by retinoic acid and sodium lauryl sulfate in human skin in vivo. Whereas alterations in transforming growth factor-beta 1 expression were observed in both retinoic acid- and sodium lauryl sulfate-treated skin, accumulation of mucin was specific to retinoic acid-treated skin.

Induction of proliferation of growth-inhibited keratinocytes and fibroblasts in monolayer culture by sodium lauryl sulfate: comparison with all-trans retinoic acid

We have previously shown that all-trans retinoic acid (RA) has the capacity to stimulate proliferation of growth-inhibited human epidermal keratinocytes and growth-inhibited human dermal fibroblasts. The same treatment also stimulates extracellular matrix synthesis by fibroblasts (J Invest Dermatol 93:449; 94:717). In the present study we have examined the capacity of sodium lauryl sulfate to stimulate keratinocyte and fibroblast proliferation under the same conditions. Our data show that both cell types are stimulated to proliferate. Sodium lauryl sulfate is less potent than RA; it requires a higher molar concentration to achieve optimal stimulation and the number of responding cells at optimal concentrations is less with sodium lauryl sulfate than with RA. Further, there is a rapid onset of toxicity at concentrations of sodium lauryl sulfate that are only slightly higher than the optimal stimulatory concentration. Finally, sodium lauryl sulfate is less effective than RA in stimulating production of extracellular matrix (fibronectin, thrombospondin, and laminin) by dermal fibroblasts. Despite its ability to partially mimic RA as a stimulant of keratinocyte and fibroblast growth, sodium lauryl sulfate does not activate chloramphenicol acetyl transferase in cells co-transfected with retinoic acid receptors and a retinoic acid responsive element linked to the chloramphenicol acetyl transferase gene.

A review and update of the clinical uses of cyclosporine in dermatology

Cyclosporine is a hitherto unique immunosuppressive agent that has provided a new approach to therapy in autoimmune diseases and has been increasingly used as a molecular tool for the investigation of immune regulation. It has produced excellent therapeutic responses in the treatment of psoriasis, acrodermatitis continua of Hallopeau, pyoderma gangrenosum, lichen planus, pityriasis lichenoides chronica, Behçets disease, and alopecia areata. Cyclosporine's mechanism of action, side effects, pharmacokinetics, and guidelines for patient monitoring, are discussed in this article.

Human immunodeficiency virus (HIV) transcripts identified in HIV-related psoriasis and Kaposi's sarcoma lesions

Persons with HIV infection sometimes develop aggressive psoriasis or Kaposi's sarcoma (KS) not usually seen in other immunosuppressed patients. However, a specific and direct pathophysiological role for HIV-1 in these AIDS-associated disorders remains unclear since HIV has not been easily detected in these skin lesions. By combining in situ hybridization with the sensitive detection technique of confocal laser scanning microscopy, we have demonstrated HIV RNA transcripts in 5 of 15 lesional skin biopsies from HIV-infected psoriasis patients, and in 3 of 8 Kaposi's sarcoma biopsies from HIV-infected patients. HIV transcripts were not detected in normal appearing skin from HIV-infected patients or in psoriatic and normal skin biopsies from uninfected individuals (P = 0.006). Although previous attempts to demonstrate viral sequences in psoriasis and KS lesions have been unsuccessful, in situ hybridization with confocal microscopy has shown the presence of HIV RNA transcripts predominantly within CD4+, Factor XIIIa positive dermal dendrocytes. HIV or cytokines produced by infected cells in skin lesions may therefore play a direct role in the pathogenesis of HIV-associated psoriasis and KS.

Modulation of leucocyte adhesion molecules, a T-cell chemotaxin (IL-8) and a regulatory cytokine (TNF-alpha) in allergic contact dermatitis (rhus dermatitis)

To understand the molecular events which are important in leucocyte trafficking in cutaneous inflammation, poison ivy/oak extract was applied topically to the skin, and the simultaneous assessment of a variety of clinical and immunopathological parameters performed. The clinical response of subjects was divided into three main groups: I, 2-24h after application, before the onset of erythema; II, 48 h-1 week after application during maximal clinical changes; III, 2-3 weeks after application when the inflammation had subsided. Six different biopsies per subject were evaluated over the study period and the density of dermal cellular infiltrate, and the distribution of intercellular adhesion molecule-1, (ICAM-1), endothelial leucocyte adhesion molecule-1, (ELAM-1), vascular cell adhesion molecule-1, (VCAM-1), interleukin 8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha), determined. Eight hours after exposure, before lymphocytes and monocytes had entered the dermal interstitium or epidermis, the keratinocytes expressed TNF-alpha and ICAM-1, whilst the endothelial cells expressed ELAM-1, VCAM-1 and ICAM-1. Group II biopsies revealed increasing keratinocyte expression of TNF-alpha and ICAM-1 with the appearance of IL-8, which correlated with the onset of epidermal T-cell trafficking. The endothelium was strongly positive for ELAM-1 and VCAM-1, but there was no influx of neutrophils. Group III biopsies showed a decrease in the expression of ICAM-1, VCAM-1 and ELAM-1 by both keratinocytes and endothelium with a reduction in epidermal/dermal inflammation, although the endothelial cell staining of VCAM-1 and ELAM-1 did not completely disappear. These results suggest that on exposure to poison ivy/oak, keratinocytes rapidly produce TNF-alpha which leads to an early autoinduction of ICAM-1, and later IL-8. There is also a paracrinemediated induction and augmentation of underlying endothelial cell ELAM-1, VCAM-1 and ICAM-1.

