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Background An ever-increasing number of cancer patients are being treated with checkpoint inhibitors such as anti-PD-1 antibodies, and a small percentage of these patients develop a psoriasis-like skin eruption or severe flares of prior psoriasis. Objective We investigated the role of obesity in immune checkpoint inhibitors-exacerbated psoriasiform eruption. Methods We fed female C57BL/6 mice a so-called Western diet (WD) or a control diet (CD). Imiquimod (IMQ) was applied topically on ears for 5 consecutive days to induce psoriasiform dermatitis (PsD). Psoriasis-related markers were examined by quantitative real-time PCR. Then we induced PsD in WD- and CD-fed mice in the presence or absence of systemic treatment of anti-PD-1 antibodies to examine if obese mice are more susceptible to anti-PD-1 related PsD than lean mice. Results WD-fed mice showed higher baseline mRNA expression levels of psoriasis-associated cytokines such as IL-17, S100A8, and S100A9 compared to mice fed with CD. Furthermore, WD-fed mice had more γδ low (GDL) T cells in the whole skin and higher expression of PD-1 on GDL T cells than CD-fed mice. WD-fed mice receiving anti-PD-1 had more prominent ear swelling than lean mice receiving anti-PD-1 during the 5-day IMQ course (2-fold increase, P Conclusion WD-induced obesity enhances IMQ-induced psoriasiform inflammation. The finding that WD-fed mice have a more dramatic response to anti-PD-1 than lean mice in terms of IMQ-induced ear swelling suggests that obesity could be a risk factor in the development of psoriasiform eruption during anti-PD-1 therapy.

Author(s): Yu, Sebastian; Wu, Xuesong; Zhou, Yan; Sheng, Lili; Jena, Prasant Kumar; Han, Dan; Wan, Yu Jui Yvonne; Hwang, Samuel T

A Western diet (WD)-characterized by its high fat and simple sugar content-is thought to predispose individuals to inflammatory skin diseases such as psoriasis through the development of obesity. This scenario, however, is being challenged by emerging data suggesting that dietary components, rather than obesity itself, may exacerbate psoriasis. We herein show that short-term feeding with a diet analogous to the WD in mice leads to T helper type 1-/T helper type 17-biased skin inflammation before significant body weight gain. Feeding for as little as 4 weeks with a WD promoted mild dermatitis and accumulation of IL-17A-producing γδ T cells in the skin. Strikingly, γδ T cells from WD-fed mice exhibited enriched IL-23 receptor expression and increased the potential to produce IL-17A after IL-23 stimulation. In contrast to wild-type mice, WD-fed TCRδ-deficient and CCR6-deficient mice had reduced skin inflammation and IL-17A expression. Supplementation with a bile acid sequestrant, cholestyramine, prevented WD-induced skin inflammation along with a reduction in the infiltration of γδ T cells and the expression of proinflammatory mediators. In summary, our data revealed dietary influences in inflammatory signaling in the skin. The dysregulation of IL-23 pathways and bile acid pathways may be key to the development of WD-associated psoriasiform dermatitis.

Exposure to arsenic is a global health issue. Long-term arsenic exposure may associate with various cancers and many other pathological effects. Over 100 million people worldwide are exposed to arsenic particularly in countries such as Bangladesh, Chile, China, India, Mexico, Taiwan and the USA. Drinking of water contaminated with arsenic is the major route of human exposure. Skin lesions are considered to be the most common adverse effects associated with chronic arsenic exposure. Skin lesions usually develop with the latency period spanning more than 20 years from first exposure. Arsenic-induced Bowen's disease, the most frequently encountered carcinoma in situ resulting from chronic arsenic exposure, is characterized by multiple and recrudescent lesions. Long-term arsenic exposure results in impaired immunity in susceptible individuals. In the prenatal stage, enhanced placental inflammatory responses and reduced placental T cells by arsenic may result in decreased thymic size and functions in newborns. In childhood, arsenic exposure may reduce peripheral CD4+ cells and interleukin-2 secretion which leads to susceptibility to opportunistic infections. There was an impairment of macrophage function and oxidative DNA damage of peripheral polymorphonuclear leukocytes in adults with skin lesions. In arsenic-induced Bowen's disease lesions, a decrease in the number and functions of Langerhans cells and, in parallel, a selective CD4+ cell apoptosis was noticed. These findings provide scientific evidence for understanding the phenomenon of arsenic-induced immune escape in the early stage of carcinogenesis and a reasonable explanation for multiple and recrudescent arsenic cancers in the skin.

