Psoriasis

IL-23 stimulates epidermal hyperplasia via TNF and IL-20R2-dependent mechanisms with implications for psoriasis pathogenesis

Aberrant cytokine expression has been proposed as an underlying cause of psoriasis, although it is unclear which cytokines play critical roles. Interleukin (IL)-23 is expressed in human psoriasis and may be a master regulator cytokine. Direct intradermal administration of IL-23 in mouse skin, but not IL-12, initiates a tumor necrosis factor-dependent, but IL-17A-independent, cascade of events resulting in erythema, mixed dermal infiltrate, and epidermal hyperplasia associated with parakeratosis. IL-23 induced IL-19 and IL-24 expression in mouse skin, and both genes were also elevated in human psoriasis. IL-23-dependent epidermal hyperplasia was observed in IL-19-/- and IL-24-/- mice, but was inhibited in IL-20R2-/- mice. These data implicate IL-23 in the pathogenesis of psoriasis and support IL-20R2 as a novel therapeutic target.

In vivo pharmacological disease models for psoriasis and atopic dermatitis in drug discovery

In order to perform relevant in vivo pharmacological investigations in drug discovery within dermatology it is fundamental to master or have access to relevant skin disease models that makes it possible to identify and validate targets and to screen and discover drugs in vivo. There is a strong need for highly predictive in vivo models in order to introduce the right drug candidates into the clinical phases of development. Recent advances in dermatological in vivo pharmacological disease models for psoriasis and atopic dermatitis are reviewed together with a discussion of the rationale for their application in drug discovery.

Psoriasisschulung für erwachsene Patienten nach den Regeln der Arbeitsgemeinschaft Dermatologische Prävention

BACKGROUND

Psoriasis vulgaris is a chronic inflammatory skin disease with a substantial impairment of quality of life. Interdisciplinary outpatient educational programs are an innovative supplementary therapy form for the management of this disorder.

SUBJECTS AND METHODS

The Task Force on Dermatological Prevention developed a concept for outpatient instruction of psoriasis patients. Five 2-hour classes by dermatologists, psychotherapists/psychologists and dieticians focus on central topics relevant for the patients and the management of the disease.

RESULTS

The results presented are based on own experiences with this educational program. The interdisciplinary program is accepted very well and seen as helpful by the concerned. A structure analysis of the effects in a greater number of cases is a current goal. In some areas, health insurance companies are paying for the classes.

CONCLUSION

The educational program for the management of psoriasis vulgaris according to the rules of the Task Force on Dermatological Prevention is a supplement of the treatment of patients with this chronic skin disease. Broader implementation in Germany is desirable.

Spondyloarthropathy: disease at the crossroads of immunity

Up until recently, the prevailing paradigm relating to spondyloarthropathy (SpA) pathogenesis was that they were human leukocyte antigen (HLA)-associated, T-cell-driven autoimmune diseases. This view is now being questioned. Careful studies of well-characterised cohorts of patients with SpA, including detailed analysis of involved tissue, together with clinical trials of targeted treatments, in particular anti-tumour necrosis factor (TNF) therapies, have contributed enormously to both interest in and understanding of disease pathogenesis. In this chapter, our current knowledge and understanding of the relative contributions of the components of the innate and adaptive arms of the immune response to SpA pathogenesis is reviewed. It is clear that both arms of the immune response are involved and inter-dependent in SpA. With continued emphasis on discovery research, including detailed analysis of novel therapeutic interventions, significant additional breakthroughs in SpA are likely to be forthcoming.

Prevalence of cardiovascular risk factors in patients with psoriasis

BACKGROUND

Previous studies suggest that patients hospitalized for psoriasis have an increased frequency of a variety of cardiovascular comorbidities. Limited population-based data exist on this association, and few studies have determined which factors are independently associated with psoriasis.

OBJECTIVE

We sought to determine whether the prevalence of the major cardiovascular risk factors was higher in mild and severe psoriasis than in patients without psoriasis.

METHODS

We conducted a population-based study in the United Kingdom using the General Practice Research Database. Patients were classified as having severe psoriasis if they received a code for psoriasis as well as systemic therapy. Patients were defined as having mild psoriasis if they ever received a psoriasis code but no systemic therapy. Control subjects were selected from the same practices and start dates as psoriasis patients. Patients were classified as having risk factors if they received codes for diabetes, hypertension, hyperlipidemia, obesity, or smoking. Analyses were performed by using conditional logistic regression, and adjustments were made considering age, gender, person-years, and all cardiovascular risk factors.

RESULTS

We identified 127,706 patients with mild psoriasis and 3854 with severe psoriasis. Respective prevalence rates of risk factors in those with severe psoriasis, mild psoriasis, and in controls were as follows: diabetes (7.1%, 4.4%, 3.3%), hypertension (20%, 14.7%, 11.9%), hyperlipidemia (6%, 4.7%, 3.3%), obesity (20.7%, 15.8%, 13.2%), and smoking (30.1%, 28%, 21.3%). Patients with mild psoriasis had a higher adjusted odds of diabetes (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.08-1.18]), hypertension (OR, 1.03; 95% CI, 1.01-1.06), hyperlipidemia (OR, 1.16; 95% CI, 1.12-1.21), obesity (OR, 1.27; 95% CI, 1.24-1.31), and smoking (OR, 1.31; 95% CI, 1.29-1.34) than controls. Patients with severe psoriasis had a higher adjusted odds of diabetes (OR, 1.62; 95% CI, 1.3-2.01), obesity (OR, 1.79; 95% CI, 1.55-2.05), and smoking (OR, 1.31; 95% CI, 1.17-1.47) than controls. Additionally, diabetes (OR, 1.39; 95% CI, 1.22-1.58) and obesity (OR, 1.47; 95% CI, 1.32-1.63) were more prevalent in those with severe psoriasis than with mild psoriasis.

