Current concepts in the immunopathogenesis of psoriasis

Gut microbiota and skin pathologies: Mechanism of the gut-skin axis in atopic dermatitis and psoriasis

Atopic dermatitis (AD) and psoriasis are chronic skin diseases with a global impact, posing significant challenges to public health systems and severely affecting patients' quality of life. This review delves into the key role of the gut microbiota in these diseases, emphasizing the importance of the gut-skin axis in inflammatory mediators and immune regulation and revealing a complex bidirectional communication system. We comprehensively assessed the pathogenesis, clinical manifestations, and treatment strategies for AD and psoriasis, with a particular focus on how the gut microbiota and their metabolites influence disease progression via the gut-skin axis. In addition, personalized treatment plans based on individual patient microbiome characteristics have been proposed, offering new perspectives for future treatment approaches. We call for enhanced interdisciplinary cooperation to further explore the interactions between gut microbiota and skin diseases and to assess the potential of drugs and natural products in modulating the gut-skin axis, aiming to advance the treatment of skin diseases.

Brodalumab: an evidence-based review of its potential in the treatment of moderate-to-severe psoriasis

Advances in knowledge regarding the pathogenesis of psoriasis have allowed the development of a new class of agents known as biologic drugs. Data confirm that T helper (Th)17 and interleukin (IL)-17 signaling has a crucial role in the pathogenesis of the disease. High levels of IL-17 and Th17-related cytokines have been reported in psoriasis, leading to the suggestion of agents targeting IL-17 as a potential therapeutic strategy in psoriasis. Brodalumab is a human monoclonal antibody that targets IL-17 receptor A, blocking the effects of IL-17A, IL-17F, and IL-17E. Data from Phase I and Phase II clinical trials indicate that brodalumab has a favorable safety and tolerability profile, with strong clinical activity, suggesting that it is a potential tool for use in the treatment of moderate-to-severe psoriasis.

Picea mariana polyphenolic extract inhibits phlogogenic mediators produced by TNF-α-activated psoriatic keratinocytes: Impact on NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Picea mariana ((Miller) Britton, Sterns, and Poggenburg; Pinaceae) bark has been traditionally used by North American natives for treating topical inflammations. It has been also suggested to improve various inflammatory skin disorders like Psoriasis vulgaris. Extracts from this bark storage protein contain polyphenolic compounds which have well-known antiinflammatory activities. Based on the capacity of polyphenolic compounds to modulate functions of normal human keratinocytes, this study was set up to decipher the mechanisms of action of a chemically characterized polyphenolic extract from Picea mariana bark (BS-EAcf) on lesional keratinocytes of skin with psoriasis vulgaris, a disease driven by the immune system in which TNF-α plays a significant role.

MATERIALS AND METHODS

BS-EAcf corresponds to the ethyl acetate soluble fraction from the hot water extract of Picea mariana bark. BS-EAcf effects were evaluated in normal human (NHK) and psoriatic (PK) keratinocytes stimulated by TNF-α. Cell viability was assessed by lactate deshydrogenase release and propidium iodide (PI) staining. The mechanisms of action of BS-EAcf in keratinocytes were investigated by flow cytometry, ELISAs, RT-PCR and western blot analyses.

RESULTS

PK exhibited a higher response to TNF-α than NHK regarding the ICAM-1 expression and the production of NO, IL-6, IL-8, fractalkine and PGE2, whereas BS-EAcf significantly inhibited this TNF-α-induced increase at concentrations without causing keratinocyte toxicity. Additionally, this extract significantly inhibited the TNF-α-induced release of elafin and VEGF by PK and NHK. Since TNF-α activation of most of these factors is dependent on the NF-κB pathway, this latter was studied in TNF-α-activated PK. BS-EAcf inhibited the TNF-α-induced phosphorylation and degradation of total IκBα as well as phosphorylation of NF-κB p65.

