Potential role of the chemokine receptors CXCR3, CCR4, and the integrin alphaEbeta7 in the pathogenesis of psoriasis vulgaris

The human cutaneous chemokine system

Irrespective of the immune status, the vast majority of all lymphocytes reside in peripheral tissues whereas those present in blood only amount to a small fraction of the total. It has been estimated that T cells in healthy human skin outnumber those present in blood by at least a factor of two. How lymphocytes within these two compartments relate to each other is not well understood. However, mounting evidence suggest that the study of T cell subsets present in peripheral blood does not reflect the function of their counterparts at peripheral sites. This is especially true under steady-state conditions whereby long-lived memory T cells in healthy tissues, notably those in epithelial tissues at body surfaces, are thought to fulfill a critical immune surveillance function by contributing to the first line of defense against a series of local threats, including microbes, tumors, and toxins, and by participating in wound healing. The relative scarcity of information regarding peripheral T cells and the factors regulating their localization is primarily due to inherent difficulties in obtaining healthy tissue for the extraction and study of immune cells on a routine basis. This is most certainly true for humans. Here, we review our current understanding of T cell homing to human skin and compare it when possible with gut-selective homing. We also discuss candidate chemokines that may account for the tissue selectivity in this process and present a model whereby CCR8, and its ligand CCL1, selectively regulate the homeostatic migration of memory lymphocytes to skin tissue.

Targeting chemokine receptors in chronic inflammatory diseases: an extensive review

The traffic of the different types of immune cells is an important aspect in the immune response. Chemokines are soluble peptides that are able to attract cells by interaction with chemokine receptors on their target cells. Several different chemokines and receptors exist enabling the specific trafficking of different immune cells. In chronic inflammatory disorders there is abundance of immune cells present at the inflammatory site. This review focuses on the role of chemokine receptors in chronic inflammatory disorders of the lungs, intestine, joints, skin and nervous system and the potential of targeting these receptors as therapeutic intervention in these disorders.

The mode of actions of the Adacolumn therapeutic leucocytapheresis in patients with inflammatory bowel disease: a concise review

Patients with active inflammatory bowel disease (IBD) have elevated and activated myeloid leucocytes which infiltrate the colonic mucosa in vast numbers. Myeloid leucocytes such as the CD14(+) CD16(+) monocytes are major sources of tumour necrosis factor (TNF)-α, and therefore selective granulocyte/monocyte (GM) adsorption (GMA) should promote remission or enhance efficacy of pharmacological therapy. However, studies in IBD have reported both impressive as well as disappointing efficacy outcomes, indicating that patients' demographic factors might determine responders or non-responders to GMA. Nonetheless, this non-drug intervention has an excellent safety profile, and therapeutic GMA is expected to expand. In this review, attempts have been made to compile an update on the mode of actions (MoA) of the Adacolumn GMA. The MoA of GMA appears to be more than adsorption of excess neutrophils and TNF-producing CD14(+) CD16(+) monocytes per se. Adsorbed GMs release interleukin (IL)-1 receptor antagonist, hepatocyte growth factor and soluble TNF receptors, which are anti-inflammatory. Additionally, a sustained increase in lymphocytes including the regulatory CD4(+) CD25(+) T cells (lymphocyte sparing) is seen post-GMA. The impact of GMA on the immune system is potentially very interesting in the context of treating immune-related diseases. Future studies are expected to add intriguing insights to the MoA of GMA.

The mode of actions of the Adacolumn therapeutic leucocytapheresis in patients with inflammatory bowel disease: a concise review

Patients with active inflammatory bowel disease (IBD) have elevated and activated myeloid leucocytes which infiltrate the colonic mucosa in vast numbers. Myeloid leucocytes such as the CD14(+) CD16(+) monocytes are major sources of tumour necrosis factor (TNF)-α, and therefore selective granulocyte/monocyte (GM) adsorption (GMA) should promote remission or enhance efficacy of pharmacological therapy. However, studies in IBD have reported both impressive as well as disappointing efficacy outcomes, indicating that patients' demographic factors might determine responders or non-responders to GMA. Nonetheless, this non-drug intervention has an excellent safety profile, and therapeutic GMA is expected to expand. In this review, attempts have been made to compile an update on the mode of actions (MoA) of the Adacolumn GMA. The MoA of GMA appears to be more than adsorption of excess neutrophils and TNF-producing CD14(+) CD16(+) monocytes per se. Adsorbed GMs release interleukin (IL)-1 receptor antagonist, hepatocyte growth factor and soluble TNF receptors, which are anti-inflammatory. Additionally, a sustained increase in lymphocytes including the regulatory CD4(+) CD25(+) T cells (lymphocyte sparing) is seen post-GMA. The impact of GMA on the immune system is potentially very interesting in the context of treating immune-related diseases. Future studies are expected to add intriguing insights to the MoA of GMA.

