Efficacy and safety of infliximab monotherapy for plaque-type psoriasis: a randomised trial

BACKGROUND

Currently available treatments for moderate to severe psoriasis are either incompletely effective in some patients, or are associated with toxic effects. Since tumour necrosis factor alpha (TNF-alpha) is thought to have a role in the pathogenesis of psoriasis, we did a double-blind, randomised trial to assess the clinical benefit and safety of infliximab-a monoclonal antibody against TNF-alpha.

METHODS

33 patients with moderate to severe plaque psoriasis were randomly assigned intravenous placebo (n=11), infliximab 5 mg/kg (n=11), or infliximab 10 mg/kg (n=11) at weeks 0, 2, and 6. Patients were assessed at week 10 for the primary endpoint (score on the physician's global assessment [PGA]). Analysis was by intention to treat.

FINDINGS

Of the 33 patients enrolled, three dropped out. Nine of 11 (82%) patients in the infliximab 5 mg/kg group were responders (good, excellent, or clear rating on PGA), compared with two of 11 (18%) in the placebo group (difference 64% [95% CI 20-89], p=0.0089), and ten of 11 (91%) patients in the infliximab 10 mg/kg group were responders (difference from placebo 73% [30-94], p=0.0019). The median time to response was 4 weeks for patients in both infliximab groups. There were no serious adverse events, and infliximab was well tolerated.

INTERPRETATION

In this controlled trial, patients receiving the anti-TNF-alpha agent infliximab as monotherapy experienced a high degree of clinical benefit and rapid time to response in the treatment of moderate to severe plaque psoriasis compared with patients who received placebo. These findings suggest that TNF-alpha has a pivotal role in the pathogenesis of psoriasis.

Concomitant administration of vitamin E does not change the side effects of isotretinoin as used in acne vulgaris: a randomized trial

BACKGROUND

Isotretinoin treatment is frequently associated with reversible, dose-related side effects. Recent studies claimed that combining vitamin E with high-dose isotretinoin ameliorated isotretinoin-induced side effects.

OBJECTIVE

The purpose of this double-blind, randomized study was to determine the effects of a fixed dose of vitamin E on the side effects of isotretinoin for treatment-resistant acne vulgaris.

METHODS

One hundred forty subjects were randomly assigned to one of two treatment programs with isotretinoin (1 mg/kg) together with either vitamin E (800 IU/day) or a vitamin E placebo for 20 weeks. The incidence, severity, and duration of the side effects (eg, dry eyes, dry lips) were assessed.

RESULTS

A fixed 800 IU/day dose of vitamin E did not improve the incidence, severity, or duration of side effects associated with isotretinoin (1 mg/kg per day).

CONCLUSION

Vitamin E did not significantly ameliorate retinoid side effects when combined with 1 mg/kg of isotretinoin in the treatment of acne.

Anti-CD4 monoclonal antibody treatment of moderate to severe psoriasis vulgaris: results of a pilot, multicenter, multiple-dose, placebo-controlled study

BACKGROUND

OKTcdr4a (IMUCLONE) is a humanized anti-CD4 IgG4 monoclonal antibody that retains the binding and in vitro immunosuppressive properties of the parent murine antibody. Psoriasis is a chronic disease for which treatment with multiple doses of monoclonal antibodies is likely to be required for adequate control.

OBJECTIVE

This study was performed to test the efficacy and safety of OKTcdr4a, given in sequential courses over a period of several weeks, in the treatment of moderate to severe psoriasis vulgaris.

METHODS

Twenty-eight patients (45.6 +/- 10.1 years of age) were studied, with a mean pretreatment Psoriasis Area and Severity Index (PASI) score of 18.3. In the first double-blind phase of the study, patients were randomized to receive OKTcdr4a as a 225 mg/course (low dose), 750 mg/course (high dose), or placebo divided into 3 identical infusions over a 5-day period. After 42 days, patients who met the criteria for re-treatment with OKTcdr4a were re-treated with the 750 mg/course in an open phase of the study.