CONCLUSIONS

The ethyl acetate fraction from Picea mariana bark extract showed inhibitory effects of cytokines, chemokines, adhesion molecules, nitric oxide and prostaglandins produced by keratinocytes under TNF-α activation through down-regulating the NF-κB pathway. This study demontrated that this extract could be a potential antiinflammatory agent capable of improving psoriatic skin.

Study of the genetic factors predisposing to the development of psoriasis

Background papers on psoriasis epidemiology, pathogenesis and genetics are presented. Special attention is given to genetic factors of the aptitude to psoriasis development. Were analysed researches, dedicated to the genome-wide screening of associations of polymorphic genetic locus with psoriasis development. Obtained results allow to reveal pathogenic psoriasis mechanisms, to forecast the character of the clinical course of the disease, as well as the efficiency of therapy and forecast the risk of psoriasis origination at patient’s relatives.

Cutaneous microdialysis: cytokine evidence for altered innate reactivity in the skin of psoriasis patients?

Cutaneous microdialysis demonstrates cytokine production in living human skin. In the present study, microdialysis samples taken from uninvolved and lesional skin in three test subjects with psoriasis over 24 h have been investigated for cytokine content with a bead-based multiplex immunoassay from Luminex. Concentration curves for a set of Th1/Th2 and pro-inflammatory cytokines measured differed from a reference group of ten subjects without psoriasis. The time to return to near baseline values after innate insertion reactivity is between 9 and 16 h. Post-equilibration levels (17-24 h) for the three main cytokines elevated in the reference group were differentially elevated outside the range of the reference group for interleukin-1β (IL1β) and IL8 but not so for IL6. Two further cytokines, granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-α not generally elevated in the reference group, showed elevated values in the test subjects. Multivariate time series analysis (chemometry) showed that cytokine patterns for the individual test subjects often fell outside the 99% confidence intervals of a model generated from the reference group. In a clinical research situation, cutaneous microdialysis is feasible, gives generally higher cytokine levels than in the blood and generates interpretable data on an individual's reactivity compared with a reference group. This may well prove useful in delineation of pathogenetic issues, selection of appropriate therapy and monitoring of subsequent response in inflammatory dermatoses such as psoriasis.

Serum cytokine profile in psoriasis-a case-control study in a tertiary care hospital from northern India

Psoriasis is chronic autoimmune hyperproliferative skin disease with a population prevalence of 1.5-3%. The cause of psoriasis is still not fully understood. It has been hypothesized to be an immune-mediated disorder in which the excessive reproduction of keratinocytes is due to cytokines such as interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha, secreted by infiltrating CD4(+) and CD8(+) T cells and natural killer cells. The aim of our study was to determine the serum levels of TNF-α, IL-4, IL-6 & IL-10 in psoriasis patients and compare it with healthy controls. 30 clinically diagnosed psoriasis patients and 30 age and sex matched healthy controls were included in the study. The serum cytokine levels were measured by solid phase sandwich ELISA (DIACLONE Research, France). TNF-α and IL-6 levels were significantly raised in patients and the results were statistically significant (P < 0.001). IL-4 levels were higher in patients than in controls (1.91 ± 4.7 pg/ml in cases & 0.9 ± 0.3 pg/ml in controls) but were not statistically significant. Interestingly, IL-10 levels were found to be higher in controls than in patients but again, it was not statistically significant. Pro-inflammatory cytokines play a pivotal role in the pathogenesis of psoriasis and it is the type 1(TH1) cytokine pattern, i.e., IL-6 & TNF-α, which predominate in the psoriatic T cell response. Further studies on IL-10 levels in psoriasis are recommended to establish their exact role in the pathogenesis of the disease.