CCR6 as a possible therapeutic target in psoriasis

IMPORTANCE OF THE FIELD

Psoriasis is a common, chronic autoimmune disease of the skin. Despite a number of effective treatments, new therapies are needed with enhanced efficacy, safety and convenience. Chemokine receptors are GPCRs that control leukocyte trafficking, and like other GPCRs, are good potential drug targets. The chemokine receptor CCR6 is expressed on the T(H)17 subset of CD4(+) T cells, which produces IL-17A/F, IL-22, TNF-alpha and other cytokines, and which has been implicated in the pathogenesis of psoriasis. CCR6 and its ligand, CCL20/MIP-3alpha, are highly expressed in psoriatic skin and CCR6 is necessary for the pathology induced in a mouse model of psoriasis-like inflammation.

AREAS COVERED IN THIS REVIEW

This review summarizes the evidence for the importance of the IL-23/T(H)17 axis, and in particular CCR6 and CCL20 in psoriasis, dating from 2000 to the present, and discusses the possibility of inhibiting CCR6 as a treatment for the disease.

WHAT THE READER WILL GAIN

The review informs the reader of the current thinking on the mechanisms of inflammation in psoriasis and the possible roles for CCR6 (and CCL20) in disease pathogenesis.

TAKE HOME MESSAGE

We conclude that CCR6 should be investigated as a potential therapeutic target in psoriasis.

Drug-induced Hemolytic Anemia and Thrombocytopenia Associated with Alterations of Cell Membrane Lipids and Acanthocyte Formation

CXCR3 is a chemokine receptor, upregulated upon activation of T cells and expressed on nearly 100% of T cells in sites of inflammation. SCH 900875 is a selective CXCR3 receptor antagonist. Thrombocytopenia and severe hemolytic anemia with acanthocytosis occurred in rats at doses of 75, 100, and 150 mg/kg/day. Massively enlarged spleens corresponded histologically to extramedullary hematopoiesis, macrophages, and hemosiderin pigment and sinus congestion. Phagocytosed erythrocytes and platelets were within splenic macrophages. IgG and/or IgM were not detected on erythrocyte and platelet membranes. Ex vivo increased osmotic fragility of RBCs was observed. Lipid analysis of the RBC membrane revealed modifications in phosphatidylcholine, overall cholesterol, and/or sphingomyelin. Platelets exhibited slender filiform processes on their plasma membranes, analogous to those of acanthocytes. The presence of similar morphological abnormalities in acanthocytes and platelets suggests that possibly similar alterations in the lipid composition of the plasma membrane have taken place in both cell types. This phenotype correlated with alterations in plasma lipids (hypercholesterolemia and low triglycerides) that occurred after SCH 900875 administration, although other factors cannot be excluded. The increased cell destruction was considered triggered by alterations in the lipid profile of the plasma membranes of erythrocytes and platelets, as reflected morphologically.

Assessment of the psoriatic transcriptome in a large sample: additional regulated genes and comparisons with in vitro models

To further elucidate molecular alterations in psoriasis, we performed a gene expression study of 58 paired lesional and uninvolved psoriatic and 64 control skin samples. Comparison of involved psoriatic (PP) and normal (NN) skin identified 1,326 differentially regulated transcripts encoding 918 unique genes (549 up- and 369 downregulated), of which over 600 are to our knowledge previously unreported, including S100A7A, THRSP, and ELOVL3. Strongly upregulated genes included SERPINB4, PI3, DEFB4, and several S100-family members. Strongly downregulated genes included Wnt-inhibitory factor-1 (WIF1), beta-cellulin (BTC), and CCL27. Enriched gene ontology categories included immune response, defense response, and keratinocyte differentiation. Biological processes regulating fatty acid and lipid metabolism were enriched in the down-regulated gene set. Comparison of the psoriatic transcriptome to the transcriptomes of cytokine-stimulated cultured keratinocytes (IL-17, IL-22, IL-1alpha, IFN-gamma, TNF-alpha, and OSM) showed surprisingly little overlap, with the cytokine-stimulated keratinocyte expression representing only 2.5, 0.7, 1.5, 5.6, 5.0, and 1.9% of the lesional psoriatic dysregulated transcriptome, respectively. This comprehensive analysis of differentially regulated transcripts in psoriasis provides additional insight into the pathogenic mechanisms involved and emphasizes the need for more complex yet tractable experimental models of psoriasis.

Psoriatic skin lesions induced by tumor necrosis factor antagonist therapy: clinical features and possible immunopathogenesis

OBJECTIVE

The induction or exacerbation of psoriasis in patients treated with tumor necrosis factor (TNF) antagonists is a well-established phenomenon. The goals of this comprehensive literature analysis were to update currently available data regarding this adverse event, to identify any clinical patterns in the cohort of reported patients, and to review the possible immunopathogenesis.

