Reduction of inflammatory slan (6‐sulfo LacNAc) dendritic cells in psoriatic skin of patients treated with etanercept

Dermal dendritic cells (DCs) play a central role in the immunopathology of psoriasis. We previously identified slanDCs as pro‐inflammatory TNF‐α, IL‐23‐ and IL‐12‐producing DCs in human blood and as prominent inflammatory dermal TNF‐α secreting and CD11c‐positive DC subset in psoriasis. Here, we ask for the effects of TNF‐α‐inhibition on inflammatory slanDCs in skin and blood of 10 patients with psoriasis during 24 weeks of treatment with etanercept. Treatment with etanercept reduced the frequency of dermal slanDCs but did not induce apoptosis as determined by lack of increased active caspase‐3‐expression. In parallel, we found increased frequencies of slanDCs in blood which expressed lower levels of HLA‐DR. Stimulating slanDCs isolated from the blood of healthy donors in vitro induced a strong production of IL‐1β, IL‐6, IL‐23 and IL‐12p70. This capacity was efficiently reduced in the presence of etanercept, thereby indicating that TNF‐α is an autocrine stimulus for maturation and pro‐inflammatory cytokine production of slanDCs. In vivo, we noticed that treatment with etanercept did reduce the number of dermal slanDCs in parallel to the overall expression of TNF‐α and IL‐23p19. However, successful treatment did not down‐regulated the percentage of dermal slanDCs that stained positive for TNF‐α and IL‐23p19 indicating that remaining slanDCs kept their pro‐inflammatory capacity. This study provides novel insights into the immune regulatory properties of etanercept at the level of inflammatory slanDCs in vivo in skin and blood as well as in vitro.     

IL‐33 is secreted by psoriatic keratinocytes and induces pro‐inflammatory cytokines via keratinocyte and mast cell activation

IL‐33 is a novel pro‐inflammatory cytokine and ligand for the orphan receptor ST2. Although originally defined as an inducer of Th2‐mediated responses, IL‐33 was recently found to be involved in arthritis, a Th1/Th17‐mediated disease. Here, we assessed the ability of IL‐33 to promote inflammation via mast cells (MCs) and keratinocytes (KCs) activation in psoriasis. IL‐33 resulted elevated in the skin but not in the serum of psoriasis patients. IL‐33 was secreted by psoriasis KCs and HaCaT cells after TNF‐α stimulation. In HMC‐1, TNF‐α, but not IL‐17, could induce a robust increase in IL‐33 expression. In HaCaT cells, TNF‐α was able to induce IL‐6, MCP‐1 and VEGF, and the addition of IL‐33 reinforced these increases. TNF‐α + IL‐33 combination showed similar results in primary KCs and ex vivo skin organ culture. In conclusion, our study suggests that IL‐33 may be involved in psoriasis biology via MCs and KCs.     

Lipocalin‐2 exacerbates psoriasiform skin inflammation by augmenting T‐helper 17 response

Lipocalin‐2 (LCN2) is an antimicrobial protein and adipokine associated with insulin resistance, obesity and atherosclerotic disease. Psoriasis is a T‐helper (Th)1/Th17‐mediated, chronic inflammatory dermatosis related to metabolic syndromes and serum LCN2 levels are elevated in psoriatic patients. We examined the in vivo effects of LCN2 on topical imiquimod (IMQ)‐induced psoriasiform skin in BALB/c mice and in vitro on human keratinocytes (KC). Clinically, i.p. injected LCN2 exacerbated erythema and scaling in IMQ‐treated murine skin compared with phosphate‐buffered saline injection alone, and it augmented interleukin (IL)‐17A, IL‐17F, IL‐22, IL‐23p19, IL‐12p40, CCL20, tumor necrosis factor‐α, chemokine (C‐X‐C motif) ligand (CXCL)1, CXCL2, DEFB4, DEFB14, LCN2 and S100A7 mRNA levels of IMQ‐treated murine skin while it did not increase the mRNA levels of interferon‐γ, IL‐12p35 or CXCL10. LCN2 in synergy with IL‐17 increased mRNA levels of CCL20, LCN2 and DEFB4A but not of CXCL10 in human KC in vitro. These results suggest that LCN2 enhances the expression of Th17 cytokines/chemokines and antimicrobial peptides in murine IMQ‐treated psoriatic skin and KC. LCN2 may potentiate the development of psoriasis via the enhancement of Th17‐ and antimicrobial peptide‐mediated inflammation.     

