Tumor necrosis factor-α inhibitor-induced psoriasis: Systematic review of clinical features, histopathological findings, and management experience

Paradoxical Psoriasis Induced by Anti-TNFα Treatment: Evaluation of Disease-Specific Clinical and Genetic Markers

Paradoxical psoriasis (PP) may occur during treatment with anti-tumor necrosis factor-alpha (TNF-α) drugs in various chronic immune-mediated diseases, mainly inflammatory bowel diseases (IBD) and psoriasis. In this study, clinical and genetic characteristics of PP arising in IBD and psoriatic patients were investigated to identify disease-specific markers of the paradoxical effect. A total of 161 IBD and psoriatic patients treated with anti-TNF-α drugs were included in the study. Of these patients, 39 developed PP. All patients were characterized for the main clinical–pathologic characteristics and genotyped for six candidate single nucleotide polymorphisms (SNPs) selected for their possible role in PP susceptibility. In IBD patients, the onset of PP was associated with female sex, presence of comorbidities, and use of adalimumab. IBD patients with PP had a higher frequency of the TNF-α rs1799964 rare allele (p = 0.006) compared with cases without the paradoxical effect, and a lower frequency of the human leucocyte antigen (HLA)-Cw06 rs10484554 rare allele (p = 0.03) compared with psoriatic patients with PP. Overall, these findings point to specific clinical and genetic characteristics of IBD patients with PP and provide data showing that genetic variability may be related to the paradoxical effect of anti-TNF-α drugs with possible implications into clinical practice.

Psoriasis and Antimicrobial Peptides

Psoriasis is a systemic inflammatory disease caused by crosstalk between various cells such as T cells, neutrophils, dendritic cells, and keratinocytes. Antimicrobial peptides (AMPs) such as β-defensin, S100, and cathelicidin are secreted from these cells and activate the innate immune system through various mechanisms to induce inflammation, thus participating in the pathogenesis of psoriasis. In particular, these antimicrobial peptides enhance the binding of damage-associated molecular patterns such as self-DNA and self-RNA to their receptors and promote the secretion of interferon from activated plasmacytoid dendritic cells and keratinocytes to promote inflammation in psoriasis. Neutrophil extracellular traps (NETs), complexes of self-DNA and proteins including LL-37 released from neutrophils in psoriatic skin, induce Th17. Activated myeloid dendritic cells secrete a mass of inflammatory cytokines such as IL-12 and IL-23 in psoriasis, which is indispensable for the proliferation and survival of T cells that produce IL-17. AMPs enhance the production of some of Th17 and Th1 cytokines and modulate receptors and cellular signaling in psoriasis. Inflammation induced by DAMPs, including self-DNA and RNA released due to microinjuries or scratches, and the enhanced recognition of DAMPs by AMPs, may be involved in the mechanism underlying the Köbner phenomenon in psoriasis.

Tumor necrosis factors-α inhibition-induced paradoxical psoriasis: A case series and literature review

Today, anti-12/IL23, anti-IL17, and anti-IL23 provide more efficacious and/or safer treatment options for psoriasis. Though, anti-TNF remains a gold standard in the therapy of chronic inflammatory diseases. Paradoxical psoriasis has been reported to occur in patients treated with TNF-α inhibitors. According to the existing literature, including case reports, most patients with paradoxical psoriasis chose to stop the treatment immediately. This article presents a case series involving 150 patients with psoriasis who received treatments with TNF-α inhibitors. We observed 10 (6.7%) patients developing paradoxical psoriasis, and they rejected the recommendation of immediate discontinuation and decided to continue the original treatment. Surprisingly, 80% of them achieved remission again after the aggravation of symptoms and did not have any other serious adverse event. However, there is currently little research that has clarified the mechanism of paradoxical psoriasis. Therefore, we also presented a review of the literature to determine the pathogenesis of paradoxical psoriasis and speculated on the possible causes of the observed transient exacerbation cases. Investigation of the pathogenesis of this paradoxical adverse reaction not only is helpful to guide clinicians to better manage patients, but also may contribute to the discovery of new therapeutic targets in the future.

The role of xenobiotics in triggering psoriasis

Psoriasis is a common inflammatory skin disease affecting approximately 2% of the world population. A complex interplay of genetic predisposition and risk factors contributes to the risk of its onset. Several xenobiotics have been implicated in the pathogenesis of psoriasis. Drugs are among the most investigated trigger factors; strong association with disease induction or exacerbation has been reported for β-blockers, lithium, NSAIDs and ACE inhibitors, all of which are commonly used in the management of various comorbidities in psoriasis patients. Furthermore, inhibitors of TNF have a well-documented potential for triggering new-onset psoriasis when used for other indications (e.g. Crohn's disease or rheumatoid arthritis), while post-marketing data have revealed the same association for ustekinumab. Several other drugs have been connected with psoriasis, but the evidence is less compelling. Smoking and alcohol have been reported to increase the risk for occurrence of psoriasis, but can also affect unfavorably the course of the disease and its response to treatment. Furthermore, exposure to secondhand smoke, especially in childhood, also mediates the risk. Emerging data now suggest that air pollution also has a detrimental effect on skin disease, including psoriasis, but this association needs further investigation. Understanding of the toxic effect of xenobiotics on the initiation and clinical course of psoriasis can contribute to its better control, as it can help with the avoidance of triggering factors and, in some cases, influence the success of pharmacological treatment. It, therefore, has an important place in the comprehensive management of psoriasis.