Functional connectivity magnetic resonance imaging (fcMRI), a specific form of MRI imaging, quantitatively assesses connectivity between brain regions that share functional properties. Functional connectivity magnetic resonance imaging has already provided unique insights into changes in the brain in patients with conditions such as depression and pain and symptoms that have been reported by patients with psoriasis and are known to impact quality of life. To identify the central neurological impact of psoriasiform inflammation of the skin, we applied fcMRI analysis to mice that had been topically treated with the Toll-like receptor agonist, imiquimod (IMQ) to induce psoriasiform dermatitis. Brain insula regions, due to their suggested role in stress, were chosen as seed regions for fcMRI analysis. Mouse ear and head skin developed psoriasiform epidermal thickening (up to 4-fold, P < .05) and dermal inflammation after 4 days of topical treatment with IMQ. After fcMRI analysis, IMQ-treated mice showed significantly increased insula fc with wide areas throughout the brain, including, but not limited to, the somatosensory cortex, anterior cingulate cortex, and caudate putamen ( P < .005). This reflects a potential central neurological impact of IMQ-induced psoriasis-like skin inflammation. These data indicate that fcMRI may be valuable tool to quantitatively assess the neurological impact of skin inflammation in patients with psoriasis.

The number of elderly patients with chronic pruritus has been gradually increasing in aging countries. Bullous pemphigoid, a common autoimmune blister disease in the elderly, is always heralded by pruritic eczematous dermatitis and is often associated with neurodegenerative diseases. We hypothesized that chronic eczematous dermatitis in patients with neurodegenerative diseases may be an early marker of bullous pemphigoid. By conducting retrospective chart review, we found neurodegenerative diseases are more prevalent in elderly patients with chronic eczematous dermatitis. The mean time delay between the diagnosis of neurodegenerative diseases and onset of skin lesions is 4.17years. In all 6 patients who received skin biopsy, eosinophils in the upper dermis or at the dermo-epidermal junction were obvious, which are remnant of the pathological finding of bullous pemphigoid. Together with the well-known association between bullous pemphigoid and neurodegenerative diseases, the results suggested that unlocalized eczematous dermatitis in the elderly may be an early manifestation of bullous pemphigoid. Inter-discipline communication among neurology, dermatology and geriatrics/gerontology is required to tailor specific managements for elderly patients with pruritus and neurodegenerative diseases.

CCR6 is important for the trafficking of IL-17A–producing γδ T cells and required for the development of psoriasiform dermatitis in an IL-23 intradermal injection model. The role of CCR6, however, in IL-23–mediated joint inflammation is unclear. We herein hydrodynamically delivered IL-23 minicircle DNA into wild-type and CCR6-deficient (CCR6-knockout) mice to induce overexpression of IL-23 systemically. After IL-23 gene transfer, wild-type mice exhibited concurrent skin and joint changes that recapitulate some features found in human psoriatic skin and joints. CCR6-knockout mice were resistant to IL-23–induced skin inflammation but exhibited no changes in joint inflammation compared with wild-type mice. Depletion of neutrophils protected wild-type mice from skin and joint disease without suppressing T helper type 17 cytokine expression. In contrast, mice lacking γδ T cells showed a partial reduction in neutrophilic recruitment and a significant decrease in IL-17A expression in skin and paw tissue. Thus, in an IL-23–mediated model that allows concurrent assessment of both skin and joint disease, we showed that CCR6 is critical for inflammation in the skin but not in the joint. Furthermore, our data suggest that neutrophils and γδ T cells are key effector cells in IL-23–mediated skin and joint inflammation in mice.