From bench to bedside--translational research in psoriasis

For many years, psoriasis was firmly believed to be a disease of epidermal keratinocytes, but now is attributed to a combination of genetic and environmental factors that promote a T-cell mediated immune response in the skin. Psoriasis is now understood to be a systemic T-cell mediated autoimmune disease with the innate immune system playing an important role. Progress in understanding the pathogenesis of psoriasis has shown that following a stimulus, dendritic and T cell activation leads to the release of cytokines, chemokines and growth factors that initiate the proliferation and altered differentiation of keratinocytes. These factors subsequently lead to continuous activation of T cells and antigen-presenting cells, particularly dendritic cells, within the psoriatic plaque. This vicious cycle of psoriasis, in which the cytokines interleukin 12 (IL-12) and IL-23 play a pivotal role, is a logical target for biological therapy.

Are cutaneous microdialysis cytokine findings supported by end point biopsy immunohistochemistry findings?

Insertion of a cutaneous microdialysis catheter into normal dermis has been shown to induce the production of IL1b, IL6 and IL8 in an innate response to minimal trauma. In the present study, skin biopsy for immunohistochemistry has been performed at the site of the microdialysis catheter to compare the findings with that of the microdialysis findings 24 h after insertion. Of the three named cytokines, concordance between the two investigated technologies was highest for IL8 (100%) followed by IL6 (70%) and IL1b (50%). For seven other pro-inflammatory and T cell-relevant cytokines studied, concordance ranged between 50% and 80%. The total number of positive (microdialysis or immunofluorescence) findings was similar between the two methodologies. Technical and biological phenomenon can explain the differences. We conclude that both methodologies illustrate important features of tissue biology and that a combination of the two methods in clinical research can provide the chronology of soluble mediator participation and the more classic, but also more invasive, biopsy-based methodology at a point which constitutes the end of the observation period. We conclude further that at the 24-h time period here studied, microdialysis catheters are still functional and thus capable of producing relevant data which can be corroborated and extended by the "end point biopsy".

Psoriasis genetics: breaking the barrier

Psoriasis is a common incurable inflammatory skin disease affecting 2-3% of the European population. Psoriatic skin contains large numbers of immune cells which produce many cytokines, chemokines and inflammatory molecules. The epidermis divides much faster than normal and has a defective outer layer or barrier which under normal circumstances protects from infection and dehydration. Psoriatic skin is characterized by a distinct set of inflammation and epidermal proliferation and differentiation markers, and it has been unclear whether the genetic basis of psoriasis reflects defects of the immune system or of the skin. One genetic determinant lies within the major histocompatibility complex class 1 region. Genome-wide association studies have revealed genetic susceptibility factors that play a role in the formation of immune cells found in psoriasis lesions. Others affect epidermal proliferation and skin barrier formation. Hence, genetic components of both the immune system and the epidermis can predispose to disease.

Immune mechanisms of psoriasis. New strategies of biotherapy

Psoriasis is a chronic skin disease - according to numerous studies, about 2% of the population suffer from it. Psoriasis degrades the life quality, and such concomitant pathologies as metabolic disorders, cardiovascular diseases and depression shorten the life expectancy of psoriasis patients. Substantial progress has been achieved today in understanding the mechanisms of the disease, searching for new treatment techniques and standardizing the disease severity According to the recent studies, psoriasis belongs to immune-dependent diseases with genetic predisposition to its development. Dendritic cells and T lymphocytes play an important part in psoriasis development. Their interaction launches a number of mechanisms ultimately leading to the inflammatory process development and formation of psoriatic skin affections. Such cytokines as IL-12, IL-23, IFN-y and TNF-a secreted by immunocompetent cells serve as mediators during such processes. An advanced therapeutic approach to the treatment of psoriasis means creating pathogenetically important cytokine specific monoclonal antibodies and placing them into the body Today there are drugs successfully blocking the development of psoriatic skin affections by means of specific binding of IL-12, IL-23 and TNF-a cytokines. Drugs called ustekinumab and ABT-874 confirmed their therapeutic activity with regard to psoriasis at Phases 2 and 3 of clinical trials. In the course of further trials, ustekinumab also demonstrated a safety profile comparable to that of placebo.