A promising therapeutic target for psoriasis: Neuropeptides in human skin

Psoriasis is a chronic inflammatory skin disease featured by excessive proliferation of keratinocytes, clearly defined round erythema and dry, scaly plaques, long-term inflammatory cells infiltration in skin lesions. However, the physiopathological mechanism of psoriasis is still not clearly understood. Neuropeptides, a class of peptides secreted by the nervous system, may play important roles in promoting excessive proliferation of keratinocyte, enhancing angiogenesis, vasodilation, plasma extravasation and chemotaxis of inflammatory cells during the development of psoriasis. To understand the pathogenesis of neuropeptides in psoriasis, we summarized the function of several common neuropeptides in psoriasis and hypothesize neuropeptides may serve as therapeutic potential novel targets in psoriasis.

Secukinumab retreatment associated psoriasis flare with pustules

This case report describes a patient with plaque psoriasis and psoriatic arthritis who experienced IL-17A blocking antibody secukinumab treatment-interruption followed by re-treatment. The patient showed heterogeneous responses; significant improvement at initial introduction of secukinumab with rapid deterioration after discontinuation, followed by worsening symptoms and pustular eruption with reintroduction, and skin clearance after dose escalation.

Paradoxical Skin Reaction to Certolizumab, an Overlap of Pyoderma Gangrenosum and Psoriasis in a Young Woman Treated for Ankylosing Spondylitis: Case Report with Literature Review

Introduction

Biologic agents form an indispensable part of modern therapeutic regimens for the treatment of severe inflammatory diseases, especially in the fields of rheumatology, dermatology and gastroenterology. They are favoured by both physicians and patients due to their high effectiveness, good patient tolerance and safety. However, interference in the regulation and dynamics of inflammatory cytokines can on occasion lead to an onset of a dermatological condition also known as paradoxical skin reaction. Here, we present a case of paradoxical skin reaction induced by certolizumab.

Case Report

A young woman with ankylosing spondylitis developed a severe and complex cutaneous reaction after 6 months of otherwise successful treatment with certolizumab. The diagnosis of a rare paradoxical cutaneous reaction post anti-tumour necrosis factor alpha treatment was based on overlapping features of pyoderma gangrenosum and palmoplantar pustular psoriasis. Alopecia developed and there was also nail involvement. Treatment proved to be challenging as the disease did not remit after the patient ceased treatment with certolizumab. The patient was started on a combination of secukinumab and methotrexate to control the symptoms, with a promising outcome.

Conclusion

Paradoxical skin reactions are an emerging clinical entity that require further research in order to establish risk factors and best personalized treatment.

Effect of adalimumab on the expression profile of mRNA, and protein associated with JAK/STAT signaling pathway in fibroblast exposed to lipopolysaccharide

The aim of this study was to assess the effect of adalimumab on the expression level of mRNA and protein TNF-α, IFN-γ, IL-17, IL12A, IL12B, and IL23A in the culture of normal human fibroblasts, in which the LPS inflammation process was induced. The NHDF culture was exposed to the effect of LPS in the concentrations of 1, 2, and 10 μg/mL for 2, 8, and 24 hour periods, and then adalimumab was added at the concentration of 8 μg/mL, it was then incubated for 2, 8, and 24 hour. Cells unexposed to LPS and adalimumab constituted the control. The microarray expression techniques, RTqPCR, and ELISA assay were used. Irrespectively of the concentration of LPS used and the incubation time of it with cells overexpression of the analyzed genes is present, with increasing factor concentration used to induce inflammation and incubation time with it, expression of the assessed genes was greater. In turn, adding the anti-TNF drug to the culture caused the silencing of the expression of the mRNAs and proteins. It was confirmed that LPS and adalimumab above all affect the expression of genes and proteins dependent on the interaction of IL-12 with receptors, which are TNF-α and IFN-γ, and to a lesser extent also modulate IL-17.

Global expression and CpG methylation analysis of primary endothelial cells before and after TNFa stimulation reveals gene modules enriched in inflammatory and infectious diseases and associated DMRs

Endothelial cells are a primary site of leukocyte recruitment during inflammation. An increase in tumor necrosis factor-alpha (TNFa) levels as a result of infection or some autoimmune diseases can trigger this process. Several autoimmune diseases are now treated with TNFa inhibitors. However, genomic alterations that occur as a result of TNF-mediated inflammation are not well understood. To investigate molecular targets and networks resulting from increased TNFa, we measured DNA methylation and gene expression in 40 human umbilical vein endothelial cell primary cell lines before and 24 hours after stimulation with TNFa via microarray. Weighted gene co-expression network analysis identified 15 gene groups (modules) with similar expression correlation patterns; four modules showed a strong association with TNFa treatment. Genes in the top TNFa-associated module were all up-regulated, had the highest proportion of hypomethylated regions, and were associated with 136 Disease Ontology terms, including autoimmune/inflammatory, infectious and cardiovascular diseases, and cancers. They included chemokines CXCL1, CXCL10 and CXCL8, and genes associated with autoimmune diseases including HLA-C, DDX58, IL4, NFKBIA and TNFAIP3. Cardiovascular and metabolic disease genes, including APOC1, ACLY, ELOVL6, FASN and SCD, were overrepresented in a module that was not associated with TNFa treatment. Of 223 hypomethylated regions identified, several were in promoters of autoimmune disease GWAS loci (ARID5B, CD69, HDAC9, IL7R, TNIP1 and TRAF1). Results reveal specific gene groups acting in concert in endothelial cells, delineate those driven by TNFa, and establish their relationship to DNA methylation changes, which has strong implications for understanding disease etiology and precision medicine approaches.