High‐fat diet exacerbates imiquimod‐induced psoriasis‐like dermatitis in mice

Psoriasis, a chronic inflammatory skin disease, is closely related to systemic metabolism. An elevated body mass index (BMI) is a risk factor for psoriasis; inflammasomes are activated by adipose tissue macrophages in obese subjects. We hypothesized that hyperlipidaemia is involved in the pathogenesis of psoriasis and examined the role of a high‐fat diet (HFD) in the development of psoriasis in imiquimod (IMQ)‐treated mice. The body weight and serum level of cholesterol were significantly higher in mice fed an HFD than in a regular diet (RD). HFD mice had higher psoriasis skin scores, and the number of neutrophils infiltrating into the lesional skin was elevated. IL‐17A mRNA expression was significantly increased in the skin of IMQ‐treated HFD mice; the expression of IL‐22, IL‐23 and TNF‐α mRNA was not enhanced. Caspase‐1 and IL‐1β were activated in the skin of IMQ‐treated HFD mice, and their serum level of IL‐17A, TNF‐α and IL‐1β was significantly upregulated. Our findings strongly suggest that hyperlipidaemia is involved in the development and progression of psoriasis via systemic inflammation and inflammasome activation.     

Interleukin‐21 receptor signalling is not critically required for imiquimod‐induced psoriasiform dermatitis in mice

Psoriasis is largely mediated by interleukin (IL)‐23/T helper (Th) 17 axis, and IL‐21 is a pleiotropic cytokine expressed by Th17 cells. Despite previously reported possible pathogenic roles of IL‐21 in human psoriasis, we found that IL‐21 receptor (IL‐21R) signalling was not crucial for imiquimod‐induced psoriatic inflammation, using IL‐21R^?/? mice. The severity of imiquimod‐induced psoriatic manifestation and pro‐inflammatory Th17 cytokine levels, IL‐17A‐producing γδ T cells and CD4+ T cells, and in vitro IL‐17A production by γδ T cells after IL‐23 stimulation was comparable between wild‐type and IL‐21R^?/? mice. Collectively, IL‐21R signalling was not critically involved in IMQ‐induced psoriatic inflammation despite an increased IL‐21 expression in the IMQ‐treated mouse skin. Our data may represent the significant differences between human psoriasis and murine psoriasis model, and further studies using other models will be required to elucidate the role of IL‐21 in psoriasis pathogenesis.     

CCL7 contributes to the TNF‐alpha‐dependent inflammation of lesional psoriatic skin

Chemokines are small chemotactic proteins that have a crucial role in leukocyte recruitment into tissue. Targeting these mediators has been suggested as a potential therapeutic option in inflammatory skin diseases such as psoriasis. Using quantitative RT‐PCR, we found CCL7, a chemokine ligand known to interact with multiple C‐C chemokine receptors, to be markedly increased in lesional psoriasis as opposed to atopic dermatitis, lichen planus, non‐lesional psoriatic and normal control skin. Surprisingly, this increase in CCL7 mRNA expression exceeded that of all other chemokines investigated, and keratinocytes and dermal blood endothelial cells were identified as its likely cellular sources. In an imiquimod‐induced psoriasis‐like mouse model, CCL7 had a profound impact on myeloid cell inflammation as well as on the upregulation of key pro‐psoriatic cytokines such as CCL20, IL‐12p40 and IL‐17C, while its blockade led to an increase in the antipsoriatic cytokine IL‐4. In humans receiving the TNF‐α‐blocker infliximab, CCL7 was downregulated in lesional psoriatic skin already within 16 hours after a single intravenous infusion. These data suggest that CCL7 acts as a driver of TNF‐α‐dependent Th1/Th17‐mediated inflammation in lesional psoriatic skin.     

