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Palmoplantar pustular psoriasis (PPPP) and non‒pustular palmoplantar psoriasis (NPPP) are localized, debilitating forms of psoriasis. The inflammatory circuits involved in PPPP and NPPP are not well-understood. To compare the cellular and immunological features that differentiate PPPP and NPPP, skin biopsies were collected from a total of 30 participants with PPPP, NPPP, and psoriasis vulgaris (PV) and from 10 healthy participants. A subset consented to a second biopsy after 3 additional weeks off medication. Histologic staining of lesional and nonlesional skin showed higher neutrophil counts in PPPP than in NPPP and PV and higher CD8 + T-cell counts in NPPP. RNA sequencing and transcriptional analysis of skin biopsies showed enhanced IFN-γ pathway activation in NPPP lesions but stronger signatures of IL-17 pathway and neutrophil-related genes (e.g., IL36A) in PPPP lesional skin. Serum analysis on the Olink platform detected higher concentrations of T helper type 1, IFN-γ‒inducible chemokines in NPPP, and higher neutrophil-associated cytokines in PPPP. Taken together, this evidence suggests more pronounced T helper 1‒mediated inflammation in NPPP than in PV and PPPP and stronger neutrophil-associated activity in PPPP than in NPPP and PV. These data support targeting inflammatory pathways associated with neutrophilic inflammation (e.g., IL-36 signaling) for therapeutic development in PPPP., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Cutaneous adverse events (AEs) have been observed in clinical studies of daclizumab high-yield process (HYP) in relapsing-remitting multiple sclerosis (RRMS). Here, we report cutaneous AEs observed in the randomized, double-blind, active-comparator DECIDE study (ClinicalTrials.gov identifier, NCT01064401)., Methods: DECIDE was a randomized, double-blind, active-controlled phase 3 study of daclizumab HYP 150 mg subcutaneous every 4 weeks versus interferon (IFN) beta-1a 30 mcg intramuscular (IM) once weekly in RRMS. Treatment-emergent AEs were classified and recorded by investigators. Investigators also assessed the severity of each AE, and whether it met the criteria for a serious AE. Cutaneous AEs were defined as AEs coded to the Medical Dictionary for Regulatory Activities System Organ Class of skin and subcutaneous tissue disorders. The incidence, severity, onset, resolution, and management of AEs were analyzed by treatment group., Results: Cutaneous AEs were reported in 37% of daclizumab HYP-treated patients and 19% of IFN beta-1a-treated patients. The most common investigator-reported cutaneous AEs with daclizumab HYP were rash (7%) and eczema (4%). Most patients with cutaneous AEs remained on treatment (daclizumab HYP, 81%; IM IFN beta-1a, 90%) and had events that were mild or moderate (94% and 98%) and subsequently resolved (78% and 82%). Most patients with cutaneous AEs did not require treatment with corticosteroids or were treated with topical corticosteroids (daclizumab HYP, 73%; IM IFN beta-1a, 81%). Serious cutaneous AEs were reported in 14 (2%) daclizumab HYP patients and one (<1%) IM IFN beta-1a patient., Conclusion: There was an increased risk of cutaneous AEs with daclizumab HYP. While physicians should be aware of the potential for serious cutaneous AEs, the typical cutaneous AEs were mild-to-moderate in severity, manageable, and resolved over time., Funding: Biogen and AbbVie Biotherapeutics Inc., Trial Registration: ClinicalTrials.gov identifier, NCT01064401.

Genomic signature maps of different cell types can aid in the interpretation of genomic data of specimens collected during disease states. We have defined "lineage-specific" genes, as well as "activation" genes, for cellular components of the skin: keratinocytes, fibroblasts, macrophages, monocytes, T cells, immature, and mature dendritic cells (DCs). Re-analysis of a previously published gene set of psoriasis then provided a model for assessing the usefulness of these maps. We were able to ascribe over 90% of these genes to specific cell types, and there was a surprisingly large contribution from DCs. This shows the utility of such cellular gene maps.

Sarcoidosis, a chronic granulomatous disease of unknown etiology, is treated with immune suppressive drugs such as corticosteroids. Sarcoidosis patients have been reported to benefit clinically from treatment with thalidomide. We administered thalidomide for 16 weeks to eight patients with chronic skin sarcoidosis and evaluated the drug's effects before and with treatment. After thalidomide treatment, all skin biopsies showed decreases in granuloma size and reduction in epidermal thickness. We also observed extensive T cell recruitment into the granulomas, the appearance of multinucleated giant cells, and increased numbers of dermal Langerhans cells (CD1a(+)) and mature dendritic cells (CD83(+) or DC-LAMP(+)). Plasma IL-12 levels increased and remained elevated during the treatment period. We noted increased HLA-DR expression on peripheral blood lymphocytes and a corresponding drop in the naive T cell marker CD45RA. Our data suggest that thalidomide treatment of sarcoidosis results in granuloma differentiation to a Th1-type cellular immune response usually associated with protective immunity to tuberculosis and tuberculoid leprosy.