Long-term safety of adalimumab for patients with moderate-to-severe hidradenitis suppurativa

Introduction: Hidradenitis suppurativa (HS) is a chronic debilitating inflammatory skin disorder that affects regions rich in apocrine glands. Although the etiology of HS is not clear, inflammatory cytokines, like tumor necrosis factor (TNF)-α, participate in pathogenesis. Adalimumab (ADA), a human IgG1 monoclonal antibody that selectively targets TNFα, is the only EMA/FDA-approved biologic agent available for the therapy of moderate-to-severe HS.Areas covered: A comprehensive literature search was conducted to present existing studies with an emphasis on the safety profile of ADA for the treatment of moderate-to-severe HS. ADA is prescribed for more than 15 years for varied indications and has improved the therapeutic outcomes of many diseases. Clinical trials and real-life safety data from ADA administration in HS were presented, with particular attention to special populations, such as children, elderly, and pregnant women.Expert opinion: Existing data advise for limited safety concerns with long-term ADA treatment provided that patients are thoroughly screened for infections, latent tuberculosis, and history of malignancy before the start of treatment.

Histologic comparison of tumor necrosis factor-α inhibitor-induced psoriasis and psoriasis vulgaris

BACKGROUND

Tumor necrosis factor-α inhibitor (TNFi)-induced psoriasis is a paradoxic reaction characterized by the development of a psoriasiform rash that mimics idiopathic psoriasis subtypes both clinically and histologically. Few studies have investigated the histologic features of TNFi-induced psoriasis skin lesions, and most of these are limited by inclusion of few specimens.

OBJECTIVE

We aimed to characterize histologic features of TNFi-induced psoriasis and identify histologic differences between TNFi-induced psoriasis and idiopathic psoriasis.

METHODS

We characterized 60 biopsy specimens obtained from 47 unique patients at a single tertiary care referral center between 2004 and 2016 who developed TNFi-induced psoriasis, and we compared histologic features to those of 85 biopsy specimens from a control group of 85 patients with idiopathic psoriasis.

RESULTS

The most common histologic reaction pattern in TNFi-induced psoriasis biopsy specimens was psoriasiform (80.0%). Five histologic parameters were significantly different in TNFi-induced psoriasis biopsy specimens compared with idiopathic psoriasis biopsy specimens: at least 3 dermal eosinophils per histologic section, neutrophils in the stratum corneum, neutrophils in the epidermis, papillary plate thinning, and absence of parakeratosis.

LIMITATIONS

Inability to exclude lesion selection bias as a potential reason for some significant histologic differences.

CONCLUSIONS

This study supports the idea that histologic differences exist between TNFi-induced psoriasis and idiopathic psoriasis may help distinguish between these conditions, especially for dermal eosinophil counts of 3 or greater.

Clinicopathologic overlap of psoriasis, eczema, and psoriasiform dermatoses: A retrospective study of T helper type 2 and 17 subsets, interleukin 36, and β-defensin 2 in spongiotic psoriasiform dermatitis, sebopsoriasis, and tumor necrosis factor α inhibitor-associated dermatitis

BACKGROUND

T helper (Th) type 17 and Th2 cells mediate psoriasis and eczema, respectively. Some dermatoses exhibit overlapping clinicopathologic features, and their immunopathology is relatively unexplored.

OBJECTIVE

To determine whether Th17 and Th2 subsets and interleukin (IL) 36 and β-defensin 2 (BD-2) markers of IL-17 signaling expression can discriminate between biopsy samples of psoriasis and eczematous/spongiotic dermatitis and to use those markers to immunophenotype cases with clinicopathologic overlap.

METHODS

A retrospective study was performed on biopsy samples of psoriasis, eczema/spongiotic dermatitis, sebopsoriasis, tumor necrosis factor α inhibitor-associated psoriasiform dermatitis, and ambiguous cases diagnosed as spongiotic psoriasiform dermatitis. Dual CD4/GATA3 and CD4/RORC, IL-36, and BD-2 immunohistochemistry was performed.

RESULTS

IL-36 and BD-2 were strongly expressed in biopsy samples of psoriasis compared with eczema/spongiotic dermatitis. No significant differences were observed in the percentages of Th2 and Th17 cells between disease types. Strong expression of IL-36 and BD-2 was observed in a subset of spongiotic psoriasiform dermatitis, sebopsoriasis, and tumor necrosis factor α inhibitor-associated psoriasiform dermatitis biopsy samples.

LIMITATIONS

This was an exploratory study with a small sample size. No multiple testing adjustment was done. Clinical follow-up was limited.