RESULTS

After the double-blind course of treatment, the mean PASI decreased by 11% in the placebo group, by 4% in the low-dose group, and by 17% in the high-dose group at 15 days. Twenty patients met the criteria for re-treatment (ie, did not experience a decrease in PASI score of 50% at 42 days). They were re-treated with OKTcdr4a at 43 days with the 750 mg/course in the open phase of the study. By day 99, the mean PASI score decreased from 19.9 at baseline to 17 in those patients who had received either placebo or low-dose OKTcdr4a followed by high-dose OKTcdr4a. In contrast, the mean PASI score decreased from 17.4 at baseline to only 7.7 in those patients who had received high-dose OKTcdr4a for both courses. Sustained CD4 saturation was not necessary for sustained clinical response. No patients had significant changes in circulating CD4(+) T-cell counts. The infusions were well tolerated.

CONCLUSION

Targeting CD4 using sequential treatments with a humanized monoclonal antibody (OKTcdr4a) may offer another therapeutic option for the treatment of moderate to severe psoriasis.

Successful in vivo blockade of CD25 (high-affinity interleukin 2 receptor) on T cells by administration of humanized anti-Tac antibody to patients with psoriasis

BACKGROUND

Daclizumab is a humanized antibody to the alpha-subunit (CD25) of the interleukin 2 (IL-2) receptor that blocks normal IL-2 binding to this receptor. Because IL-2 is a major stimulus for T-cell growth, blockade of the IL-2 receptor could be useful in treating T-cell-mediated (autoimmune) diseases.

OBJECTIVE

Our purpose was to determine whether adequate concentrations of antibody were achieved in circulating blood and in psoriatic skin lesions to saturate CD25 receptors. We also intended to measure clinical effect and safety of this agent when used alone (without other immunosuppressive drugs) in psoriasis.

METHODS

Nineteen patients with psoriasis in two centers received daclizumab at an initial dose of 2 mg/kg, then 1 mg/kg at weeks 2, 4, 8, and 12. To determine whether CD25 was blocked in vivo, flow cytometric studies measured (1) expression of CD25 on CD3(+) T cells derived from blood and (2) immuno-histochemistry measures of CD25(+) cells done on pretreatment and posttreatment biopsy specimens. Patients were followed up clinically with photographs and Psoriasis Area and Severity Index scores.

RESULTS

This study showed a consistent blockade of CD25 in peripheral blood and tissue during the first 4 weeks of therapy while the dosing was every 2 weeks. Variable desaturation of receptors began after 4 weeks, which correlated with a reversal in disease improvement. Patients with a pretreatment Psoriasis Area and Severity Index score of less than 36 showed a mean reduction in severity by 30% at 8 weeks (P =.02). During the 16 weeks of treatment, a 44.8% decrease in expression of the IL-2 receptor alpha-subunit was found. The absolute T-cell counts were calculated and showed no significant changes during the course of the study. No significant adverse events were produced by daclizumab during this study.

CONCLUSION

We therefore conclude that daclizumab is a well-tolerated agent that blocks CD25 expression in peripheral blood and skin. Furthermore, it may be useful in treating psoriasis in some patients.

Two considerations for patients with psoriasis and their clinicians: what defines mild, moderate, and severe psoriasis? What constitutes a clinically significant improvement when treating psoriasis?