Hidradenitis suppurativa (HS) is an inflammatory skin disease characterized by painful nodules, abscesses and purulent secretions in intertriginous regions. Intense pruritus frequently accompanies HS lesions, adding further discomfort for patients. While Th17 pathway activation is implicated in HS pathogenesis, disease mechanisms are still not fully understood, and therapeutics are lacking. Previous reports raise a potential role for eosinophils in HS, showing a strong association of eosinophil levels with disease severity. To investigate eosinophils in HS, we recruited patients and matched healthy controls and then performed flow‐cytometry studies, eosinophil stimulation assays, and lesional skin staining for eosinophils. We found that HS patients reported similar levels of pain and itch. Compared to matched controls, HS blood exhibited decreased mature eosinophils and increased numbers of immature eosinophils, coupled with a significant increase in dermal eosinophilic infiltrates. Additionally, IL‐17RA+ eosinophils were highly and significantly correlated with multiple HS‐related clinical scores. In both stimulated and unstimulated conditions, HS eosinophils showed an inflammatory phenotype versus controls, including an increase in costimulatory T‐ and B‐cell markers (e.g. CD5 and CD40) following all stimulations (TNFα/IL‐17A/IL‐17F). These findings highlight the significance of pruritus in HS and suggest a higher turnover of eosinophils in HS blood, potentially due to the consumption of eosinophils in skin lesions. Our data delineate the features and functions of eosinophils in HS and suggest that eosinophils participate in disease pathogenesis, advancing Th17‐related inflammation. Further studies are needed to investigate eosinophils' response to current HS treatments and their potential as a therapeutic target in the disease. [ABSTRACT FROM AUTHOR]

Background: Atopic dermatitis (AD) is a heterogeneous, chronic inflammatory skin disease linked to skin microbiome dysbiosis with reduced bacterial diversity and el)evated relative abundance of Staphylococcus aureus (S. aureus). Objectives: We aimed to characterize the yet incompletely understood association between the skin microbiome and patients' demographic and clinical cofactors in relation to AD severity. Methods: The skin microbiome in 48 adult moderate-to-severe AD patients was investigated using next-generation deep sequencing (16S rRNA gene, V1–V3 re)gion) followed by denoising (DADA2) to obtain amplicon sequence variant (ASV) composition. Results: In lesional skin, AD severity was associated with S. aureus relative abun)dance (rS = 0.53, p<0.001) and slightly better with the microbiome diversity measure Evenness (rS = −0.58, p<0.001), but not with Richness. Multiple regression confirmed the association of AD severity with microbiome diversity, including Shannon (in le)sional skin, p<0.001), Evenness (in non-lesional skin, p = 0.015) or S. aureus relative abundance (p<0.012), and with patient's IgE levels (p<0.001), race (p<0.032), age (p<0.034) and sex (p = 0.012). The lesional model explained 62% of the variation in AD severity, and the non-lesional model 50% of the variation. Conclusions: Our results specify the frequently reported “reduced diversity” of the AD-related skin microbiome to reduced Evenness, which was in turn mainly driven by S. aureus relative abundance, rather than to a reduced microbiome Richness. Finding associations between AD severity, the skin microbiome and patient's cofac)tors is a key aspect in developing new personalized AD treatments, particularly those targeting the AD microbiome. [ABSTRACT FROM AUTHOR]

Background: Treatment of inflammatory skin diseases, including atopic dermatitis (AD) and psoriasis, is undergoing transformative changes, highlighting the need to develop experimental models of skin inflammation in humans to predict treatment responses. Methods: We topically or intradermally administered four common sensitizers (dust mite (DM), diphencyprone (DPCP), nickel (Ni), and purified protein derivative (PPD)) to the backs of 40 healthy patients and the skin hypersensitivity response was biopsied and evaluated using immunohistochemistry, RNA‐seq, and RT‐PCR. Results: All agents induced strong increases in cellular infiltrates (T‐cells and dendritic cells) as compared to untreated skin (p <.05), with variable T helper polarization. Overall, DPCP induced the strongest immune responses across all pathways, including innate immunity (IL‐1α, IL‐8), Th1 (IFNγ, CXCL10), Th2 (IL‐5, CCL11), and Th17 (CAMP/LL37) products, as well as the highest regulatory tone (FOXP3, IL‐34, IL‐37) (FDR <0.01). Nickel induced Th17 (IL‐17A), Th1 (CXCL10) and Th2 (IL‐4R) immune responses to a lesser extent than DPCP (p <.05). PPD induced predominantly Th1 (IFNγ, CXCL10, STAT1) and Th17 inflammation (IL‐17A) (p <.05). DM induced modulation of Th2 (IL‐13, CCL17, CCL18), Th22 (IL‐22), and Th17/Th22 (S100A7/9/12) pathways (p <.05). Barrier defects that characterize both AD and psoriasis were best modeled by DPCP and Ni, followed by PPD, including downregulation of terminal differentiation (FLG, FLG2, LOR, LCEs), tight junction (CLDN1/CLDN8), and lipid metabolism (FA2H, FABP7)‐related markers. Conclusion: Our data imply that DPCP induced the strongest immune response across all pathways, and barrier defects characteristic of AD and psoriasis. [ABSTRACT FROM AUTHOR]