CONCLUSIONS

In cases with clinicopathologic overlap between psoriasis and spongiotic dermatitis, IL-36, and to a lesser extent BD-2, may be used to assess for a psoriasis-like/IL-17 phenotype, which could inform therapeutic clinical decisions.

Paradoxical psoriasis induced by TNF-α blockade shows immunological features typical of the early phase of psoriasis development

Immunomodulation with anti‐TNF‐α is highly effective in the treatment of various immune‐mediated inflammatory diseases, including hidradenitis suppurativa (HS). However, this may be responsible for unexpected paradoxical psoriasiform reactions. The pathogenic mechanisms underlying the induction of these events are not clear, even though the involvement of innate immune responses driven by plasmacytoid dendritic cells (pDC) has been described. In addition, the genetic predisposition to psoriasis of patients could be determinant. In this study, we investigated the immunological and genetic profiles of three HS patients without psoriasis who developed paradoxical psoriasiform reactions following anti‐TNF‐α therapy with adalimumab. We found that paradoxical psoriasiform skin reactions show immunological features common to the early phases of psoriasis development, characterized by cellular players of innate immunity, such as pDC, neutrophils, mast cells, macrophages, and monocytes. In addition, IFN‐β and IFN‐α2a, two type I IFNs typical of early psoriasis, were highly expressed in paradoxical skin reactions. Concomitantly, other innate immunity molecules, such as the catheledicin LL37 and lymphotoxin (LT)‐α and LT‐β were overproduced. Interestingly, these innate immunity molecules were abundantly expressed by keratinocytes, in addition to the inflammatory infiltrate. In contrast to classical psoriasis, psoriasiform lesions of HS patients showed a reduced number of IFN‐γ and TNF‐α‐releasing T lymphocytes. On the contrary, IL‐22 immunoreactivity was significantly augmented together with the IL‐36γ staining in leukocytes infiltrating the dermis. Finally, we found that all HS patients with paradoxical reactions carried allelic variants in genes predisposing to psoriasis. Among them, SNPs in ERAP1, NFKBIZ, and TNFAIP genes and in the HLA‐C genomic region were found.

Successful management of infliximab-induced generalized pustular psoriasis without therapy discontinuation in a patient with psoriatic arthritis

While infliximab has been shown to be paradoxically associated with the development of pustular psoriasis in patients with rheumatoid arthritis, spondyloaripathies, juvenile idiopathic, and inflammatory bowel disease, there are few cases of pustular psoriasis induced by infliximab in patients with psoriasis. We here present a 55-year-old female patient with longstanding plaque psoriasis and psoriatic arthritis who developed generalized pustular psoriasis 1 month after the fifth infusion of infliximab. Given the lack of other side effects and the rapid initial response of the underlying psoriatic arthritis, we opted against discontinuing infliximab therapy, and the sixth infusion of infliximab was administered 10 days ahead of schedule. Topical corticosteroids were added for the management of pustular lesions on initial presentation. One week after the sixth infusion, the pustular psoriatic lesions almost completely disappeared. No recurrence of pustular psoriasis was observed during the 3-month follow-up. Our experience shows that pustular lesions associated with infliximab can be successfully managed with topical corticosteroids without discontinuing infliximab therapy or compromising therapeutic benefit seen upon the underlying condition.

Evaluation of expression pattern of selected genes associated with IL12/23 signaling paths in psoriatic patients during cyclosporine A therapy

Molecular analysis is key to a better understanding of drug resistance during therapy. The aim of this study was to evaluate changes in the expression of tumor necrosis factor α (TNF-α), interleukin (IL)-IL12A, IL12B, IL23A, interferon gamma (IFN-γ) in psoriatic patients during 84 days of treatment and TNF-α on the protein level. The study group consisted of 32 psoriatic patients during cyclosporine A therapy. The molecular analysis was made by using real-time reverse transcription polymerase chain assay (RTqPCR) and MALDI ToF mass spectroscopy three times: after 0, 42, 84 days of treatment. Statistically significant differences (p < .05) in transcriptional activity were observed for genes: TNF-α (0 vs. 42nd days p = .006; 0 vs. 84th days p = .005), IL23A (0 vs. 42nd days p = .041), IFN-γ (0 vs. 42th days p = .040; 0 vs. 84th days p = .041), IL17 (0 vs. 42nd p = .000003 0 vs. 84th p = .001650), IL12A (0 vs. 42nd p = .0047 vs. 84th p = .0063). The expression of TNF-α was downregulated during therapy, IL23A was upregulated during CsA treatment, while the expression of IFN-γ and IL17 were higher after 42 days and lower after 84 days compared to 0 days of CsA treatment. It seems that TNF-α, IL12A, IL23A, IFN-γ, and IL17 can be useful complementary molecular markers to assess the efficacy of psoriasis treatment.

Rituximab-Induced Psoriasis in a Patient with Granulomatosis with Polyangitis Treated with Adalimumab

Rituximab (RTX) is a chimeric B-cell-depleting monoclonal antibody against CD-20 positive cells that has been approved for the induction and maintenance of granulomatosis with polyangiitis (GPA). Reports have identified RTX to cause drug-related psoriasis. Many theories of underlying pathways have been proposed. However, further workup around the mechanism and treatment is required. Here, we present a 38-year-old woman known to have GPA that developed drug-related psoriasis that was successfully treated with treatment discontinuation and starting adalimumab along with a literature review.