LIMITATIONS

The study was cross-sectional and therefore the directionality of the associations could not be determined.

CONCLUSION

Multiple cardiovascular risk factors are associated with psoriasis. Cardiovascular risk factors that are key components of the metabolic syndrome are more strongly associated with severe psoriasis than with mild psoriasis.

Identification of Susceptibility Loci for Skin Disease in a Murine Psoriasis Model

Psoriasis is a frequently occurring inflammatory skin disease characterized by thickened erythematous skin that is covered with silvery scales. It is a complex genetic disease with both heritable and environmental factors contributing to onset and severity. The CD18 hypomorphic PL/J mouse reveals reduced expression of the common chain of beta(2) integrins (CD11/CD18) and spontaneously develops a skin disease that closely resembles human psoriasis. In contrast, CD18 hypomorphic C57BL/6J mice do not demonstrate this phenotype. In this study, we have performed a genome-wide scan to identify loci involved in psoriasiform dermatitis under the condition of low CD18 expression. Backcross analysis of a segregating cross between susceptible CD18 hypomorphic PL/J mice and the resistant CD18 hypomorphic C57BL/6J strain was performed. A genome-wide linkage analysis of 94 phenotypically extreme mice of the backcross was undertaken. Thereafter, a complementary analysis of the regions of interest from the genome-wide screen was done using higher marker density and further mice. We found two loci on chromosome 10 that were significantly linked to the disease and interacted in an additive fashion in its development. In addition, a locus on chromosome 6 that promoted earlier onset of the disease was identified in the most severely affected mice. For the first time, we have identified genetic regions associated with psoriasis in a mouse model resembling human psoriasis. The identification of gene regions associated with psoriasis in this mouse model might contribute to the understanding of genetic causes of psoriasis in patients and pathological mechanisms involved in development of disease.

Pathogenic role for skin macrophages in a mouse model of keratinocyte-induced psoriasis-like skin inflammation

Psoriasis is a common skin disease, the pathogenesis of which has not yet been resolved. In mice, epidermis-specific deletion of inhibitor of NF-kappaB (IkappaB) kinase 2 (IKK2) results in a skin phenotype that mimics human psoriasis in several aspects. Like psoriasis, this skin disease shows pronounced improvement when mice are treated with a TNF-neutralizing agent. We have found previously that this phenotype does not depend on the presence of alphabeta T lymphocytes. In order to evaluate contributions of other immune cell populations to the skin disease, we selectively eliminated macrophages and granulocytes from the skin of mice with epidermis-specific deletion of IKK2 (K14-Cre-IKK2fl/fl mice). Elimination of skin macrophages by subcutaneous injection of clodronate liposomes was accompanied by inhibition of granulocyte migration into the skin and resulted in a dramatic attenuation of psoriasis-like skin changes. The hyperproliferative, inflammatory skin disease in K14-Cre-IKK2fl/fl mice was a direct consequence of the presence of macrophages in the skin, as targeted deletion of CD18, which prevented accumulation of granulocytes but not macrophages, did not lead to major changes in the phenotype. Targeted deletion of the receptor for IFN-gamma revealed that the pathogenesis of the skin disease does not depend on classical IFN-gamma-mediated macrophage activation. Our results demonstrate that in mice epidermal keratinocytes can initiate a hyperproliferative, inflammatory, IFN-gamma-independent, psoriasis-like skin disease whose development requires essential contributions from skin macrophages but not from granulocytes or alphabeta T lymphocytes.

Activated macrophages are essential in a murine model for T cell-mediated chronic psoriasiform skin inflammation

The CD18 hypomorphic (CD18hypo) PL/J mouse model clinically resembling human psoriasis is characterized by reduced expression of the common chain of beta2 integrins (CD11/CD18) to only 2-16% of WT levels. Previously we found that this chronic psoriasiform skin inflammation also depends on the presence of CD4+ T cells. Herein we investigated the role of macrophages in this CD18hypo mouse model. Activated macrophages were significantly increased in lesional skin as well as in inflamed skin draining lymph nodes (DLNs) of affected CD18hypo mice and were identified as being an important source of TNF-alpha in vivo. Both depletion of macrophages and neutralization of TNF-alpha resulted in a significant alleviation of psoriasiform skin inflammation. As monocyte chemotactic protein 1 was enhanced in lesional skin of affected CD18hypo mice, we intradermally injected recombinant murine monocyte chemotactic protein-1 (rJE/MCP-1) alone or in combination with rTNF-alpha into the skin of healthy CD18hypo mice. Only simultaneous injection of rJE/MCP-1 and rTNF-alpha, but neither substance alone, resulted in the induction of psoriasiform skin inflammation around the injection sites with recruitment and activation of macrophages. Collectively, our data suggest that maintenance of psoriasiform skin inflammation critically depends on efficient recruitment and activation of macrophages with sufficient release of TNF-alpha.