METHODS

A systematic literature review was performed utilizing PubMed and Medline databases (1996 to August 2009) searching the index terms "tumor necrosis factor alpha inhibitor," "TNF," "infliximab," "etanercept," "adalimumab," combined with the terms "psoriasis," "pustular," "skin," "rash," "palmoplantar," and "paradoxical." All relevant articles were reviewed. Patients who did not appear to meet accepted classification criteria for their treated disease, who had a more probable explanation or other likely diagnosis for their skin findings or known possible triggering factor for the skin eruption, including infection, were excluded from this analysis.

RESULTS

Two hundred seven cases met inclusion criteria for review. Of these, 43% were diagnosed with rheumatoid arthritis, 26% with seronegative spondyloarthropathy, and 20% with inflammatory bowel disease. Mean patient age was 45 years and 65% were female. Fifty-nine percent were being treated with infliximab, 22% with adalimumab, and 19% with etanercept. Lesion morphology included pustular psoriasis in 56%, plaque psoriasis in 50%, and guttate lesions in 12%; 15% experienced lesions of more than 1 type. No statistically significant predisposing factors for the development of new-onset psoriasis were found. Sixty-six percent of patients were able to continue TNF antagonist therapy with psoriasis treatments. The pathogenesis appears to involve disruption of the cytokine milieu with production of unopposed interferon-α production by plasmacytoid dendritic cells in genetically predisposed individuals. Genetic polymorphisms may play a role in this paradoxical reaction to TNF blockade.

CONCLUSIONS

TNF antagonist induced psoriasis is a well-described adverse event without any known predisposing risk factors. Most patients can be managed conservatively without drug withdrawal. Registry data reporting is necessary to define the true incidence and prevalence of this condition. Genomic studies of affected patients may assist with identification of predisposed patients and elucidation of the molecular trigger of this perplexing response.

A subpopulation of CD163-positive macrophages is classically activated in psoriasis

Macrophages are important cells of the innate immune system, and their study is essential to gain greater understanding of the inflammatory nature of psoriasis. We used immunohistochemistry and double-label immunofluorescence to characterize CD163(+) macrophages in psoriasis. Dermal macrophages were increased in psoriasis compared with normal skin and were identified by CD163, RFD7, CD68, lysosomal-associated membrane protein 2 (LAMP2), stabilin-1, and macrophage receptor with collagenous structure (MARCO). CD163(+) macrophages expressed C-lectins CD206/macrophage mannose receptor and CD209/DC-SIGN, as well as costimulatory molecules CD86 and CD40. They did not express mature dendritic cell (DC) markers CD208/DC-lysosomal-associated membrane glycoprotein, CD205/DEC205, or CD83. Microarray analysis of in vitro-derived macrophages treated with IFN-γ showed that many of the genes upregulated in macrophages were found in psoriasis, including STAT1, CXCL9, Mx1, and HLA-DR. CD163(+) macrophages produced inflammatory molecules IL-23p19 and IL-12/23p40 as well as tumor necrosis factor (TNF) and inducible nitric oxide synthase (iNOS). These data show that CD163 is a superior marker of macrophages, and identifies a subpopulation of "classically activated" macrophages in psoriasis. We conclude that macrophages are likely to contribute to the pathogenic inflammation in psoriasis, a prototypical T helper 1 (Th1) and Th17 disease, by releasing key inflammatory products.

Peripheral blood gene expression patterns discriminate among chronic inflammatory diseases and healthy controls and identify novel targets

Background

Chronic inflammatory diseases including inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis), psoriasis and rheumatoid arthritis (RA) afflict millions of people worldwide, but their pathogenesis is still not well understood.

It is also not well known if distinct changes in gene expression characterize these diseases and if these patterns can discriminate between diseased and control patients and/or stratify the disease. The main focus of our work was the identification of novel markers that overlap among the 3 diseases or discriminate them from each other.

Methods

Diseased (n = 13, n = 15 and n = 12 in IBD, psoriasis and RA respectively) and healthy patients (n = 18) were recruited based on strict inclusion and exclusion criteria; peripheral blood samples were collected by clinicians (30 ml) in Venous Blood Vacuum Collection Tubes containing EDTA and peripheral blood mononuclear cells were separated by Ficoll gradient centrifugation. RNA was extracted using Trizol reagent. Gene expression data was obtained using TaqMan Low Density Array (TLDA) containing 96 genes that were selected by an algorithm and the statistical analyses were performed in Prism by using non-parametric Mann-Whitney U test (P-values < 0.05).

Results

Here we show that using a panel of 96 disease associated genes and measuring mRNA expression levels in peripheral blood derived mononuclear cells; we could identify disease-specific gene panels that separate each disease from healthy controls. In addition, a panel of five genes such as ADM, AQP9, CXCL2, IL10 and NAMPT discriminates between all samples from patients with chronic inflammation and healthy controls. We also found genes that stratify the diseases and separate different subtypes or different states of prognosis in each condition.