Osteopontin deficiency affects imiquimod‐induced psoriasis‐like murine skin inflammation and lymphocyte distribution in skin,draining lymph nodes and spleen

Osteopontin (OPN) that enhances autoimmunity is expressed in psoriasis lesions; however, its functions in psoriatic inflammation are unknown. We investigated the role of OPN in OPN deficient mice (OPN?/?) by inducing psoriasis‐like inflammation through skin application of imiquimod (IMQ). OPN?/? mice treated with IMQ showed delayed onset ear swelling and attracted less inflammatory cells to the skin. IMQ‐induced lymph node swelling was reduced in the absence of OPN, and IMQ‐mediated expansion of B cells was inhibited. Further, reduction of CD4⁺ T‐cell numbers by IMQ in lymph nodes was suppressed in OPN?/? mice, with an increase in the CD4/CD8 ratio. A comparable pattern was found in spleen. Importantly, IMQ‐induced IL‐17 and IL‐4 expression by CD4⁺ lymph node T cells was reduced in OPN?/? mice. In conclusion, OPN may modulate psoriasis‐like inflammation through altering lymphocyte distribution in skin and draining lymph nodes and by inducing IL‐17 expression of inflammatory T cells.     

Interleukin (IL)‐22, IL‐17, IL‐23, IL‐8, vascular endothelial growth factor and tumour necrosis factor‐α levels in patients with psoriasis before,during and after psoralen–ultraviolet A and narrowband ultraviolet B therapy

Background Several cross‐sectional studies have shown that different cytokines and growth factors are enhanced in psoriasis. Objectives We aimed to understand the role/relation of interleukin (IL)‐22, IL‐17, IL‐23, IL‐8, vascular endothelial growth factor (VEGF) and tumour necrosis factor (TNF)‐α in psoriasis vulgaris, addressing their levels and changes before, during and after psoralen–ultraviolet A (PUVA) and narrowband ultraviolet B (NB‐UVB) treatment. Methods A cross‐sectional and a longitudinal study (n = 34) – before (T0) and at 3 (T3), 6 (T6) and 12 (T12) weeks of NB‐UVB and PUVA therapy – were performed; 17 patients started NB‐UVB and 17 PUVA, and IL‐22, IL‐17, IL‐23, IL‐8, TNF‐α and VEGF levels were evaluated. Results At T0, compared with controls (n = 20), all the parameters were significantly higher in patients, except for TNF‐α. Both NB‐UVB and PUVA treatment gave, at T3, a significant decrease in TNF‐α and IL‐23; IL‐22 and IL‐17 decreased significantly at T6; all parameters and Psoriasis Area and Severity Index decreased significantly at T12. However, in both groups, at T12, VEGF was still significantly higher than control. Conclusions Psoriasis seems to be a complex disease in which the cytokine network is disturbed, namely in levels of IL‐22, IL‐17, IL‐23, IL‐8, TNF‐α and VEGF. NB‐UVB and PUVA follow‐up studies suggested that the reduction in the IL‐23/Th17 axis might be important in the pathogenic mechanisms of psoriasis. Further follow‐up studies of patients with psoriasis treated with these and other therapies could be very helpful for the understanding of the disturbance in the cytokine network in psoriasis and indirectly in its pathogenesis.     

TRIM21 is important in the early phase of inflammation in the imiquimod‐induced psoriasis‐like skin inflammation mouse model

Tripartite motif‐containing protein 21 (TRIM21) regulates pro‐inflammatory cytokines and type I interferons and acts as an autoantigen in certain autoimmune diseases, but TRIM21 has not been investigated in psoriasis. It has been suggested that TRIM21 may have a dual function; in the early phase of inflammation, it may function as a stimulator; but upon immune stimulation, its ubiquitinating mode of action may shift from stabilization to degradation of IRF3 causing inhibition of the immune responses. The imiquimod (IMQ)‐induced psoriasis‐like mouse model displays features similar to those of human psoriasis. However, chronicity is lacking in this model. We investigated whether the role of TRIM21 in psoriasis was pro‐inflammatory or anti‐inflammatory. We hypothesized that a shift of the TRIM21‐ubiquitinating mode of action may explain the lack of chronicity in the IMQ‐induced psoriasis‐like mouse model. We showed that TRIM21 expression is increased in lesional psoriatic skin and in the early phase of IMQ‐induced inflammation both in vitro and in vivo. Surprisingly, inflammation was significantly less pronounced in TRIM21 knockout mice than in wild‐type mice as shown by ear thickness measured at days 8, 9 and 10 after treatment start, by spleen weight as a marker of systemic effect of IMQ at 10 days after treatment start and by expression of IL‐12p40 at days 3 and 10 after treatment start and IL‐17A at day 3 after treatment start. Therefore, induction of TRIM21 expression cannot explain the lack of chronicity in the IMQ‐induced psoriasis‐like skin inflammation mouse model.     