The definitions of psoriasis severity and clinically significant improvement in psoriasis are used to classify treatments, obtain Food and Drug Administration approval, and determine product labeling and reimbursement. The Medical Advisory Board of the National Psoriasis Foundation has addressed these issues because of their importance in the clinical trials that are conducted to gain FDA approval of indications. Narrow indications, which are without a sound rational basis, will-in this era of constant oversight by third party payers-affect physicians' ability to manage patients with psoriasis. Body surface area (BSA) is usually used to define severity for clinical trials. It is not optimal for defining psoriasis severity because there are some patients with low BSA involvement who have very severe psoriasis and some patients with high BSA involvement who have mild psoriasis. We conclude that a quality of life (QOL) standard is better than BSA measurement for identifying patients with severe psoriasis. The second issue is what defines clinically significant improvement for patients with psoriasis. Setting an arbitrarily high criterion of clinical efficacy for new psoriasis treatments will likely limit the development and approval of useful treatments. To maximize the availability of useful psoriasis treatments, it is our thesis that psoriasis treatments should be approved when they have been shown to produce a statistically significant level of improvement in well-designed clinical trials.

Treatment with anti-tumor necrosis factor alpha (TNF-alpha) monoclonal antibody dramatically decreases the clinical activity of psoriasis lesions

We treated a 57-year-old woman for refractory inflammatory bowel disease with a humanized anti-tumor necrosis factor alpha monoclonal antibody (Infliximab). The patient also had a 15-year history of Crohn's disease and a 20-year history of moderate to severe psoriasis. She received a single infusion of Infliximab (5 mg/kg). Two weeks after the infusion her psoriasis had dramatically improved in appearance. To our knowledge, our case is the first reported instance of successful anti-tumor necrosis factor alpha therapy in psoriasis.

Staphylococcal scalded skin syndrome in an immunocompetent adult: possible implication of low-dosage prednisone

Staphylococcal scalded skin syndrome (SSSS) mainly affects infants and young children. Very few cases of adult SSSS have been reported. Adult SSSS is usually associated with immunosuppression, overwhelming sepsis, and kidney failure. We report the case of an immunocompetent 51-year-old woman without renal failure who sustained SSSS after a 7-day course of oral prednisone administered postoperatively.

Intravenous cyclosporine therapy in the treatment of pyoderma gangrenosum secondary to Crohn's disease

Pyoderma gangrenosum is a destructive, ulcerative skin condition often associated with systemic illnesses such as inflammatory bowel disease, myeloproliferative disorders, and the inflammatory arthritides. We present a patient with long-standing pyoderma gangrenosum associated with Crohn's disease. Multiple deep leg ulcerations were unresponsive over the course of several years to treatment with azathioprine, systemic corticosteroids, 6-mercaptopurine, and dapsone. The patient was hospitalized and treated with a ten-day course of intravenous cyclosporine therapy followed by outpatient oral cyclosporine and showed significant improvement.

Identification of aberrantly regulated genes in diseased skin using the cDNA differential display technique

It is hypothesized that psoriasis may be caused by aberrant gene expression. In an effort to identify and clone psoriasis-specific genes, we compared gene expression in normal, tape-stripped (wounded), and psoriatic skin using the cDNA differential display technique. Four genes not previously described in psoriasis--connexin 26, a gap junction protein; squamous cell carcinoma antigen-1 (SCCA1), a serine protease inhibitor; and mitochondrial NAD subunits 5 and 6--were identified as having very high expression levels in psoriatic skin. In situ hybridizations showed that connexin 26 mRNA was expressed 10-fold higher in psoriatic and 4-fold higher in tape-stripped epidermis than in controls. SCCA1 showed a 40-fold increase in mRNA expression, whereas mitochondrial NAD5 and NAD6 expression was increased 10- and 20-fold, respectively, in psoriatic skin. Northern blots confirmed the increased expression of connexin 26, SCCA1, and NAD6 genes in psoriatic skin. Immunohistochemistry showed that connexin 26 protein was strongly expressed in spinous keratinocytes from psoriatic skin and chronic wounds, but was absent in normal epidermis. These studies demonstrate the usefulness of this approach for identifying genes that are conditionally expressed in growth-activated human skin.