Conclusions

These findings and the identification of five universal markers of chronic inflammation suggest that these diseases have a common background in pathomechanism, but still can be separated by peripheral blood gene expression. Importantly, the identified genes can be associated with overlapping biological processes including changed inflammatory response. Gene panels based on such markers can play a major role in the development of personalized medicine, in monitoring disease progression and can lead to the identification of new potential drug targets in chronic inflammation.

Integrated network analysis of transcriptomic and proteomic data in psoriasis

BACKGROUND

Psoriasis is complex inflammatory skin pathology of autoimmune origin. Several cell types are perturbed in this pathology, and underlying signaling events are complex and still poorly understood.

RESULTS

In order to gain insight into molecular machinery underlying the disease, we conducted a comprehensive meta-analysis of proteomics and transcriptomics of psoriatic lesions from independent studies. Network-based analysis revealed similarities in regulation at both proteomics and transcriptomics level. We identified a group of transcription factors responsible for overexpression of psoriasis genes and a number of previously unknown signaling pathways that may play a role in this process. We also evaluated functional synergy between transcriptomics and proteomics results.

CONCLUSIONS

We developed network-based methodology for integrative analysis of high throughput data sets of different types. Investigation of proteomics and transcriptomics data sets on psoriasis revealed versatility in regulatory machinery underlying pathology and showed complementarities between two levels of cellular organization.

Up-regulation of CC chemokine receptor 6 on tonsillar T cells and its induction by in vitro stimulation with alpha-streptococci in patients with pustulosis palmaris et plantaris

Pustulosis palmaris et plantaris (PPP) is a tonsil-related disease; tonsillectomy is somewhat effective in treating the condition. However, the aetiological association between the tonsils and PPP has not yet been elucidated fully. Recently, some chemokines and chemokine receptors, including CC chemokine receptor (CCR) 4, CCR6 and CX chemokine receptor (CXCR) 3, have been reported to play important roles in the development of psoriasis, a disease related closely to PPP. In this study, we found that CCR6 expression on both tonsillar and peripheral blood T cells was up-regulated more intensively in PPP patients than in non-PPP patients (P < 0.001 for both), but CCR4 and CXCR3 expressions were not. In vitro stimulation with alpha-streptococcal antigen enhanced CCR6 expression significantly on tonsillar T cells in PPP patients (P < 0.05), but this was not observed in non-PPP patients. The chemotactic response of tonsillar T cells to the CCR6 ligand CC chemokine ligand (CCL) 20 was significantly higher in PPP patients than in non-PPP patients (P < 0.05). The percentage of CCR6-positive peripheral blood T cells decreased after tonsillectomy in PPP patients (P < 0.01); this decrease correlated with an improvement of skin lesions (P < 0.05, r = -0.63). The numbers of CCR6-positive cells and the expression of CCL20 were increased significantly in pathological lesions compared with non-pathological lesions in PPP skin (P < 0.01, P < 0.05 respectively). These results suggest that a novel immune response to alpha-streptococci may enhance CCR6 expression on T cells in tonsils and that CCR6-positive T cells may move to peripheral blood circulation, resulting in recruitment to target skin lesions expressing CCL20 in PPP patients. This may be one of the key roles in pathogenesis of the tonsil-related disease PPP.

Novel CXCR3 antagonists with a piperazinyl-piperidine core

High-throughput screening of an encoded combinatorial aryl piperazine library led to the identification of a novel series of potent piperazinyl-piperidine based CXCR3 antagonists. Analogs of the initial hit were synthesized via solid and solution phase methods to probe the influence of structure on the CXCR3 binding of these molecules. Various functional groups were found to contribute to the overall potency and essential molecular features were identified.

Genome-wide association scan yields new insights into the immunopathogenesis of psoriasis

Psoriasis is a common, immunologically mediated, inflammatory and hyperproliferative disease of the skin and joints, with a multifactorial genetic basis. We earlier mapped PSORS1, the major psoriasis susceptibility gene in the major histocompatibility complex (MHC), to within or very near HLA-Cw6. In an effort to identify non-MHC psoriasis genes, we carried out a collaborative genome-wide association study. After the initial follow-up genotyping of 21 single nucleotide polymorphisms from 18 loci, showing strong evidence of association in the initial scan, we confirmed evidence of association at seven loci. Three of these loci confirm earlier reports of association (HLA-C, IL12B, IL23R) and four identify novel signals located near plausible candidate genes (IL23A, IL4/IL13, TNFAIP3 and TNIP1). In other work, we have also shown that interferon-gamma (IFN-gamma) treatment induces interleukin (IL)-23 mRNA and protein in antigen-presenting cells (APC), leading to the proliferation of CD4+ and CD8+ memory T cells expressing IL-17. Although functional variants remain to be identified, we speculate that genetic variants at the IL4/IL13 locus contribute to the Th1 bias that is characteristic of psoriasis, that Th1-derived IFN-gamma supports expansion of IL-17+ T cells through APC-derived IL-23 and that negative regulation of inflammatory signaling through the NF-kappaB axis is impaired because of genetic variants of TNFAIP3 and TNIP1.