Background: Hidradenitis suppurativa (HS) is an inflammatory skin disease with dysregulation of the interleukin (IL)‐17 axis. Recently, we reported the clinical benefit of brodalumab, a human anti‐IL‐17 receptor A (IL‐17RA) monoclonal antibody, in moderate‐to‐severe HS. Objectives: To characterize the molecular response to brodalumab in HS skin and serum, and to identify biomarkers of treatment response. Methods: Ten participants, who received brodalumab 210 mg /1·5 mL subcutaneously at weeks 0, 1, 2, 4 and every 2 weeks thereafter, were included in this molecular profiling study (NCT03960268). RNA sequencing and immunohistochemistry of nonlesional, perilesional and lesional HS skin biopsies, and Olink high‐throughput proteomics of serum at baseline, weeks 4 and 12 were assessed. Results: At week 12, brodalumab led to a decrease of overall inflammation, and improvement of psoriasis‐, keratinocyte‐ and neutrophil‐related pathways. Despite perilesional and lesional skin exhibiting no differentially expressed genes at baseline, treatment response was best assessed in perilesional skin. In serum, brodalumab treatment decreased pathways involved in neutrophil inflammation. Patients with higher baseline expression of neutrophil‐associated lipocalin‐2 (LCN2) in the skin or IL‐17A in the serum demonstrated greater decreases of HS‐related inflammatory cytokines as measured in skin biopsies at week 12. Conclusions: IL‐17RA inhibition by brodalumab decreases several pathogenic inflammatory axes in HS. Perilesional skin provides a valid and robust assessment of treatment response. Expression of LCN2 in skin or IL‐17A in serum may be used as biomarkers to stratify patients that may have a superior molecular response to brodalumab. [ABSTRACT FROM AUTHOR]

Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic inflammatory skin disease with still largely unknown pathogenesis. While infectious organisms have been identified in lesions of the disease since the 1980s, questions remain over the role that bacteria and microbiome play. Recent studies using 16S ribosomal RNA gene sequencing and larger culture‐based studies have begun to paint a clearer picture of the microbial world of HS. With this systematic review, we summarize all the work that has been done to date in HS bacteriology, analyse potential pitfalls and limitations of the current studies, and address future directions of investigation. This systematic review attempted to collate and analyse all bacteriology studies done to date. This review was prospectively registered with PROSPERO (1670769) performed in line with the PRISMA checklist. Twenty two studies were identified comprising 862 individual HS patients for culture studies and 206 HS patients for 16S rRNA gene sequencing studies. Methodology tended to be varied, with different sampling, culturing and sequencing methods as well as amount of analysis and stratification of patients. Bacteria identified as elevated in HS lesions in sequencing studies as well as grown from HS lesions in culture studies are identified and discussed. These primarily included the anerobic Gram‐negative bacilli Prevotella, Porphyromonas and Fusibacterium, the Gram‐positive bacilli Corynebacterium, and the Gram‐positive cocci Staphylococcus, Streptococcus and Parvimonas. Potential interactions, as well as work in other disease models with related bacteria are also discussed. Areas of further investigation include in vitro studies of interactions between bacteria and keratinocytes, gut and oral microbiome studies and deep sequencing studies for virulence and phage factors. [ABSTRACT FROM AUTHOR]