Excimer Laser versus Narrow-Band UVB (311 nm) in the Treatment of Psoriasis Vulgaris

BACKGROUND

The excimer laser is a new therapeutic option in the treatment of psoriasis vulgaris.

OBJECTIVE

The purpose of this study was to determine the response of psoriasis lesions to the 308-nm excimer laser compared to 311-nm UVB phototherapy.

METHODS

In this prospective right/left comparative, open, single-blinded trial, selected psoriasis plaques of 16 patients were treated with the excimer laser whereas the rest of the body was treated with UVB narrow-band phototherapy. A modified PASI score was used to evaluate the results.

RESULTS

After 12 treatments, 15 patients were evaluated. In 2 patients no difference between the two body sides was observed. In 9 patients the laser-treated lesions showed better results, whereas in 4 patients the side treated with 311-nm UVB showed more clearing. The mean reduction in PASI score was 5.6 and 4.9, respectively (difference not significant).

CONCLUSION

The use of the 308-nm xenon chloride excimer laser is an additional effective therapeutic option for the treatment of psoriasis vulgaris.

A characteristic subset of psoriasis-associated genes is induced by oncostatin-M in reconstituted epidermis

The pathological manifestations of psoriasis are orchestrated by many secreted proteins, but only a handful, tumor necrosis factor-alpha, IFN-gamma and IL-1, have been studied in great detail. Oncostatin-M (OsM) has also been found in psoriatic skin and we hypothesized that it makes a unique and characteristic contribution to the psoriatic processes. To define in-depth the molecular effects of OsM in epidermis, we used high-density DNA microarrays for transcriptional profiling of OsM-treated human skin equivalents. We identified 374 unambiguously OsM-regulated genes, out of 22,000 probed. OsM suppressed the expression of the "classical" epidermal differentiation markers, but strongly and specifically induced the S100A proteins. Cytoskeletal and complement proteins, proteases, and their inhibitors were also induced by OsM. Interestingly, a large set of genes was induced by OsM at early time points but suppressed later; these genes are known regulatory targets of IFN and thus provide a nexus between the OsM and IFN pathways. OsM induces IL-4 and suppresses the T-helper 1-type and IL-1-responsive signals, potentially attenuating the psoriatic pathology. The data suggest that OsM plays a unique role in psoriasis, different from all other, more thoroughly studied cytokines.

Identification of avarol derivatives as potential antipsoriatic drugs using an in vitro model for keratinocyte growth and differentiation

Avarol, a marine sesquiterpenoid hydroquinone, and 14 avarol derivatives have shown interesting anti-inflammatory properties in previous studies. In this study, avarol and derivatives were evaluated in high-throughput keratinocyte culture models using cytokeratin 10 and SKALP/Elafin expression as markers for respectively normal and psoriatic differentiation. Avarol and five of its derivatives (5, 10, 13, 14 and 15) were selected for further study. Only 10, 13, 14 and 15 were able to inhibit keratinocyte cell growth. Changes in expression levels of 22 genes were assessed by quantitative real time PCR (qPCR). From these genes, TNFalpha mRNA levels showed the strongest changes. For compound 13, 15 and dithranol (used as a model antipsoriatic drug), a dose-dependent downregulation of TNFalpha mRNA was found. The changes in TNFalpha mRNA were confirmed at the protein level for compound 13. Additionally, this compound was able to reduce also IL-8 and COX-2 mRNA levels and this effect was correlated with a reduction in COX-2 protein expression. The mechanism of action of this compound involves at least the inhibition of NF-kappaB-DNA binding activity. In conclusion, our high-throughput screening models in combination with quantitative assessment of changes in gene expression profiles identified the avarol derivative 13, a benzylamine derivative of avarol at the 4' position of benzoquinone ring, as an interesting anti-psoriatic drug candidate that inhibits keratinocyte cell growth and TNFalpha and COX-2 expression.

Fumaric acid esters are effective in chronic experimental autoimmune encephalomyelitis and suppress macrophage infiltration

Fumaric acid esters (FAE) have proven their therapeutic efficacy in psoriasis, a Th1 mediated skin disease. More recently, preliminary data have suggested an activity in multiple sclerosis (MS) as well. To investigate further possible mechanisms of action of these compounds in inflammatory diseases, we studied the FAE methyl hydrogen fumarate (MHF) and dimethyl fumarate (DMF) in chronic experimental autoimmune encephalomyelitis (EAE) induced by immunization of C57BL/6 mice with MOG peptide aa 35-55. Preventive treatment with these FAE was delivered twice a day by oral gavage. Both esters had a significant therapeutic effect on the disease course and histology showed a strongly reduced macrophage inflammation in the spinal cord. Multiparameter cytokine analysis from blood detected an increase of IL-10 in the treated animals. We conclude that the underlying biological activity of FAE in EAE is complex and, to elucidate the molecular mechanisms, further investigation is needed.

Ist der Psoriasis-Plaque-Test im Zeitalter der Biologics noch aktuell?

