The Interleukin-17 Pathway in Psoriasis and Psoriatic Arthritis: Disease Pathogenesis and Possibilities of Treatment

Impact of Adalimumab Treatment on Interleukin-17 and Interleukin-17 Receptor Expression in Skin and Synovium of Psoriatic Arthritis Patients with Mild Psoriasis

Interleukin (IL)-17 and tumor necrosis factor-alpha (TNF)-α are key players in psoriatic arthritis (PsA) pathogenesis. While both cytokines can be therapeutically targeted with beneficial clinical outcome, it is unclear whether inhibiting one cytokine will affect the other at sites of inflammation. If both act independently, this might provide a rationale for dual or combined inhibition of both cytokines. Here, we evaluated the effect of TNF blockade in PsA patients on IL-17 levels in both skin and synovial tissue biopsies. PsA patients with mild psoriatic skin lesions were randomized to receive either adalimumab or placebo for four weeks. Synovial and skin biopsies were obtained at weeks zero and four. Skin from healthy donors (HDs) was used for comparison. Expression of IL-17A, IL-17F, IL-17RA and IL-17RC was assessed by immunohistochemistry and analyzed with digital image analysis. We found relatively low levels of IL-17 and its receptors in the skin of PsA patients compared to HD, and only IL-17F in the dermis of lesional psoriatic skin was significantly higher compared to HD skin (p = 0.0002). Histologically IL-17A, IL-17F, IL-17RA and IL-17RC in skin and synovial tissue were not downregulated by adalimumab treatment. Thus, in this cohort of PsA patients with mild psoriasis, TNF blockade did not affect the protein levels of IL-17 cytokines and its receptors in skin and synovium, despite reduced cellular inflammation and improved clinical outcome for joint involvement.

Lipid-based nanoparticles for psoriasis treatment: a review on conventional treatments, recent works, and future prospects

Psoriasis is a lingering inflammatory skin disease that attacks the immune system. The abnormal interactions between T cells, immune cells, and inflammatory cytokines causing the epidermal thickening. International guidelines have recommended topical treatments for mild to moderate psoriasis whilst systemic and phototherapy treatments for moderate to severe psoriasis. However, current therapeutic approaches have a wider extent to treat moderate to severe type of psoriasis especially since the emergence of diverse biologic agents. In the meantime, topical delivery of conventional treatments has prompted many unsatisfactory effects to penetrate through the skin (stratum corneum). By understanding the physiology of stratum corneum barrier functions, scientists have developed different types of lipid-based nanoparticles like solid lipid nanoparticles, nanostructured lipid carriers, nanovesicles, and nanoemulsions. These novel drug delivery systems help the poorly solubilised active pharmaceutical ingredient reaches the targeted site seamlessly because of the bioavailability feature of the nanosized molecules. Lipid-based nanoparticles for psoriasis treatments create a paradigm for topical drug delivery due to their lipids' amphiphilic feature to efficiently encapsulate both lipophilic and hydrophilic drugs. This review highlights different types of lipid-based nanoparticles and their recent works of nano formulated psoriasis treatments. The encapsulation of psoriasis drugs through lipid nanocarriers unfold numerous research opportunities in pharmaceutical applications but also draw challenges for the future development of nano drugs.

Efficacy and safety of interleukin-17A inhibitors in patients with ankylosing spondylitis: a systematic review and meta-analysis of randomized controlled trials

To assess the efficacy and safety of interleukin (IL)-17A inhibitors in patients with ankylosing spondylitis (AS). PubMed, EMBASE, and Web of Science were searched up to 5 February 2020 for randomized controlled trials (RCTs) that assessed the efficacy and safety of IL-17A inhibitors in patients with AS. We used a meta-analytic approach to perform a random effects analysis or fixed effects analysis according to heterogeneity. Subgroup analyses between studies included medication, time to primary endpoint, and data source. Odds ratios (ORs) or mean differences (MDs) were used to assess the efficacy and safety of IL-17A inhibitors in AS. A total of ten RCTs with 2613 patients were eligible for inclusion in the analysis (six for secukinumab, two for ixekizumab, one for netakimab, and one for bimekizumab). Compared to placebo, IL-17A inhibitors improved ASAS20 response rate (OR = 2.58; p < 0.01) and ASAS40 response rate (OR = 2.80; p < 0.01), and significantly increased the risk of AEs (OR = 1.23; p = 0.03) and nasopharyngitis (OR = 1.72; p < 0.01), but not SAEs (OR = 0.87; p = 0.60). IL-17A inhibitors demonstrated better efficacy in patients with AS in several evaluation indicators. However, the safety of IL-17A inhibitors remains to be further studied in studies with larger sample size and longer follow-up times.