Background: Skin biopsies promote our understanding of atopic dermatitis/AD pathomechanisms in infants/toddlers with early‐onset AD, but are not feasible in pediatric populations. Tape strips are an emerging, minimally invasive alternative, but global transcriptomic profiling in early pediatric AD is lacking. We aimed to provide global lesional and nonlesional skin profiles of infants/toddlers with recent‐onset, moderate‐to‐severe AD using tape strips. Methods: Sixteen tape strips were collected for RNA‐seq profiling from 19 infants/toddlers (<5 years old; lesional and nonlesional) with early‐onset moderate‐to‐severe AD (≤6 months) and 17 healthy controls. Results: We identified 1829 differentially expressed genes/DEGs in lesional AD and 662 DEGs in nonlesional AD, vs healthy skin (fold‐change ≥2, FDR <0.05), with 100% sample recovery. Both lesional and nonlesional skin showed significant dysregulations of Th2 (CCL17 and IL4R) and Th22/Th17 (IL36G, CCL20, and S100As)‐related genes, largely lacking significant Th1‐skewing. Significant down‐regulation of terminal differentiation (FLG and FLG2), lipid synthesis/metabolism (ELOVL3 and FA2H), and tight junction (CLDN8) genes were primarily seen in lesional AD. Significant negative correlations were identified between Th2 measures and epidermal barrier gene‐subsets and individual genes (FLG with IL‐4R and CCL17; r < −0.4, P <.05). Significant correlations were also identified between clinical measures (body surface area/BSA, pruritus ADQ, and transepidermal water loss/TEWL) with immune and barrier mRNAs in lesional and/or nonlesional AD (FLG/FLG2 with TEWL; r < −0.4, P <.05). Conclusion: RNA‐seq profiling using tape strips in early‐onset pediatric AD captures immune and barrier alterations in both lesional and nonlesional skin. Tape strips provide insight into disease pathomechanisms and cutaneous disease activity. [ABSTRACT FROM AUTHOR]

Scalp psoriasis shows a variable clinical spectrum and in many cases poses a great therapeutic challenge. However, it remains unknown whether the immune response of scalp psoriasis differs from understood pathomechanisms of psoriasis in other skin areas. We sought to determine the cellular and molecular phenotype of scalp psoriasis by performing a comparative analysis of scalp and skin using lesional and nonlesional samples from 20 Caucasian subjects with untreated moderate to severe psoriasis and significant scalp involvement and 10 control subjects without psoriasis. Our results suggest that even in the scalp, psoriasis is a disease of the inter-follicular skin. The immune mechanisms that mediate scalp psoriasis were found to be similar to those involved in skin psoriasis. However, the magnitude of dysregulation, number of differentially expressed genes, and enrichment of the psoriatic genomic fingerprint were more prominent in skin lesions. Furthermore, the scalp transcriptome showed increased modulation of several gene-sets, particularly those induced by interferon-gamma, compared with that of skin psoriasis, which was mainly associated with activation of TNFα/L-17/IL-22-induced keratinocyte response genes. We also detected differences in expression of gene-sets involving negative regulation, epigenetic regulation, epidermal differentiation, and dendritic cell or Th1/Th17/Th22-related T-cell processes. [ABSTRACT FROM AUTHOR]

Diphencyprone (DPCP) is a hapten that induces delayed-type hypersensitivity (DTH) reactions. MicroRNAs (miRNAs) are short non-coding RNAs that negatively regulate gene expression and have been implicated in various inflammatory skin diseases, but their role in DTH reactions is not well understood. We generated global miRNA expression profiles (using next-generation sequencing) of DPCP reactions in skin of seven healthy volunteers at 3, 14 and 120 days after challenge. Compared to placebo-treated sites, DPCP-challenged skin at 3 days (peak inflammation) had 127 miRNAs significantly deregulated. At 14 days (during resolution of inflammation), 43 miRNAs were deregulated and, at 120 days (when inflammation had completely resolved), six miRNAs were upregulated. While some miRNAs have been observed in psoriasis or atopic dermatitis, most of the deregulated miRNAs have not yet been studied in the context of skin biology or immunology. Across the three time points studied, many but not all miRNAs were uniquely expressed. As various miRNAs may influence T cell activation, this may indicate that the miRNAs exclusively expressed at different time points function to promote or resolve skin inflammation, and therefore, may inform on the paradoxical ability of DPCP to treat both autoimmune conditions (alopecia areata) and conditions of ineffective immunity (melanoma). [ABSTRACT FROM AUTHOR]

Background: Vitiligo is a common skin disorder, characterized by progressive skin de-pigmentation due to the loss of cutaneous melanocytes. The exact cause of melanocyte loss remains unclear, but a large number of observations have pointed to the important role of cellular immunity in vitiligo pathogenesis. Methodology/Principal Findings: In this study, we characterized T cell and inflammation-related dermal dendritic cell (DC) subsets in pigmented non-lesional, leading edge and depigmented lesional vitiligo skin. By immunohistochemistry staining, we observed enhanced populations of CD11c+ myeloid dermal DCs and CD207+ Langerhans cells in leading edge vitiligo biopsies. DC-LAMP+ and CD1c+ sub-populations of dermal DCs expanded significantly in leading edge and lesional vitiligo skin. We also detected elevated tissue mRNA levels of IL-17A in leading edge skin biopsies of vitiligo patients, as well as IL- 17A positive T cells by immunohistochemistry and immunofluorescence. Langerhans cells with activated inflammasomes were also noted in lesional vitiligo skin, along with increased IL-1β mRNA, which suggest the potential of Langerhans cells to drive Th17 activation in vitiligo. Conclusions/Significance: These studies provided direct tissue evidence that implicates active Th17 cells in vitiligo skin lesions. We characterized new cellular immune elements, in the active margins of vitiligo lesions (e.g. populations of epidermal and dermal dendritic cells subsets), which could potentially drive the inflammatory responses. [ABSTRACT FROM AUTHOR]