Cellular actions of etretinate in psoriasis: enhanced epidermal differentiation and reduced cell-mediated inflammation are unexpected outcomes

Retinoids are potent cell growth and differentiation modulators, but cellular effects of therapeutic retinoids in psoriasis are unknown. We studied the effects of etretinate on pathological activation of keratinocytes and lymphocytes in patients treated systemically with this agent for 8 weeks. Ten patients with extensive psoriasis vulgaris were treated with etretinate at 0.75 mg/kg for 8 weeks. Skin biopsies obtained before and at 8 weeks of treatment were studied using immunohistochemical markers for keratinocyte proliferation or differentiation and for the presence of T-lymphocyte subsets or associated inflammatory proteins. During 8 weeks of treatment, the clinical severity decreased by a mean of 64% (p < 0.001). Compared to a similar group of patients treated with bath PUVA, psoriatic plaque erythema resolved more slowly and less completely (p < 0.05), but improvements in plaque thickness and scale were not significantly different between etretinate and PUVA treatments. Etretinate produced a 44% decrease in epidermal thickness (p < 0.001) and a 62% reduction in keratinocyte proliferation (p < 0.001) after 8 weeks of treatment. Unexpectedly, keratinocyte differentiation was enhanced following etretinate treatment as indicated by increased filaggrin production, increased number and size of keratohyaline granules, greater abundance of keratin filaments, and increased secretion of intercellular lipids from Odland bodies. The stratum corneum in resolving psoriatic lesions was unusually thin, probably caused by retinoid-induced shedding of corneocytes. "Regenerative" epidermal growth was maintained during etretinate treatment, as marked by continued expression of keratin 16 and alpha 3-integrin by suprabasal keratinocytes. Surprisingly the inflammation-associated proteins HLA-DR and ICAM-1 were no longer produced by epidermal keratinocytes following etretinate treatment, and CD3+, CD8+, and CD25+ T-lymphocyte subsets were reduced by 50-65% in lesional tissue (p < 0.01). Etretinate shows unexpected anti-inflammatory and pro-differentiation actions in psoriasis. Etretinate appears to function as a disease suppressive agent which improves hyperplasia, keratinocyte differentiation and tissue inflammation mediated by cellular immune elements.

Modulation of epidermal differentiation, tissue inflammation, and T-lymphocyte infilitration in psoriatic plaques by topical calcitriol

Psoriasis is characterized by immune activation, increased proliferation and abnormal differentiation of keratinocytes. The reported anti-psoriatic mechanisms of action in vivo of vitamin D analogues include reduction of keratinocyte proliferation and induction of keratinocyte terminal differentiation. We investigated whether the anti-psoriatic effect of the natural active vatamin D analogue, calcitriol, applied topically, is due to direct effects on keratinocytes alone or also due to immunoregulatory effects of calcitriol. Psoriasis patients were treated with topical calcitriol (0.005%) and a vehicle control for 8 weeks. Disease activity was assessed by a severity index and quantitative histopathological markers. In vitro studies of lymphocyte proliferation and gamma interferon secretion and of keratinocyte proliferation complemented the clinicohistopathologic studies. A heterogeneous response to calcitriol treatment could be segregated based upon elimination of K-16 keratin expression. Calcitriol treatment decreased keratinocyte proliferation, normalized keratinocyte differentiation and decreased immune activation in plaques. The histologic response to vitamin D treatment of psoriasis includes suppression of both immune and keratinocyte activation in situ. These studies provide a basis for rational combination of anti-psoriatic treatments and for the design of new vitamin D analogues to treat psoriasis.

