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Recent studies indicate that hepatic diseases are associated with psoriasis. Non-invasive tests, including the Fibrosis-4 (FIB-4) index, which can confidently rule out the presence of advanced fibrosis, are currently receiving attention. However, data on the FIB-4 index in psoriasis patients and the effects of biologics on the FIB-4 index are limited. We investigated the relationships between the FIB-4 index and demographic or clinical characteristics as well as the effects of biologics on the FIB-4 index in psoriasis patients. Psoriasis patients aged 36-64 years, whose treatment was initiated with interleukin (IL)-17 inhibitors or IL-23 inhibitors for psoriasis from May 2015 to December 2022, were consecutively included. Data were collected retrospectively from the patients' charts. A total of 171 psoriasis patients were included in this study. Thirty-four, 43, 21, 32, and 41 psoriasis patients were treated with secukinumab, ixekizumab, brodalumab, guselkumab, or risankizumab, respectively. In biologics-naïve patients, a significant but weak positive correlation was observed between the FIB-4 index and age (r = 0.3246, p = 0.0018). There was no significant correlation between the FIB-4 index and other demographic or clinical characteristics. Regarding the effects of biologics on the FIB-4 index, no significant change was observed in psoriasis patients treated with any biologics. However, in psoriasis patients with a baseline FIB-4 index of >1.3, patients treated with guselkumab and those treated with either IL-23 inhibitor showed significantly decreased FIB-4 index scores 6 months after initiating the biologics (p = 0.0323, p = 0.0212). In contrast, no change was observed in FIB-4 index scores in patients treated with IL-17 inhibitors. In conclusion, our study revealed that the FIB-4 index was correlated with age in psoriasis patients. Furthermore, IL-23 inhibitors (but not IL-17 inhibitors) decreased the FIB-4 index score at 6 months in psoriasis patients with elevated FIB-4 index scores at baseline. Further studies are needed to clarify whether IL-23 inhibitors improve liver fibrosis physiologically and functionally., (© 2024 Japanese Dermatological Association.)

Palmoplantar pustulosis (PPP) is relatively rare and recognition of PPP is different in different countries. Therefore, real-world data are limited. Local phototherapy for the palms and the soles is commonly used to treat PPP due to tolerable safety. However, data on the effectiveness of 308-nm excimer light are limited. In our study, we retrospectively investigated the effectiveness of treatments for PPP, especially phototherapy (308-nm excimer light), in our department. In addition, we examined whether smoking status and focal infection affected responsiveness to treatment of PPP. Patients who were diagnosed with PPP by board-certified dermatologists and visited our hospital from April 2015 to August 2018 were analyzed in this study. We collected data on PPP area severity index (PPPASI) before treatment. We also collected data on PPPASI in May to August 2018 as "after treatment" from all patients. Patients who received any treatment for less than 3 months were excluded. Nineteen patients (16 women and three men) were analyzed in this study. In patients treated with phototherapy (n = 12), PPPASI significantly decreased from a mean ± SD of 16.5 ± 10.3 to 4.5 ± 3.6 (p = 0.004), whereas it did not in patients treated without phototherapy (n = 7). Patients who quit smoking showed a significant decrease in PPPASI after treatment (16.8 ± 12.7 to 2.4 ± 2.9, p = 0.008). Regarding focal infection, in patients treated without phototherapy, the reduction rate of PPPASI was significantly lower in patients with focal infection than in those without focal infection (17.7 ± 21.5%, 71.1 ± 19.3%, p = 0.035), indicating that focal infection is associated with intractability. Meanwhile, in patients treated with phototherapy, PPPASI decreased regardless of the presence or absence of focal infection. In conclusion, our study demonstrated the effectiveness of local phototherapy consisting of 308-nm excimer light, regardless of focal infection. Patients who quit smoking were responsive to any treatment, indicating the importance of smoking cessation., (© 2024 Japanese Dermatological Association.)

It has recently been revealed that mutation of the IL36RN gene contributes to the development of generalized pustular psoriasis (GPP). The IL36RN gene encodes interleukin (IL)-36 receptor antagonist (IL-36Ra), which has antagonistic roles against IL-36α, -36β, and -36γ. Previously, sanger sequencing performed in 62 Chinese GPP patients to identify IL36RN mutations revealed a new variant, c.245C>T (p.Pro82Leu), in a single heterozygous state in a patient with adult-onset GPP with psoriasis vulgaris. Since this p.Pro82Leu variant was not found in the psoriasis vulgaris or control groups in their study, they speculated that this variant might lead to exacerbated inflammatory responses. Meanwhile, Sorting Intolerant From Tolerant and PolyPhen-2, pathogenicity prediction tools, predict this variant as tolerated and benign. To date, its pathogenicity is unknown. We experienced a patient with GPP harboring the p.Pro82Leu variant, and investigated mRNA and protein expressions of IL-36Ra. Polymerase chain reaction conducted on hair follicle samples obtained from the scalp of the patient with GPP harboring the p.Pro82Leu using primers to detect mRNA of exons 2 and 5 in IL36RN demonstrated mRNA expression of IL36RN. Immunohistochemical staining revealed IL-36Ra expression in the keratinocytes of the patient with GPP harboring the p.Pro82Leu as in those of a GPP patient without the mutation (positive control). Furthermore, quantitative analysis of the immunofluorescent staining by ImageJ revealed that the expression level of IL-36Ra in the keratinocytes of the patient with GPP harboring p.Pro82Leu was higher than that in the healthy control and not lower than that in the GPP patients without the mutation. Our results indicate no aberrant splicing in this variant. In addition, according to the 1000 Genomes Project, this variant could be a founder mutation. Considering these factors together, this variant is unlikely to be associated with the development of GPP., (© 2023 Japanese Dermatological Association.)