A variety of approaches (in vitro-/ex vivo studies, animal models, human studies and clinical trials) are available to assess compounds with potential antipsoriatic properties. Over the past few years various rodent models that mirror aspects of psoriasis phenotypes and/or pathogenesis have been created (e. g. knockout rodents, xenotransplantation models). Unfortunately these animal models do not reflect the complete pathogenesis of psoriasis. Therefore, screening procedures involving psoriatic lesions in humans are necessary. Even in the era of biologicals, the psoriasis plaque test (PPT) remains an important in vivo tool. In addition to screening potential antipsoriatic substances, the PPT can help answer other questions (frequency of use, dose-response relationship). A prerequisite for correct performance of PPT is knowledge of the toxicological and pharmacological data of the investigational compounds. The PPT is relatively simple, not time-consuming and allows the simultaneous testing of multiple substance. All the results from PPT must be confirmed by controlled clinical trials.

In situ profiling and quantification of cytokines released during ultraviolet B-induced inflammation by combining dermal microdialysis and protein microarrays

In skin, an evolving inflammatory or immune response is triggered by early release of a cytokine cascade into the extracellular space. Investigation of extracellular cytokine secretion in situ has been limited by low cut-off filtering membranes and sample volume size and the inability to monitor changes in cytokine protein levels in real-time in situ. Here, we combine for the first time the methods of intradermal microdialysis and antibody protein arraying to profile the early cascade of multiple cytokines in a complex inflammatory response exemplified by ultraviolet B (UVB)-induced inflammation. We observed significant differences of the cytokine and growth factor responses after tissue injury by catheter placement and UVB-induced inflammation. UVB irradiation initiates a rapid proinflammatory response followed by a mixed TH1/TH2 response in which ultimately TH2 cytokines IL-4 and IL10 predominated after 24 h. This most likely indicates the termination and self limitation of the inflammatory response. We conclude that the combination of dermal microdialysis and protein microarray offers a powerful tool to analyze in real-time the complex and rapidly changing interstitial protein milieu during cutaneous inflammatory responses.

Prevention of psoriasis-like lesions development in fsn/fsn mice by helminth glycans

The helminth glycan LNFPIII is an immunomodulatory molecule, driving CD4(+) Th2-type biasing as well as immune suppression. Psoriasis is an autoimmune disease where the immune mechanisms as well as the antigens responsible for development of immune autoreactivity are still not known. In the absence of defined immunological mechanisms, we asked whether LNFPIII would function as novel therapy for psoriasis. We tested the therapeutic efficacy of LNFPIII using the flaky skin (fsn)/fsn mutant mouse model of psoriasis-like lesion development. We found that treatment of mice with LNFPIII prevented the appearance of psoriatic skin lesions on fsn/fsn mice. Examination of the skin 2 weeks after treatment demonstrated that prevention of skin lesions was associated with maintenance of normal epidermis thickness in LNFPIII-treated mice as compared with a significantly thickened epidermis in control treated and diseased mice. In addition, cells from skin of LNFPIII-treated mice produced lower amounts of interferon-gamma as compared with cells from skin of control treated diseased mice. Examination of macrophages and T cells from peripheral lymph nodes of control and LNFPIII-treated fsn/fsn mice showed that glycan treatment reduced the numbers of Gr1(+)F4/80(+) macrophages and the numbers of CD8(+) T cells, restoring the numbers of these two cell populations as well as the CD4 : CD8 ratio to near normal levels. Overall, the results from this study suggest that the helminth immunomodulatory glycan LNFPIII functions to prevent development of psoriatic-like skin lesions in fsn/fsn mice.

Efalizumab-induced autoimmune pancytopenia

Efalizumab is a recombinant, humanized monoclonal anti-CD11a antibody used for the treatment of moderate to severe plaque psoriasis. Immune-mediated thrombocytopenia and anaemia have previously been reported with this therapy. We describe the first case of immune-mediated pancytopenia in a patient treated with efalizumab. Close monitoring of all blood cell counts is warranted in light of this case.

Increased expression of Wnt5a in psoriatic plaques

Psoriasis vulgaris is characterized by hyperproliferation and incomplete terminal differentiation of epidermal keratinocytes. Despite the established role of Wnt pathways in the regulation of stem cell proliferation and differentiation, they have not yet been associated with the pathophysiology of psoriasis. Here, we took biopsies from uninvolved and from lesional skin of 20 patients with plaque-type psoriasis. The biopsies were used for microarray RNA expression profiling. Based on paired samples from 13 patients, we defined 179 genes that were more than 2-fold differentially expressed in lesional skin. This list included 16 genes with known or possible association to the canonical Wnt/beta-catenin or the non-canonical Wnt/Ca2+ pathway. The expression of Wnt5a was 4-fold higher in lesional skin. Other Wnt molecules were largely unchanged (Wnt4 and Wnt16), or tended to be expressed at lower levels (Wnt7b). The mRNA expression levels of two inhibitory factors related to Wnt signaling, frizzled-related protein, and dickkopf homolog 2, were reduced in lesional skin, as was mRNA expression of cyclin D1. These findings were confirmed by quantitative reverse transcription-PCR experiments. We conclude that Wnt5a and other Wnt pathway genes are differentially expressed in psoriatic plaques. Their functional contribution to the pathophysiology of psoriasis needs to be elaborated.