The insulin-like growth factor 1 receptor is expressed by epithelial cells with proliferative potential in human epidermis and skin appendages: correlation of increased expression with epidermal hyperplasia

Ligand-mediated activation of the insulin-like growth factor 1 (IGF-1) receptor is critical for epidermal keratinocyte proliferation in vitro, and its expression in normal and psoriatic epidermis suggests that it might regulate keratinocyte proliferation in vivo. In this study, we used a monoclonal antibody (alpha-IR3) that binds to the alpha-chain of this receptor to study its expression (i) in other epithelial cell types in human skin and (ii) in growth-activated epidermis associated with various cutaneous pathologies. In normal skin, IGF-1 receptors were expressed by basal epidermal keratinocytes as well as by basal-like or undifferentiated germinative epithelial cells associated with the follicular outer root sheath, sebaceous glands, and the hair matrix. There was minimal IGF-1 receptor expression in differentiating outer root sheath, hair shaft, and sebaceous epithelial cells. IGF-1 receptor expression in non-growth-activated epidermis of long-standing seborrheic keratoses was confined to the basal epidermal layer, as in normal epidermis. In contrast, hyperplastic epidermis undergoing "regenerative" differentiation (keratin 16+, Ki67+ suprabasal keratinocytes) from psoriasis, chronic skin wounds, and plaques of mycosis fungoides consistently showed increased expression of IGF-1 receptor. In these conditions, the region of expanded IGF-1 receptor expression delimited the epidermal zone of keratinocyte proliferation. In cultured keratinocytes, the subcellular localization of the IGF-1 receptor could be modulated from plasma membranes to the cell cytoplasm by ligand binding, suggesting that the in vivo cytoplasmic staining occasionally observed represents internalization of receptors following ligand stimulation. Our results suggest that cell surface IGF-1 receptors are widely expressed by epithelial cells with proliferative potential, that receptor expression can be modulated with differing epidermal growth states, and that these receptors are largely downregulated in highly differentiated epithelial cells.

In vivo expression of the insulin-like growth factor-I (IGF-I) receptor in congenital pigmented nevi

Growth of normal melanocytes, nevus cells and primary melanoma cells is enhanced by insulin/insulin-like growth factor-I (IGF-I) in vitro. It has been shown that a melanoma cell line possesses the IGF-I receptor which plays a role in activation of the chemotactic response. Little is known about the in vivo expression of the IGF-I receptor and its role in melanocytic lesions. In an immunohistochemical study, we investigated the expression of IGF-I receptor in frozen sections of congenital pigmented nevi from 10 patients (ages 8 months to 4 yrs) using the monoclonal antibody alpha IR3, which specifically recognizes the extracellular alpha subunit of the IGF-I receptor. The proliferative activity of the nevus cells was examined by staining with Ki67 monoclonal antibody (reactive with all actively cycling cells). IGF-I receptor was found to be widely expressed by the cell surface of the nevus cells. Membrane staining was occasionally stronger in the superficial portion of the congenital pigmented nevi. In contrast, Ki67-positive cells were only sparsely scattered throughout the nevi with some tendency to localization to the superficial portion. This study indicates that in vivo the IGF-I receptor is widely expressed by congenital pigmented nevus cells. As opposed to keratinocytes, in which IGF-I receptor expression defines the proliferation pool of the normal and disordered epidermis, the IGF-I receptor is expressed by all nevus cells, irrespective of their proliferative status. Further studies are needed to assess whether the IGF-I receptor expression can serve as a marker for increased risk for development of malignancy in various types of benign melanocytic lesions.

Pharmacokinetics and pharmacodynamics of AC137 (25,28,29 tripro-amylin, human) after intravenous bolus and infusion doses in patients with insulin-dependent diabetes

A study was conducted to evaluate the effect of 30-mug, 100-mug, and 300-mug 2-minute bolus doses and 2-hour infusion doses of AC137 (25,28,29 tripro-amylin, human) on plasma AC137 concentrations and plasma glucose and lactate responses in patients with insulin-dependent diabetes mellitus (IDDM). The study design was an imbedded two-way cross-over wherein patients received placebo and active boluses in one period and placebo and active infusions in the other period. Two patients in each dose group received placebo throughout the two periods. Pharmacokinetics and pharmacodynamics (PK/PD) were determined during the 6-hour period after initiation of dosing. Data were fitted with a linked PK/PD model. Pharmacokinetics were linear over the dose range studied, and attenuation of glucose and lactate responses to a mixed meal was dose and concentration dependent. The results of the PK/PD model indicate that the attenuation of glucose and lactate responses was greater after AC137 infusion doses than after the same doses given as a bolus. Glucose and lactate responses to a mixed meal were essentially negated by the 300-mug infusion dose.