Biological and synthetic target DMARDs in psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic multi-faceted immune-mediated systemic disorder, characterized by articular, cutaneous, enthesis, nail and spine involvement. Articular manifestations of PsA are particularly common and highly disabling for patients, while the heterogeneous clinical subsets of the disease are challenging for clinicians. In recent years, research has made many advances in understanding the pathogenesis of the disease from genetic, epigenetic and molecular points of view. New drugs are now available for the treatment of this condition, and, in particular, TNF-alfa inhibitors, historically the first biologicals approved in PsA, are now juxtaposed by new biological disease modifying anti-rheumatic drugs (bDMARDs) with different modes of action. Targeting IL-12/IL-23 p40 common subunit with ustekinumab, IL-17A with secukinumab and ixekizumab, T cells co-stimulation with abatacept, is now possible, safe and effective. Moreover, targeted synthetic molecules with oral administration are available, with the possibility to interfere with phosphodiesterase-4 and JAK/STAT pathways. Indeed, new drugs are under development, with the possibility to target selectively IL-17 receptor, IL-23, and other key molecular targets in the pathogenesis of this condition. In this narrative review, we provide an up-to-date overview of the current application of biological and targeted synthetic DMARDs in the field of PsA, with particular regard to the clinical significance of this possibility to target a higher number of distinct immune-pathways.

Risk Factors for the Development of Psoriasis

Psoriasis is an immune-mediated genetic skin disease. The underlying pathomechanisms involve complex interaction between the innate and adaptive immune system. T cells interact with dendritic cells, macrophages, and keratinocytes, which can be mediated by their secreted cytokines. In the past decade, biologics targeting tumor necrosis factor-α, interleukin (IL)-23, and IL-17 have been developed and approved for the treatment of psoriasis. These biologics have dramatically changed the treatment and management of psoriasis. In contrast, various triggering factors can elicit the disease in genetically predisposed individuals. Recent studies suggest that the exacerbation of psoriasis can lead to systemic inflammation and cardiovascular comorbidity. In addition, psoriasis may be associated with other auto-inflammatory and auto-immune diseases. In this review, we summarize the risk factors, which can be divided into two groups (namely, extrinsic and intrinsic risk factors), responsible for the onset and exacerbation of psoriasis in order to facilitate its prevention.

Different risk profiles of biologic agents for new-onset psoriasis in patients with rheumatoid arthritis

OBJECTIVE

To investigate rates and risk factors for incident and recurrent psoriasis in rheumatoid arthritis (RA) patients treated with different biologic (b) and conventional synthetic (cs) disease-modifying antirheumatic drugs (DMARDs).

METHODS

RA patients enrolled in the German biologics register RABBIT without (n = 14,525) or with a history of psoriasis (n = 375) were analyzed separately. All first events of psoriasis reported until October 2017 were assigned to the treatments prescribed in the previous 3 months. Crude incidence rates (IR) of psoriasis were calculated per 1000 patient-years. To investigate risk factors for psoriasis, cox regressions with and without inverse probability weights were applied to adjust for confounding by indication.

RESULTS

117 incident and 37 recurrent psoriatic events were reported. Patients exposed to TNFi had a significantly higher incidence rate (IR = 3.04/1,000 PY) than those exposed to csDMARDs only (IR = 0.65), whereas IRs for abatacept, rituximab and tocilizumab did not differ significantly from csDMARDs. Adjusted Cox regression confirmed a higher risk for TNFi. Female sex (HR: 1.7) and smoking (HR: 2.1) were significantly associated with incident psoriasis while methotrexate decreased the risk (HR: 0.5). For recurrent psoriasis, IRs for TNFi, abatacept and rituximab were significantly higher than for csDMARDs.

CONCLUSIONS

Our data confirm a previously observed increased risk of incident psoriasis in patients exposed to TNFi compared to csDMARDs. However, the overall risk is low and the event is usually non-serious. Comedication of TNFi with methotrexate seems to lower the risk of incident psoriasis. In patients with a history of psoriasis, recurrence as adverse event is rare.

Th17 Cells and the IL-23/IL-17 Axis in the Pathogenesis of Periodontitis and Immune-Mediated Inflammatory Diseases

Innate immunity represents the semi-specific first line of defense and provides the initial host response to tissue injury, trauma, and pathogens. Innate immunity activates the adaptive immunity, and both act highly regulated together to establish and maintain tissue homeostasis. Any dysregulation of this interaction can result in chronic inflammation and autoimmunity and is thought to be a major underlying cause in the initiation and progression of highly prevalent immune-mediated inflammatory diseases (IMIDs) such as psoriasis, rheumatoid arthritis, inflammatory bowel diseases among others, and periodontitis. Th1 and Th2 cells of the adaptive immune system are the major players in the pathogenesis of IMIDs. In addition, Th17 cells, their key cytokine IL-17, and IL-23 seem to play pivotal roles. This review aims to provide an overview of the current knowledge about the differentiation of Th17 cells and the role of the IL-17/IL-23 axis in the pathogenesis of IMIDs. Moreover, it aims to review the association of these IMIDs with periodontitis and briefly discusses the therapeutic potential of agents that modulate the IL-17/IL-23 axis.