Etanercept suppresses regenerative hyperplasia in psoriasis by acutely downregulating epidermal expression of interleukin (IL)-19, IL-20 and IL-24

Background  Psoriasis is a Th17/Th1‐mediated skin disease that often responds to antitumour necrosis factor (TNF)‐α therapies, such as etanercept. Objectives  To better define mechanisms by which etanercept improves psoriasis and to gain insight into disease pathogenesis. Methods  We investigated the early biochemical and cellular effects of etanercept on skin lesions in responder patients prior to substantial clinical improvement (≤ 4 weeks). Results  By 1 week, etanercept acutely suppressed gene expression of the interleukin (IL)‐20 subfamily of cytokines (IL‐19, IL‐20, IL‐24), which were found to be predominantly epidermis‐derived and which are implicated in stimulating epidermal hyperplasia. Additionally, by 1 week of therapy, suppression of other keratinocyte‐derived products (chemokines, antimicrobial proteins) occurred, while suppression of epidermal regenerative hyperplasia occurred within 1–3 weeks. Th17 elements (IL‐23p19, IL‐12p40, IL‐17A, IL‐22) were suppressed by 3–4 weeks. In vitro, TNF‐α and IL‐17A coordinately stimulated the expression of the IL‐20 subfamily in normal keratinocytes. Conclusions  Based on the rapid suppression of regenerative hyperplasia, chemokines and other keratinocyte‐derived products, including the IL‐20 subfamily, we propose that epidermal activation is a very early target of etanercept. As many of these keratinocyte markers are stimulated by TNF‐α, their rapid downregulation is likely to reflect etanercept’s antagonism of TNF‐α. Additionally, decreased epidermal hyperplasia might result specifically from acute suppression of the IL‐20 subfamily, which is also a likely consequence of etanercept’s antagonism of TNF‐α. Thus, the IL‐20 subfamily has potential importance in the pathogenesis of psoriasis and therapeutic response to etanercept.     

Skin‐penetrating methotrexate alleviates imiquimod‐induced psoriasiform dermatitis via decreasing IL‐17‐producing gamma delta T cells

Accumulating evidence has shown that the Toll‐like receptor 7 agonist imiquimod (IMQ) induces psoriasiform skin inflammation in mice and that this inflammation is dependent on the IL‐23/IL‐17 axis. Moreover, it has been demonstrated that the main source of IL‐17 is not Th17 but is dermal gamma delta (γδ) T cells in mouse psoriasiform skin. Recent advances in the understanding of immunopathogenesis of psoriasis led to an alteration in the treatment paradigm to the use of highly efficacious biologics. However, their high cost impedes the extensive use of these agents. Thus, inexpensive and safe medications are still considered valuable. In this study, we introduce the therapeutic efficacy of a newly formulated methotrexate (MTX), a chemical conjugate of MTX with cell permeable peptide, for the treatment of psoriasis. Topically applied skin‐penetrating (SP)‐MTX reduced the psoriasiform skin phenomenon, epidermal thickness and infiltrating immune cells into the dermis. IL‐17A‐producing dermal γδ T cells in the cellular infiltrate that contribute IL‐23/IL‐17 axis were well abrogated by SP‐MTX. Furthermore, SP‐MTX had no toxic effects on liver, kidney or myeloid cells, unlike systemic administration of MTX. In conclusion, topically applied SP‐MTX ameliorated psoriasiform skin inflammation in mice with the criteria of clinical phenomenon, histopathology and immunology, without inducing systemic toxic effects.     

Research in practice: IL‐22 and IL‐20: significance for epithelial homeostasis and psoriasis pathogenesis