Background Dietary interventions are implicated in the development of atopic dermatitis, psoriasis, and acne. Objective To investigate the effect of diet and the bile acid (BA) receptors, such as TGR5 (Takeda G protein receptor 5) and S1PR2 (sphingosine-1-phosphate receptor 2) in the development of dermatitis. Methods C57BL/6 mice were fed a control diet (CD) or Western diet (WD) since weaning until they were 10 months old followed by analyzing histology, gene expression, and BA profiling. Results Mice developed dermatitis as they aged and the incidence was higher in females than males. Additionally, WD intake substantially increased the incidence of dermatitis. Cutaneous antimicrobial peptide genesS100A8, S100A9, and Defb4 were reduced in WD-fed mice, but increased when mice developed skin lesions. In addition, Tgr5 and TGR5-regulated Dio2 and Nos3 were reduced in WD intake but induced in dermatitic lesions. Trpa1 and Trpv1, which mediate itch, were also increased in dermatitic lesions. The expression of S1pr2 and genes encoding sphingosine kinases, S1P phosphatases, binding protein, and transporter were all reduced by WD intake but elevated in dermatitic lesions. Furthermore, dermatitis development increased total cutaneous BA with an altered profile, which may change TGR5 and S1PR2 activity. Moreover, supplementation with BA sequestrant cholestyramine reduced epidermal thickening as well as cutaneous inflammatory cytokines. Conclusion In summary, activation of TGR5 and S1PR2, which regulate itch, keratinocyte proliferation, metabolism, and inflammation, may contribute to WD-exacerbated dermatitis with Th2 and Th17 features. In addition, elevated total BA play a significant role in inducing dermatitis and cutaneous inflammation.

Tumor-associated macrophages (TAMs) recruited from blood monocytes are key in establishing an immunosuppressive tumor microenvironment (TME) for the support of tumor growth. We hypothesize that blocking monocyte trafficking (through the inhibition of specific chemokine receptors) into skin can positively affect tumor development. Herein, the authors examined the effects of oral administration of a small molecule inhibitor for CCR2, CCR2i, which blocks CCR2-mediated chemotaxis of monocytes in a syngeneic mouse T-cell lymphoma in skin. Following CCR2i administration, the depletion of macrophages was achieved as early as 2 days after tumor initiation in ear TME. Quantitative real-time PCR detected an increase in the levels of immune stimulatory inflammatory cytokines, for example, IFN-γ and IL-12, in CCR2i- versus vehicle-treated mice. Within 2 weeks, the tumors from the control groups attained the maximum size, whereas CCR2i-treated mice exhibited much smaller tumor sizes and weights. Immunohistochemistry revealed that CCR2i-treated tumors possessed considerably more CD8+ T cells, which demonstrated their essential role in CCR2i-induced tumor inhibition. Finally, the combination of anti-programmed cell death protein 1 with CCR2i considerably increased the efficacy of tumor eradication related to the activation of IFN-γ–producing CD8 T cells. Our findings provide strong evidence that the CCR2i, particularly in combination with an immune checkpoint inhibitor, reduces tumor growth and is a potential future treatment option for cutaneous T-cell lymphomas.

Psoriasis is associated with certain psychiatric disorders such as anxiety and depression. Although a growing body of literature has indicated high prevalence of anxiety in patients with psoriasis, it is unclear if the incidence of anxiety is correlated with severity of psoriasis. In this article, we hypothesize that anxiety is not correlated with severity of psoriasis, and therefore the issue of anxiety should not be neglected in patients with mild psoriasis. To testify this hypothesis, we performed a pilot study to investigate the correlation between anxiety questionnaires and severity of psoriasis. Thirty-two patients with psoriasis were recruited. The patients were further classified into mild or moderate to severe psoriasis according to their body surface area or Psoriasis Area Severity Index (PASI). Zung's self-rating anxiety scale (SAS) and SF-36 were adopted to evaluate anxiety and quality of life, respectively. Spearman's rank correlation coefficients were calculated between SAS and each scale of SF-36 among these 32 patients. SAS is negatively correlated with role limitation due to emotional problems, vitality, emotional well-being of SF-36. Although SAS is not significantly different between mild and moderate to severe psoriasis, the detected levels of anxiety were higher than normative standards. Physicians should not neglect potential anxiety in patients who have mild psoriasis. Inter-discipline collaboration between psychiatry and dermatology is required to provide comprehensive patient care.