[Psychoneuroimmunology: an update]

Psychoneuroimmunology (PNI) is closely associated with the bidirectional pathways between mind/brain and the immune system. PNI research represents a rapidly growing area within psychosomatic research. Recent studies in PNI are based mainly on the immunological concepts of Th1/Th2 dichotomy and inflammation. This review covers human PNI studies dealing with stress-associated changes in cytokine (Th1, Th2) levels in immune-related processes such as wound healing, atopic diseases as well as autoimmune and other inflammatory diseases. It is shown that PNI studies measuring immune activity near the site of the disease (e. g. woundhealing) and dealing with objective stressors show more consistent findings (stress-associated Th1/Th2 shift, stress-associated proinflammatory activation) than those dealing with chronic and complex diseases (e. g., autoimmune disease). This warrants the expansion of the methodological repertoire in future PNI research toward designs allowing for the investigation of complex psychosomatic phenomena.

Epidermal vascular endothelial growth factor production is required for permeability barrier homeostasis, dermal angiogenesis, and the development of epidermal hyperplasia: implications for the pathogenesis of psoriasis

Primary abnormalities in permeability barrier function appear to underlie atopic dermatitis and epidermal trauma; a concomitant barrier dysfunction could also drive other inflammatory dermatoses, including psoriasis. Central to this outside-inside view of disease pathogenesis is the epidermal generation of cytokines/growth factors, which in turn signal downstream epidermal repair mechanisms. Yet, this cascade, if sustained, signals downstream epidermal hyperplasia and inflammation. We found here that acute barrier disruption rapidly stimulates mRNA and protein expression of epidermal vascular endothelial growth factor-A (VEGF-A) in normal hairless mice, a specific response to permeability barrier requirements because up-regulation is blocked by application of a vapor-impermeable membrane. Moreover, epidermal vegf(-/-) mice display abnormal permeability barrier homeostasis, attributable to decreased VEGF signaling of epidermal lamellar body production; a paucity of dermal capillaries with reduced vascular permeability; and neither angiogenesis nor epidermal hyperplasia in response to repeated tape stripping (a model of psoriasiform hyperplasia). These results support a central role for epidermal VEGF in the maintenance of epidermal permeability barrier homeostasis and a link between epidermal VEGF production and both dermal angiogenesis and the development of epidermal hyperplasia. Because psoriasis is commonly induced by external trauma [isomorphic (Koebner) phenomenon] and is associated with a prominent permeability barrier abnormality, excess VEGF production, prominent angiogenesis, and epidermal hyperplasia, these results could provide a potential outside-inside mechanistic basis for the development of psoriasis.

The role of dendritic cells in the immunopathogenesis of psoriasis

Psoriasis vulgaris is a chronic inflammatory skin disease that is marked by a complex interplay of dendritic cells (DCs), T-cells, cytokines, and downstream transcription factors as part of a self-sustaining type 1 cytokine network. As integral players of the immune system, DCs represent antigen-presenting cells that are crucial for efficient activation of T-cells and B-cells. DCs have also been linked to distinct chronic inflammatory conditions, including psoriasis. In the setting of psoriasis therapy, DC/T cell interactions serve as a potential target for biologic response modifiers. Here we describe the major DC subsets as well as the immunologic involvement of DCs within the context of psoriatic lesions.

Treatment of psoriasis with adalimumab

BACKGROUND

Adalimumab is an anti-tumour necrosis factor agent of use in psoriatic arthritis.

AIM

The objective of this study was to assess the efficacy and safety of adalimumab in patients with plaque psoriasis unresponsive to previous therapies.

METHODS

We present nine patients with psoriasis and psoriatic arthropathy treated with adalimumab, including a woman with a history of breast cancer and a man with hepatitis C virus-related liver disease.

