A study on the expression of interleukin (IL)-10 and IL-12 P35, P40 mRNA in the psoriatic lesions

The Role of Inflammation in the Pathogenesis of Psoriasis

"Psoriasis is a chronic inflammatory skin condition with genetic determinism characterized by the presence of welldefined, erythematous plaques, covered by white, pearly, stratified scales, located on the extension areas, the skin of the scalp, intertriginous regions. The origin of psoriasis is multifactorial, involving hereditary and environmental pathogenic mechanisms. It is triggered by various risk factors involving a variety of processes, such as inflammation, antigen presentation, cell signaling, and transcriptional regulation. "

An Analysis of IL-10, IL-17A, IL-17RA, IL-23A and IL-23R Expression and Their Correlation with Clinical Course in Patients with Psoriasis

Being one of the most common dermatological inflammatory disorders, psoriasis is a frequent subject of research. It is considered to be a T cell-dependent immune disease whose pathogenesis is influenced by cytokines, such as IL-10, IL-17A, IL-17RA, IL-23A and IL-23R. The present study examines whether the expression of selected genes is correlated with the clinical course of psoriasis, assessed by the PASI, BSA and DLQI scales. Skin biopsies and blood from 60 patients with psoriasis and 24 healthy controls were obtained for RNA isolation. These were subjected to RT-PCR for IL-10, IL-17A, IL-17RA, IL-23A and IL-23R genes. The results were presented as an RQ value. IL-17A and IL-23R expression levels were higher in psoriatic skin compared to controls, while IL-10 expression was lower. A positive correlation was also found between RQ for IL-23A and PASI index. Psoriatic skin is characterised by elevated expression of IL-17A and IL-23R and decreased expression of IL-10. This indicates that the selected cytokines may be one of the factors involved in the pathogenesis and pathomechanism of psoriasis, but more studies need to be made before we can elucidate the exact reason for the unbalance in cytokine expression levels.

Current Developments in the Immunology of Psoriasis

Psoriasis is a frequent inflammatory skin disease. Fundamental research on the pathogenesis of psoriasis has substantially increased our understanding of skin immunology, which has helped to introduce innovative and highly effective therapies. Psoriasis is a largely T lymphocyte-mediated disease in which activation of innate immune cells and pathogenic T cells result in skin inflammation and hyperproliferation of keratinocytes. B cells have thus far largely been neglected regarding their role for the pathogenesis of psoriasis. However, recent data shed light on their role in inflammatory skin diseases. Interestingly, interleukin (IL)-10-producing regulatory B cells have been assumed to ameliorate psoriasis. In this review, we will discuss the development of disease, pathogenicity, and current developments in therapeutic options. We describe different roles of T cells, B cells, and cytokines for the immunopathology and disease course of psoriasis.

Th1, Th17, and Treg Responses are Differently Modulated by TNF-α Inhibitors and Methotrexate in Psoriasis Patients

Psoriasis is a chronic, recurrent, immune-mediated, hyperproliferative inflammatory skin disease. The role of the adaptive immune system, particularly of Th1 and Th17 lymphocytes, has been regarded as prominent in the immunopathogenesis of psoriasis, as well as decreased Tregs function. Immunobiological drugs were administered in therapeutic pulses and a few studies evaluate their effects on the immune repertoire. The aim of this study was to evaluate the adaptive immune profile of patients with severe psoriasis under immunobiological treatment in two time points. Thirty-two psoriasis patients and 10 control patients were evaluated. In the group of psoriasis patients, 10 patients were on anti-TNF and 14 patients on methotrexate treatment, while 8 individuals were not treated. IL-17, IFN-γ, TNF-α, IL-6, IL-2, and IL-10 were analyzed. CD4 T cell intracellular cytokines were analyzed. It was observed that stimulation could significantly increase the production of IL-17, IFN-γ, TNF-α, and IL-10 only before anti-TNF pulse therapy. The activation of Th1 and Treg cells after stimulation was significantly higher before anti-TNF pulse. Patients on methotrexate or anti-TNF therapy produced significantly lower levels of TNF-α, IL-10, and IL-6. Furthermore, these patients showed a significant decrease in the activated CD4+ T cells. The treatment with immunomodulator or methotrexate modulates the activation of CD4+ T cells, and anti-TNF treatment appears to have a modulating effect on the activation and production of Th1, Th17, and Treg cells.