Blaschko lines are manifestations of cutaneous mosaicism, with apparent contrast between normal cells and abnormal cells, which carry postzygotic mutations. Linear cutaneous lupus erythematosus is a rare subset of cutaneous lupus erythematosus (CLE), characterized by skin lesions along Blaschko lines. In this paper, we presented a 47-year-old female with subacute CLE lesions along Blaschko lines. Although the antinuclear antibody and anti-Ro titers were remarkably high, there were no systemic symptoms. The histopathology showed atrophic epidermis with vacuolization of basal keratinocytes and papillary edema. While no typical linear lupus band was found, the direct immunofluorescence revealed cytoid bodies with immunoglobulin G, immunoglobulin M, C3, and C4 depositions in the papillary dermis. The skin lesions completely resolved after topical tacrolimus treatment, and the clinical course was 10 months without recurrence. We reviewed the literature and summarized that CLE along Blaschko lines supports the functional role of Ro antigens and keratinocytes in the development of CLE.

Background Transient Receptor Potential Vanilloid 1 (TRPV1) is known to mediate itch and neurogenic inflammation, but the role of TRPV1 in psoriasiform dermal inflammation is poorly understood. Objective To investigate the function of TRPV1 in imiquimod (IMQ)-induced psoriasiform dermatitis (PsD) in mice. Methods Following daily treatment of topical IMQ cream for consecutive 5 days in C57BL/6 wide-type (WT) and TRPV1 gene knockout (KO) mice, we assessed the psoriasis severity index (PSI) scores, transepidermal water loss (TEWL), dermal inflammatory infiltrates, as well as gene expression levels for psoriasis related genes in mouse skin lesions. Results Compared with WT mice, the clinical and TEWL scores, the extent of skin hyperplasia, the area of Munro microabscesses (MM) and angiogenesis of psoriasis were all significantly decreased in TRPV1 KO mice triggered with IMQ, suggesting a reduction in skin inflammation and barrier defects. In addition, the infiltration of CD45+ leukocytes, mast cells as well as CD3+ T cells was all reduced in the IMQ-treated skin of TRPV1 KO mice. Quantitative Real-time PCR (RT-qPCR) revealed that expression levels of IL-1β, IL-6, IL-23, S100A8 were decreased while IL-10 was increased in TRPV1 KO mice. Conclusions In summary, key markers of psoriatic inflammation and epidermal hyperplasia are reduced in TRPV1 KO mice, indicating the involvement of TRPV1 in the psoriasiform inflammation and suggesting its potential as a therapeutic target.

Background Schizophrenia is a complex disease proceeds from an interaction between genetic background and environmental factors. Recent studies showed T helper 17 (Th17) signaling, which is the main downstream immune response of psoriasis, is activated in schizophrenia. Objective To investigate if patients with schizophrenia have higher risk of psoriasis. Methods In this nationwide retrospective cohort study, we analyzed the 1-million-enroll cohort from Taiwan's National Health Insurance Research Database. Psoriasis and schizophrenia were ascertained by International Classification of Diseases, 9th revision, Clinical Modification coding. The study cohort was comprised of enrollees diagnosed with schizophrenia during the period from January 1, 1996 through December 31, 2010, while the comparison population consisted of enrollees who had not been diagnosed with schizophrenia during the study period. Hazard ratio (HR) and 95% confidence interval (CI) were calculated for the risk of psoriasis associated with schizophrenia using Cox proportional hazards regression. Results The adjusted HR of psoriasis associated with schizophrenia was 2.32(95% CI = 1.81-2.98). After 15 years, the cumulative incidence of psoriasis in patients with schizophrenia and comparison population was 2.82% and 1.17%, respectively. The Kaplan-Meier curves for the cumulative incidence of psoriasis in individuals with and without schizophrenia differed significantly(P