Cellular, immunologic and biochemical characterization of topical retinoic acid-treated human skin

Histologic and clinical improvement of sun-exposed skin following topical treatment with retinoic acid has been reported. Daily application of retinoic acid typically results within 2-5 d in an erythematous scaling reaction, which lessens with continued usage. The cellular, immunologic, and biochemical basis of this retinoid reaction and its role in the repair of photodamaged skin are not known. To investigate the retinoid reaction in man, we have treated non-sun-exposed skin with 0.1% retinoic acid cream (Retin-A, Ortho Pharmaceutical Corporation, Raritan, NJ) under occlusion for 4 d to induce erythema and then examined changes in 1) histology, 2) expression of cell-surface molecules, 3) the enzymes and second messengers of the phospholipase C/protein kinase C signal-transduction system, 4) levels of eicosanoids, and 5) levels of interleukin-1 protein and mRNA. These parameters were chosen for measurement both because they are indicators of epidermal function and previous studies suggest they may be responsive to retinoic acid treatment. Epidermal cell growth as judged by increased epidermal thickness and mitotic figures was significantly increased in retinoic acid-treated skin compared to vehicle-treated controls. Increased numbers of CD4+ T cells accompanied by prominence of dermal dendrocytes in the papillary dermis and focal keratinocyte expression of intercellular adhesion molecule-1 were observed in retinoic acid-treated biopsies. Phosphoinositide-specific phospholipase C activity and 1,2-diacylglycerol content were also elevated in retinoic acid-treated epidermis. Protein kinase C activity was reduced by one third in both the soluble and membrane fraction, suggesting down-regulation. Surprisingly, in view of the inflammatory nature of the retinoid reaction, no increases were observed in arachidonic acid, its metabolites, interleukin-1 alpha, or interleukin-1 beta. To examine the specificity of the retinoid reaction, subjects were treated with the irritant sodium lauryl sulfate, under conditions that resulted in a reaction clinically similar to that observed with retinoic acid. The histologic alterations induced by sodium lauryl sulfate were found to be indistinguishable from those induced by retinoic acid. These data indicate that, although a wide range of cellular and molecular alterations occur in retinoic acid-treated skin, these changes may not be necessarily specific or unique for retinoic acid.

Keratinocytes as initiators of inflammation

Environmental stimuli responsible for inducing cutaneous inflammation include contact allergens and ultraviolet light. We postulate that these diverse stimuli trigger a cutaneous inflammatory response by directly inducing epidermal keratinocytes to elaborate specific pro-inflammatory cytokines and adhesion molecules. The consequences are activation of dermal microvascular endothelial cells and selective accumulation of specific mononuclear cells in the dermis and epidermis. Thus, keratinocytes may act as "signal transducers", capable of converting exogenous stimuli into the production of cytokines, adhesion molecules, and chemotactic factors (acting in an autocrine and paracrine fashion) responsible for initiation of "antigen-independent" cutaneous inflammation. The initiation phase may facilitate or promote an amplification phase with additional production of tumour-necrosis factor alpha and interferon gamma via an "antigen-dependent" pathway, and keratinocyte/T cell/antigen-presenting dendritic cellular associations. The direct activation of keratinocytes, with their ability to produce the complete repertoire of pro-inflammatory cytokines, can profoundly influence endogenous and recruited immunocompetent cells, thereby providing the critical trigger responsible for the swift and clinically dramatic alterations that occur following contact between the epidermis and a host of "noxious" agents.