Background: Psoriasis is a common, chronic relapsing inflammatory skin disease. Lately, there is increasing evidence that psoriasis is more than "skin deep". Epidemiological studies showed that severe psoriasis might have also important systemic manifestations such as metabolic deregulations, cardiovascular disease (CVD) and increased mortality. Moreover, recently psoriasis patients were found to have platelet hyperactivity. Case Presentation: This is a case report and review of the literature. We present a patient with long standing severe psoriasis vulgaris with marked thrombocytosis. His thrombocytosis did not correlate with disease severity but rather with the different treatments that he was exposed to, subsiding only during treatment with anti Tumor Necrosis Factor (TNF)- agents. A literature review revealed that in rheumatoid arthritis, another systemic inflammatory disease; interleukin (IL)-6 might be implicated in causing thrombocytosis. Conclusion: This unique case report illustrates that different systemic treatments for psoriasis might have implications beyond the care of skin lesions. This insight is especially important in psoriasis patients in view of their deranged hemostatic balance toward a prothrombotic state, which might increase the risk of thrombosis and CVD. Therefore, further studies analyzing the effect of different drugs on platelets physiology are warranted. [ABSTRACT FROM AUTHOR]

Psoriasis is one of the most common human skin diseases and is considered to have key genetic underpinnings. It is characterized by excessive growth and aberrant differentiation of keratinocytes, but is fully reversible with appropriate therapy. The trigger of the keratinocyte response is thought to be activation of the cellular immune system, with T cells, dendritic cells and various immune-related cytokines and chemokines implicated in pathogenesis. The newest therapies for psoriasis target its immune components and may predict potential treatments for other inflammatory human diseases. [ABSTRACT FROM AUTHOR]

Background: Newer biological therapies for moderate-to-severe psoriasis are being used more frequently, but unexpected effects may occur. Case presentations: We present a group of 15 patients who developed inflammatory papules while on efalizumab therapy (Raptiva, Genentech Inc, anti-CD11a). Immunohistochemistry showed that there were increased CD11b+, CD11c+ and iNOS+ cells (myeloid leukocytes) in the papules, with relatively few CD3+ T cells. While efalizumab caused a decreased expression of CD11a on T cells, other circulating leukocytes from patients receiving this therapy often showed increased CD11b and CD11c. In the setting of an additional stimulus such as skin trauma, this may predispose to increased trafficking into the skin using these alternative β2 integrins. In addition, there may be impaired immune synapse formation, limiting the development of these lesions to small papules. There is little evidence for these papular lesions being "allergic" in nature as there are few eosinophils on biopsy, and they respond to minimal or no therapy even if efalizumab is continued. Conclusion: We hypothesize that these papules may represent a unique type of "mechanistic" inflammatory reaction, seen only in the context of drug-induced CD11a blockade, and not during the natural disease process. [ABSTRACT FROM AUTHOR]

Background: Alefacept (anti-CD2) biological therapy selectively targets effector memory T cells (Tem) in psoriasis vulgaris, a model Type 1 autoimmune disease. Methods: Circulating leukocytes were phenotyped in patients receiving alefacept for moderate to severe psoriasis. Results: In all patients, this treatment caused a preferential decrease in effector memory T cells (CCR7- CD45RA-) (mean 63% reduction) for both CD4+ and CD8+ Tem, while central memory T cells (Tcm) (CCR7+CD45RA-) were less affected, and naïve T cells (CCR7+CD45RA+) were relatively spared. Circulating CD8+ effector T cells and Type 1 T cells (IFN-γγ-producing) were also significantly reduced. Conclusion: Alefacept causes a selective reduction in circulating effector memory T cells (Tem) and relative preservation of central memory T cells (Tcm) in psoriasis. [ABSTRACT FROM AUTHOR]

Background: Etanercept is a tumor necrosis factor-α binding fusion protein that demonstrates efficacy in the treatment of psoriasis, which is accompanied by decreased plaque infiltration of T cells and myeloid dendritic cells. We hypothesized that etanercept decreases inflammatory cell infiltration by inducing apoptosis. Objective: We sought to investigate the effect of etanercept on circulating and plaque leukocyte apoptosis in psoriasis. Methods: Blood and plaque specimens were obtained from 10 patients with psoriasis treated with etanercept (25 mg subcutaneously twice weekly) for 24 weeks. Apoptosis was determined in tissue samples using immunohistochemistry and flow cytometry. Results: Etanercept selectively induced apoptosis in dermal dendritic cells in plaques of responding patients at 1 month, before most of the clinical and histologic response was achieved. No apoptosis was detected in plaque or circulating T cells or in circulating monocytes. Limitations: Addition of multiple time points earlier than 1 month would be valuable to establish the time point of maximum induction in cell apoptosis. Conclusion: Etanercept selectively induces apoptosis of pathogenic dermal dendritic cells in responding patients early in the course of treatment. [Copyright &y& Elsevier]