Lack of association of the IL-1RN and IL-10 polymorphisms with risk of psoriasis: A meta-analysis

BACKGROUND

The present study carried out a meta-analysis to investigate whether the interleukin-1 receptor antagonist (IL-1RN) VNTR polymorphism and three IL-10 single-nucleotide polymorphisms (SNPs) rs1800896, rs3021097, and rs1800872 are associated with psoriasis risk.

METHODS

Wanfang, China National Knowledge Infrastructure, Medline, and PubMed databases were searched for potential studies published until 2 November 2017. Forest plots were generated.

RESULTS

Thirteen case-control studies were included in the review. The results of meta-analyses revealed no association of the IL-1RN*2 allele with psoriasis in the overall populations (odds ratio [OR] = 1.16, 95% confidence intervals [CI]: 0.89-1.50, p = 0.279), Asians (OR = 1.27, 95% CI: 0.73-2.23, p = 0.403), and Caucasians (OR = 1.04, 95% CI: 0.88-1.23, p = 0.669). Under the allelic model, there was no statistically significant association of psoriasis with the IL-10 SNPs rs1800896 (G allele vs. A allele: OR = 1.03, 95% CI: 0.90-1.18, p = 0.639), rs3021097 (C allele vs. T allele: OR = 1.17, 95% CI: 0.88-1.56, p = 0.288), and rs1800872 (C allele vs. A allele: OR = 1.01, 95% CI: 0.81-1.25, p = 0.951). No publication bias was found by Egger's test and Begg's funnel plots.

CONCLUSION

Current published studies fail to support an association of the IL-1RN VNTR polymorphism and IL-10 SNPs rs1800896, rs3021097, and rs1800872 with psoriasis risk.

Imiquimod-applied Interleukin-10 deficient mice better reflects severe and persistent psoriasis with systemic inflammatory state

Previous studies have shown that imiquimod-induced psoriasis-like skin inflammation in mice resembles phenotypic changes and cytokine profiles of human psoriasis. However, a psoriasis animal model reflecting the chronic inflammatory course and comorbidities has not yet been established. We aimed to evaluate the imiquimod-applied interleukin (IL)-10 deficient mouse model in comparison with previous models. IL-10 deficient and wild-type (WT) mice received either imiquimod or vehicle cream for 12 days and were sacrificed on day 15. For earlier time point data, either imiquimod or vehicle cream was applied for 2 days, and the mice were sacrificed on day 3. Imiquimod-applied IL-10 deficient mice showed more persistent psoriasis-like inflammation and higher severity index than did WT between day 8 and 15. Histopathologically, they demonstrated significantly thicker epidermis and larger number of CD45+, myeloperoxidase+ and IL-17+ cell counts on day 15. Quantitative reverse transcription-polymerase chain reaction with skin tissue revealed significantly higher imiquimod-induced IL-23p19 expression in imiquimod-applied IL-10 deficient mice on day 15. IL-10 deficient mice also showed significantly higher serum levels of imiquimod-induced IL-17A and tumor necrosis factor-α by enzyme-linked immunosorbent assay on day 15. Furthermore, IL-10 deficient mice showed more prominent increase of spleen weight and decrease of body weight in response to imiquimod application on day 3 and 15. In conclusion, IL-10 deficient mice model with imiquimod application may better reflect severe and persistent psoriasis with systemic inflammatory state.

Association of IL-12B gene rs6887695 polymorphism with hereditary susceptibility and clinical characterization of psoriasis vulgaris in the Chinese Han population

We aimed to investigate the role of IL-12B gene polymorphism (rs6887695) in the disease susceptibility and clinical phenotypes of psoriasis vulgaris patients in the Chinese Han population. The genotype data of the IL-12B gene polymorphism (rs6887695) in 575 psoriasis patients and 1,403 normal controls were investigated using TaqMan technology. The Chi-square test was used to compare the genotype and allele frequency distribution among the groups. The genotypic and allelic frequencies of rs6887695 in the IL-12B gene between the cases and controls, as well as between the guttate and plaque psoriasis cases, were statistically significant (P genotype <0.01, P allele <0.01). However, the differences between the pediatric and adult onset psoriasis patients, between familial and sporadic cases, and between female and male cases were not statistically significant (P > 0.05). The genetic polymorphism of the IL-12B gene (rs6887695) may be associated with the psoriasis susceptibility in the Chinese Han population, especially for the plaque cases, but not associated with the age at onset, family history, or sex.