In the past, psoriasis was considered a skin disease caused only by keratinocyte disorders. However, the efficacy of immunosuppressive drugs and biologics used to treat psoriasis proves that psoriasis is an immune-mediated disease. Indeed, a variety of immune cells are involved in the pathogenesis of psoriasis, including dendritic cells, Th17 cells, and resident memory T cells. Furthermore, keratinocytes play a role in the development of psoriasis as immune cells by secreting antibacterial peptides, chemokines, tumor necrosis factor-α, interleukin (IL)-36, and IL-23. These immune cells and skin cells interact and drive the aberrant differentiation and proliferation of keratinocytes. This crosstalk between keratinocytes and immune cells critical in the pathogenesis of psoriasis forms an inflammatory loop, resulting in the persistence or exacerbation of psoriasis plaques., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Kamata and Tada.)

Psoriasis is characterized by increased dermal vascularity, indicating that aberrant angiogenesis is associated with the pathogenesis of psoriasis. Data on angiogenesis-related factors in psoriasis patients are limited. We explored serum levels of angiogenesis-related factors in patients with psoriasis, and investigated their association with clinical severity and laboratory data. Psoriasis patients visiting our hospital from April 2013 to April 2018 and healthy controls were included in this study. Serum levels of angiopoietin-1, fibroblast growth factor (FGF)-basic, epidermal growth factor (EGF), platelet endothelial cell adhesion molecule (PECAM)-1, placental growth factor, and vascular endothelial growth factor (VEGF) were measured by LEGENDplex. Serum samples obtained from 10 healthy controls, 18 patients with psoriasis vulgaris (PsV), 24 patients with psoriatic arthritis (PsA), and 13 patients with generalized pustular psoriasis (GPP) were analyzed. The serum angiopoietin-1 level was elevated in the PsV, PsA, and GPP patients. GPP patients had a higher serum VEGF level than healthy controls. In contrast, serum levels of EGF and PECAM-1 were lower in the PsV, PsA, and GPP patients than in healthy controls. The serum FGF-basic level was lower in the PsA and GPP patients than in healthy controls. Serum levels of FGF-basic in PsA and GPP patients, PECAM-1 in PsA patients, and VEGF in GPP patients became closer to the respective levels in healthy controls after systemic therapy. The serum FGF-basic level was positively correlated with the psoriasis area and severity index and the number of circulating eosinophils in GPP patients. The serum VEGF level was correlated positively with the serum C-reactive protein (CRP) level and erythrocyte sedimentation rate, and negatively with the serum albumin level in GPP patients. In conclusion, our exploratory study revealed that psoriasis affects serum levels of certain angiogenesis-related factors. Some of these factors could be biomarkers of treatment outcomes, clinical severity, and systemic inflammation., (© 2022 Japanese Dermatological Association.)

Competing Interests: Conflicts of interest Dr Tada received honoraria for lectures and a grant for research that is not related to this article from JIMRO Co. Drs Uchida, Kamata, Egawa, Nagata, Fukaya, Hayashi, Fukuyasu, Tanaka, Ishikawa, Ohnishi, and Sugiura have no conflicts of interest to declare.

Psoriasis is a chronic inflammatory skin disease characterized by scaly indurated erythema. This disease impairs patients' quality of life enormously. Pathological findings demonstrate proliferation and abnormal differentiation of keratinocytes and massive infiltration of inflammatory immune cells. The pathogenesis of psoriasis is complicated. Among immune cells, dendritic cells play a pivotal role in the development of psoriasis in both the initiation and the maintenance phases. In addition, it has been indicated that macrophages contribute to the pathogenesis of psoriasis especially in the initiation phase, although studies on macrophages are limited. In this article, we review the roles of dendritic cells and macrophages in the pathogenesis of psoriasis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kamata and Tada.)

The impact of the COVID-19 pandemic on biologic treatment for psoriasis in Japan remains to be elucidated. This study aimed to investigate changes in biologic treatment and patients' behavior of visiting our department, especially in psoriasis patients treated with biologics before and during the pandemic. Data were collected from medical records retrospectively. The numbers of new psoriasis patients before (2019) and during (2020) the pandemic were compared. Patients' behavior of visiting our department was evaluated. The number of new psoriasis patients who visited our department in 2020 decreased by 35.7% compared with that in 2019. The reduction rate of new patients with psoriasis vulgaris was 49.3%, whereas the numbers of new patients with psoriatic arthritis (PsA) and generalized pustular psoriasis (GPP) were almost the same in 2019 and 2020. The number of patients who newly initiated biologics did not decrease in 2020 compared with that in 2019. As of January 1, 2020, 215 psoriasis patients were treated with biologics. Six patients (2.8%) discontinued biologics treatment possibly due to COVID-19 in 2020. Among 212 patients with good adherence to visiting our department in the previous year, 24 patients (11.3%) refrained from their visits for at least 1 month. In most cases, refrainment was observed in April and May when the first state of emergency was in effect in Japan. In conclusion, the COVID-19 pandemic hindered patients from visiting our department. However, its impact on patients who needed intensive care, such as patients with PsA and GPP, and psoriasis patients treated with biologics, was limited., (© 2022 Japanese Dermatological Association.)