Psoriasis is a chronic inflammatory disorder of the skin that is mediated by T cells, dendritic cells and inflammatory cytokines. We now understand many of the cellular alterations that underlie this disease, and genomic approaches have recently been used to assess the alterations of gene expression in psoriatic skin lesions. Genetic susceptibility factors that contribute to predisposition to psoriasis are now also being identified. It is hoped that we will soon be able to correlate the cellular pathogenesis that occurs in psoriasis with these genetic factors. In this Review article, we describe what is known about genes that confer increased susceptibility to psoriasis, and we integrate this with what is known about the molecular and cellular mechanisms that occur in other inflammatory and autoimmune disorders. [ABSTRACT FROM AUTHOR]

Background: Severe psoriasis vulgaris can be extremely difficult to treat in some patients, even with the newer biological therapies available today. Case presentations: We present two patients with severe chronic plaque psoriasis who received numerous systemic anti-soriatic therapies with varied results. Both responded well to initial treatment with efalizumab (anti-CD11a), but then experienced a flare of their disease after missing a dose. However, after disease stablization, both patients responded well to re-introduction of efalizumab, one patient requiring concurrent treatment with infliximab (anti-TNF-á). Conclusion: These cases are presented to characterize this "flare" reaction, and to inform health care providers that efalizumab can still be administered after disease flare, and again may be a successful therapy. [ABSTRACT FROM AUTHOR]

Psoriasis is characterized by epidermal hyperplasia, altered epidermal maturation, and local accumulation of acute and chronic inflammatory cells. Keratinocyte hyperplasia in psoriasis may be explained in part by overproduction of growth factors or cytokines which stimulate epidermal proliferation and by altered metabolism of growth-factor receptors in affected skin. Psoriatic epidermis displays overproduction of TGF-alpha and interleukin-6 (IL-6), factors produced by keratinocytes and other cell types in psoriatic skin. TGF-alpha and IL-6 are mitogens for normal human keratinocytes and act via specific receptors. The TGF-alpha receptor (EGF receptor) is overexpressed in psoriatic epithelium and its altered expression could be caused in part by gamma interferon which prevents normal receptor down-regulation in response to EGF binding. Several phenotypic features of the psoriatic keratinocyte, including growth activation and expression of HLA-DR, gamma-IP-10, ICAM-1, and other molecules, are best explained as resulting from the combined effects of TGF-alpha, IL-6, and gamma interferon (and possibly other cytokines) on epidermal keratinocytes. The multiple histologic features of psoriasis, including epidermal hyperplasia and accumulation of acute and chronic inflammatory cells, may be mediated by defined growth factors and cytokines that are produced in psoriatic skin and affect the function of diverse cell types. [ABSTRACT FROM AUTHOR]

Psoriasis is a chronic inflammatory skin disease that affects 2% to 3% of the U.S. population. The immune response in psoriasis includes enhanced activation of T cells and myeloid cells, platelet activation, and up-regulation of interferons, tumor necrosis factor-α, and interleukins (ILs) IL-23, IL-17, and IL-6, which are linked to vascular inflammation and atherosclerosis development. Patients with psoriasis are up to 50% more likely to develop cardiovascular disease (CV) disease, and this CV risk increases with skin severity. Major society guidelines now advocate incorporating a psoriasis diagnosis into CV risk prediction and prevention strategies. Although registry data suggest treatment targeting psoriasis skin disease reduces vascular inflammation and coronary plaque burden, and may reduce CV risk, randomized placebo-controlled trials are inconclusive to date. Further studies are required to define traditional CV risk factor goals, the optimal role of lipid-lowering and antiplatelet therapy, and targeted psoriasis therapies on CV risk. [ABSTRACT FROM AUTHOR]

The article offers information on a study related to psoriasis, an immune-mediated disease that affects the skin. As per the study, the psoriasis skin lesion contains homing T cells which are activated by cutaneous dendritic cells to produce inflammatory cytokines. The study further highlights that the disease is associated with increased risk of cardiovascular disease, obesity and diabetes.