Paradoxical Skin Reactions to Biologics in Patients With Rheumatologic Disorders

Targeted immune-modulating treatment with biological agents has revolutionized the management of immune-mediated inflammatory diseases, including rheumatologic conditions. The efficacy and tolerability of biological agents, from the initial tumour necrosis factor (TNF)-α inhibitors to the new anti-cytokine monoclonal antibodies, have dramatically changed the natural history of debilitating conditions such as rheumatoid arthritis and seronegative spondyloarthropathies. The widening use of biologics across several rheumatologic diseases has been associated with a new class of adverse events, the so-called paradoxical reactions. These events are inflammatory immune-mediated tissue reactions, developing paradoxically during treatment of rheumatologic conditions with targeted biologics that are commonly used for treating the idiopathic counterparts of these drug-induced reactions. The skin is frequently involved, and, even if considered rare to uncommon, these cutaneous manifestations are an important cause of biologic agent discontinuation. TNF-α antagonist-induced psoriasis, which can manifest de novo or as exacerbation of a pre-existing form, is the prototypic and most frequent paradoxical skin reaction to biologics while other reactions, such as eczematous and lichenoid eruptions, hidradenitis suppurativa, pyoderma gangrenosum, Sweet’s syndrome and granulomatous skin diseases, occur much more rarely. Management of these reactions consists of topical or systemic skin-directed therapies, depending on the severity and extension of the cutaneous picture, and it is generally associated with switching over to other disease-modifying regimens for treating the underlying rheumatologic condition. Here, we review in detail the current concepts and controversies on classification, pathogenesis and clinical management of this new class of cutaneous adverse events induced by biologics in rheumatologic patients.

Psoriasis: Classical vs. Paradoxical. The Yin-Yang of TNF and Type I Interferon

Chronic plaque psoriasis is a common debilitating skin disease. The identification of the pathogenic role of the TNF/IL-23/T_H17 pathway has enabled the development of targeted therapies used in the clinic today. Particularly, TNF inhibitors have become a benchmark for the treatment of numerous chronic inflammatory diseases such as psoriasis. Although being highly effective in psoriasis treatment, anti-TNFs can themselves induce psoriasis-like skin lesions, a side effect called paradoxical psoriasis. In this review, we provide a comprehensive look at the different cellular and molecular players involved in classical plaque psoriasis and contrast its pathogenesis to paradoxical psoriasis, which is clinically similar but immunologically distinct. Classical psoriasis is a T-cell mediated autoimmune disease driven by TNF, characterised by T-cells memory, and a relapsing disease course. In contrast, paradoxical psoriasis is caused by the absence of TNF and represents an ongoing type-I interferon-driven innate inflammation that fails to elicit T-cell autoimmunity and lacks memory T cell-mediated relapses.

The Safety Profile of Tumor Necrosis Factor Inhibitors in Ankylosing Spondylitis: Are TNF Inhibitors Safer Than We Thought?

Tumor necrosis factor (TNF) inhibitors significantly improved the treatment options for patients with ankylosing spondylitis. Unfortunately, currently, there is no strategy for sustaining remission of the disease with TNF inhibitors; after discontinuation, a high percentage of patients experience flares in a short time. Therefore, up-to-date, long-term use of TNF inhibitors in patients with ankylosing spondylitis remains necessary. For this reason, the issue of the long-term safety of TNF inhibitors in patients with ankylosing spondylitis raises concerns. Although TNF inhibitors are well established in ankylosing spondylitis treatment, the majority of studies on TNF inhibitors' safety have been performed in patients with rheumatoid arthritis. Until recently, there were very few studies of TNF inhibitors' safety in ankylosing spondylitis. Meanwhile, TNF inhibitors appear to have different safety profiles in ankylosing spondylitis and rheumatoid arthritis. In this review, we describe available data on the occurrence of adverse events associated with TNF inhibitor treatment in ankylosing spondylitis, including serious adverse events, infections, serious infections, tuberculosis, opportunistic infections, hepatitis B reactivation, malignancies, laboratory test abnormalities, autoimmune diseases, paradoxical adverse events, and heart failure.

TNF Inhibitor-Induced Psoriasis: Proposed Algorithm for Treatment and Management

Tumor necrosis factor a (TNF-α)-targeted therapies have expanded the therapeutic options for patients with inflammatory bowel disease (IBD), rheumatoid arthritis (RA), psoriasis, and psoriatic arthritis (PsA) and have significantly improved patients' quality of life. Paradoxically, anti-TNF-α agents may induce psoriatic eruptions or worsen preexisting psoriatic skin disease. Currently, there is no standard approach for the management of TNF inhibitor-induced psoriasis. Here, we conduct a literature review on TNF inhibitor-induced psoriasis and introduce a novel treatment algorithm for maintaining otherwise effective anti-TNF therapy versus switching to a different class as appropriate in the management of patients with IBD, RA, psoriasis, or PsA.