Psoriasis vulgaris is a frequent, chronically relapsing, immune‐mediated, systemic disease with characteristic skin changes. Despite the importance of this disease there are currently limited therapeutic options indicating a need for effective, long‐lasting treatment strategies with few side effects. The most recent discoveries regarding psoriasis pathogenesis, particularly our results regarding two cytokines – IL‐22 and IL‐20 – could prove to be the foundation for such therapies. Whereas IL‐22 is mainly produced by activated T‐cell sub‐populations (Th22, Th1, Th17), monocytes, dendritic cells and keratinocytes produce IL‐20. Blood and lesional skin samples from psoriasis patients demonstrate high levels of IL‐22 and IL‐20. Interestingly, both cytokines act principally on keratinocytes and do not impact the immune system. Similar to the changes in the psoriasis epidermis these cytokines inhibit the terminal differentiation of keratinocytes although they simultaneously increase their innate defense, mobility, and the production of some chemokines. Some IL‐22 effects are amplified by TNF‐α, IL‐17, and IFN‐α. IL‐22/IL‐20 lends the reconstructed epidermis a psoriasis‐like appearance with acanthosis, hypogranularity, and hyperkeratosis. In addition, mice that constitutively express high levels of IL‐22 or IL‐20 demonstrate a psoriasis‐like appearance. A therapy counteracting IL‐22 and IL‐20 would be an innovative treatment with the potential for few side effects that would act on the final phase of psoriasis pathogenesis.     

Toll‐like receptor 4 attenuates a murine model of atopic dermatitis through inhibition of langerin‐positive DCs migration

Atopic dermatitis (AD) is a common chronic inflammatory skin disease that is often associated with skin barrier dysfunction leading to a higher frequency of bacterial and viral skin infections. Toll‐like receptor (TLR) 4 on resident skin cells was involved in sensing pathogens and eliciting pathogen‐specific innate and adaptive immune responses. Previous studies have demonstrated that TLR4 was linked to AD severity in context of pathogen infection. However, the immune regulatory role of TLR4 in AD remains to be defined. We here investigated the immune regulatory function of TLR4 in AD induced by repeated epicutaneous application of a hapten, 2,4‐dinitrochlorobenzene (DNCB). Our results showed that TLR4‐deficient (TLR4^?/?) mice exhibited more severe AD symptoms than WT mice after DNCB challenge. The DNCB‐treated TLR4^?/? mice also displayed higher expression levels of inflammatory cytokines and stronger Th2 response than WT counterparts. Moreover, the skin expression of thymic stromal lymphopoietin (TSLP), an important potential contributor to allergic inflammation, was significantly elevated in TLR4^?/? mice compared with that in WT mice upon DNCB administration. Furthermore, we demonstrated that the migration of langerin‐positive dendritic cells (DCs) into draining lymph nodes was enhanced in TLR4^?/? mice following DNCB challenge, which is partially dependent on the production of pro‐inflammatory cytokine TNF‐α. Together, these results determined that TLR4 affected the hapten‐induced skin inflammation in the absence of exogenous pathogen infection, suggesting that TLR4 not only regulates infection but also may serve as a modulator of the immune response during AD development.     

The single‐chain anti‐TNF‐α antibody DLX105 induces clinical and biomarker responses upon local administration in patients with chronic plaque‐type psoriasis

It is not clear whether TNF‐α antagonists used in the treatment of psoriasis need to act systemically, or whether local inhibition of skin‐produced TNF‐α would be sufficient to silence skin inflammation. To answer this question, we conducted two multicentre, double‐blinded, randomized, placebo‐controlled clinical trials with the novel single‐chain anti‐TNF‐α‐PENTRA^®‐antibody DLX105. Upon intra‐dermal injection, DLX105 induced a mean local PASI decrease of 33% over baseline after 2 weeks of treatment, while the placebo response was only 12% (P = 0.001). The clinical response was accompanied by changes in biomarkers such as reductions in K16, Ki67 and epidermal thickness as well as decreased mRNA levels of IL‐17, TNF‐α, IL‐23p19, IL‐12p40 and IFN‐γ. Next, we applied the drug topically twice daily in a 0.5% hydrogel formulation. While the local PASI did not change, topical DLX105 mediated significant reductions of mRNA levels of key proinflammatory cytokines when compared to placebo, and this effect was further enhanced after weekly tape stripping of plaques to increase drug penetration. These results suggest that longer treatment periods and/or increased local drug concentrations might result in better therapeutic efficacy of topically applied DLX105. In sum, we can show for the first time that local inhibition of TNF‐α is sufficient to mediate a biological response in psoriasis that translates into clinical efficacy.     