Interleukin-23: as a drug target for autoimmune inflammatory diseases

Interleukin-23 (IL-23) is a member of the IL-12 family of cytokines with pro-inflammatory properties. Its ability to potently enhance the expansion of T helper type 17 (Th17) cells indicates the responsibility for many of the inflammatory autoimmune responses. Emerging data demonstrate that IL-23 is a key participant in central regulation of the cellular mechanisms involved in inflammation. Both IL-23 and IL-17 form a new axis through Th17 cells, which has evolved in response to human diseases associated with immunoactivation and immunopathogeny, including bacterial or viral infections and chronic inflammation. Targeting of IL-23 or the IL-23 receptor or IL-23 axis is a potential therapeutic approach for autoimmune diseases including psoriasis, inflammatory bowel disease, rheumatoid arthritis and multiple sclerosis. The current review focuses on the immunobiology of IL-23 and summarizes the most recent findings on the role of IL-23 in the pre-clinical and ongoing clinical studies.

Targeting IL-23 in human diseases

IMPORTANCE OF THE FIELD

IL-23 is one of the most intriguing cytokine for its many immunological functions, which are the basis of its important role in host defense but also of its possible contribution to the pathogenesis of several diseases.

AREAS COVERED IN THIS REVIEW

The literature and patents about IL-23 pathway and their targeting in therapeutic potential applications. Findings published within the last 5 years receive particular attention.

WHAT THE READER WILL GAIN

An overview of the emerging role of IL-23 in physiological and pathological conditions and a review of the different approaches (IL-23 pathway-based) currently used for autoimmune diseases and cancer therapies and the results obtained both in preclinical models and in clinical trials.

TAKE HOME MESSAGE

Inhibition/targeting of IL-23 may be a good and novel therapeutic strategy, especially in the treatment of diseases like psoriasis, for which current treatments show more pronounced side effects than those of IL-23-blocking and employed as part of specific patient-tailored therapies in inflammatory bowel diseases.

Reconciling id, ego, and superego within interleukin-23

The study of interleukin-23 (IL-23) over the past 8 years has led to the realization that cellular immunity is far more complex than previously appreciated, because it is controlled by additional newly identified players. From the analysis of seemingly straightforward cytokine regulation of autoimmune diseases, many limitations of the established paradigms emerged that required reevaluation of the 'rules' that govern the initiation and maintenance of immune responses. This information led to a major revision of the T-helper 1 (Th1)/Th2 hypothesis and discovery of an unexpected link between transforming growth factor-beta-dependent Th17 and inducible regulatory T cells. The aim of this review is to explore the multiple characteristics of IL-23 with respect to its 'id' in autoimmunity, 'ego' in T-cell help, and 'superego' in defense against mucosal pathogens.

Cytokines and anticytokines in psoriasis

BACKGROUND

Psoriasis is a chronic autoimmune hyperproliferative skin disease of varying severity affecting approximately 2-3% of the general population in the USA and Europe. Although the pathogenesis of psoriasis has not been fully elucidated, an immunologic-genetic relationship is likely. Cutaneous and systemic overexpression of various proinflammatory cytokines (TNF, interleukins, interferon-gamma) has been demonstrated in psoriatic patients.

METHODS

We reviewed the current database literature and summarized the involvement of cytokines and their receptors in the pathogenesis and treatment of psoriasis.

RESULTS

Although many cytokine/anti-cytokine therapies have been conducted, TNF antagonists in the treatment of both psoriasis arthropatica and vulgaris appear to be the most widely used clinically. Interestingly, the efficacy and tolerability of some cytokines (rhIL-11 or ABX-IL-8,) were found to be much lower than expected.