Background: Apremilast, a selective inhibitor of the enzyme phosphodiesterase 4, is efficacious for psoriasis. However, detailed in vivo effects of apremilast on psoriasis remain to be elucidated., Objective: To examine the in vivo effects of apremilast on psoriasis., Methods: Psoriasiform dermatitis was induced by applying imiquimod (IMQ) on the murine shaved back skin for six days. Mice were treated with apremilast or vehicle intraperitoneally daily., Results: Apremilast alleviated IMQ-induced psoriasiform dermatitis clinically and pathologically on days 3-6 by reducing infiltration of antigen-presenting cells and interleukin (IL)-17A-positive cells and increasing infiltration of Foxp3-postive cells into the skin on day 6, although a significant increase in IL-10 mRNA level was not observed on day 2. In addition, mRNA expression of IL-17A, IL-17F, and IL-22 was lower in the skin of IMQ-applied mice treated with apremilast than in those without apremilast on day 2, and apremilast inhibited infiltration of IL-17A-producing γδ T cells into the dermis on day 6. Furthermore, apremilast induced regulatory T cells and regulatory B cells in the spleen but not in the draining lymph nodes., Conclusion: Apremilast downregulated IL-17 production and induced splenic regulatory B cells and regulatory T cells in an IMQ-induced psoriasiform dermatitis mouse model., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2021 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

Background: Psoriasis is a chronic inflammatory skin disease. Interleukin (IL)-17A plays a key role in the pathogenesis of psoriasis. Fingolimod, which is available for the treatment of multiple sclerosis, exerts anti-inflammatory effects by sequestrating inflammatory lymphocytes in secondary lymphoid tissues and the thymus. The effect of fingolimod on psoriasis has not been reported yet., Objective: Our objectives were to investigate the effect of fingolimod on psoriasis utilizing mice with imiquimod (IMQ)-induced psoriasiform dermatitis, and explore the possibility of fingolimod as a therapeutic agent for psoriasis., Methods: Psoriasiform dermatitis was induced by imiquimod application on murine shaved back skin for six days. Fingolimod prepared in phosphate-buffered saline (PBS), or PBS alone as a control, was administered intraperitoneally daily from days 0 to 5., Results: Fingolimod ameliorated IMQ-induced psoriasis dermatitis clinically and histologically. On day 6, the mRNA expression level of IL-17A was lower in the skin of fingolimod-treated mice than in that of PBS-treated mice, whereas it was higher in the inguinal lymph nodes of fingolimod-treated mice than in those of PBS-treated mice. Flow cytometric analyses revealed that fingolimod reduced IL-17A-producing ?d T cells infiltrating into the skin, whereas it increased these cells in the inguinal lymph nodes. Fingolimod inhibited egress of Langerhans cells from the skin to lymph nodes., Conclusion: Our results demonstrated that fingolimod showed effectiveness for IMQ-induced psoriasiform dermatitis by hindering the emigration of IL-17A-producing ?d T cells from the lymph nodes to the skin, and suggest that fingolimod is a promising candidate for the treatment of psoriasis., Competing Interests: Declaration of Competing Interest M.K. and Y.T. received honoraria for lectures and a grant for the other researches from Novartis Pharma. Y.T. received honoraria for lectures and a grant for other research studies from Mitsubishi Tanabe Pharma., (Copyright © 2021 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

Thymus and activation-regulated chemokine (TARC) is designated as a T-helper 2-type chemokine and its expression is upregulated in patients with atopic dermatitis. Previous studies reported that serum TARC levels in patients with psoriasis vulgaris (PsV) were comparable with those in healthy controls. However, the association of clinical severity of psoriasis with serum TARC levels and serum TARC levels in patients with psoriatic arthritis (PsA) or generalized pustular psoriasis (GPP) have never been reported. We investigated the association of serum TARC level with psoriasis by the type of psoriasis, and examine correlations of serum TARC levels with clinical severity scores and other results of blood tests. Data on 75 patients (51 men and 24 women; PsV, 30 patients; PsA, 29 patients; GPP, 16 patients) were analyzed. The serum TARC level was significantly higher in patients with GPP than in patients with PsV and patients with PsA. There was a positive correlation between serum TARC level and Psoriasis Area and Severity Index score (r = 0.3499, P = 0.0030). The serum TARC levels decreased after treatment in GPP patients. Our study revealed that the serum TARC level can potentially be one of the biomarkers reflecting the severity or systemic inflammation caused by psoriasis in patients with psoriasis, although not as much as in patients with atopic dermatitis. Furthermore, serum TARC levels were high in patients with GPP. Those were decreased by treatment, suggesting that serum TARC levels could be utilized as an objective biomarker to evaluate a therapeutic effect in individual GPP patients. Further accumulation of cases and further research are needed to elucidate the role of TARC in psoriasis., (© 2020 Japanese Dermatological Association.)