Successful ultraviolet B treatment of psoriasis is accompanied by a reversal of keratinocyte pathology and by selective depletion of intraepidermal T cells

Skin irradiation with ultraviolet B (UVB) is a common and often durable treatment for psoriasis and other inflammatory skin disorders. We studied the effects of UVB on keratinocytes and leukocytes in psoriatic tissue and in culture. In nine patients treated repetitively, most of the cellular and molecular changes that typify the psoriatic epidermis reverted to normal. Keratinocyte hyperplasia, assessed by expression of the Ki-67 cell cycle antigen, decreased by 70%, and residual cell proliferation was appropriately confined to the basal layer. Epidermal thickening was reduced by 60%, and a granular layer reformed. Expression of keratin 16, as well as suprabasal integrin alpha 3 and insulin-like growth factor-1 receptors, was eliminated, whereas filagrin increased markedly. UVB also depleted > 90% of the CD3+, CD8+, and CD25+ T cells from the psoriatic epidermis, whereas dermal T cells were only minimally depressed. The latter finding parallels the known inability of these doses of UVB to penetrate the dermis. In tissue culture, UVB was antiproliferative and cytotoxic toward T cells and keratinocytes, but the T cells were 10-fold more sensitive. Furthermore, low doses of UVB induced apoptosis in lymphocytes but not keratinocytes, as detected by the TUNEL (TdT-mediated dUTP-biotin nick end labeling) technique. The selective effects of UVB on intraepidermal T cells in situ and in culture support the hypothesis that epidermal alterations in psoriasis can be normalized by a depletion of activated intraepidermal T cells.

Short-contact anthralin treatment augments therapeutic efficacy of cyclosporine in psoriasis: a clinical and pathologic study

BACKGROUND

Psoriasis is characterized by immune activation and increased epidermal proliferation. Cyclosporine acts by reducing T lymphocyte numbers and lymphokine production. Anthralin inhibits keratinocyte proliferation.

OBJECTIVE

We investigated whether topical anthralin would augment clearing of psoriasis produced by systemic cyclosporine.

METHODS

Twelve patients with psoriasis were treated with cyclosporine (5 mg/kg per day). Patients applied anthralin only to plaques on half of their body. They were treated until a remission or maximum benefit was achieved. Disease activity was assessed by a severity index and quantitative histopathologic markers.

RESULTS

Of the 12 patients, the skin of five cleared within 10 weeks irrespective of anthralin use. The other seven (slow responders) continued treatment for a mean of 18 weeks. Slow responders had a significantly lower severity index, a thinner epidermis, fewer CD8+ cells, and fewer proliferating keratinocytes on the anthralin-treated side than on the non-anthralin-treated side.

CONCLUSION

The combination of cyclosporine and topical anthralin is effective in patients who are slow to respond to cyclosporine alone.

Response of psoriasis to a lymphocyte-selective toxin (DAB389IL-2) suggests a primary immune, but not keratinocyte, pathogenic basis

Psoriasis is a hyperproliferative and inflammatory skin disorder of unknown aetiology. A fusion protein composed of human interleukin-2 and fragments of diphtheria toxin (DAB389IL-2), which selectively blocks the growth of activated lymphocytes but not keratinocytes, was administered systemically to ten patients to gauge the contribution of activated T cells to the disease. Four patients showed striking clinical improvement and four moderate improvement, after two cycle of low dose IL-2-toxin. The reversal of several molecular markers of epidermal dysfunction was associated with a marked reduction in intraepidermal CD3+ and CD8+ T cells, suggesting a primary immunological basis for this widespread disorder.