CONCLUSIONS

Preliminary results obtained with cytokine and anti-cytokine therapies appear promising and as such continued research is clearly indicated.

Interleukin-12, interleukin-23, and psoriasis: Current prospects

The clinical phenotype of psoriasis results from infiltration of T cells in the skin and elaboration of inflammatory cytokines. Interleukin (IL)-12 and, more recently, IL-23 have been implicated in the pathogenesis of psoriatic lesions. New therapies, including a monoclonal antibody against a subunit shared by IL-12 and IL-23, have been developed to treat psoriasis. Our purpose was to review the literature on IL-12 and IL-23 as a basis for understanding the use of anti-IL-12/IL-23 therapy for psoriasis. A review of English-language articles was performed using PubMed to identify articles pertaining to IL-12, IL-23, and psoriasis. IL-12 and IL-23 share a common subunit (p40) and have a distinct subunit (p35 and p19, respectively). Transgenic mice that overexpress IL-12 p40 develop inflammatory skin lesions. Both IL-12 knockout mice, which are deficient in IL-12, and human beings with a genetic IL-12 deficiency show increased susceptibility to intracellular pathogens and defective delayed-type hypersensitivity responses. These genetic deficiency states suggest the potential for adverse side effects from clinical administration of anti IL-12 p40 therapy. IL-12 p40 antibody was well tolerated in a phase I clinical trial with few adverse events and substantial improvements in psoriasis in most individuals. There was dose-dependent efficacy and substantial improvement in a larger cohort of patients in a phase II clinical trial. Larger and longer trials of anti IL-12/IL-23 therapies are needed to assess their clinical use and potential for infection and other adverse events.

The role of interleukin-12 in the pathogenesis of psoriasis

OBJECTIVES

To verify the role of IL-12 in the pathogenesis of psoriasis and determine its relation to IFNgamma.

DESIGN AND METHODS

Skin biopsies from lesional and non-lesional skin of 30 patients and 10 healthy controls were obtained for quantitative PCR examination of IL-12 (P40) and IFNgamma mRNA as well as in situ PCR of IL-12 (P40) and IFNgamma mRNA.

RESULTS

IL-12 and IFNgamma levels were higher in lesional skin than in non-lesional and control skin. A significant correlation between IL-12 and IFNgamma was found. By in situ PCR hybridization, IL-12 expression was only found in the dermis, while IFNgamma was invariably expressed in the dermis and/or epidermis.

CONCLUSION

We suggest that IL-12 independently and through IFNgamma induction may have a crucial role in the development of the active psoriatic lesion itself, where it is probably produced locally in the dermis as a step in the evolution of the psoriatic lesion.

p16 expression in psoriatic lesions following therapy with propylthiouracil, an antithyroid thioureylene

Plaque formation is a characteristic finding in patients with psoriasis and reflects cytokine-induced keratinocyte proliferation and/or impaired apoptosis of keratinocytes. Antithyroid thioureylenes such as propylthiouracil (PTU) and methimazole (MMI) are effective in the treatment of plaque psoriasis. Following PTU and MMI treatment, proliferative cell nuclear antigen (PCNA) expression is significantly reduced, suggesting that these medications have an antiproliferative effect. p16 is an antiapoptotic protein that is present in relative abundance in psoriatic plaques and is believed to play a potential role in the persistent senescence and impaired apoptosis of the keratinocytes in the plaque. This study examined p16 expression in biopsy samples of eight patients with plaque psoriasis given 300 mg of propylthiouracil in divided doses for 3 months. Despite significant clinical and histological improvement with PTU treatment, p16 expression was essentially unchanged, suggesting that the beneficial effect of PTU in psoriasis is not mediated through a decrease in p16 expression. The effect of PTU on other antiapoptotic proteins such as bcl-xL remains to be determined.

Current concepts in the immunopathogenesis of psoriasis

There is much evidence to support the concept that psoriasis is a type 1 autoimmune disease, primarily mediated by interferon gamma and other inflammatory cytokines. There has been renewed interest in the role of components of the innate immune system, however,and it may be that overlap between the innate and acquired arms of the immune system can better explain immunopathogenesis in psoriasis. Relevant cell types, receptors, and immune mediators within these traditional boundaries of the immune system are discussed.Finally, pathogenic contributions from important psoriatic mouse models and recent genomic data using the new gene chip technology are elaborated.