Psoriasis is a chronic inflammatory skin disease characterized by scaly indurated erythema. It impairs patients' quality of life enormously. It has been recognized not only as a skin disease but as a systemic disease, since it also causes arthritis (psoriatic arthritis) and mental disorders. Furthermore, an association with cardiovascular events is indicated. With the advent of biologics, treatment of psoriasis dramatically changed due to its high efficacy and tolerable safety. A variety of biologic agents are available for the treatment of psoriasis nowadays. However, characteristics such as rapidity of onset, long-term efficacy, safety profile, and effects on comorbidities are different. Better understanding of those characteristic leads to the right choice for individual patients, resulting in higher persistence, longer drug survival, higher patient satisfaction, and minimizing the disease impact of psoriasis. In this paper, we focus on the efficacy and safety profile of biologics in psoriasis patients, including plaque psoriasis and psoriatic arthritis. In addition, we discuss the impact of biologics on comorbidities caused by psoriasis., Competing Interests: M.K. received grants for research from Torii Pharmaceutical, Eisai, Maruho, and Novartis Pharma, and honoraria for lectures from Maruho, LEO Pharma, Eisai, AbbVie, Kyowa Kirin, Eli Lilly, Taiho Pharmaceutical, Mitsubishi Tanabe Pharma, and Janssen Pharmaceutical. Y.T. received grants for research from Maruho, LEO Pharma, Eisai, AbbVie, Kyowa Hakko Kirin, Taiho Pharmaceutical, Celgene, and Eli Lilly, and honoraria for lectures from Maruho, LEO Pharma, Eisai, AbbVie, Kyowa Kirin, Eli Lilly, Taiho Pharmaceutical, Mitsubishi Tanabe Pharma, and Janssen Pharmaceutical.

The association of psoriasis with thyroid dysfunction has been investigated; however, it remains controversial. Some papers indicate it, and others do not. Thereby, we investigated the prevalence of thyroid dysfunction in patients with psoriasis vulgaris (PsV), psoriatic arthritis (PsA) and generalized pustular psoriasis (GPP), and the relationship between the severity of psoriasis with serum free triiodothyronine (fT3), free thyroxine (fT4) and thyroid-stimulating hormone levels. Data on 85 psoriatic patients visiting our hospital from January 2015 to November 2017 (54 men and 31 women; 51 PsV, 23 PsA 23 and 11 GPP) were retrospectively analyzed. Fourteen percent of psoriatic patients had thyroid dysfunction. The percentage of patients with thyroid dysfunction was the highest in those with GPP (45% GPP, 13% PsA, 8% PsV). Patients with thyroid dysfunction demonstrated significantly higher Psoriasis Area and Severity Index scores and elevated serum C-reactive protein (CRP) levels than those without thyroid dysfunction. A significant negative correlation was observed between the serum levels of CRP and fT3 (P = 0.0032, r = -0.4635). Our data indicate that thyroid dysfunction in patients with psoriasis is associated with inflammation caused by psoriasis., (© 2019 Japanese Dermatological Association.)

Psoriasis is a T-helper (Th)1/Th17-mediated, chronic inflammatory dermatitis that is commonly treated with topical corticosteroids and vitamin D 3 analogs. The combination of a topical corticosteroid and vitamin D 3 analog showed superior efficacy to each alone in clinical trials; however, the mechanisms by which the topical corticosteroid and vitamin D 3 analog exert their effects on lesional skin in combination and each alone remain unknown. In this study, we examined the effects of combined calcipotriol (Cal)/betamethasone dipropionate (BD) ointment on psoriasis in vivo, utilizing imiquimod (IMQ)-induced murine psoriasiform skin inflammation, compared with each alone. Vehicle, Cal/BD, Cal or BD was applied on the shaved back skin for 3 consecutive days. Then, IMQ was applied for 6 consecutive days. Twenty-four hours after the last IMQ treatment, the murine skin was evaluated clinically and pathologically. mRNA expressions were examined by quantitative polymerase chain reaction. All ointments alleviated IMQ-induced psoriasiform skin inflammation clinically in comparison with vehicle application. Cal/BD suppressed mRNA expressions of cytokines involved in psoriasis pathogenesis such as interleukin (IL)-17A and IL-22 efficiently. Cal alone induced IL-10 expression, whereas BD alone reduced IL-6 mRNA expression and the number of phosphorylated signal transducer and activator of transcription 3-positive cells in lesional skin. Our study revealed that Cal and BD have different effects on IMQ-induced psoriasiform skin. Some of the immune effects of Cal and BD may be additive or synergistic, which may account for the superior clinical efficacy of their combination., (© 2019 Japanese Dermatological Association.)

Background: Psoriasis is a chronic inflammatory skin disease. Anti-TNFα, IL-17A and IL-23p19 antibodies are effective for psoriasis. However, the contribution of regulatory T cells (Treg) in their effectiveness remains to be elucidated., Objective: We investigated the effects of TNFα, IL-17A and IL-23p19 inhibition on Tregs in imiquimod-induced psoriasiform dermatitis., Methods: Psoriasiform dermatitis was induced by imiquimod application on murine shaved back skin for six days. Mice were treated with anti-TNFα, IL-17A or IL-23p19 monoclonal antibodies every other day from one day before imiquimod application., Results: Administration of anti-TNFα, IL-17A or IL-23p19 antibodies improved the clinical score and downregulated Th17-related cytokines and chemokines, while IL-23p19 antibodies upregulated IL-10 mRNA expression. Anti-IL-17A or IL-23p19 antibody-treated imiquimod-applied mice showed a significant increase in the number of Foxp3 + IL-10 + Tregs. Recipient mice adoptively transferred with Tregs derived from donor mice treated with antibodies demonstrated clinical and pathological improvement in imiquimod-induced psoriasiform dermatitis. Anti-IL-17A or IL-23p19 antibody-induced Tregs significantly increased the number of Foxp3 + cells and IL-10 expression in imiquimod-induced psoriasiform dermatitis in recipient mice but anti-TNFα antibody-induced Tregs did not., Conclusion: Anti-IL-17A or IL-23p19 antibody inhibits the IL-17/IL-23 signaling pathway, and induces expansion of Tregs and their suppressive capacity in imiquimod-induced psoriasiform dermatitis., (Copyright © 2019 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