Vascular endothelial growth factor gene polymorphisms increase the risk to develop psoriasis

We investigated the relationship between eight polymorphisms in the gene encoding for vascular endothelial growth factor (VEGF) (-1540C > A, -1512Ins18, -1451C > T, -460T > C, -160C > T, -152G > A, -116G > A and +405G > C) and plaque-type psoriasis stratified for age at onset, gender and family history of dermatosis. For this purpose, 117 patients with chronic plaque-type psoriasis and 215 healthy subjects were enrolled. We found that being homozygous -1540AA, -1512InsIns, -1451TT, -460CC and -152AA conferred a significant risk in developing psoriasis compared with heterozygous (-1540CA, -1512 + Ins, -1451CT, -460CT and -152AG) and homozygous genotypes (-1540CC, -1512 + +-1451CC, -460TT and -152GG) grouped together [odds ratio (ORs) = 1.73, 1.73, 1.73, 1.77 and 1.87, respectively]. Conversely, having the -116AA or +405GG genotype did not significantly increase the risk of disease expression compared with other genotypes of the same loci. Interestingly, we found that -1540AA, -1512InsIns, -1451TT, -460CC and -152AA homozygous genotypes have a significant two-fold increased risk in developing psoriasis after the age of 40 years (late-onset psoriasis) (ORs = 2.19, 2.19, 2.19, 2.05 and 2.26; P = 0.02, 0.02, 0.02, 0.04 and 0.02, respectively) as compared with controls. On the contrary, we found no phenotype-genotype association of the same magnitude among the patients in whom psoriasis developed at or before the age of 40 years (early-onset psoriasis) compared with controls. Genotype distributions were not significantly different when cases and controls were stratified either by gender or family history of psoriasis. Finally, VEGF plasma concentration was not significantly different between patients and controls and was not correlated with the severity of the disease.

Chronic inflammation in psoriasis and obesity: implications for therapy

A recent study has shown an indisputable relationship between psoriasis and obesity. Obesity leads to a higher risk in developing psoriasis and a poorer long-term clinical outcome of psoriasis. Furthermore, loosing weight may improve the psoriasis. A network of pro-inflammatory cytokines (especially tumour necrosis factor alpha (TNF-alpha)) is believed to play an important role in the pathophysiology of both obesity and psoriasis. The chronic low-level inflammation- as seen in obesity--may contribute to the extent of psoriatic lesions in obese patients. TNF-alpha in obesity is presumed to be derived from inflammatory cells (macrophages) in the adipose tissue and in psoriasis from activated T cells. Several drugs, such as peroxisome proliferator activated receptor (PPAR)-gamma agonists and TNF-alpha blocking agents, that target the pro-inflammatory pathways involved in both psoriasis and obesity have proven their benefit in the treatment of these entities. Furthermore, changes in levels of metabolic hormones as ghrelin and leptin in obesity may also play a role in the pathogenesis of deterioration of psoriasis by their potency to release pro-inflammatory mediators (e.g. interleukin (IL) 6 and TNF-alpha). We hypothesize that the treatment of obese psoriasis patient could be focused on reducing the obesity-induced inflammation. Reducing this obesity-induced inflammation may finally lead to a better clinical outcome. Weight loss could lead to a less inflammatory state by reducing concentrations of TNF-alpha, IL-6, leptin and improving insulin sensitivity.

Sequence and haplotype analysis supports HLA-C as the psoriasis susceptibility 1 gene

Previous studies have narrowed the interval containing PSORS1, the psoriasis-susceptibility locus in the major histocompatibility complex (MHC), to an approximately 300-kb region containing HLA-C and at least 10 other genes. In an effort to identify the PSORS1 gene, we cloned and completely sequenced this region from both chromosomes of five individuals. Two of the sequenced haplotypes were associated with psoriasis (risk), and the other eight were clearly unassociated (nonrisk). Comparison of sequence of the two risk haplotypes identified a 298-kb region of homology, extending from just telomeric of HLA-B to the HCG22 gene, which was flanked by clearly nonhomologous regions. Similar haplotypes cloned from unrelated individuals had nearly identical sequence. Combinatorial analysis of exonic variations in the known genes of the candidate interval revealed that HCG27, PSORS1C3, OTF3, TCF19, HCR, STG, and HCG22 bore no alleles unique to risk haplotypes among the 10 sequenced haplotypes. SPR1 and SEEK1 both had messenger RNA alleles specific to risk haplotypes, but only HLA-C and CDSN yielded protein alleles unique to risk. The risk alleles of HLA-C and CDSN (HLA-Cw6 and CDSN*TTC) were genotyped in 678 families with early-onset psoriasis; 620 of these families were also typed for 34 microsatellite markers spanning the PSORS1 interval. Recombinant haplotypes retaining HLA-Cw6 but lacking CDSN*TTC were significantly associated with psoriasis, whereas recombinants retaining CDSN*TTC but lacking HLA-Cw6 were not associated, despite good statistical power. By grouping recombinants with similar breakpoints, the most telomeric quarter of the 298-kb candidate interval could be excluded with high confidence. These results strongly suggest that HLA-Cw6 is the PSORS1 risk allele that confers susceptibility to early-onset psoriasis.