Psoriasis Is Not Associated with IL-12p70/IL-12p40 Production and IL12B Promoter Polymorphism

Psoriasis is a type-1 T cell-mediated, chronic inflammatory disease. Since interleukin (IL)-12p70 promotes the development of type-1 T cells, we investigated whether psoriasis is associated with an increased production of this cyctokine by blood cells. Results revealed that the production of IL-12p70 by cells of psoriasis patients stimulated by 1 and 10 ng per mL, but not 100 ng per mL of lipopolysaccharide (LPS) was higher (p=0.03) than that by cells of healthy volunteers. The production of IL-12p40 by patients cells upon stimulation with 0.1 ng per mL LPS, but not higher concentrations, was higher (p=0.02) than that by cells of healthy volunteers. No association between IL-12p70 production by blood cells and the severity of psoriasis was observed, nor was there a difference in the LPS-stimulated production of this cytokine between cells of the early and late onset type of patients. The frequencies of the various genotypes for the promoter region of the gene encoding IL-12p40 (IL12B) did not differ between psoriasis patients and controls. No association was observed between the various IL12B promoter genotypes and the LPS-stimulated production of IL-12p70 or IL-12p40 by blood cells. Together, psoriasis is not associated with a promoter polymorphism in the IL12B gene nor with the production of IL-12p70 by LPS-stimulated blood cells.

Anti-thyroid thioureylenes in the treatment of psoriasis

Psoriasis is a common skin disorder associated with significant morbidity. Many agents are used in the medical management of this debilitating condition with the newer anti-cytokine agents being the most recent addition to the pharmacological armamentarium to battle the disorder. Cost concerns are very important with the newer "biologic" treatments costing in excess of 10,000 US dollars annually. The need for cheaper, orally administered agents is therefore imperative. This paper addresses the potential role of anti-thyroid thioureylenes, propylthiouracil and methimazole, in the treatment of psoriasis and reviews the possible mechanism of action of these drugs in this disorder. It is hypothesized that the beneficial effect of anti-thyroid thioureylenes in psoriasis is linked to their effect as anti-proliferative agents as reflected by significant decrease in markers of cellular proliferation such as proliferative cell nuclear antigen in biopsy specimens after treatment with these drugs. Propylthiouracil has been shown to bind to the hepatic T 3 receptor and it is possible that propylthiouracil (6-n-propyl-2-thiouracil) binding to the ligand-binding site normally occupied by T 3 impairs transcription by inactivating the effect of T 3 as well as by squelching retinoic X receptor heterodimer formation with other receptors of the steroid receptor superfamily such as the peroxisome proliferator-activated receptor, retinoic acid receptor and vitamin D receptors.

CD1a expression in psoriatic skin following treatment with propylthiouracil, an antithyroid thioureylene

BACKGROUND

The antithyroid thioureylenes, propylthiouracil (PTU) and methimazole (MMI), are effective in the treatment of patients with plaque psoriasis. The mechanism of action of the drugs in psoriasis is unknown. Since the drugs reduce circulating IL-12 levels in patients with Graves' hyperthyroidism, the effect of propylthiouracil on CD1a expression in psoriatic lesions was examined in biopsy samples of patients with plaque psoriasis. CD1a is a marker of differentiated skin antigen presenting cells (APC, Langerhans cells). Langerhans cells and skin monocyte/macrophages are the source of IL-12, a key cytokine involved in the events that lead to formation of the psoriatic plaque.

METHODS

Biopsy specimens were obtained from six patients with plaque psoriasis who were treated with 300 mg propylthiouracil (PTU) daily for three months. Clinical response to PTU as assessed by PASI scores, histological changes after treatment, and CD1a expression in lesional skin before and after treatment were studied.

RESULTS

Despite significant improvement in clinical and histological parameters the expression of CD1a staining cells in the epidermis did not decline with propylthiouracil treatment.

CONCLUSIONS

It appears that the beneficial effect of propylthiouracil in psoriasis is mediated by mechanisms other than by depletion of skin antigen-presenting cells.