RESULTS

After 12 weeks, 66.6%, 55.5% and 11.1% of the patients showed a Psoriasis Assessment and Severity Index response of 50%, 75% and 90%, respectively. After 20 weeks, these levels had increased to 75%, 62.5% and 37.5%, respectively. After 12 weeks, the Psoriasis Global Assessment (PGA) score was clear or almost clear in 33.3% of the patients. By week 20, this clearance rate had almost doubled (62.5%). In two patients, the treatment was prolonged for 52 weeks, with a sustained response. One patient presented nonspecific colitis and died as a result of in-hospital pneumonia; any implication of adalimumab in the death is not clear. No other serious adverse effects were observed.

CONCLUSION

In this series adalimumab was found to be effective for psoriasis refractory to other treatments including infliximab and etanercept.

Evidence for a Novel Psoriasis Susceptibility Locus at 9q33–9q34 in Chinese Hans

Psoriasis is a heterogeneous disease for which nine linkage loci (PSORS loci 1-5 and PSORS7-10) have been accepted by the Human Genome Nomenclature Committee and an additional 16 potential susceptibility loci have been reported so far. Our previous genome-wide scan in 61 Chinese Han psoriasis vulgaris families found two susceptibility loci at 6p21.3 and 4q31 and additional suggestive linkage evidence at other regions, including 9q33. In this follow-up study, the linkage evidence at 9q33 was further investigated using an expanded sample of 160 families and improved marker coverage. Our follow-up linkage analysis of the 160 families demonstrated strong linkage evidence (P < or = 0.000022) throughout a region between 133.38 and 146.23 cM with a maximum nonparametric linkage (NPL) score of 4.64 (P = 0.00000023) and a heterogeneity LOD (HLOD) score of 5.03 (alpha = 46%) at 142.39 cM near the marker D9S290. By stratifying the 160 families into the subtypes of 130 early-onset and 30 late-onset families, we revealed stronger linkage evidence in the early-onset psoriasis families with a maximum multipoint HLOD score of 6.48 (alpha = 58%) and a maximum NPL score of 4.69 (P = 0.00000012) near marker D9S290. Our follow-up study has confirmed a novel susceptibility locus at 9q33-34 for early-onset psoriasis in the Chinese population.

Effects of tumour necrosis factor-alpha on human sperm motility and apoptosis

The aim of this study was to evaluate the effects of tumour necrosis factor-alpha (TNF-alpha) on sperm motility, mitochondrial membrane potential (DeltaPsi), phosphatidylserine (PS) externalization, sperm chromatin packaging quality, and DNA fragmentation. Motile spermatozoa, obtained from 10 normozoospermic men, were incubated with increasing concentrations of TNF-alpha and analyzed 1, 3, 6, and 24 h after incubation by flow cytometry. TNF-alpha decreased total motility 24 h after incubation at 10 ng/mL and progressive motility 3 h after incubation. Accordingly, TNF-alpha reduced sperm DeltaPsi in a concentration- and time-dependent manner. TNF-alpha increased the percentage of spermatozoa with PS externalization from the concentration of 1 ng/mL 1 h after incubation. TNF-alpha produced sperm chromatin and DNA damage in a concentration- and time-dependent manner. In conclusion, these findings may explain the reduction of fertility, secondary to upregulated production of TNF-alpha, in men with urogenital infections.

Altered distribution of leukocyte subsets and cytokine production in response to acute psychosocial stress in patients with psoriasis vulgaris