Psoriatic arthritis: A systematic review of non-HLA genetic studies and important signaling pathways

Psoriatic arthritis (PsA) is a common, chronic inflammatory disease with complex pathogenesis. In recent years, a number of susceptibility non-human leukocyte antigen (HLA) genes of PsA have been revealed, which also act as important factors in the pathogenesis of PsA as well as HLA genes. By searching the databases National Center for Biotechnology Information, Google and PubMed, 37 articles are included and 50 susceptibility non-HLA genes for PsA are presented, such as IL23A, TNIP1, TYK2, STAT4, IL12B, RUNX3 and TRAF3IP2. In these non-HLA genes, some are common genes shared with other diseases, whereas most of these susceptibility genes are related to the pathogenesis of PsA by activation or inhibition of the signaling pathways. Several signaling pathways possibly implicated in the pathogenesis of PsA are introduced in this paper, including the 2 mainly signaling pathways, IL23/Th17 signaling pathway and NF-κB signaling pathway, and the other involved signaling pathways, such as JAK-STAT signaling pathway and MAPK signaling pathway.

Myasthenia gravis after etanercept and ustekinumab treatment for psoriatic arthritis: A case report

A 35-year-old man was diagnosed with psoriatic arthritis treated with methotrexate and cyclosporine, the latter was then interrupted. Subsequently, etanercept was introduced, administered for 10 years and then replaced with ustekinumab. Six months after treatment with ustekinumab, patient underwent a chest CT scan for pneumonia, showing an anterior mediastinal mass which turned out to be a thymoma. He was referred to our department with fatigue, difficulty in raising arms and transient episodes of diplopia after exertion. Clinical history revealed that these symptoms had begun about 7 years previously but were ascribed to psoriatic arthritis. A diagnosis of anti-acetylcholine receptor antibodies positive myasthenia gravis was made; a higher dosage of methotrexate and prednisone were started with regression of symptoms. Our case increases the number of clinical reports of myasthenia gravis onset in patients with a history of rheumatic disease treated with anti-TNFα drugs. We speculate that ustekinumab could contribute to clinical worsening.

A review of ustekinumab in the treatment of psoriatic arthritis

Psoriatic arthritis is an inflammatory arthritis associated with psoriasis. The IL-23/IL-17 axis is an important pathway in the development of psoriatic disease. Ustekinumab is a fully human monoclonal IgG1 antibody that binds to the p40 subunit of IL-12 and IL-23, which, in turn, inhibits downstream signaling pathways. PSUMMIT-1 and PSUMMIT-2 are two pivotal Phase III trials demonstrating global improvement in primary and secondary outcomes including inhibition of radiographic progression. Therapeutic benefit of ustekinumab for synovitis appears independent of previous disease modifying antirheumatic disease or anti-TNF exposure. At present, the data support the use of ustekinumab in the treatment of psoriatic arthritis after the failure of NSAIDs and conventional disease modifying antirheumatic diseases as an alternative to, or after failure of an anti-TNF agent.

Anti-IL-23 and Anti-IL-17 Biologic Agents for the Treatment of Immune-Mediated Inflammatory Conditions

Advancements in the immunopathogenesis of psoriasis have identified interleukin (IL)-23 and IL-17 as fundamental contributors in the immune pathways of the disease. Leveraging these promising therapeutic targets has led to the emergence of a number of anti-IL-23 and -17 biologic agents with the potential to treat multiple conditions with common underlying pathology. The unprecedented clinical efficacy of these agents in the treatment of psoriasis has paved way for their evaluation in diseases such as psoriatic arthritis, Crohn's disease, rheumatoid arthritis, in addition to other immune-mediated conditions. Here we review the IL-23/IL-17 immune pathways and discuss the key clinical and safety data of the anti-IL-23 and anti-IL-17 biologic agents in psoriasis and other immune-mediated diseases.