New insights into the pathogenesis and genetics of psoriatic arthritis

Psoriasis vulgaris and psoriatic arthritis (PsA) are inter-related heritable diseases. Psoriatic skin is characterized by hyperproliferative, poorly differentiated keratinocytes and severe inflammation. Psoriatic joints are characterized by highly inflamed synovia and entheses with focal erosions of cartilage and bone. Genetic analyses have uncovered risk factors shared by both psoriasis and PsA. Predisposition to psoriasis and PsA arising from common variation is most strongly conferred by the HLA class I region. Other genetic risk factors implicate the interleukin (IL)-23 pathway and the induction and regulation of type 17 T-helper cells in the pathogenesis of both diseases. Secretion of cytokines, such as IL-22 and IL-17, could result in the hyperproliferative phenotype of keratinocytes and potentially synoviocytes, leading to a vicious cycle of cellular proliferation and inflammation in both the skin and joints. In synovial tissue, disease-related cytokines could also promote osteoclast formation, resulting in bone erosion. The next step will be to identify genetic risk factors specifically associated with PsA. Although therapies that target tumor necrosis factor are often highly successful in the treatment of both diseases, genetic findings are likely to lead to the development of treatments tailored to an individual's genetic profile.

The Increased Expression of Matrix Metalloproteinase-9 Messenger RNA in the Non-lesional Skin of Patients with Large Plaque Psoriasis Vulgaris

BACKGROUND

A difference of the interleukin-18 (IL-18) mRNA expression among several proinflammatory genes was previously observed between large plaque (LP) psoriasis patients (more than 5 cm lesions are typical) and small plaque (SP) psoriasis patients (1~2 cm lesions are typical). Therefore, it is necessary to test whether there is any difference in the expression of the genes that activate IL-18 or the expression of genes that are induced by IL-18.

OBJECTIVE

To test the differential mRNA expressions of caspase-1, STAT-6, MMP-1, MMP-2, MMP-9 and TIMP-1 according to the clinical types of psoriasis vulgaris lesions in Korean patients, we have analyzed the skin samples of psoriasis vulgaris patients.

METHODS

The total cellular RNA of skin samples from groups of patient with LP and SP psoriasis was analyzed by performing real-time PCR (the Taqman method) to compare the differences in the mRNA expressions.

RESULTS

The caspase-1 and STAT-6 mRNA expression levels from the SP lesional skin of the patients were increased compared with the caspase-1 and STAT-6 mRNA expression levels from SP non-lesional skin or normal skin, but these expression levels from the SP non-lesional skin were not significantly different from those of the LP non-lesional skin. Among MMP-1, MMP-2, MMP-9 and TIMP-1, the expressions of MMP-1, MMP-2 and MMP-9 mRNA were increased in the SP lesional skin compared with those of the SP non-lesional skin. The MMP-1 mRNA expressions in both the LP and SP lesional skin were increased compared with those in the normal skin (p=0.028 and p=0.007 respectively). The MMP-9 mRNA expression in the LP non-lesional skin was elevated compared with the MMP-9 mRNA expression in the SP non-lesional skin (p=0.047). The TIMP-1 mRNA expression levels from the non-lesional skin and the lesional skin of the psoriasis patients and the normal skin samples were not significantly different.

CONCLUSION

The increased expression of MMP-9 mRNA in the LP non-lesional skin compared to that of the SP non-lesional skin in the psoriatic skin suggests that the increased MMP-9 mRNA expression is related to the large size type of lesion.

Potent and orally bioavailable CCR4 antagonists: Synthesis and structure-activity relationship study of 2-aminoquinazolines

Starting with a series of CC chemokine receptor-4 (CCR4) antagonists developed in a previous study, the potency was improved by replacing the pyrrolidine moiety of N-(4-chlorophenyl)-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine 2 with a 3-(hydroxymethyl)piperidine. The resulting compound (1'-{4-[(4-chlorophenyl)amino]-6,7-dimethoxyquinazolin-2-yl}-1,4'-bipiperidin-3-yl)methanol 8ic was a strong inhibitor of human/mouse chemotaxis. Oral administration of 8ic showed anti-inflammatory activity in a murine model of acute dermatitis (oxazolone-induced contact hypersensitivity test) in a dose-dependent manner.

Th17 cytokines interleukin (IL)-17 and IL-22 modulate distinct inflammatory and keratinocyte-response pathways

BACKGROUND

Psoriasis vulgaris is an inflammatory skin disease mediated by Th1 and Th17 cytokines, yet the relative contribution of interferon (IFN)-gamma, interleukin (IL)-17 and IL-22 on disease pathogenesis is still unknown.

OBJECTIVES

In this study, we sought to identify the cytokines produced by skin-resident T cells in normal skin, localize the receptors for these cytokines, and examine how these cytokines alter gene expression profiles of the cells bearing cognate receptors.