In psoriasis, an IL-17-mediated inflammatory skin disease, skin lesions resolve with therapy, but often recur in the same locations when therapy is discontinued. We propose that residual T cell populations in resolved psoriatic lesions represent the pathogenic T cells of origin in this disease. Utilizing high-throughput screening (HTS) of the T cell receptor (TCR) and immunostaining, we found that clinically resolved psoriatic lesions contained oligoclonal populations of T cells that produced IL-17A in both resolved and active psoriatic lesions. Putative pathogenic clones preferentially utilized particular Vβ and Vα subfamilies. We identified 15 TCRβ and 4 TCRα antigen receptor sequences shared between psoriasis patients and not observed in healthy controls or other inflammatory skin conditions. To address the relative roles of αβ versus γδ T cells in psoriasis, we carried out TCR/δ HTS. These studies demonstrated that the majority of T cells in psoriasis and healthy skin are αβ T cells. γδ T cells made up 1% of T cells in active psoriasis, less than 1% in resolved psoriatic lesions, and less than 2% in healthy skin. All of the 70 most frequent putative pathogenic T cell clones were αβ T cells. In summary, IL-17-producing αβ T cell clones with psoriasis-specific antigen receptors exist in clinically resolved psoriatic skin lesions. These cells likely represent the disease-initiating pathogenic T cells in psoriasis, suggesting that lasting control of this disease will require suppression of these resident T cell populations. [ABSTRACT FROM AUTHOR]

The article discusses a study on the association of the dermal clusters of mature dendritic cells and T cells with the CCL20/CCR6 chemokine system in chronic psoriasis. The study assesses whether the CCL20/CCR6 pair is also related to the characteristic cellular aggregates present in chronic psoriatic lesion. It also shows grouping tendencies of DC-LAMP mature DCs and lesional T cells in the dermal part of psoriatic skin.

Psoriasis is a complex disease with an expanding definition of its pathological features. We sought to expand/refine the psoriasis transcriptome using 85 paired lesional and non-lesional samples from a cohort of patients with moderate-to-severe psoriasis vulgaris who were not receiving active psoriasis therapy. This new analysis identified 4,175 probe sets (representing 2,725 unique known genes) as being differentially expressed in psoriasis lesions compared with matched biopsies of non-lesional skin when the following criteria were applied: >2-fold change and false discovery rate <0.05. These probe sets represent the largest and most comprehensive set of genes defining psoriasis at the molecular level and within the previously unidentified genes, a link to functional pathways associated with metabolic diseases/diabetes and to cardiovascular risk pathways is identified. In addition, we profiled the serum of moderate-to-severe psoriatics compared with healthy controls to assess the overlap of overexpressed lesional genes with overexpressed systemic proteins. We identified linkage of functional pathways in lesional skin associated with metabolic diseases/diabetes and cardiovascular risk with those pathways overexpressed in the serum, suggesting a potential linkage between altered gene transcription in the skin and comorbidities commonly seen in patients with moderate-to-severe psoriasis. [ABSTRACT FROM AUTHOR]

Psoriasis is a chronic, debilitating, immune-mediated inflammatory skin disease. As IFN-γ is involved in many cellular processes, including activation of dendritic cells (DCs), antigen processing and presentation, cell adhesion and trafficking, and cytokine and chemokine production, IFN-γ-producing Th1 cells were proposed to be integral to the pathogenesis of psoriasis. Recently, IFN-γ was shown to enhance IL-23 and IL-1 production by DCs and subsequently induce Th17 cells, which are important contributors to the inflammatory cascade in psoriatic lesions. To determine whether IFN-γ indeed induces the pathways expressed in psoriatic lesions, a single intradermal injection of IFN-γ was administered to an area of clinically normal, non-lesional (NL) skin of psoriasis patients and biopsies were collected 24 hours later. Although there were no visible changes in the skin, IFN-γ induced many molecular and histological features characteristic of psoriatic lesions. IFN-γ increased a number of differentially expressed genes in the skin, including many chemokines concomitant with an influx of T cells and inflammatory DCs. Furthermore, inflammatory DC products tumor necrosis factor (TNF), inducible nitric oxide synthase, IL-23, and TNF-related apoptosis-inducing ligand were present in IFN-γ-treated skin. Thus, IFN-γ, which is significantly elevated in NL skin compared with healthy skin, appears to be a key pathogenic cytokine that can induce many features of the inflammatory cascade of psoriasis. [ABSTRACT FROM AUTHOR]

Filaggrin (FLG), loricrin (LOR), and involucrin are important epidermal barrier proteins. As psoriasis is characterized by overexpression of tumor necrosis factor-α (TNF-α) and impaired skin barrier, we investigated the expression of skin barrier proteins in psoriasis patients and whether their expression was modulated by TNF-α. The expression of FLG and LOR was found to be decreased in lesional and non-lesional skin of psoriasis patients. A correlation was found between the expression of TNF-α and epidermal barrier proteins in psoriasis. TNF-α was found to modulate the expression of FLG and LOR via a c-Jun N-terminal kinase-dependent pathway. Importantly, we report that clinical treatment of psoriasis patients with a TNF-α antagonist results in significant enhancement of epidermal barrier protein expression. Our current study suggests that TNF inhibits barrier protein expression, and TNF-α antagonists may contribute to clinical improvement in patients with psoriasis by improving barrier protein expression. [ABSTRACT FROM AUTHOR]