GM-CSF activates regenerative epidermal growth and stimulates keratinocyte proliferation in human skin in vivo

Granulocyte/macrophage-colony-stimulating factor (GM-CSF), an immunomodulator of hematopoietic cells, has also been shown to stimulate human keratinocyte proliferation in vitro and speed healing of wounds in the skin of lepromatous leprosy patients. In this study we have examined the in vivo effects of recombinant human GM-CSF on epidermal keratinocyte proliferation and on expression of proteins marking regenerative epidermal growth. Skin biopsies from GM-CSF injected cutaneous sites were obtained between 1 and 6 d following administration of 7.5 or 15 micrograms of the growth factor. Activation of keratinocyte proliferation, quantified as the expression of the Ki67+ nuclear antigen, was noted 1 d following GM-CSF administration. A regenerative epidermal phenotype, demonstrated by immunohistochemical staining of cellular proteins involucrin, filaggrin, and keratin 16, was similarly noted as early as 1 d following GM-CSF injection. This phenotype persisted as late as 6 d post-injection. These results suggest that GM-CSF injection into human skin induces keratinocyte proliferation as well as regenerative differentiation of the epidermis. To date no other cytokine has been shown to be mitogenic for human keratinocytes both in vivo and in vitro or to alter keratinocyte differentiation along the "alternate" or regenerative pathway.

PUVA bath therapy strongly suppresses immunological and epidermal activation in psoriasis: a possible cellular basis for remittive therapy

Psoriasis is characterized by alterations in both the epidermis and dermis of the skin. Epidermal keratinocytes display marked proliferative activation and differentiate along an "alternate" or "regenerative" pathway, while the dermis becomes infiltrated with leukocytes, particularly interleukin 2 (IL-2) receptor-bearing "activated" T cells. Psoralens, administered by the oral route, have therapeutic effects in psoriasis when photochemically activated by ultraviolet A light (PUVA therapy). Recently psoralen bath therapy has been introduced to more effectively deliver this agent to the diseased skin. We have correlated the efficacy of PUVA bath therapy with its effects on specific molecular and cellular parameters of disease, in 10 consecutive patients with recalcitrant psoriasis. Rapid clearing of lesions occurred in 8 out of 10 patients. Biopsies were taken from lesional and nonlesional skin before and after a single round of therapy, and observation was continued in our Clinical Research Center at The Rockefeller University. Enumeration of cycling keratinocytes with the Ki-67 monoclonal antibody showed that PUVA reduced cell proliferation by 73%. The pathological increase in insulin-like growth factor 1 (IGF-1) receptors was reversed, whereas epidermal growth factor (EGF) receptors, which are also increased in psoriasis, remained unchanged. Keratinocyte proteins that are expressed in abnormal sites of the epidermis during psoriasis, i.e., keratin 16, filaggrin, and involucrin, were, after PUVA treatment, localized to their normal sites. Epidermal and dermal T-lymphocytes (CD3+), as well as CD4+, CD8+, and IL-2 receptor+ subsets, were strongly suppressed by PUVA, with virtual elimination of IL-2 receptor+ T cells in some patients. Consistent with diminished lymphocyte activation, HLA-DR expression by epidermal keratinocytes was markedly reduced in treated skin. In comparison to cyclosporine treatment of psoriasis, PUVA therapy leads to more complete reversal of pathological epidermal and lymphocytic activation, changes which we propose to be the cellular basis for a more sustained remission of disease after PUVA treatment.