Differential gene and protein expression of chemokines and cytokines in synovial fluid of patients with arthritis

Background

Psoriatic arthritis (PsA), an inflammatory musculoskeletal disease, develops in approximately 30% of patients with psoriasis. Previously, chemokine (C-X-C motif) ligand 10 (CXCL10) was identified as a predictive biomarker of PsA in patients with psoriasis and was reduced after development of PsA. The purpose of the present study was to explore messenger RNA (mRNA) and protein expression of CXCL10 and its receptor, chemokine (C-X-C motif) receptor 3 (CXCR3), in the joints of patients with PsA to gain insight into their role in the pathogenesis of the disease.

Methods

Sera from 47 patients with PsA and 33 healthy control subjects were compared for expression of CXCL10 by Luminex assay. Synovial fluid (SF) was obtained from patients with PsA (n = 40), osteoarthritis (OA; n = 14), gout (n = 8), and rheumatoid arthritis (RA; n = 11) during clinical care. SF mRNA and protein expression of CXCL10, interleukin-17A (IL-17A), CXCR3, TBX21, RORC and/or interferon γ (IFNγ) were compared among the above-mentioned disease groups, as well as in paired SF and serum samples from patients with PsA using real-time polymerase chain reaction and Luminex assays, respectively.

Results

Serum CXCL10 was significantly higher in patients with PsA than in control subjects (p = 0.0007). CXCL10, IL-17A, and TBX21 expression were elevated in SF cells of patients with PsA compared with those of patients with OA and gout, but not those of patients with RA. CXCR3 and RORC were elevated in PsA SF cells compared with all other patient groups. Concordant results were obtained for CXCL10 and IL-17A protein expression. IFNγ was elevated in PsA SF compared with OA SF (p = 0.015). CXCL10 protein expression was substantially increased in SF (median 7283.9 pg/ml, interquartile range [IQR] 1330–10,362 pg/ml) compared with paired serum samples (median 282.06, IQR 180.7–395.8 pg/ml; p = 0.001), whereas IFNγ was significantly reduced (SF median 6.03 pg/ml, IQR 4.47–8.94 pg/ml; versus serum median 23.70 pg/ml, IQR 3.2–104.6 pg/ml; p = 0.001).

Conclusions

CXCL10 may have an important etiological role in PsA that is analogous to that in RA, and it is a candidate biomarker to distinguish PsA from healthy individuals and from patients with OA and gout.

Management of psoriatic arthritis in 2016: a comparison of EULAR and GRAPPA recommendations

Psoriatic arthritis (PsA) is a heterogeneous, potentially severe disease. Many therapeutic agents are now available for PsA, but treatment decisions are not always straightforward. To assist in this decision making, two sets of recommendations for the management of PsA were published in 2016 by international organizations - the European League Against Rheumatism (EULAR) and the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA). In both sets of recommendations, the heterogeneity of PsA is recognized and the place of various drugs in the therapeutic armamentarium is discussed. Such agents include conventional DMARDs, such as methotrexate, and targeted therapies including biologic agents, such as ustekinumab, secukinumab and TNF inhibitors, or the targeted synthetic drug apremilast. The proposed sequential use of these drugs, as well as some other aspects of PsA management, differ between the two sets of recommendations. This disparity is partly the result of a difference in the evaluation process; the focus of EULAR was primarily rheumatological, whereas that of GRAPPA was balanced between the rheumatological and dermatological aspects of disease. In this Perspectives article, we address the similarities and differences between these two sets of recommendations and the implications for patient management.