Paradoxical Reactions to Biologic Therapy in Psoriasis: A Review of the Literature

Biologic drugs, which are molecules designed to act on specific immune system targets, have been shown to be very effective in treating various dermatological, rheumatological, and systemic diseases. As a group, they have an acceptable safety profile, but their use has been associated with the onset of both systemic and organ-specific inflammatory conditions. True paradoxical reactions are immune-mediated disorders that would usually respond to the biologic agent that causes them. There is still debate about whether certain other adverse reactions can be said to be paradoxical. The hypotheses proposed to explain the pathogenesis of such reactions include an imbalance in cytokine production, with an overproduction of IFN-α and altered lymphocyte recruitment and migration (mediated in part by CXCR3), and the production of autoantibodies. Some biologic therapies favor granulomatous reactions. While most of the paradoxical reactions reported have been associated with the use of TNF-α inhibitors, cases associated with more recently introduced biologic therapies -such as ustekinumab, secukinumab, and ixekizumab- are increasingly common. The study of paradoxical adverse events not only favors better management of these reactions in patients receiving biologic therapy, but also improves our knowledge of the pathogenesis of chronic inflammatory diseases and helps to identify potential therapeutic targets.

Paradoxical skin lesions induced by anti-TNF-α agents in SAPHO syndrome

The objectives of the study were to characterize the clinical picture of paradoxical skin lesions in SAPHO patients treated with anti-TNF-α agents and to explore its pathogenesis. Patients treated with anti-TNF-α therapy were identified from a cohort of 164 SAPHO patients. The clinical data and skin biopsies were collected. The usage, efficacy, and side effects of anti-TNF-α therapy were recorded. Forty-one (25.0%) patients received anti-TNF-α therapy, of which seven (17.1%) developed paradoxical skin lesions after 1 to 14 infusions. Patients with such lesions were older at onset of skin lesions than those without (p = 0.034). Expression of TNF-α in palmoplantar pustulosis increased after anti-TNF-α therapy in the two examined patients with exacerbated skin lesions. Anti-TNF-α therapy induces paradoxical skin lesions in 17.1% SAPHO patients. Late onset of skin manifestations is associated with an increased risk of such lesions. The paradoxical elevation of TNF-α expression in lesions may contribute to this phenomenon.

Generalized Pustular Psoriasis Induced by Infliximab in a Patient With Inflammatory Bowel Disease

The incidence of anti–tumour necrosis factor (TNF)–induced psoriasiform eruptions has ranged in the literature between 0.5% and 10.9% of patients with inflammatory bowel disease (IBD). The morphology of the rash varies, with plaque psoriasis being the most common form. Generalized pustular eruption is reported in 10.2% of cases of anti–TNF-induced psoriasis. We are reporting a unique case of anti–TNF-associated psoriasiform eruption due to the severity of the rash presenting as a generalized pustular eruption in association with plaque psoriasiform rash requiring systemic therapy.

Cutaneous Manifestations of Reactions to Biologics

PURPOSE OF REVIEW

The goal of this paper is to review the major adverse cutaneous reactions that have been reported to the most commonly used biologics.

RECENT FINDINGS

Anti-TNF agents and immune checkpoint inhibitors have significant, immune-mediated cutaneous manifestations that can necessitate discontinuation. Anti-TNF agents, IL-6 inhibitors, and IL-12/23 inhibitors can paradoxically cause psoriasis flares or unmask previously undiagnosed psoriasis. IL-17 inhibitors are unique in increasing risk for Candida infections. Benign injection site reactions, non-specific rash, cellulitis, and hypersensitivity reactions are relatively common adverse events. A wide variety of cutaneous reactions caused by biologics have been reported, ranging from benign injection site reactions to life-threatening cutaneous reactions necessitating discontinuation of the implicated biologic agent.

TNF blockade induces a dysregulated type I interferon response without autoimmunity in paradoxical psoriasis

Although anti-tumor necrosis factor (TNF) agents are highly effective in the treatment of psoriasis, 2–5% of treated patients develop psoriasis-like skin lesions called paradoxical psoriasis. The pathogenesis of this side effect and its distinction from classical psoriasis remain unknown. Here we show that skin lesions from patients with paradoxical psoriasis are characterized by a selective overexpression of type I interferons, dermal accumulation of plasmacytoid dendritic cells (pDC), and reduced T-cell numbers, when compared to classical psoriasis. Anti-TNF treatment prolongs type I interferon production by pDCs through inhibition of their maturation. The resulting type I interferon overexpression is responsible for the skin phenotype of paradoxical psoriasis, which, unlike classical psoriasis, is independent of T cells. These findings indicate that paradoxical psoriasis represents an ongoing overactive innate inflammatory process, driven by pDC-derived type I interferon that does not lead to T-cell autoimmunity.

The pathogenesis of paradoxical psoriasis in patients receiving anti-TNF treatments for classical psoriasis is unclear. Here, the authors show that anti-TNF drugs enhance the production of type I interferon by plasmacytoid dendritic cells, causing skin lesions that, unlike classical psoriasis, lack T- cell autoimmunity.