METHODS

We used intracellular cytokine staining and flow cytometry to evaluate T cell cytokine production, and immunohistochemistry and double-label immunofluorescence to localize cytokine receptors in skin. Gene array analysis of cytokine-treated keratinocytes was performed using moderated paired t-test controlling for false discovery rate using the Benjamini-Hochberg procedure.

RESULTS

We demonstrate that T-helper cells producing IL-17, IL-22 and/or IFN-gamma, as well as the cells bearing cognate cytokine receptors, are present in normal human skin. Keratinocytes stimulated with IL-17 expressed chemokines that were different from those induced by IFN-gamma, probably contributing to the influx of neutrophils, dendritic cells and memory T cells into the psoriatic lesion. In contrast, IL-22 downregulated genes associated with keratinocyte differentiation and caused epidermal alterations in an organotypic skin model.

CONCLUSIONS

Our results suggest that the Th17 cytokines IL-17 and IL-22 mediate distinct downstream pathways that contribute to the psoriatic phenotype: IL-17 is more proinflammatory, while IL-22 retards keratinocyte differentiation.

Chemokines in neuroectodermal cancers: the crucial growth signal from the soil

Although chemokines and their receptors were initially identified as regulators of cell trafficking during inflammation and immune response, they have emerged as crucial players in all stages of tumor development, primary growth, migration, angiogenesis, and establishment as metastases in distant target organs. Neuroectodermal tumors regroup neoplasms originating from the embryonic neural crest cells, which display clinical and biological similarities. These tumors are highly malignant and rapidly progressing diseases that disseminate to similar target organs such as bone marrow, bone, liver and lungs. There is increasing evidence that interaction of several chemokine receptors with corresponding chemokine ligands are implicated in the growth and invasive characteristics of these tumors. In this review we summarize the current knowledge on the role of CXCL12 chemokine and its CXCR4 and CXCR7 receptors in the progression and survival of neuroectodermal tumors, with particular emphasis on neuroblastoma, the most typical and enigmatic neuroectodermal childhood tumor.

Potent CCR4 antagonists: synthesis, evaluation, and docking study of 2,4-diaminoquinazolines

A series of CC chemokine receptor-4 (CCR4) antagonists were examined in a previous report in an attempt to improve metabolic stability in human liver microsomes. In this study, the cycloheptylamine moiety of N-cycloheptyl-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine 1 was replaced with the p-chloroaniline moiety, and the resulting compound, N-(4-chlorophenyl)-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine (8c), retained its potency ([(35)S]GTPgammaS-binding inhibition and CCL22-induced chemotaxis in humans/mice). Based on the structure-activity relationships (SAR), a homology model was constructed for CCR4 to explain the binding mode of 8c. Overall, there was good agreement between the docking pose of the CCR4 homology model and the human [(35)S]GTPgammaS assay results. Administration of 8c in a murine model of acute dermatitis showed anti-inflammatory activity (oxazolone-induced contact hypersensitivity test).

Discovery of potent CCR4 antagonists: Synthesis and structure-activity relationship study of 2,4-diaminoquinazolines

A new series of quinazolines that function as CCR4 antagonists were discovered during the screening of our corporate compound libraries. Subsequent compound optimization elucidated the structure-activity relationships and led the identification of 2-(1,4'-bipiperidine-1'-yl)-N-cycloheptyl-6,7-dimethoxyquinazolin-4-amine 14a, which showed potent inhibition in the [(35)S]GTPgammaS-binding assay (IC(50)=18nM). This compound also inhibited the chemotaxis of human and mouse CCR4-expressing cells (IC(50)=140nM, 39nM).

Three decades of psoriasis research: where has it led us?

Psoriasis is a common chronic skin disease. Its pathogenesis has intensively been investigated in the last 3 decades. In the 1970s, the observed increased proliferation of keratinocytes and their altered differentiation were considered to be the most important signs and causes of psoriatic skin lesions. Since the early 1980s, T cells slid into the focus of psoriasis research. It was then postulated that a subpopulation of T cells, so-called T1 cells, and their prominent cytokine interferon-gamma, had a dominant role in the pathogenesis of psoriasis. In the last decade, new data regarding macrophages and dendritic cells and the high therapeutic success of anti-tumor necrosis factor alpha biologics led to the assumption that antigen-presenting cells are important not only in the induction of psoriasis but also in its maintenance. The knowledge gained over the past 3 decades let us postulate that psoriasis is an immunologically induced, overshot, regeneration-like reaction of the skin in which various cells play a dominant role at different stages. This hypothesis is also supported by the very recent discoveries about interleukin (IL)-22, IL-20, and IL-23.