Connexin 26 regulates epidermal barrier and wound remodeling and promotes psoriasiform response

Inflammatory skin disorders result in significant epidermal changes, including keratinocyte hyperproliferation, incomplete differentiation, and impaired barrier. Here we test whether, conversely, an impaired epidermal barrier can promote an inflammatory response. Mice lacking the transcription factor Kruppel-like factor 4 (Klf4) have a severe defect in epidermal barrier acquisition. Transcription profiling of Klf4(-/-) newborn skin revealed similar changes in gene expression to involved psoriatic plaques, including a significant upregulation of the gap junction protein connexin 26 (Cx26). Ectopic expression of Cx26 from the epidermis-specific involucrin (INV) promoter (INV-Cx26) demonstrated that downregulation of Cx26 is required for barrier acquisition during development. In juvenile and adult mice, persistent Cx26 expression kept wounded epidermis in a hyperproliferative state, blocked the transition to remodeling, and led to an infiltration of immune cells. Mechanistically, ectopic expression of Cx26 in keratinocytes resulted in increased ATP release, which delayed epidermal barrier recovery and promoted an inflammatory response in resident immune cells. These results provide a molecular link between barrier acquisition in utero and epidermal remodeling after wounding. More generally, these studies suggest that the most effective treatments for inflammatory skin disorders might concomitantly suppress the immune response and enhance epidermal differentiation to restore the barrier.

Bronchial asthma as neurogenic paroxysmal inflammatory disease: a randomized trial with carbamazepine

PURPOSE

Based on the assumption that bronchial asthma has not only inflammatory, but also certain neurogenic paroxysmal mechanism and pathophysiological links with other non-epileptic paroxysmal inflammatory diseases--migraine and trigeminal neuralgia, we decided to investigate efficacy of antiepileptic drug carbamazepine in patients with moderate persistent or severe asthma.

METHODS

Sixty-three patients completed randomized double-blind, placebo-controlled trial.

RESULTS

Stable remission was achieved after carbamazepine treatment in 25 patients in active group (n=33). No significant improvement was registered in patients of placebo group (n=30). Following open-label treatment shows high and stable antiasthmatic efficacy of carbamazepine monotherapy.

CONCLUSIONS

Carbamazepine showed high efficacy in therapy of moderate persistent or severe bronchial asthma. Antiasthmatic activity of carbamazepine can be considered as influence on neurogenic mechanisms of asthma. We suppose that it is possible to use carbamazepine for therapy of bronchial asthma in clinical practice.

Structure–Function Relation of Efomycines, a Family of Small-Molecule Inhibitors of Selectin Functions

Selectin-mediated leukocyte adhesion to endothelia, the crucial first step initiating the pathogenic cascade of inflammation, is an attractive target for specific therapies. The small-molecule macrolide, efomycine M, inhibits selectin-mediated leukocyte adhesion in vitro and in vivo, and effectively alleviates inflammatory disorders in vivo. To define the molecular basis of the therapeutically relevant antiadhesive properties of efomycines, several new species of this family were purified and/or synthesized. Efomycines E and G were isolated from Steptomyces BS1261. Efomycine O was synthesized by Lewis acid-catalyzed acetalization and efomycine M was generated by base-catalyzed deglycosylation. Efomycine S resulted from ester cleavage of the macrolide ring system, and efomycine T represents the peracetylated form of efomycine M. When the functional activity of efomycines on adhesion of leukocytes to vascular endothelium was studied, some remarkable differences between the compounds became apparent, inasmuch as efomycines E, G, M, and O significantly inhibited adhesion of both human and porcine leukocytes to the vascular endothelium, whereas efomycines S and T did not show any biological activity. A novel docking engine (ProPose), generating an improved, fully configurable protein-ligand interaction model, demonstrated that biological activities of efomycines can be predicted in silico, thus highlighting the utility of such combinatorial approaches.

Phase II randomized, placebo-controlled trial of M. vaccae-derived protein (PVAC) for the treatment of psoriasis

The treatment effect against psoriasis of an antigen (delipidated, deglycolipidated form of M. vaccae-PVAC) was investigated. One hundred and sixty-five patients were enrolled in three arms (50 or 15 microg or placebo), each receiving a total of two intradermal injections (days 0 and 21). At week 12, a 75% decrease in psoriasis area and severity index was similar among the studied groups (13, 9 and 18%, p=0.429). The overall incidence of adverse events was significantly higher in the PVAC treated groups when compared to placebo (98.2, 87.3 and 70.9%; p<0.001) largely due to local reactions that were limited for the most part to grades 1 and 2 in severity and were self-limiting. Despite its overall safety, PVAC was not clearly indicated to be superior to placebo in the treatment of psoriasis in this study.

Co-localization of COX-2, CYP4F8, and mPGES-1 in epidermis with prominent expression of CYP4F8 mRNA in psoriatic lesions

Cyclooxygenase-2 (COX-2), cytochrome P450 4F8 (CYP4F8), and microsomal PGE synthase-1 (mPGES-1) form PGE and 19-hydroxy-PGE in human seminal vesicles. We have examined COX-2, CYP4F8, and mPGES-1 in normal skin and in psoriasis. All three enzymes were detected in epidermis by immunofluorescence and co-localized in the suprabasal cell layers. In lesional psoriasis the enzymes were also co-localized in the basal cell layers. Real-time RT-PCR analysis suggested that CYP4F8 mRNA was induced 15-fold in lesional compared to non-lesional epidermis. mRNA of all enzymes were present in cultured HEK and HaCaT cells, but the prominent induction of CYP4F8 mRNA in psoriasis could not be mimicked by treatment of these keratinocytes with a mixture of inflammatory cytokines or with phorbol 12-myristate-13-acetate. The function of CYP4F8 in epidermis might be related to lipid oxidation and keratinocyte proliferation.