Drug-induced psoriasis: clinical perspectives

Exposure to certain drugs can elicit an induction or exacerbation of psoriasis. Although well-conducted systematic studies on drug-related psoriasis are mostly lacking, traditionally strong associations have been documented for beta-blockers, lithium, antimalarial drugs such as (hydroxy)chloroquine, interferons, imiquimod, and terbinafine. More recently, new associations have been reported for monoclonal antibody- and small-molecule-based targeted therapies used for oncological and immunological indications, such as tumor necrosis factor-alpha antagonists and anti-programmed cell death protein 1 immune checkpoint inhibitors. Recognizing potential drug-related psoriasis is of clinical relevance to allow an optimal management of psoriasis. However, in clinical practice, identifying medication-related exacerbations and induction of psoriasis can be challenging. The clinical and histopathological features of drug-provoked psoriasis may differ little from that of “classical” nondrug-related forms of psoriasis. In addition, the latency period between start of the medication and onset of psoriasis can be significantly long for some drugs. Assessment of the Naranjo adverse drug reaction probability scale could be used as a practical tool to better differentiate drug-related psoriasis. The first step in the management of drug-related psoriasis is cessation and replacement of the offending drug when deemed clinically possible. However, the induced psoriasis skin lesions may persist after treatment withdrawal. Additional skin-directed treatment options for drug-related psoriasis follows the conventional psoriasis treatment guidelines and includes topical steroids and vitamin D analogs, ultraviolet phototherapy, systemic treatments, such as acitretin, methotrexate, and fumaric acid esters, and biological treatments.

Biologics in pediatric psoriasis - efficacy and safety

INTRODUCTION

Childhood psoriasis is a special situation that is a management challenge for the treating dermatologist. As is the situation with traditional systemic agents, which are commonly used in managing severe psoriasis in children, the biologics are being increasingly used in the recalcitrant disease despite limited data on long term safety.

AREAS COVERED

We performed an extensive literature search to collect evidence-based data on the use of biologics in pediatric psoriasis. The relevant literature published from 2000 to September 2017 was obtained from PubMed, using the MeSH words 'biologics', 'biologic response modifiers' and 'treatment of pediatric/childhood psoriasis'. All clinical trials, randomized double-blind or single-blind controlled trials, open-label studies, retrospective studies, reviews, case reports and letters concerning the use of biologics in pediatric psoriasis were screened. Articles covering the use of biologics in pediatric psoriasis were screened and reference lists in the selected articles were scrutinized to identify other relevant articles that had not been found in the initial search. Articles without relevant information about biologics in general (e.g. its mechanism of action, pharmacokinetics and adverse effects) and its use in psoriasis in particular were excluded. We screened 427 articles and finally selected 41 relevant articles.

EXPERT OPINION

The available literature on the use of biologics such as anti-tumor necrosis factor (TNF)-α agents, and anti-IL-12/23 agents like ustekinumab suggests that these are effective and safe in managing severe pediatric psoriasis although there is an urgent need to generate more safety data. Dermatologists must be careful about the potential adverse effects of the biologics before administering them to children with psoriasis. It is likely that with rapidly evolving scenario of biologics in psoriasis, these will prove to be very useful molecules particularly in managing severe and recalcitrant psoriasis in pediatric age group.

Therapeutic Effects of Methanol Extract from Euphorbia kansui Radix on Imiquimod-Induced Psoriasis

The roots of Euphorbia kansui, which belong to the family Euphorbiaceae, have been used as a traditional medicine for the treatment of various diseases such as diabetes, ascites, and leukemia. Recently, it was reported that the methylene chloride fraction of E. kansui radix (EKC) regulated the differentiation of Th17 cells and alleviated the symptoms of Th17-related inflammatory bowel disease. Imiquimod (IMQ), a TLR7/8 agonist, has been used to induce psoriasis in a mouse model. In this study, we evaluated the effect of EKC in an IMQ-induced psoriasis model. EKC effectively inhibited the production of interleukin-17A and interferon-γ in vitro. On this basis, EKC was administered to an animal model of psoriasis. Acanthosis and the infiltration of inflammatory cells into the dermis were significantly reduced by EKC. EKC also inhibited the expression of IL-17A, IL-22, IL-23, IL-12, and RAR-related orphan receptor gamma t (RORγt) in the spleen, skin-draining lymph nodes, and the skin. Additionally, EKC inhibited the activity of dendritic cells but not that of keratinocytes. In conclusion, EKC ameliorated the symptoms of psoriasis through inhibition of Th17 differentiation and activation of dendritic cells. These effects are expected to be beneficial in the treatment and prevention of psoriasis.

Challenges for epigenetic research in inflammatory bowel diseases

The human epigenome may link environmental exposures and commensal microbiota changes to host pathology in respect to the developmental origins of inflammatory bowel diseases (ulcerative colitis [UC] and Crohn's disease [more appropriately Crohn disease, CD]). Genetic predisposition - prenatal, perinatal and pediatric environmental influences - microbiome aberration (dysbiosis) and immune dysregulation appear to be important elements in disease development, progression and maintenance. The prevalence of combined genetic and epigenetic susceptibility toward UC and CD is calculated herein to be as high as 2%, and approximately 1% for UC and CD in highly developed countries, respectively. This review emphasizes the significant challenges for epigenetic research in inflammatory bowel diseases. Overcoming these challenges, however, could reveal unique opportunities for disease prevention, treatment and possible cure.