Increased expression of glucagon‐like peptide‐1 receptors in psoriasis plaques

Recent case reports suggest that treatment with glucagon‐like peptide‐1 (GLP‐1) agonists results in clinical improvement of psoriasis. The purpose of this study was to determine whether GLP‐1 receptors (GLP‐1Rs) are found in the skin of healthy volunteers and psoriasis patients and if so, whether GLP‐1Rs are located on keratinocytes or immune cells. Three mm‐punch skin biopsies were taken for gene expression analysis from six healthy volunteers and from affected and unaffected skin of six psoriasis patients. In addition, a blood sample was obtained from all participants. Cultured human keratinocytes were either untreated or incubated with tumor necrosis factor‐ α (TNF‐α), interferon‐γ (IFN‐γ) or a combination of TNF‐α and IFN‐γ for 48 h. Total RNA was extracted from all the samples, reversely transcribed and analysed for the expression of GLP‐1R using real‐time PCR. Gene expression analysis showed expression of GLP‐1Rs in five of six skin biopsies from psoriasis plaques, in one of six biopsies from unaffected psoriatic skin and in one of six biopsies from healthy skin. GLP‐1R expression was found in the blood of both healthy volunteers and psoriasis patients. No GLP‐1R expression was found in either stimulated or unstimulated cultured human keratinocytes. Our results show increased presence of GLP‐1Rs in psoriasis plaques and that this most likely is due to infiltration with immune cells. This offers a possible explanation for the positive effect of treatment with GLP‐1R agonists in patients with psoriasis.     

TNF‐α and IL‐10 gene polymorphisms show a weak association with pemphigus vulgaris in the Slovak population

Backround Pemphigus vulgaris is a rare chronic autoimmune disease of skin and mucous membranes, with several cytokines participating in its development. The role of their gene polymorphisms in susceptibility to the disease is, however, not fully understood. Objective The aim of our case‐control study was to investigate whether some of 22 single nucleotide polymorphisms (SNPs) in 13 cytokine genes (IL‐1α, IL‐1β, IL‐1RI, IL‐1Ra, IL‐4Rα, IL‐12, IFN‐γ, TGF‐β1, TNF‐α, IL‐2, IL‐4, IL‐6 and IL‐10) are associated with pemphigus vulgaris in the Slovak population. Methods DNA samples were obtained from 34 pemphigus vulgaris patients and 140 healthy controls of Slovak origin. Cytokine gene SNPs were determined using the polymerase chain reaction with sequence‐specific primers (PCR‐SSP) method. Results We found a weak association between pemphigus vulgaris and polymorphic variants in TNF‐α and IL‐10 genes only, with haplotypes TNF‐α–308G/–238G and IL‐10 –1082A/–819C/–592C being significantly overrepresented in pemphigus vulgaris patients (TNF‐α GG: 94.12% vs. 82.86%, P = 0.0216; IL‐10 ACC: 44.12% vs. 30.00%, P = 0.0309). Conclusions Our preliminary results suggest that certain TNF‐α and IL‐10 gene polymorphisms might contribute to genetic susceptibility to pemphigus vulgaris; however, their overall impact on disease development will be rather limited.     

Circulating adipokine levels in Portuguese patients with psoriasis vulgaris according to body mass index,severity and therapy

Background Psoriasis vulgaris is associated with overweight/obesity and with increased C‐reactive protein (CRP), tumour necrosis factor (TNF)‐α, interleukin (IL)‐6, leptin and resistin levels and decreased adiponectin levels. Objectives To understand the role/relationship of adipokines, as well as CRP, in a Portuguese psoriatic population, by assessing the relationship of their levels with psoriasis severity, defined by Psoriasis Area and Severity Index (PASI), with obesity, defined by body mass index (BMI), and psoriasis therapy. Methods A cross‐sectional (n = 66) and longitudinal study (before and after 12 weeks of therapy; n = 44) was performed; 10 patients started topical treatment, 17 narrow‐band ultraviolet B (NBUVB) and 17 psolaren associated with UVA (PUVA). Results Patients presented significantly higher BMI, leptin, resistin, TNF‐α, IL‐6 and CRP and significantly lower adiponectin values. CRP and IL‐6 correlated with PASI. Adiponectin and leptin were more altered in patients with higher BMI. Concerning severity, CRP, resistin and adiponectin were more altered in the severer forms. After treatment, a significant reduction in PASI, CRP, resistin, TNF‐α and IL‐6, and a significant rise in adiponectin were observed. Nonetheless, CRP and adiponectin remained different from those of control. Concerning therapies, topical therapy was not associated with any significant change, except for TNF‐α. After NBUVB, a significant reduction was observed in TNF‐α and in CRP. For PUVA, we observed a significant reduction in TNF‐α, IL‐6 and CRP, and a significant increase in adiponectin. Conclusion In psoriatic patients, increased overweight/obesity was associated with raised leptin levels and decreased adiponectin levels. Leptin may contribute to enhance the inflammatory process in overweight/obese psoriatic patients. Resistin, IL‐6, CRP and adiponectin levels appear to be dependent on psoriasis severity. CRP, together with IL‐6, appears to be a useful marker of psoriasis severity. Both NBUVB and PUVA were effective; however, PUVA results seem to be more successful. Nonetheless, after NBUVB and PUVA, a low‐grade inflammation still persists.     