CD56brightCD16(-) NK cells accumulate in psoriatic skin in response to CXCL10 and CCL5 and exacerbate skin inflammation

Psoriasis is an immune-mediated skin disease characterized by lymphocytic infiltration and altered keratinocyte differentiation. Using immunohistochemical techniques we found that the cellular infiltrate in acute psoriatic plaques includes 5-8% CD3(-)CD56(+) natural killer (NK) cells, mostly localized in the mid and papillary dermis. NK lymphocytes isolated from punch biopsy specimens of psoriatic plaques showed a CD56(bright)CD16(-)CD158b(-) phenotype, failed to express the skin homing cutaneous lymphocyte-associated antigen and released abundant IFN-gamma upon stimulation. Supernatants from psoriatic NK cells induced MHC class II and ICAM-1 expression and release of CXCL10 and CCL5 by cultured psoriatic keratinocytes. Skin NK cells expressed high levels of the chemokines receptors CXCR3 and CCR5, intermediate amounts of CXCR1, CCR6 and CCR8, and low levels of CCR1, CCR2, CCR4, CCR7 and CX3CR1. In addition, they promptly migrated in vitro toward CXCL10, CCL5, supernatants of IFN-gamma-activated psoriatic keratinocytes and, to a lower extent, CCL20 and CCL4. In contrast, they failed to migrate toward CXCL8, CCL1, CCL2, CCL3, CCL17, CCL19 and CX3CL1. Taken together, our results implicate NK lymphocytes as newly identified protagonists in the pathogenesis of psoriasis. Their distinctive homing properties should be taken into account in the design of specific therapy aimed at blocking pathogenic cell accumulation in the skin.

Fos/AP-1 proteins in bone and the immune system

The skeleton and the immune system share a variety of different cytokines and transcription factors, thereby mutually influencing each other. These interactions are not confined to the bone marrow cavity where bone cells and hematopoietic cells exist in proximity but also occur at locations that are target sites for inflammatory bone diseases. The newly established research area termed 'osteoimmunology' attempts to unravel these skeletal/immunological relationships. Studies towards a molecular understanding of inflammatory bone diseases from an immunological as well as a bone-centered perspective have been very successful and led to the identification of several signaling pathways that are causally involved in inflammatory bone loss. Induction of receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) signals by activated T cells and subsequent activation of the key transcription factors Fos/activator protein-1 (AP-1), NF-kappaB, and NF for activation of T cells c1 (NFATc1) are in the center of the signaling networks leading to osteoclast-mediated bone loss. Conversely, nature has employed the interferon system to antagonize excessive osteoclast differentiation, although this counteracting activity appears to be overruled under pathological conditions. Here, we focus on Fos/AP-1 functions in osteoimmunology, because this osteoclastogenic transcription factor plays a central role in inflammatory bone loss by regulating genes like NFATc1 as well as the interferon system. We also attempt to put potential therapeutic strategies for inflammatory bone diseases in perspective.

Neuroimmunoendocrine circuitry of the ‘brain-skin connection’

The skin offers an ideally suited, clinically relevant model for studying the crossroads between peripheral and systemic responses to stress. A 'brain-skin connection' with local neuroimmunoendocrine circuitry underlies the pathogenesis of allergic and inflammatory skin diseases, triggered or aggravated by stress. In stressed mice, corticotropin-releasing hormone, nerve growth factor, neurotensin, substance P and mast cells are recruited hierarchically to induce neurogenic skin inflammation, which inhibits hair growth. The hair follicle is both a target and a source for immunomodulatory stress mediators, and has an equivalent of the hypothalamus-pituitary-adrenal axis. Thus, the skin and its appendages enable the study of complex neuroimmunoendocrine responses that peripheral tissues launch upon stress exposure, as a basis for identifying new targets for therapeutic stress intervention.

From the brain-skin connection: the neuroendocrine-immune misalliance of stress and itch

Perceived stress has long been allied with disturbances of the dynamic equilibrium established between the nervous, endocrine and immune systems, thus triggering or aggravating disease manifestation. Several common skin diseases are now acknowledged to be worsened by psychological stress, particularly immunodermatoses such as atopic dermatitis, psoriasis, seborrheic eczema, prurigo nodularis, lichen planus, chronic urticaria, alopecia areata and pruritus sine materia. Itch (pruritus) is perhaps the most common symptom associated with a majority of these inflammatory skin diseases, and acute as well as chronic stress perceptions are recognized to trigger or enhance pruritus. A wealth of mediators released systemically or locally in the skin in response to stress increase sensory innervation, upregulate the production of other pruritogenic agents, perpetuate (neurogenic) inflammation and lower the itch threshold. In the present review, we explore recent frontiers in both stress and pruritus research and portray the perpetuation of chronic skin inflammation and itch as a neuroendocrine-immune 'misalliance'. We argue that key candidate molecules of the stress response with strong pruritogenic potential, such as nerve growth factor, corticotropin-releasing hormone and substance P, and mast cells, which may be considered as 'central cellular switchboards of pruritogenic inflammation', need to be further explored systematically in order to develop more effective therapeutic combination strategies for itch management in chronic, stress-vulnerable inflammatory skin diseases.