Cellular localization of interleukin-8 and its inducer, tumor necrosis factor-alpha in psoriasis

The importance of immunologic mechanisms in psoriasis has been deduced from the ability of immunosuppressive therapies to ameliorate this common and chronic skin disease. Certainly the histology of psoriatic lesions suggests a dialogue between the hyperplastic keratinocytes and infiltrating T lymphocytes and macrophages. To begin dissecting the cytokine network involved in the pathophysiology of psoriasis, the location, in both epidermal and dermal compartments, of tumor necrosis factor-alpha, interleukin-8, intercellular adhesion molecule-1, and transforming growth factor-alpha at the protein and/or mRNA levels were identified. Tumor necrosis factor-alpha was selected as a potentially key regulatory cytokine, first because it induces cultured keratinocyte interleukin-8, intercellular adhesion molecule-1, and transforming growth factor-alpha production, and second because intercellular adhesion molecule-1 expression by keratinocytes in psoriatic epidermis had been identified previously. Using immunohistochemical localization, tumor necrosis factor-alpha was identified in 12 psoriatic lesions as intense and diffuse expression by dermal dendrocytes (macrophages) in the papillary dermis (without significant staining of endothelial cells, mast cells, or dermal Langerhans cells), and focally by keratinocytes and intraepidermal Langerhans cells. Functional interaction between the dermal dendrocytes and keratinocytes was suggested by the presence of interleukin-8 expression of suprabasal keratinocytes immediately above the tumor necrosis factor-alpha-positive dermal dendrocytes. Interleukin-8 mRNA and transforming growth factor-alpha mRNA were detectable in the epidermal roof of psoriatic lesions, but neither was detectable at the protein or mRNA levels in any normal skin specimens. Treatment of cultured human keratinocytes with phorbol ester (which experimentally produces psoriasiform changes on mouse skin) or tumor necrosis factor-alpha also increased interleukin-8 and transforming growth factor-alpha mRNAs. Further elucidation of the cellular and molecular basis for the genesis and evolution of psoriasis will provide the framework for a better evaluation of the cause and treatment of this skin disease.

Systemic and local administration of cyclosporine in the treatment of psoriasis

Since 1984, cyclosporine has been used increasingly for indications other than in prophylaxis of transplant rejection. Current awareness that psoriasis is, at least in part, a T cell-mediated condition has led to the initiation of several studies of cyclosporine's role in the treatment of this disease. The remarkable efficacy of systemically administered cyclosporine, even in severely refractory cases of psoriasis, has not only provided us with a new therapeutic option but also has helped further our understanding of the pathophysiology of psoriasis. Although it has been hailed as a breakthrough, systemic cyclosporine usage is associated with undesirable sequelae, principally hypertension and decreased renal function. These effects limit its more widespread use. This review assesses current knowledge of the capabilities and prospects of systemic cyclosporine in the treatment of psoriasis, as well as the status of topical preparations.

Disseminated dermal dendrocytomas. A new cutaneous fibrohistiocytic proliferative disorder?

A 77-year-old white woman presented with 1 1/2-year history of progressively enlarging cutaneous papules, nodules, and plaques, some of which had spontaneously regressed. Her past medical history included untreated chronic lymphocytic leukemia for 10 years' duration. Multiple skin biopsy specimens revealed a diffuse superficial and deep dermal spindle-cell infiltrate accompanied by occasional foamy round cells and multinucleated giant cells. The spindle-shaped cells were focally arranged in a storiform pattern with prominent fibrous stroma. The spindle-shaped cells stained positively for numerous macrophage markers including CD45, factor XIIIa, Leu M5, HLA-DR, CD4, and Leu M3, consistent with dermal dendrocytes. They were also positive for nonspecific esterase and acid phosphatase, which is typical of tissue macrophages. The spindle-shaped cells were negative for CD-1, S-100, and ATPase activity, thus excluding a Langerhans cell immunophenotype. Combining the clinical features, light microscopy, immunohistochemistry, and enzymatic analysis, this patient appears to represent a novel cutaneous fibrohistiocytic proliferative disorder that features large numbers of dermal dendrocytes.

Effect of topical cyclosporine rinse on oral lichen planus. A double-blind analysis

BACKGROUND

Oral lichen planus is a relatively common disorder of the mouth that can be debilitating. It is frequently palliated with topical or systemic corticosteroids and retinoids. These treatments require prolonged use, however, and are not always effective.

METHODS

In a double-blind trial, 16 patients with symptomatic oral lichen planus were randomly assigned to receive either topical cyclosporine or its vehicle. The patients swished and expectorated 5 ml of medication (containing 100 mg of cyclosporine per milliliter) three times daily.

RESULTS

After eight weeks, the eight recipients of cyclosporine had marked improvement in erythema (P = 0.003), erosion (P = 0.02), reticulation (presence of white lacelike lesions; P = 0.007), and pain (P = 0.002), whereas the eight recipients of vehicle had no change or minimal improvement. After a switch to cyclosporine for eight weeks, the vehicle-treated patients had improvement similar to that seen in the patients who initially received cyclosporine. There were no systemic side effects. In most cases blood cyclosporine levels were low or undertectable. Cyclosporine levels present in specimens of oral mucosa at the end of therapy four hours after the patients swished were similar to the levels previously reported in psoriatic lesions after treatment with systemic cyclosporine (14 mg per kilogram of body weight per day).

CONCLUSIONS

As a topical preparation, cyclosporine may be useful in the treatment of oral lichen planus and possibly other cutaneous disorders.