Introduction: EGFR inhibitors (EGFRIs) have been shown to be clinically effective in various cancers. Unique skin toxicity is commonly observed with EGFRIs and a correlation between the clinical benefit of EGFRIs and this characteristic rash has been reported. Erlotinib is a potent EGFRI approved for treatment of non-small cell lung cancer (NSCLC) and pancreatic cancer. Methods: This is the first time in which patients were given increasing doses of an EGFRI to induce a mechanistic rash and study its associated pathology in skin. Biopsies were collected during treatment from both rash-affected and unaffected skin of 23 NSCLC patients and compared with pre-treatment biopsies. Results: Altered differentiation of appendegeal epithelium (hair follicles and sebaceous glands) was remarkable in both affected and unaffected skin, although epidermal growth was not significantly reduced. A predominantly mononuclear leucocyte infiltrate was detected in the interfollicular dermis or around skin appendages. This infiltrate included TRAIL-positive cells with a dendritic cell (DC) morphology, although T-cells, antigen-presenting DCs and macrophages were also evident. This is the first report showing the involvement of a dendritic cell subtype with EGFRI skin toxicity. Conclusions: Altered differentiation of pilosebaceous epithelium is evident in both rash-affected and unaffected skin and constitutes the primary process of EGFRI in human skin. We propose that this eventually triggers inflammation and the EGFRI rash. TRAIL-positive inflammatory cells could link rash development and immune-triggered apoptosis of epithelial cells, including those of underlying carcinomas. [Copyright &y& Elsevier]

Myeloid dermal dendritic cells (DCs) accumulate in chronically inflamed tissues such as psoriasis. The importance of these cells for psoriasis pathogenesis is suggested by comparative T-cell and DC-cell counts, where DCs outnumber T cells. We have previously identified CD11c+-blood dendritic cell antigen (BDCA)-1+ cells as the main resident dermal DC population found in normal skin. We now show that psoriatic lesional skin has two populations of dermal DCs: (1) CD11c+BDCA-1+ cells, which are phenotypically similar to those contained in normal skin and (2) CD11c+BDCA-1− cells, which are phenotypically immature and produce inflammatory cytokines. Although BDCA-1+ DCs are not increased in number in psoriatic lesional skin compared with normal skin, BDCA-1− DCs are increased 30-fold. For functional studies, we FACS-sorted psoriatic dermal single-cell suspensions to isolate these two cutaneous DC populations, and cultured them as stimulators in an allogeneic mixed leukocyte reaction. Both BDCA-1+ and BDCA-1− myeloid dermal DC populations induced T-cell proliferation, and polarized T cells to become T helper 1 (Th1) and T helper 17 (Th17) cells. In addition, psoriatic dermal DCs induced a population of activated T cells that simultaneously produced IL-17 and IFN-γ, which was not induced by normal skin dermal DCs. As psoriasis is believed to be a mixed Th17/Th1 disease, it is possible that induction of these IL-17+IFN-γ+ cells is pathogenic. These cytokines, the T cells that produce them, and the inducing inflammatory DCs may all be important new therapeutic targets in psoriasis.Journal of Investigative Dermatology (2009) 129, 79–88; doi:10.1038/jid.2008.194; published online 17 July 2008 [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 (α-IR3) that binds to the α-chain of this receptor to study its expression (1) 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. [ABSTRACT FROM AUTHOR]

The epidermal growth factor (EGF) receptor pathway is an important mediator of keratinocyte growth in vitro and both receptor and ligand components of this pathway are abnormally expressed in hyperproliferative epidermis. The purpose of this study was to examine interactions between the EGF receptor pathway and the insulin-like growth factor I/somatomedin C (IGF-I) receptor pathway in modulating the growth of cultured normal human keratinocytes. Short-term growth of keratinocytes in a chemically defined medium demonstrated that neither EGF nor IGF-I alone could Support significant keratinocyte spreading or proliferation, but that a combination of EGF with IGF-I or high-dose insulin could. IGF-I or high-dose insulin transmodulates keratinocyte EGF receptor expression via the IGF-I receptor in a dose- and time-dependent manner, increasing EGF receptor binding an average of 1.8 times up to a maximum of fourfold without altering EGF binding affinity. Staining of normal human epidermis with an IGF-I receptor specific monoclonal antibody demonstrates that IGF-I receptors localize to the basal proliferative cell compartment, suggesting that LGF-I receptor and EGF receptor pathway interactions may play a role in the regulation of epidermal growth and in the pathogenesis of hyperproliferative skin diseases. [ABSTRACT FROM AUTHOR]