Gene expression profiling of Japanese psoriatic skin reveals an increased activity in molecular stress and immune response signals

Gene expression profiling was performed on biopsies of affected and unaffected psoriatic skin and normal skin from seven Japanese patients to obtain insights into the pathways that control this disease. HUG95A Affymetrix DNA chips that contained oligonucleotide arrays of approximately 12,000 well-characterized human genes were used in the study. The statistical analysis of the Affymetrix data, based on the ranking of the Student t-test statistic, revealed a complex regulation of molecular stress and immune gene responses. The majority of the 266 induced genes in affected and unaffected psoriatic skin were involved with interferon mediation, immunity, cell adhesion, cytoskeleton restructuring, protein trafficking and degradation, RNA regulation and degradation, signalling transduction, apoptosis and atypical epidermal cellular proliferation and differentiation. The disturbances in the normal protein degradation equilibrium of skin were reflected by the significant increase in the gene expression of various protease inhibitors and proteinases, including the induced components of the ATP/ubiquitin-dependent non-lysosomal proteolytic pathway that is involved with peptide processing and presentation to T cells. Some of the up-regulated genes, such as TGM1, IVL, FABP5, CSTA and SPRR, are well-known psoriatic markers involved in atypical epidermal cellular organization and differentiation. In the comparison between the affected and unaffected psoriatic skin, the transcription factor JUNB was found at the top of the statistical rankings for the up-regulated genes in affected skin, suggesting that it has an important but as yet undefined role in psoriasis. Our gene expression data and analysis suggest that psoriasis is a chronic interferon- and T-cell-mediated immune disease of the skin where the imbalance in epidermal cellular structure, growth and differentiation arises from the molecular antiviral stress signals initiating inappropriate immune responses.

Infliximab induction and maintenance therapy for moderate-to-severe psoriasis: a phase III, multicentre, double-blind trial

BACKGROUND

Tumour necrosis factor alpha (TNFalpha) is thought to play a part in the pathogenesis of psoriasis. We assessed the efficacy and safety of continuous treatment with infliximab, a monoclonal antibody that binds to and neutralises the activity of TNFalpha, in patients with psoriasis.

METHODS

In this phase III, multicentre, double-blind trial, 378 patients with moderate-to-severe plaque psoriasis were allocated in a 4:1 ratio to receive infusions of either infliximab 5 mg/kg or placebo at weeks 0, 2, and 6, then every 8 weeks to week 46. At week 24, placebo-treated patients crossed over to infliximab treatment. Skin and nail signs of psoriasis were assessed using the psoriasis area and severity index (PASI) and nail psoriasis severity index (NAPSI), respectively. The primary endpoint, analysed on an intention-to-treat-basis, was the proportion of patients achieving at least a 75% improvement in PASI from baseline to week 10.

FINDINGS

At week 10, 80% (242/301) of patients treated with infliximab achieved at least a 75% improvement from their baseline PASI (PASI 75) and 57% (172/301) achieved at least a 90% improvement (PASI 90), compared with 3% and 1% in the placebo group, respectively (p<0.0001). At week 24, PASI 75 (82% for infliximab vs 4% for placebo) and PASI 90 (58%vs 1%) were maintained (p<0.0001). At week 50, 61% achieved PASI 75 and 45% achieved PASI 90 in the infliximab group. Infliximab was generally well tolerated in most patients.

INTERPRETATION

Infliximab is effective in both an induction and maintenance regimen for the treatment of moderate-to-severe psoriasis, with a high percentage of patients achieving sustained PASI 75 and PASI 90 improvement through 1 year.

New onset or exacerbation of psoriatic skin lesions in patients with definite rheumatoid arthritis receiving tumour necrosis factor alpha antagonists

BACKGROUND

Blockage of tumour necrosis factor alpha (TNFalpha) is highly effective in rheumatic diseases, especially in rheumatoid arthritis (RA), ankylosing spondylitis, and psoriatic arthritis. Furthermore, TNFalpha antagonists have also been shown to significantly reduce psoriatic skin lesions.

CASE REPORTS

A series of nine patients with RA who were treated with different types of TNFalpha antagonists and who unexpectedly developed either a new onset or an exacerbation of psoriatic skin lesions are reported.

Psoriatic arthritis: pathogenesis and novel immunomodulatory approaches to treatment

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy characterized by the association of arthritis and psoriasis. PsA runs a variable course, from mild synovitis to severe, progressive, erosive arthropathy. The pathogenesis of PsA involves alteration in the components of the immune response, although the exact cause of PsA is unknown. A number of patients with severe peripheral arthritis fail to respond to standard conventional therapy. Advances in biotechnology and in our understanding of the immunopathogenesis of PsA have led to great interest and progress in regards to biologic treatments for PsA. Notable success achieved with recently introduced biologic therapies has paved the way for further research and development of additional therapies that should improve outcomes for affected patients.

[Psoriasis SCID-mouse model]

Psoriasis is characterized by a complex phenotype and pathogenesis along with polygenic determination. Several psoriasis animal models have only been able to incompletely reproduce the disease. A xenogeneic transplantation approach, grafting skin from psoriatic patients onto mice with a severe combined immunodeficiency (SCID), was the first to meet the criteria for a psoriasis model. During the last 10 years, this psoriasis SCID-mouse model not only allowed telling experiments focusing on pathogenetic aspects, but also proved being a powerful tool for drug discovery with a good predictive value.