CCR4 and CCR10 ligands play additive roles in mouse contact hypersensitivity

Psoriasis, atopic dermatitis and allergic contact dermatitis are T-cell-mediated inflammatory skin diseases; chemokine receptors (CCR) 4 and 10 play an important role in the ligand-mediated recruitment of T cells into the skin in mice and humans, specifically with regards to tethering, firm adhesion and subsequent extravasation to the sight of injury. We utilized established murine models of dinitrofluorobenzene-, trimellitic acid anhydride- or oxazalone-induced contact hypersensitivity, to reflect the various Th-polarizations of different skin diseases, and investigated the functional effect of antibody blocking of single CCR ligands or combination therapy to block all CCR4 and CCR10 ligands. Our results indicate a greater reduction in inflammatory response--measured by oedema formation, myeloid cell and neutrophil infiltration and activity and CD3+ cell infiltration at the site of injury--with combination antibody therapy to CCR4 and CCR10 ligands versus controls, in nearly every tested condition. We conclude that blocking CCR4 and CCR10 simultaneously, or their ligands, should be beneficial in the treatment of T-cell-mediated skin diseases.

A case report of steroid and immunosuppressant-resistant pyoderma gangrenosum successfully treated by granulocytapheresis

Granulocytapheresis (GCAP) therapy is a newly developed therapeutic modality for inflammatory bowel diseases such as ulcerative colitis and Crohn's disease. Pyoderma gangrenosum (PG) is a chronic inflammatory skin disease characterized by the appearance of erythematous macules and plaques with pustules or nodules that rapidly progress to ragged, undermined multiple ulcers. We attempted GCAP therapy in a patient with PG resistant to prednisolone and various other immunosuppressants. GCAP therapy was initiated at three- to four-day intervals and a good response from all skin lesions, with eventual total epithelialization, was observed after 10 sessions of this therapy. Furthermore, circulating levels of inflammatory cytokines such as interleukin-8 (IL-8) and granulocyte colony stimulating factor (G-CSF) also decreased after the GCAP therapy. Our results suggest that GCAP is a safe and useful tool for the treatment of intractable PG, and that IL-8 and G-CSF are likely to be involved in the pathogenesis of PG.

Epidermal chemokines and modulation by antihistamines, antibiotics and antifungals

Growing evidence has demonstrated that chemokines released from epidermal cells control inflammatory skin diseases. Keratinocytes elaborate both Th1- and Th2-associated chemokines, although the former is more abundantly produced than the latter. Downmodulation of keratinocyte production of chemokines is one of the therapeutic approaches for cutaneous inflammatory disorders. Recent observations have shown that keratinocyte chemokine production can be modulated by well-used drugs, including antihistamines, antibiotics and antifungals. Utilization of the beneficial side effects of these drugs may by clinically valuable.

Immunopathogenesis of psoriasis

Psoriasis is a chronic skin disease that affects about 1.5% of the Caucasian population and is characterized by typical macroscopic and microscopic skin alterations. Psoriatic lesions are sharply demarcated, red and slightly raised lesions with silver-whitish scales. The microscopic alterations of psoriatic plaques include an infiltration of immune cells in the dermis and epidermis, a dilatation and an increase in the number of blood vessels in the upper dermis, and a massively thickened epidermis with atypical keratinocyte differentiation. It is considered a fact that the immune system plays an important role in the pathogenesis of psoriasis. Since the early 1990s, it has been assumed that T1 cells play the dominant role in the initiation and maintenance of psoriasis. However, the profound success of anti-tumor necrosis factor-alpha therapy, when compared with T-cell depletion therapies, should provoke us to critically re-evaluate the current hypothesis for psoriasis pathogenesis. Recently made discoveries regarding other T-cell populations such as Th17 and regulatory T cells, dendritic cells, macrophages, the keratinocyte signal transduction and novel cytokines including interleukin (IL)-22, IL-23 and IL-20, let us postulate that the pathogenesis of psoriasis consists of distinct subsequent stages, in each of them different cell types playing a dominant role. Our model helps to explain the varied effectiveness of the currently tested immune modulating therapies and may enable the prediction of the success of future therapies.

Adhesion molecules in cutaneous immunity

Skin serves a vital role, providing protection from the broad array of pathogens present in our environment. In addition to the passive barrier functions of the skin, mammals have evolved a robust and versatile surveillance and rapid response system for recognition and elimination of invading organisms. This immune surveillance network directs the movement of immune cells, regulating homeostatic populations of immune cells in the skin, as well as recruitment to sites of inflammation. In this review, we discuss current understanding of the regulation and function of adhesion molecules in cutaneous immune surveillance and their relevance to the immunopathology of inflammatory skin disease.