Background: Tumor necrosis factor inhibitors decrease the risk of cardiovascular events in moderate to severe psoriasis, but the association between their effects on endothelial function and those on skin lesions has not been well studied. We investigated the association between infliximab effects on endothelial function during the loading phase and those on skin lesions in patients with psoriasis., Methods: We evaluated endothelial function with reactive hyperemia-peripheral arterial tonometry index (RHI) in 15 patients with psoriasis before the first and third infusions of infliximab. Patients were stratified into two groups; those who maintained Psoriasis Area and Severity Index (PASI) 75 response for more than 6 months (defined as responders) and the others (defined as nonresponders)., Results: Six weeks after the initiation of infliximab (before the third infusion), PASI scores were significantly improved compared with baseline, while RHI values were not altered in the whole patient group. However, when the responders and the nonresponders were analyzed separately, RHI values tended to be decreased before the third infusion compared with baseline in the nonresponders, while being unchanged in the responders. Importantly, the difference in ∆RHI reached a statistical significance between the two groups, and the cutoff value (mean - 2 standard deviation of RHI values in the responders) identified the nonresponders with 67% of sensitivity and 100% of specificity., Conclusions: The decrease in RHI values before the third infusion may serve as a predictor for the long-term unfavorable effect of infliximab on psoriatic skin lesions., (© 2018 The International Society of Dermatology.)

Generalized pustular psoriasis (GPP) is a systemic inflammatory disease that presents with erythema and sterile pustules, pathologically characterized by Kogoj's spongiform pustules. GPP is sometimes accompanied by mucosal involvement, and the most common lesion is on the tongue. IL36RN mutation was found to contribute to the pathogenesis of GPP especially in patients who develop GPP without a past medical history of psoriasis vulgaris. The association of IL36RN mutation with mucosal involvement in GPP is controversial. We herein report a 60-year-old male GPP patient with no past history of plaque psoriasis presenting with not only severe skin lesions and arthritis but also severe mucosal involvements of pharyngeal and gastrointestinal lesions, which led to gastrointestinal bleeding. Our case did not have any mutation in the IL36RN gene. We should be aware that severe GPP can cause gastrointestinal bleeding. The relevancy of IL36RN mutation with mucosal involvement in GPP remains to be elucidated., (© 2018 Japanese Dermatological Association.)

Background: Psoriasis is a Th1/Th17-mediated inflammatory dermatosis treated with topical corticosteroids and vitamin D 3 analogs (VD3 As)., Objective: To compare the effects of a VD3 A maxacalcitol and betamethasone valerate (BV) steroid lotion on topical imiquimod (IMQ)-induced psoriasiform skin inflammation., Methods: Female BALB/c mice were treated with vehicle, maxacalcitol or BV lotion on the skin for 3 days, and IMQ cream for 6 days. q-PCR, H&E, immunohistochemistry and immunofluorescence studies were performed on skin samples. Additionally, mice were treated with vehicle, maxacalcitol or BV lotion for 3 days and CD4 + CD25 + regulatory T cells (Tregs) and CD4 + CD25 - cells from each group were isolated from lymph nodes. Adoptive transfer of the cells was performed on recipient mice which were treated with IMQ cream for 6 days, and skin samples were obtained for q-PCR and H&E staining., Results: Maxacalcitol and BV were comparable in regards clinical improvement, although maxacalcitol reduced the MHC Class II + inflammatory cell infiltration more than BV in IMQ skin. While both treatments downregulated IL-17 A, IL-17 F, IL-22, IL-12p40, TNF-α and IL-6 mRNA expression levels, only maxacalcitol downregulated IL-23p19 expression. Significantly increased Foxp3 + cell infiltrations and IL-10 expression were noted in maxacalcitol-treated IMQ skin. Adoptive transfer of Treg cells from maxacalcitol-treated donor mice improved IMQ-induced inflammation clinically and histopathologically more than the recipients of Treg cells from BV-treated donor groups, showing reduced levels of inflammatory cytokines and increased IL-10 expression., Conclusion: These results indicate that maxacalcitol reduces psoriasiform skin inflammation by inducing Treg cells as well as downregulating IL-23 and IL-17 production., (Copyright © 2018 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

The advent of biologics brought a paradigm shift in ways to treat psoriatic patients because they have dramatic efficacy. At the same time, safety concerns about biologics have been raised. In this paper, we focus on the safety profile of biologics for psoriasis. As of 2017, six biologics are available in Japan. Two tumor necrosis factor-α inhibitors; infliximab and adalimumab, one anti-interleukin (IL)-12/23p40 antibody; ustekinumab, and IL-17 inhibitors; secukinumab, ixekizumab and brodalumab. Secukinumab and ixekizumab are anti-IL-17A antibodies. Brodalumab is an anti-IL17RA antibody. In this review, we pick up topics which have drawn attention regarding the safety of biologics and discuss them with recent published work., (© 2017 Japanese Dermatological Association.)