Infliximab partially impairs the anti‐Mycobacterium tuberculosis immune responses of severe psoriasis patients with positive tuberculin skin‐test

Background Infliximab and etarnecept are now widely used for treating severe psoriasis. However, these drugs, especially infliximab, increased the risk of tuberculosis reactivation. Surprisingly, epidemiological data suggest that the tuberculosis rate in patients taking infliximab in São Paulo State, Brazil, is similar to that of some developed, non‐endemic countries. Objective The aim of this study was to better understand the effect of infliximab on Mycobacterium tuberculosis (Mtb) immune responses of psoriasis patients in an endemic setting (Brazil). Methods We evaluated the tuberculosis‐specific immune responses of severe psoriasis patients and healthy individuals, both tuberculin skin test (TST) positive, in the presence/absence of infliximab. Patients had untreated severe psoriasis, no co‐morbidities affecting the immune responses and a TST >10 mm. Healthy TST⁺ (>10 mm) individuals were evaluated in parallel. PBMC cultures from both groups were stimulated with different Mycobacterium tuberculosis (Mtb) antigens (ESAT‐6, 85B and Mtb lysate) and phytohemagglutinin, with or without infliximab (5 μg/mL). Parameters evaluated were TNF‐α, IFN‐γ and IL‐10 secretion by ELISA, overnight IFN‐γ ELISpot and lymphocyte proliferative response (LPR). Results Infliximab almost abolished TNF‐α detection in PBMC supernatants of both groups. It also significantly reduced the LPR to phytohemagglutinin and the Mtb antigens as well as the IFN‐γ levels secreted into day 5 supernatants in both groups. There was no concomitant exaggerated IL‐10 secretion that could account for the decreases in these responses. ELISpot showed that, contrasting with the central‐memory responses above, infliximab did not affect effector‐memory INF‐γ‐releasing T‐cell numbers. Conclusions Infliximab affected some, but not all aspects of the in vitro antituberculosis immune responses tested. The preserved effector‐memory responses, putatively related to exposure to environmental mycobacteria, may help to explain the lower than expected susceptibility to tuberculosis reactivation in our setting.     

Obesity exacerbates imiquimod‐induced psoriasis‐like epidermal hyperplasia and interleukin‐17 and interleukin‐22 production in mice

Psoriasis is a chronic inflammatory skin disorder that is accompanied by an imbalance between the proliferation and differentiation of keratinocytes. A number of studies have suggested an association between obesity and severe psoriasis; however, it remains to be clarified whether obesity exacerbates psoriasis. To address this unsolved question, we induced psoriasiform dermatitis in mouse models for obesity. We found that obesity exaggerated the severity of psoriasiform dermatitis induced by topical application of the Toll‐like receptor (TLR) 7 agonist, imiquimod. Ear swelling and epidermal hyperplasia were more prominent in the obese mice than in the control mice. When compared to imiquimod‐treated control mice, imiquimod‐treated obese mice expressed higher levels of psoriasis mediators, interleukin‐17A (IL‐17A) and IL‐22 in the skin. Food intake restriction partially abrogated enhanced ear swelling and cytokine overproduction in obese mice. Furthermore, the obesity environment and imiquimod treatment synergistically induced an IL‐17A downstream molecule, regenerating islet‐derived 3γ (Reg3γ), which is a critical molecule for psoriatic epidermal hyperplasia. Palmitic acid, one of the fatty acids released by subcutaneous adipocytes, increased the expression of REG3A (a human homologue of mouse Reg3γ) in both the HaCaT keratinocyte cell line and normal human keratinocytes. Taken together, these results strongly suggest that obesity exacerbates psoriasiform dermatitis in mice by upregulating IL‐17A, IL‐22 and Reg3γ.