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.     

IL‐36γ has proinflammatory effects on human endothelial cells

Interleukin‐36 cytokines are predominantly expressed by epithelial cells. Significant upregulation of epidermal IL‐36 is now a recognised characteristic of psoriatic skin inflammation. IL‐36 is known to induce inflammatory responses in dendritic cells, fibroblasts and epithelial cells. Although vascular alterations are a hallmark of psoriatic lesions and dermal endothelial cells are well known to play a critical role in skin inflammation, the effects of IL‐36 on endothelial cells are unexplored. We here show that endothelial cells including dermal microvascular cells express a functionally active IL‐36 receptor. Adhesion molecules VCAM‐1 and ICAM‐1 are upregulated by IL‐36γ stimulation, and this is reversed by the presence of the endogenous IL‐36 receptor antagonist. IL‐36γ‐stimulated endothelial cells secrete the proinflammatory chemokines IL‐8, CCL2 and CCL20. Chemotaxis assays showed increased migration of T‐cells following IL‐36γ stimulation of endothelial cells. These results suggest a role for IL‐36γ in the dermal vascular compartment, and it is likely to enhance psoriatic skin inflammation by activating endothelial cells and promoting leucocyte recruitment.     

Influence of high dose tumescent local anaesthesia with prilocaine on systemic interleukin (IL)‐6, IL‐8 and tumour necrosis factor‐α

Background and objective Tumescent local anaesthesia (TLA) with high prilocaine doses leads to formation of methemoglobin (MHb) which is known to be a potent activator of pro‐inflammatory endothelial cell response in vitro. As TLA is widely used for large dermatological resections, the aim of this study was to investigate the effects of high prilocaine doses on the systemic inflammatory response in vivo and its clinical relevance. Methods This prospective study examines the influence of MHb on serum interleukin (IL)‐6, IL‐8 and tumour necrosis tumour necrosis (TNF)‐α levels up to 72 h after application of TLA with prilocaine in doses higher than 600 mg. Results A total of 30 patients received prilocaine in a median dose of 1500 mg (range: 880–4160 mg) for large resections. Peak prilocaine serum concentration was reached 4 h (0.72 ± 0.07 μg/mL), the maximum concentration of MHb (7.43 ± 0.87%) and IL‐6 (28.4 ± 4.1 U/L) 12 h after TLA application. TNF‐α and IL‐8 release were not found significantly increased. Three patients developed MHb concentrations >15%. Conclusions This clinical study shows for the first time that a high prilocaine serum concentration leads in vivo to elevated systemic levels of IL‐6 but not of IL‐8 and TNF‐α because of initial high MHb levels. Because of possible and unpredictable high MHb concentrations, TLA should only be performed with prilocaine in doses of 2.5 mg/kg. In general, new solutions of TLA are necessary to achieve adequate anaesthesia for large dermatological resections to decrease the risk of methemoglobinaemia.     

CD4+ T cells producing interleukin (IL)‐17, IL‐22 and interferon‐γ are major effector T cells in nickel allergy

Background It has been suggested that interleukin (IL)‐17 and IL‐22 play important roles in the elicitation of human allergic contact dermatitis; however, the frequencies of T cell subtypes producing IL‐17 and IL‐22 in human allergic contact dermatitis are unknown. Objectives To determine the frequencies of CD4⁺, CD8⁺ and γδ T cells producing IL‐17, IL‐22 and interferon (IFN)‐γ in the blood and skin from nickel‐allergic patients. Patients/materials/methods Blood samples were collected from 14 patients and 17 controls, and analysed by flow cytometry. Biopsies were taken from 5 patients and 6 controls, and analysed by immunohistochemistry and flow cytometry of skin lymphocytes. Results We found an increased frequency of γδ T cells in the blood, but no differences in the distribution of cytokine‐producing CLA⁺ T cell subtypes in nickel‐allergic patients as compared with controls. In nickel‐allergic patients, there was massive cellular infiltration dominated by CD4⁺ T cells producing IL‐17, IL‐22 and IFN‐γ in nickel‐challenged skin but not in vehicle‐challenged skin. Conclusion CD4⁺ T cells producing IL‐17, IL‐22 and IFN‐γ are important effector cells in the eczematous reactions of nickel‐induced allergic contact dermatitis in humans.     