Expression of the chemokine receptor CCR5 in psoriasis and results of a randomized placebo controlled trial with a CCR5 inhibitor

Several reports have indicated that the chemokine receptor CCR5 and its ligands, especially CCL5 (formerly known as RANTES), may play a role in the pathogenesis of psoriasis. The purpose of this investigation was to examine the expression of CCR5 and its ligands in chronic plaque psoriasis and to evaluate the clinical and immunohistochemical effect of a CCR5 receptor inhibitor. Immunohistochemical analysis showed low but significant increased total numbers of CCR5 positive cells in epidermis and dermis of lesional skin in comparison to non-lesional skin. However, relative expression of CCR5 proportional to the cells observed revealed that the difference between lesional and non-lesional skin was only statistically significant in the epidermis for CD3 positive cells and in the dermis for CD68 positive cells. Quantification of mRNA by reverse transcriptase-polymerase chain reaction only showed an increased expression of CCL5 (RANTES) in lesional skin. A randomized placebo-controlled clinical trial in 32 psoriasis patients revealed no significant clinical effect and no changes at the immunohistochemical level comparing patients treated with placebo or a CCR5 inhibitor SCH351125. We conclude that although CCR5 expression is increased in psoriatic lesions, this receptor does not play a crucial role in the pathogenesis of psoriasis.

Modulating leukocyte recruitment in inflammation

Much information has been obtained regarding how white cells are recruited in the microcirculation to sites of inflammation. In this review we summarize the leukocyte recruitment cascade, highlighting the molecular mechanisms that underlie each of the major steps. Major emphasis is placed on the selectins and integrins and their role in rolling and adhesion. Intraluminal crawling and emigration are also briefly discussed. In addition, we summarize some of the data that implicate these molecules in eosinophil recruitment in animal models of asthma and in lymphocyte recruitment in skin contact sensitivity. There is a growing body of evidence to suggest that leukocyte recruitment could be used as an effective means for future therapeutics, and some of these issues are also raised.

Modulation of CLA, IL-12R, CD40L, and IL-2Rα expression and inhibition of IL-12- and IL-23-induced cytokine secretion by CNTO 1275

Cytokines interleukin (IL)-12 and IL-23 are implicated in the pathogenesis of psoriasis. IL-12 causes differentiation of CD4+ T cells to interferon-gamma (IFN-gamma)-producing T helper 1 (Th1) cells, while IL-23 induces differentiation to IL-17-producing pathogenic Th17 cells. The effects of the monoclonal antibody to IL-12/23 p40 subunit (CNTO 1275) on IL-12 receptor (IL-12R) expression, markers associated with skin homing, activation, and cytokine secretion were investigated in vitro using human peripheral blood mononuclear cells (PBMCs) from healthy donors. PBMCs were activated in the presence or absence of recombinant human (rh) IL-12 or rhIL-23, with or without CNTO 1275. CNTO 1275 inhibited upregulation of CLA, IL-12R, IL-2Ralpha and CD40L expression and also inhibited IL-12- and IL-23-induced IFN-gamma, IL-17A, tumor necrosis factor (TNF)-alpha, IL-2, and IL-10 secretion. Thus, the therapeutic effect of CNTO 1275 may be attributed to the IL-12/23 neutralization, resulting in decreased expression of skin homing and activation markers, and IL-12- and IL-23-induced cytokine secretion.

Discovery and optimization of a series of quinazolinone-derived antagonists of CXCR3

A series of quinazolinone-derived inhibitors of the CXCR3 receptor have been synthesized and their affinity for the receptor evaluated. Compounds were evaluated in a (125)I-IP10 displacement assay and in in vitro cell migration assays to IP10, ITAC, and MIG using human peripheral blood mononuclear cells.

Survenue d’un psoriasis au cours d’un traitement par infliximab pour fasciite de Shulman

BACKGROUND

Anti-TNFalpha drugs are used in certain rheumatologic and gastrointestinal inflammatory diseases and are also effective in cutaneous psoriasis. Several case reports have recently been published concerning induction of paradoxical psoriasis during the course of anti-TNF therapy. We report a new case involving infliximab used to treat Shulman fasciitis.

CASE REPORT

A 39-year-old woman was treated with infliximab for corticoid-dependent Shulman fasciitis. No personal or familial cutaneous psoriasis was noted in her history. Two months after the third infusion, she developed psoriasis vulgaris and pustular palmoplantar psoriasis which improved under topical corticosteroids. Her psoriatic lesions worsened one month after the first maintenance infusion. Since the Shulman fasciitis was not under control, infliximab was withdrawn and replaced with azathioprine. Six months later, her psoriasis was in remission and the Shulman fasciitis was under control.

DISCUSSION

TNFalpha plays an important role in the physiopathology of psoriasis through its action on inflammatory infiltrate, angiogenesis and keratinocyte proliferation. Several studies have reported the efficiency of TNFalpha inhibitors in moderate to severe cutaneous psoriasis. However, fourteen cases of induction or worsening of psoriasis have been reported with these drugs, suggesting a class effect. We report a new case of cutaneous psoriasis induced by infliximab in a patient presenting corticoid-dependent Shulman fasciitis, and we discuss the possible immunological mechanisms responsible for this paradoxical side effect. Other cutaneous lesions have been reported during treatment with TNFalpha inhibitors. The benefits of this treatment on the underlying inflammatory disease must be balanced against the potential cutaneous side effects when deciding whether to continue with anti-TNFalpha treatment.