Background: Interleukin (IL)-33 is a recently identified cytokine, which is a member of the IL-1 family and binds to a heterodimeric receptor comprising ST2 (suppression of tumorigenicity 2) and IL-1 receptor accessory protein. Serum levels of IL-33 have been reported to be upregulated in various T helper (Th)1/Th17-mediated diseases, such as rheumatoid arthritis and inflammatory bowel disease. IL-33 expression is increased in lesional skin in patients with psoriasis, but serum levels in patients with psoriasis have not yet been studied., Aim: To study serum IL-33 levels in patients with psoriasis, a Th1/Th17-mediated skin disease, before and after anti-tumour necrosis factor (TNF)-α therapy., Methods: Serum IL-33 levels were measured in patients with psoriasis vulgaris (PV), psoriatic arthritis (PsA) or pustular psoriasis (PP), and compared with those of healthy controls. Associations between serum IL-33 levels and serum TNF-α, IL-6, vascular endothelial growth factor and C-reactive protein levels were also studied. In addition, the effect of IL-33 stimulation on IL-6, IL-8, TNF-α and VEGF secretion by human keratinocyte was analysed., Results: Serum IL-33 levels in patients with PV, PsA and PP were significantly higher than those in healthy controls. Serum IL-33 levels correlated with serum TNF-α levels in patients with psoriasis, and decreased after anti-TNF-α therapy. IL-33 stimulated IL-6 and IL-8 secretion by human keratinocytes., Conclusions: These results suggest that serum IL-33 levels generally reflect increased inflammation in patients with psoriasis., (© 2015 British Association of Dermatologists.)

Accumulating epidemiologic evidence has revealed that metabolic syndrome is an independent risk factor for psoriasis development and is associated with more severe psoriasis. Adiponectin, primarily recognized as a metabolic mediator of insulin sensitivity, has been newly drawing attention as a mediator of immune responses. Here we demonstrate that adiponectin regulates skin inflammation, especially IL-17-related psoriasiform dermatitis. Mice with adiponectin deficiency show severe psoriasiform skin inflammation with enhanced infiltration of IL-17-producing dermal Vγ4+γδ-T cells. Adiponectin directly acts on murine dermal γδ-T cells to suppress IL-17 synthesis via AdipoR1. We furthermore demonstrate here that the adiponectin level of skin tissue as well as subcutaneous fat is decreased in psoriasis patients. IL-17 production from human CD4- or CD8-positive T cells is also suppressed by adiponectin. Our data provide a regulatory role of adiponectin in skin inflammation, which would imply a mechanism underlying the relationship between psoriasis and metabolic disorders.

To assess the role of inter-cellular adhesion molecule (ICAM)-1 and L-selectin in psoriasis pathogenic process, we examined the psoriasiform skin inflammation triggered by imiquimod, a toll-like receptor 7/8 agonist, in mice lacking ICAM-1 (ICAM-1(-/-)), L-selectin (L-selectin(-/-)), or both (L-selectin/ICAM-1(-/-)). Disease severity was significantly reduced in ICAM-1(-/-) and L-selectin(-/-) mice compared with wild type mice, while it was exacerbated in L-selectin/ICAM-1(-/-) mice. Cutaneous interleukin (IL)-17A, IL-23, and tumor necrosis factor (TNF)-α expression was increased in L-selectin/ICAM-1(-/-) mice compared with wild type mice. Furthermore, only L-selectin/ICAM-1(-/-) mice was refractory to anti-TNF-α antibody treatment. The skin lesion from L-selectin/ICAM-1(-/-) mice showed augmented E-selectin expression compared with ICAM-1(-/-) and L-selectin(-/-) mice, and augmented E-selectin ligand-1 expression compared with wild type mice. The current study demonstrates that although ICAM-1 and L-selectin regulate psoriasiform inflammation, deleting both L-selectin and ICAM-1 simultaneously would rather induce refractory skin inflammation, due to compensatory up-regulation of other adhesion molecules., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Psoriasis is an inflammatory cutaneous disorder characterized by marked epidermal thickening and Th1 and Th17 cell infiltration. At present, the contribution of B cells to the pathogenesis of psoriasis is unclear. In mice, topical application of imiquimod induces inflamed skin lesions and serves as an experimental animal model for human psoriasis. In this study, we showed that imiquimod-induced skin inflammation was more severe in CD19(-/-) than WT mice. These inflammatory responses were negatively regulated by a unique IL-10-producing CD1d(hi)CD5(+) regulatory B cell subset (B10 cells) that was absent in CD19(-/-) mice and represented only 1-2% of splenic B220(+) cells in WT mice. Splenic B10 cells entered the circulation and migrated to draining LNs during imiquimod-induced skin inflammation, thereby suppressing IFN-γ and IL-17 production. Furthermore, adoptive transfer of these B10 cells from WT mice reduced inflammation in CD19(-/-) mice. The present findings provide direct evidence that B10 cells regulate imiquimod-induced skin inflammation and offer insights into regulatory B cell-based therapies for the treatment of psoriasis.