Anthralin decreases keratinocyte TGF-alpha expression and EGF-receptor binding in vitro

Anthralin is an effective topical treatment for active psoriasis; however, its mechanism of action is unknown. Both TGF-alpha and its receptor, the EGF receptor, are overexpressed in active psoriatic plaques and might, therefore, play a role in psoriatic epidermal hyperplasia. In order to assess whether anthralin might act via alteration of this growth factor pathway, we examined the in vitro effects of pharmacologic concentrations of anthralin on cultured normal human keratinocytes. Keratinocyte proliferation was inhibited by 98% at an anthralin concentration of 10 ng/ml. In contrast, lymphocyte proliferation was inhibited by only 50% at an anthralin concentration of 10 micrograms/ml. Anthralin treatment did not induce cell-cycle-specific growth arrest as assessed by flow-cytometric analysis of acridine-orange-stained keratinocytes. Northern analysis of anthralin-treated keratinocytes demonstrated a marked decrease in TGF-alpha mRNA expression. Anthralin-treated keratinocytes showed decreased binding of 125I-EGF and 125I-IGF-I to their respective receptors, but EGF receptor binding was inhibited to a greater extent. Anthralin decreased ligand-binding affinity and cell-surface numbers of EGF receptors as assessed by Scatchard analysis of 125I-EGF binding to anthralin-treated keratinocytes. These results indicate that anthralin alters components of the EGF receptor pathway in cultured keratinocytes and that these effects might contribute to the clinical efficacy of anthralin in the treatment of active psoriasis.

The insulin-like growth factor I receptor is overexpressed in psoriatic epidermis, but is differentially regulated from the epidermal growth factor receptor

Insulin-like growth factor I (IGF-I)/somatomedin C is an important mediator of keratinocyte growth in vitro, and the expression of IGF-I receptors in the basal layer of normal epidermis suggests that this growth pathway may function in the regulation of keratinocyte growth in vivo as well. The pattern of IGF-I receptor expression in normal skin is distinct from that of the epidermal growth factor (EGF) receptor, suggesting that these receptors might be differentially regulated. The purpose of this study was to obtain a better understanding of IGF-I receptor function in the skin by examining IGF-I receptor expression in psoriatic epidermis and in cultured human keratinocytes. Our findings indicate that IGF-I receptor expression is increased in psoriasis as measured by protein tyrosine kinase assays of biopsy extracts and by immunohistochemical staining with an IGF-I receptor-specific monoclonal antibody. Unlike EGF receptor expression, which is also increased in psoriatic epidermis, the pattern of IGF-I receptor expression corresponds closely with the increased size of the keratinocyte proliferative compartment in psoriasis. Biochemical agents that diminish EGF receptor ligand binding (phorbol ester or calcium ionophore treatment) produce opposite effects on the IGF-I receptor. These results suggest that cellular expression and differential regulation of both growth factor receptor systems may control critical aspects of epidermal proliferation or function.

Studies of the Effect of Cyclosporine in Psoriasis In Vivo: Combined Effects on Activated T Lymphocytes and Epidermal Regenerative Maturation

Cyclosporine (CSA) decreases lymphokine synthesis and keratinocyte proliferation in vitro, but its in vivo mechanism of action in treating recalcitrant psoriasis is incompletely understood. Ten psoriasis patients were treated with CSA (2-7.5 mg/kg/d) with clinical improvement in nine of 10 patients. Skin biopsies before and after 1-3 months of CSA treatment were studied for evidence of immune and keratinocyte activation using immunoperoxidase and Northern blotting analysis. The number of activated, IL-2 receptor+ T cells in plaques after CSA treatment was reduced in all patients by a mean of 60%. Seven of 10 patients showed a decrease in keratinocyte HLA-DR expression; five of seven showed a decrease in gamma-IP-10 immunoreactivity, suggesting a decline in gamma interferon levels in plaques after CSA therapy. We studied the effect of CSA treatment in vivo on TGF-alpha, IL-6, and keratin K16 expression, three markers of keratinocyte growth activation. Expression of keratinocyte TGF-alpha and IL-6, which are elevated in active psoriatic epidermis, did not change in these patients after CSA treatment. The majority of patients (five of eight) continued to express the hyperproliferative keratin K16 after CSA treatment. Our results suggest that the predominant direct mechanism of action of Cyclosporine in vivo is a diminution of T-cell activation in plaques, with attendant decreased lymphokine production.