Psoriasis (PSO) is a mainly T helper-type 1 (TH(1)) cell mediated chronic inflammatory skin disease characterized by epidermal hyperproliferation and psoriatic plaques. There is ample evidence that stress may trigger psoriatic eruption, however, the underlying mechanisms of stress-induced exacerbation of PSO are poorly understood. The specific goal of the present study was to investigate the impact of acute stress on pathologically relevant immune functions in PSO patients. PSO patients (n=23) and healthy controls (n=25) were exposed to a standardized laboratory stressor ("Trier Social Stress Test", TSST) including a free speech and mental arithmetics in front of an audience. Blood samples were collected 10min before and 1, 10, 20, and 60min after the TSST as well as 24h after the experiment at identical time points under resting conditions. Analyses of leukocyte subsets indicated a significantly increased number of leukocyte subpopulations (lymphocytes, granulocytes, CD3(+), CD8(+), CD16(+)/CD56(+), and CD3(+)/HLA-DR(+)) after the TSST (all p<.01) with no significant between-group differences. However, monocyte number (F(3,120)=2.7; p<.01) and number of CD4(+)cells (F(3,120)=3.09; p<.05) were found to be significantly higher in PSO sufferers than in controls. Moreover, a significant decrease of CD3(+)/CD25(+)cells was observed in the PSO, but not in the control group (F(3,120)=3.46; p<.05). After exposure to the TSST, stimulation of peripheral blood mononuclear cells (PBMCs) with phytohemagglutinin (PHA) resulted in elevated production of IFN-gamma (F(3,126)=6.9; p<.001) and IL-2 (F(3,123)=6.6; p<.001), and moreover, a decreased production of IL-10 (F(3,132)=5.22; p<.01) and IL-4 (F(3,129)=3.9; p<.01). No difference in stress-induced changes of cytokine production to PHA could be identified between the two experimental groups (all p>.05). The present findings suggest that acute psychosocial stress is associated with changes of immune functions known to be involved in PSO which may be one potential explanation of how stress may trigger psoriatic eruption.

Psoriasis: genetic associations and immune system changes

Psoriasis is a common inflammatory skin disease characterized by infiltration of inflammatory cells into the epidermis and altered keratinocyte differentiation. Psoriasis is currently thought of as a T-cell mediated 'Type-1' autoimmune disease. Gene expression changes in psoriasis lesions have been well documented, and strongly support an important role for tumor necrosis factor and interferon gamma signal pathways in its pathogenesis. The strongest genetic determinant of psoriasis identified to date lies within the class I region of the multiple histocompatibility locus antigen cluster, although its low penetrance implicates a requirement for other genetic risk factors. Multiple genome-wide linkage and an increasing number of association studies have been carried out, leading to multiple linkage peaks, and the identification of potential low risk variants. A number of these variants lie within genes encoding components of the immune system. However, the functional relationships between predisposing genetic variation is unclear, and presumably involves genetic susceptibility factors affecting both immune cell activation and keratinocyte differentiation. The interaction of environmental trigger factors with genetic effects is also not understood, but provide further evidence for the complex basis of this disease.

Prominent Production of IL-20 by CD68+/CD11c+ Myeloid-Derived Cells in Psoriasis: Gene Regulation and Cellular Effects

We assessed expression of IL-20 and its receptors in psoriasis, given the recent implication of IL-20 in epidermal hyperplasia. Psoriatic lesional (LS) skin consistently expressed more IL-20 mRNA than nonlesional (NL) skin. Immunoreactivity to IL-20 protein was greater in LS tissue and mainly localized to infiltrating CD68+/CD11c+ (myeloid-derived) dermal leukocytes. Because this contrasted with earlier reports of a keratinocyte source, we assessed IL-20 mRNA expression in a variety of cells in vitro, and confirmed a myeloid-derived cellular source (monocytes). Plastic adhesion, activation of beta2 integrins, and incubation with tumor necrosis factor-alpha stimulated expression in these cells. IL-20 receptor (IL-20R)alpha and IL-20Rbeta mRNA was decreased in LS versus NL skin, which also contrasted with earlier findings. To investigate the relationship between IL-20 and disease activity, we examined psoriasis patients treated with the CD2-targeted agent alefacept. In therapeutic responders, lesional IL-20 mRNA decreased to NL levels, suggesting that CD2+ leukocytes may proximally regulate IL-20. Finally, to assess IL-20 function, we used microarrays to screen IL-20-treated keratinocytes, which demonstrated upregulation of disease-related and IFN-gamma-induced genes. Hence, IL-20 may influence inflammation through IFN-like effects. Together, these data indicate that IL-20 may be an important effector cytokine in psoriasis, and that its inhibition may represent a potential therapeutic target.