Psoriasis, a chronic inflammatory dermatosis, is frequently associated with metabolic disorders, suggesting that adipokines are involved in its pathogenesis. We recently reported that the adipokine visfatin activates NF-κB and STAT3 in keratinocytes. Antimicrobial peptide expression is enhanced in psoriatic lesions and may promote disease development. Here, we investigated the effects of visfatin on antimicrobial peptide expression. In vitro, visfatin enhanced basal and tumor necrosis factor-α (TNF-α)-induced mRNA expression and secretion of cathelicidin antimicrobial peptide (CAMP), and enhanced TNF-α-induced human β-defensin-2 (hBD-2), hBD-3, and S100A7 mRNA expression and secretion in human keratinocytes. siRNAs targeting CCAAT/enhancer-binding protein-α (C/EBPα) suppressed visfatin-induced and visfatin plus TNF-α-induced CAMP production. siRNAs targeting NF-κB p65 and STAT3 suppressed visfatin plus TNF-α-induced hBD-2 and S100A7 production. siRNAs targeting c-Jun and STAT3 suppressed visfatin plus TNF-α-induced hBD-3 production. Visfatin and/or TNF-α enhanced C/EBP transcriptional activity and C/EBPα phosphorylation, which were suppressed by p38 mitogen-activated protein kinase (MAPK) inhibition. Visfatin and/or TNF-α induced p38 MAPK phosphorylation. Visfatin increased mRNA and protein expression of CAMP, hBD-2, hBD-3, and S100A7 orthologs in murine imiquimod-treated skin, mimicking psoriasis. In conclusion, visfatin enhances CAMP, hBD-2, hBD-3, and S100A7 production in human keratinocytes and their orthologs in murine imiquimod-treated psoriatic skin. Visfatin may potentiate the development of psoriasis via antimicrobial peptides., (Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Background: CD26 is a multifunctional type II transmembrane glycoprotein, which also exists as a secreted isoform, soluble CD26 (sCD26). The CD26 expression on circulating T cells is decreased in some skin diseases such as cutaneous T-cell lymphoma (CTCL) and psoriasis. It remains to be determined whether sCD26 can be used as a marker of skin diseases or not., Objective: To investigate utility of sCD26 as a diagnostic marker of skin diseases in combination with thymus and activation-regulated chemokine (TARC)., Methods: Serum sCD26 levels were measured using enzyme-linked immunosorbent assay in 130 participants including 32 patients with atopic dermatitis (AD); 45 patients with CTCL; 26 patients with psoriasis; and 27 healthy controls., Results: Serum sCD26 levels in patients with CTCL and psoriasis (162.1 ± 80.2 ng/mL and 125.4 ± 82.1 ng/mL respectively) were significantly lower than those of healthy controls (392.6 ± 198.7 ng/mL; P < 0.01 and 0.01 respectively). In patients with CTCL, serum sCD26 levels of patients with advanced stage were 135.0 ± 51.5 ng/mL and they were significantly lower than those with early stage (193.1 ± 96.0 ng/mL; P < 0.05). When we used serum sCD26 and TARC levels for diagnostic criteria, sensitivity, specificity, positive predictive value and negative predictive value for AD, CTCL and psoriasis were 65.2-73.7%, 81.4-97.6%, 65.2-94.4%, and 81.4-88.9% respectively., Conclusion: Serum sCD26 levels, combined with serum TARC levels, are helpful in diagnosis of AD, CTCL and psoriasis., (© 2011 The Authors. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology.)

The protein lipocalin (LCN)-2 is known to be related to insulin resistance, obesity and atherosclerotic diseases. Psoriasis is an inflammatory skin disease related to metabolic syndrome. The aim of this study was to examine the relationship between serum LCN2 levels and indicators for metabolic syndrome and inflammatory cytokine levels in patients with psoriasis. Serum LCN2 levels were measured in patients with psoriasis, atopic dermatitis (AD) or bullous pemphigoid (BP), and compared with those of healthy controls. Serum LCN2 levels were also compared with several indicators for metabolic syndrome, and with serum levels of interleukin (IL)-6 and tumour necrosis factor (TNF)-α, two markers of inflammation. Serum LCN2 levels in patients with psoriasis were significantly higher than those of healthy controls, but there was no significant correlation between serum LCN2 and body mass index. Serum LCN2 levels also correlated with serum IL-6 and TNF-α levels in patients with psoriasis. Serum LCN2 levels are a general indicator for increased inflammation in the patients with psoriasis., (© The Author(s). CED © 2012 British Association of Dermatologists.)

Gout occurs in individuals with hyperuricemia when monosodium urate (MSU) crystals precipitate in tissues and induce acute inflammation via phagocytic cells such as monocytes. MSU crystals have been demonstrated in skin diseases such as tophaceous gout or psoriasis; however, the importance of MSU crystals in the skin is totally unknown. In this study, we found that MSU crystals, through P2Y(6) receptors, stimulated normal human keratinocytes (NHK) to produce IL-1α, IL-8/CXCL8, and IL-6. P2Y(6) receptor expression increased in MSU-stimulated NHK. Both P2Y(6)-specific antagonist and P2Y(6) antisense oligonucleotides significantly inhibited the production of IL-1α, IL-8/CXCL8, and IL-6 by NHK. Similarly, the P2Y(6)-specific antagonist completely inhibited the MSU-induced production of IL-1β by THP-1 cells, a human monocytic cell line. Remarkably, the P2Y(6)-specific antagonist significantly reduced neutrophil influx in both mouse air pouch and peritonitis models. Thus, these results indicate that the P2Y(6) receptor signaling pathway may be a potential therapeutic target for MSU-associated inflammatory diseases, such as tophaceous gout.