Interleukin (IL)-9/IL-9R axis drives γδ T cells activation in psoriatic arthritis patients

Cytokines such as tumour necrosis factor (TNF)-α, interleukin (IL)-12, interferon (IFN)-γ, IL-23 and, more recently, IL-9, have been implicated in the initiation/maintenance of inflammation in psoriasis and psoriatic arthritis (PsA). In the present study we aimed to characterize the role of γδ T cells in peripheral blood and synovial fluid of PsA patients and to investigate their response to in-vitro stimulation with antigen or cytokines (IL-9 and IL-23). γδ T cells isolated from peripheral blood mononuclear cells and synovial fluid were analysed by flow cytometry to evaluate the phenotype and cytokine production. IL-23R and IL-9R gene expression were also evaluated by reverse transcription-polymerase chain reaction (RT-PCR). Peripheral blood mononuclear cells (PBMC), sorted γδ T cells and γδ cell lines were also stimulated in vitro with isopentenyl pyrophosphate (IPP), recombinant IL-9 or recombinant IL-23. Our results show an expansion of γδ T cells with a predominant effector memory phenotype in peripheral blood and synovium of untreated PsA patients, which reverses significantly after treatment with anti-TNF-α or anti-IL-12/IL-23R monoclonal antibodies (mAbs). Moreover, in PsA patients γδ T cells activation is driven prevalently by IL-9/IL-9R interaction, and not only by IL-23/IL-23R. Together these findings indicate γδ T cells and IL-9 as new players in the pathogenesis of PsA.

Secukinumab (AIN-457) for the treatment of Psoriasis

Secukinumab (also known as AIN-457) is a human monoclonal antibody targeting IL-17A, which has been recently FDA-approved for the treatment of moderate to severe psoriasis and psoriatic arthritis with coexistent moderate to severe plaque psoriasis based on clinical trials demonstrating excellent efficacy. This review will address the rationale for targeting the IL-23/Th17/IL-17 axis, the role of IL-17 and Th17 cells in psoriasis and other chronic inflammatory diseases, and will examine pre-clinical studies, pharmacologic properties, clinical efficacy, and the safety profile of secukinumab.

Palmoplantar pustular psoriasis (PPPP) is characterized by activation of the IL-17A pathway

BACKGROUND

Palmoplantar pustular psoriasis (PPPP) is a variant of psoriasis, which has significant negative impact on quality of life. The cellular and molecular inflammatory pathways involved in PPPP have not been well studied.

OBJECTIVE

Study the expression of cytokines and chemokines involved in the IL-17/IL-23 axis in palmoplantar pustular psoriasis and other difficult to treat psoriasis areas (palms, scalp, elbows and lower legs).

METHODS

Skin biopsies were performed on a total of 80 patients with PPPP, non-pustular palmoplantar psoriasis (NPPPP), or psoriasis located on elbows, knees and scalp as well as 10 healthy subjects. RT-PCR, immunohistochemistry and flow cytometry on cells extracted from skin biopsies were used to compare PPPP to other forms of psoriasis.

RESULTS

There was a significant (p<0.05) increase in the expression of IL-1β, IL-6, LL-37, IL-19, IL-17A, CXCL1 and CXCL2 in PPPP as compared to NPPPP. However, there was no significant difference in expression of IL-23 in PPPP as compared to NPPPP and other forms of psoriasis. The proportion of IL-22⁺ but not IL-17A⁺ mast cells was higher in PPPP as compared to NPPPP (p<0.05).

CONCLUSION

These results suggest that the IL-17A pathway may play a more important role in PPPP than in NPPPP.

Secukinumab: a promising therapeutic option in spondyloarthritis

Psoriatic arthritis (PsA) is the second most common chronic inflammatory joint disease. Ankylosing spondylitis (AS) is another less common but equally chronic and disabling spondyloarthritis (SpA). Therapeutic agents for the treatment of these diseases have been somewhat lacking as compared with those available for rheumatoid arthritis, which represents a significant challenge for both the treating physician and the pharmaceutical industry. A promising development for our understanding of the physiopathology of PsA and AS involves new targets to interrupt IL-17 and IL-12/IL-23 pathways. Up to 30-40 % of SpA patients have inadequate or poor response, or are intolerant to anti-TNF therapies. Therefore, there has been a clear unmet medical need in an important group of these patients. As a result, new therapeutic targets have emerged for the treatment of both axial and peripheral SpA. Interleukin 17 (IL-17) is a pro-inflammatory cytokine that is increased in psoriatic lesions as well as in the synovial fluid of patients with PsA and in sites of enthesitis in SpA. IL-23 has been shown to play an important role in the polarization of CD4+ T-cells to become IL-17 producers. Based on these evidences, blockade of the cytokine IL-17 or its receptors was considered to have therapeutic implications for the treatment of psoriasis, as well as PsA and AS.This article presents a thorough review of an IL-17 A blocking agent, its mechanism of action, its clinical efficacy and its therapeutic safety.