Genomic analysis defines a cancer-specific gene expression signature for human squamous cell carcinoma and distinguishes malignant hyperproliferation from benign hyperplasia

Using high-density oligonucleotide arrays, we measured expression of >12,000 genes in surgical excisions of invasive human squamous cell carcinomas (SCCs) versus site-matched control skin. This analysis defined >1,900 genes with altered expression in SCCs that were statistically different from controls. As SCCs are composed of epithelial cells, which are both hyperplastic and invasive, we sought to define gene sets associated with these biologic processes by comparing gene expression to psoriasis vulgaris, which is a condition of benign keratinocyte hyperplasia without invasiveness or pre-malignant potential. Through this analysis, we found genes that were commonly upregulated in both conditions and unique genes with increased expression in SCCs. Differential gene regulation in these two conditions was confirmed by real-time reverse transcription-PCR and immunohistochemistry. We found that benign hyperplasia is associated with upregulation of genes including DEFB4 (defensin B4), SERPINB3 (serine proteinase inhibitor, member 3), STAT1 (signal transducer and activator of transcription 1), K16 (keratin 16), CEACAMs (carcinoembryonic antigen-related cell adhesion molecules), and WNT 5A (wingless-type MMTV integration site family, member 5A). WNT receptor frizzled homolog 6 (FZD6) and prostaglandin-metabolizing enzyme hydroxyprostaglandin dehydrogenase were increased in SCC alone. Growth factor pleiotrophin (PTN) was expressed at higher levels in non-tumor-bearing skin adjacent to excised SCC. SCC was further characterized by upregulation of matrix metalloproteinases 1, 10, and 13, cathepsin L2, cystatin E/M as well as STAT3 and microseminoprotein, beta (MSMB), and downregulation of inducible nitric oxide synthase, granzyme B, CD8, and CD83. The current study defines a unique gene expression signature for cutaneous SCC in humans and suggests potential roles for WNT, FZD, and PTN in the pathogenesis of SCC.

Serum levels of TNF-alpha, IFN-gamma, IL-6, IL-8, IL-12, IL-17, and IL-18 in patients with active psoriasis and correlation with disease severity

Recent progress in the understanding of psoriasis has shown that the regulation of local and systemic cytokines plays an important role in its pathogenesis. The most often used psoriasis score is the psoriasis area and severity index (PASI). A simple laboratory test from a blood sample would be an attractive, patient-independent, and observer-independent marker of disease severity. To this end, we evaluated the association of serum levels of some proinflammatory cytokines in vivo and their correlation with severity of psoriasis. The serum levels of cytokines levels were determined with the use of the ELISA method. All mean values except IL-17 levels of patients were significantly higher than those of controls. There was a significant correlation between serum levels of IFN-γ, IL-12, IL-17, and IL-18, and severity of the disease. Psoriasis can be described as a T-cell-mediated disease, with a complex role for a variety of cytokines, which has led to the development of new immunomodulatory therapies. In this study, serum TNF-α, IFN-γ, IL-6, IL-8, IL-12, and IL-18 levels were significantly higher in active psoriatic patients than in controls. Furthermore, high levels of IFN-γ, IL-12, and IL-18 correlated with the clinical severity and activity of psoriasis, and those measurements of serum levels of these cytokines may be objective parameters for the disease severity.

Alefacept in the treatment of psoriasis in patients for whom conventional therapies are inadequate

BACKGROUND

Many patients with moderate to severe chronic plaque psoriasis fail to respond to or are not appropriate candidates for conventional systemic therapies and/or phototherapy.

OBJECTIVES

To assess the efficacy, quality of life and safety of alefacept among the proportion of patients who participated in the phase III studies and who were not suitable candidates for conventional systemic psoriasis therapies or phototherapy.