Psoriasis is an inflammatory dermatosis with enhanced expression of hBD-2 in keratinocytes and infiltration of cytokine-producing T cells, which in turn, up- or down-regulate hBD-2 expression. We determined the serum levels of hBD-2 and cytokines in psoriasis patients and analyzed the effects of hBD-2 on cytokine production in human peripheral blood T cells. Serum hBD-2 levels in patients were higher than those in controls and correlated with PASI, serum IFN-γ, and IL-10 levels and correlated inversely with serum IL-17 levels. IFN-γ, IL-17, IL-22, TNF-α, IL-1β, and IL-6 enhanced, and IL-10, IL-4, and IL-13 suppressed hBD-2 secretion from keratinocytes. hBD-2 enhanced secretion and mRNA levels of IFN-γ, TNF-α, IL-10, IL-1β, IL-6, and IL-22 and reduced those of IL-17 in CD3/28-stimulated T cells. These effects of hBD-2 were counteracted by PTX. hBD-2 induced phosphorylation of JNK, ERK, and Akt in T cells. Inhibitors of these signals attenuated hBD-2-induced production of IFN-γ, TNF-α, IL-10, IL-1β, IL-6, and IL-22. hBD-2 suppressed phosphorylation of STAT3 and enhanced expression of SOCS3 in CD3/28-stimulated T cells. siRNA against SOCS3 reversed hBD-2-induced suppression of IL-17 production and STAT3 phosphorylation. JNK and MEK inhibitors suppressed hBD-2-induced expression of SOCS3. In conclusion, hBD-2 may bind PTX-sensitive GPCR(s) on T cells and act as a stimulator by enhancing IFN-γ, TNF-α, IL-1β, IL-6, and IL-22 production via JNK, MEK/ERK, and PI3K/Akt and as a regulator by suppressing IL-17 production via SOCS3 or by stimulating IL-10 production.

Expression of leucine, leucine-37 (LL-37) is enhanced in keratinocytes of skin lesions with psoriasis. We examined serum LL-37 levels in patients with psoriasis vulgaris. Serum LL-37 levels in patients were higher than in normal controls, and were reduced after cyclosporine A treatment. In both groups, LL-37 and interleukin (IL)-17 levels inversely correlated. In patients, LL-37 levels correlated with interferon (IFN)-γ and IL-10 levels. In controls, LL-37 levels inversely correlated with tumor necrosis factor (TNF)-α, IL-6, IL-1β, and IL-22 levels. IFN-γ, IL-17, IL-22, TNF-α, IL-6, and IL-1β enhanced, and IL-10, IL-4, IL-13, and cyclosporine A suppressed, LL-37 secretion from keratinocytes and neutrophils. LL-37 enhanced IFN-γ, IL-4, IL-13, and TNF-α secretion from CD3/CD28-stimulated T cells, suppressed TNF-α, IL-1β, IL-6, and IL-10 secretion from lipopolysaccharide-stimulated monocytes, and IL-17, IL-22, IL-1β, IL-6, and IL-10 secretion from CD3/CD28-stimulated T cells. LL-37 may sustain its production by enhancing IFN-γ or reducing IL-10 production, while suppressing its production by reducing IL-17, IL-22, TNF-α, IL-1β, or IL-6 and enhancing IL-4 or IL-13 production. In patients, systemic LL-37 production is enhanced, and an IFN-γ/LL-37-positive feedback loop may exist. In controls, negative feedback by LL-37 on TNF-α, IL-1β, IL-22, and IL-6 may exist. In both groups, negative feedback by LL-37 on IL-17 may exist. LL-37 may act as an effector and regulator., (Copyright © 2010 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)

The immunological significance of IL-27 has been reported and discussed in various Th1/Th17-mediated inflammatory diseases. However, its importance in psoriasis is unknown. We investigated pathophysiological roles of IL-27 in psoriasis in this study. Serum IL-27 levels in psoriatic patients were significantly higher than those in healthy controls, and correlated with disease severity and serum IFN-gamma levels. An immunohistochemical analysis revealed the infiltration of IL-27-secreting cells in the papillary dermis of psoriatic skin lesions but not in skin lesions with atopic dermatitis or normal skin. Furthermore, IL-27 alone greatly induced in vitro CXCL9, CXCL10, and CXCL11 production and tyrosine phosphorylation of signal transducer and activator of transcription 1 in normal human keratinocytes, while it suppressed the tumor necrosis factor-alpha-induced production of IL-1alpha and CCL20. These results indicate that IL-27 may promote the onset of psoriasis, while it may simultaneously attenuate the expanded inflammation in this disease. Our results implicate potential therapeutic effects of IL-27 for psoriasis.

Ciclosporin (Cs)A is an effective treatment for psoriasis. However, to date, the effect of CsA on the production of interleukins ( ILs) is unknown. We investigated how CsA affects production of IL-12/23p40 and IL-23 production by the human monocyte cell line, THP-1, which is able to differentiate into macrophage-like cells or normal human keratinocytes ( NHKs). THP-1 cells were preincubated with CsA, then stimulated with lipopolysaccharide ( LPS), polyinosinic:polycytidylic acid or adenosine triphosphate. The levels of IL-12/23p40 and IL-23 released into the supernatant were assayed by ELISA. CsA significantly reduced both IL-12/23p40 and IL-23 production by LPS-stimulated THP-1 cells, but not in LPS-stimulated macrophage-like differentiated THP-1 cells. None of the stimuli used significantly induced either IL-12/23p40 or IL-23 production in NHKs. CsA inhibits not only IL-12/23p40 and IL-12p70, but also heterodimeric IL-23 production by human monocytes, which may be one possible mechanism for the therapeutic efficacy of CsA in psoriasis. [ABSTRACT FROM AUTHOR]