Genetic variants of interleukin 17A are functionally associated with increased risk of age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in elderly populations worldwide. Inflammation, among many factors, has been suggested to play an important role in AMD pathogenesis. Interleukin 17 (IL-17) is a proinflammatory cytokine that has been implicated in the pathogenesis of various autoimmune diseases. In the current study, we examined two single nucleotide polymorphisms (SNPs), rs2275913G/A and rs3748067C/T, in the IL-17A gene between AMD patients and healthy controls. Results showed that rs2275913AA genotype and rs3748067TT genotype were associated with increased susceptibility to AMD (hazard ratio [HR], 1.75; 95 % confidence interval [CI], 1.07 to 3.02; P=0.023, and HR, 2.12; 95 % CI, 1.26 to 4.01; P=0.004; data were adjusted for age and sex). Next, we investigated the functional relevance of the two SNPs. In vitro stimulated peripheral blood mononuclear cells (PBMCs) from subjects possessing the rs2275913AA genotype produced significantly more IL-17 than those with the GG genotype. However, PBMCs with rs3748067TT genotype revealed significantly higher IL-17 production than those with rs3748067CC genotype only in AMD patients but not in controls. These data indicate IL-17A polymorphisms are associated with increased risk of AMD probably by affecting gene expression.

The role of secukinumab in the treatment of ankylosing spondylitis

Ankylosing spondylitis is a chronic inflammatory disorder involving the sacroiliac joint, spine and less frequently the peripheral joints. Nonsteroidal anti-inflammatory drugs and TNF-α inhibitors are utilized to reduce signs and symptoms. Whether these agents slow disease progression, is still debatable. Secukinumab is a fully human monoclonal antibody against IL-17 that has been studied in patients with ankylosing spondylitis with promising results. It has demonstrated improvement in signs, symptoms, patient reported outcomes and functional status and has been well tolerated. The clinical improvement is also mirrored in the improvement in sacroiliac joint magnetic resonance imaging scans.

Therapeutic Targeting of IL-17 and IL-23 Cytokines in Immune-Mediated Diseases

The discovery of the biological functions of the interleukin-23/-17 axis led to the identification of IL-23 and IL-17 as important participants in the pathogenesis of several immune-mediated diseases. Therapeutic agents targeting these cytokines and/or their receptors have now been developed as potential treatment strategies for common immune-mediated diseases. Anti-IL-17 and anti-IL-12/-23 regimens appear particularly effective in psoriasis, with promising results in spondyloarthropathies also emerging. Overall, these agents appear well tolerated, with adverse-event rates that are commensurate with those in other biologic treatment programs. The strategic utility of these new agents, however, remains uncertain, and further studies will be required to determine their place in the context of existing conventional and biologic immune-modifying agents.

Biologic Therapy for Psoriatic Arthritis

Biologic medications, therapeutic proteins that inhibit or modulate proinflammatory immune cells and cytokines, have significantly altered clinicians' ability to effectively treat psoriatic arthritis (PsA). The first widely used biologics have been those targeting tumor necrosis factor alpha. Five agents (etanercept, infliximab, adalimumab, golimumab, and certolizumab) have shown significant benefit in all clinical domains of PsA as well as inhibiting progressive joint destruction. Treatment strategies such as treating PsA early in the disease course, treating to target and tight control, use of background methotrexate to reduce immunogenicity, and various cost-saving strategies are all being tested with biologic medicines for PsA.

Psoriatic arthritis for the dermatologist

Psoriatic arthritis (PsA) is a chronic, progressive, inflammatory spondyloarthropathy that affects approximately one-third of patients with all types of psoriasis. Dermatologists are in a unique position to recognize early symptoms of PsA, initiate appropriate therapy, and prevent development of further disability. The course of PsA can be modulated by immunosuppressive therapy; patients with moderate-to-severe disease require aggressive management with medications proven to halt disease progression. It is essential for the dermatologist to understand the safety, tolerability, efficacy, cost, and potential to halt disease progression with available medications for this relatively common and potentially disabling disease.