METHODS

The patient's historical responses at the baseline visit during the phase III studies of alefacept were used to identify a subpopulation in whom the use of methotrexate, ciclosporin, retinoids, ultraviolet B or psoralen plus ultraviolet A was ineffective or inappropriate. Endpoints included Psoriasis Area and Severity Index (PASI), Dermatology Life Quality Index (DLQI) and adverse events.

RESULTS

Most patients (69%) who were treated with alefacept in the phase III programme were not candidates for > or =1 of the above-mentioned therapies, and 41 and 21% were not candidates for > or =2 and > or =3, respectively. A reduction in PASI of > or =75% was achieved by 27, 23 and 26% of alefacept-treated patients who were not candidates for > or =1, > or =2 and > or =3 conventional systemic psoriasis therapies or phototherapy, respectively (all p < or = 0.001 vs. placebo). The corresponding results for PASI 50 were 53, 52 and 50% (all p < or = 0.001 vs. placebo). At 2 weeks after the last dose of alefacept, mean DLQI overall scores were reduced by -4.2, -3.9 and -5.2, respectively (all p < or = 0.001 vs. placebo). The incidence of adverse events was similar in the alefacept and placebo groups.

CONCLUSIONS

The efficacy, quality of life effects and safety of alefacept in patients who were not candidates for conventional systemic psoriasis therapies or phototherapy were similar to those reported previously for the overall alefacept-treated population in the phase III studies.

Plasmacytoid predendritic cells initiate psoriasis through interferon-alpha production

Psoriasis is one of the most common T cell–mediated autoimmune diseases in humans. Although a role for the innate immune system in driving the autoimmune T cell cascade has been proposed, its nature remains elusive. We show that plasmacytoid predendritic cells (PDCs), the natural interferon (IFN)-α–producing cells, infiltrate the skin of psoriatic patients and become activated to produce IFN-α early during disease formation. In a xenograft model of human psoriasis, we demonstrate that blocking IFN-α signaling or inhibiting the ability of PDCs to produce IFN-α prevented the T cell–dependent development of psoriasis. Furthermore, IFN-α reconstitution experiments demonstrated that PDC-derived IFN-α is essential to drive the development of psoriasis in vivo. These findings uncover a novel innate immune pathway for triggering a common human autoimmune disease and suggest that PDCs and PDC-derived IFN-α represent potential early targets for the treatment of psoriasis.

Analysis of RUNX1 binding site and RAPTOR polymorphisms in psoriasis: no evidence for association despite adequate power and evidence for linkage

BACKGROUND

A previous study identified two peaks of allelic association between psoriasis and single nucleotide polymorphisms (SNPs) mapping to distal chromosome 17q, including a disease associated SNP that leads to loss of a RUNX1 transcription factor binding site, and additional SNPs in the third intron of the RAPTOR gene. Another study found an association with SNPs in the RAPTOR gene, but not with the RUNX1 binding site polymorphism.

METHODS

In an effort to confirm these observations, we genotyped 579 pedigrees containing 1285 affected individuals for three SNPs immediately flanking and including the RUNX1 binding site, and for three SNPs in the RAPTOR gene.

RESULTS

Here we report further evidence for linkage to distal chromosome 17q, with a linkage peak mapping 1.7 cM distal to the RUNX1 binding site (logarithm of the odds 2.26 to 2.73, depending upon statistic used). However, we found no evidence for association to individual SNPs or haplotypes in either of the previously identified peaks of association. Power analysis demonstrated 80% power to detect significant association at genotype relative risks of 1.2 (additive and multiplicative models) to 1.5 (dominant and recessive models) for the RUNX1 binding site, and 1.3 to 1.4 for the RAPTOR locus under all models except dominant.

CONCLUSIONS

Our data provide no support for the previously identified RUNX1 binding site or for the RAPTOR locus as genetic determinants of psoriasis, despite evidence for linkage of psoriasis to distal chromosome 17q.