The role of adhesion molecules, chemotactic factors, and cytokines in inflammatory and neoplastic skin disease--1990 update

In 1986 it was discovered that cultured human keratinocytes, when treated with gamma interferon, attract and bind T lymphocytes and monocytes. More is now known about trafficking of inflammatory cells in the skin, with specific molecular details involving various cytokines, chemotactic factors, and adhesion molecules. One key element is the in vivo movement of T cells that express LFA-1 into the epidermis, and their subsequent binding to keratinocytes via the surface expression of intercellular adhesion molecule-1 (ICAM-1). This interaction represents a common immunologic pathway, which has been identified in a wide variety of different skin diseases. This review provides a synopsis of advances in this field, which have grown rapidly during the past few years, and adds recent results dealing with coordinate regulation at the gene-transcriptional level of keratinocyte chemotactic factor production and adhesion molecule expression. Moreover, epidermal keratinocytes appear to play a pre-eminent role in the skin, serving as transducing elements converting exogenously applied low-molecular-weight chemical stimuli such as phorbol ester and urushiol (the active ingredient in poison ivy extracts) into the production of endogenously derived immunoregulatory proteins. These keratinocyte-derived molecules may then influence immunocytes and endothelial cells to further amplify the inflammatory response. The identification of keratinocyte-derived molecules such as IL-8 and ICAM-1, which influence the chemotaxis and adherence of T cells, adds substantial evidence supporting an active participatory role for keratinocytes in cutaneous immunohomeostasis. Finally, we highlight the importance of these immunoregulatory molecules in two malignant cutaneous disorders (cutaneous T-cell lymphoma and basal-cell carcinoma) and attempt to integrate these new findings into novel pathophysiologic models for two inflammatory dermatoses (rhus dermatitis and psoriasis).

Sulfasalazine improves psoriasis. A double-blind analysis

In an 8-week double-blind trial of sulfasalazine for the treatment of moderate-to-severe psoriasis, 23 and 27 patients received the active and placebo tablets, respectively. At the end of the double-blind phase, there were 17 assessable patients receiving sulfasalazine; 7 (41%) had marked improvement, 7 (41%) had moderate improvement, and 3 (18%) demonstrated minimal change. Only 1 patient receiving placebo demonstrated moderate improvement, whereas the rest had minimal improvement or worsening of psoriasis. When the randomization code was broken, patients receiving sulfasalazine were allowed to continue therapy for an additional 4 weeks in an open manner, while those using placebo left the study. Six of 23 patients discontinued sulfasalazine therapy during the double-blind phase because of side effects, 4 due to the development of a cutaneous eruption and 2 due to nausea. Fourteen of 17 patients, who were assessable at the end of the 8-week double-blind phase, completed the additional 4 weeks of sulfasalazine therapy. Of these 14 patients, marked improvement occurred in 8 (57%), moderate improvement in 2 (14%), and minimal improvement in 4 (29%), compared with pretherapy. The low incidence of severe side effects makes sulfasalazine a consideration for oral therapy in patients whose disease severity does not justify use of methotrexate, etretinate, or psoralen plus UV-A, but whose disease severity is too widespread for safe and practical use of topical corticosteroids.

Constitutive absence and interferon-gamma-induced expression of adhesion molecules in basal cell carcinoma

Adhesion of lymphocytes to target cells via certain cell surface molecules is important in cytotoxic T lymphocyte-mediated immune reactions. The binding of lymphocyte function-associated (LFA) antigens 1 and 2, with their respective ligands, intercellular adhesion molecule-1 (ICAM-1) and LFA-3, which are expressed on the surface of nonlymphoid cells, has been shown to be critical for lymphocyte adhesion. To determine whether basal cell carcinomas (BCCs) can escape immunodetection as a result of the inability of cytotoxic T lymphocytes to bind tumor cells, the expression of adhesion molecules on numerous BCCs, before and after exposure to interferon-gamma (IFN-gamma), was examined. Ninety-three percent of 30 freshly excised invasive BCCs did not express ICAM-1 and 73% of 11 BCCs did not express LFA-3. However, the normal-appearing basal keratinocytes in epidermis overlying nests of BCC, did express ICAM-1, particularly when a marked LFA-1+ and LFA-2+ dermal lymphocytic infiltrate was present. After BCC tissue was incubated in vitro with IFN-gamma the expression of ICAM-1 was induced on 85% of tumors studied. Thus tumor cells did not possess an absolute inability to express adhesion molecules; rather the constitutive absence of such molecules may be due to insufficient in vivo cytokine levels necessary to induce expression or a barrier preventing cytokines from reaching and interacting with tumor cells. We conclude that the absence of ICAM-1 and LFA-3 adhesion molecules is a mechanism by which BCCs can avoid immunosurveillance.