Interleukin (IL)‐6 modulates transforming growth factor‐β receptor I and II (TGF‐βRI and II) function in epidermal keratinocytes

It been shown that IL‐6 modulates TGF‐β1 expression in fibroblasts, however, what role IL‐6 plays concerning TGF‐βR expression and function in skin is unknown. Therefore, the aim of this study was to investigate the mechanism by which IL‐6 might modulates TGF‐β receptors in skin. Skin from WT, IL‐6 over‐expressing mice and IL‐6 treated keratinocyte cultures was analysed for TGF‐βRI and TGF‐βRII expression via histology, PCR and flow cytometry. Receptor function was assessed by cell migration, bromodeoxyuridine (BrdU) proliferation assays, and Smad7 expression and Smad2/3 phosphorylation. Receptor localization within the membrane was determined by co‐immunoprecipitation. IL‐6 overexpression and treatment increased TGF‐βRII expression in the epidermis. IL‐6 treatment of keratinocytes induced TGF‐βRI and II expression and augmented TGF‐β1‐induced function as demonstrated through increased migration and decreased proliferation. Additionally, IL‐6 treatment of keratinocytes altered receptor activity as indicated by altered Smad2/3 phosphorylation and increased Smad7 and membrane localization. These results suggest that IL‐6 regulates keratinocyte function by modulating TGF‐βRI and II expression and signal transduction via trafficking of the receptor to lipid raft pools.     

Epidermal keratinocytes sense dsRNA via the NLRP3 inflammasome,mediating interleukin (IL)‐1β and IL‐18 release

Skin epidermis, in addition to its barrier function, is able to actively sense harmful pathogens using pattern recognition receptors. In immune cells, the nucleotide‐binding oligomerization domain, leucine‐rich repeat and pyrin domain containing 3 (NLRP3) inflammasome can mediate innate immunity against viral infection via a mechanism involving viral dsRNA recognition. Epidermal keratinocytes express NLRP3 inflammasome, which can sense contact sensitizers and mite allergens, leading to pro‐interleukin (IL)‐1β and pro‐IL‐18 cleavage into their active forms. Skin often faces viral infection. However, it is unknown whether viral dsRNA can be detected by the keratinocyte NLRP3 inflammasome. We transfected polyinosinic:polycytidylic acid (poly I:C), a synthetic viral dsRNA analogue, into cultured primary human keratinocytes at the aid of Lipofectamine 2000, and found that transfected poly I:C activated caspase‐1 and induced caspase‐1‐dependent release of IL‐1β and IL‐18, which were suppressed on transfection with NLRP3 siRNA. The activation of keratinocyte NLRP3 inflammasome by transfected poly I:C was dependent on dsRNA‐induced protein kinase (PKR) activation, and priming with type I interferons upregulated NLRP3 inflammasome activation through promoting PKR activation in poly I:C‐transfected keratinocytes. In conclusion, the NLRP3 inflammasome can act as a sensor of dsRNA in epidermal keratinocytes, which may be important in both skin innate immune defense against viral infection and skin inflammation.     

IL‐17A synergistically enhances TLR3‐mediated IL‐36γ production by keratinocytes: A potential role in injury‐amplified psoriatic inflammation

Skin injury can trigger formation of new lesions in psoriasis (Koebner phenomenon). The mechanisms through which injury exacerbates psoriasis are unclear. During wound repair, epidermal keratinocytes are activated and produce abundant IL‐36γ, further promoting the skin inflammation. IL‐17A is the cornerstone cytokine in the pathogenesis of psoriasis. We sought to investigate the effects of IL‐17A on injury‐induced keratinocyte activation and IL‐36γ production. Here, we demonstrated that dsRNA released from necrotic keratinocytes induced the expression of IL‐36γ. Silencing of TLR3 by siRNA decreased the IL‐36γ induction by necrotic keratinocyte supernatant. Co‐stimulation with dsRNA and IL‐17A synergistically increased the expression of IL‐36γ and other proinflammatory mediators (CCL20, CXCL8, DEFB4 and LCN2) in keratinocytes. The synergistic effects were not dependent on TLR3 upregulation, TNF receptor signalling and mRNA stabilization. Co‐stimulation with dsRNA and IL‐17A resulted in an accumulation of IκBζ. The synergistic upregulation of IL‐36γ and proinflammatory mediators were inhibited by IκBζ siRNA. Co‐stimulation with IL‐17A and poly(I:C) markedly activated the p38 MAPK and NF‐κB pathway, compared with poly(I:C). Blockade of p38 MAPK and NF‐κB suppressed dsRNA/IL‐17A–mediated IκBζ and IL‐36γ induction. These findings demonstrated that IL‐17A synergistically enhanced the dsRNA‐mediated IL‐36γ production through a p38 MAPK‐, NF‐κB–, and IκBζ‐dependent mechanism.     

Interferon‐γ (INF‐γ) release test can detect cutaneous adverse effects to statins

Background An increasing number of cutaneous adverse effects are being reported as use of statins becomes more widespread. A study was undertaken to establish the relationship between statin and a cutaneous reaction by the in vitro interferon‐γ (INF‐γ) release test. Methods The lymphocytes of 20 patients with suspected drug‐induced skin reaction were incubated with and without the drug. The level of INF‐γ from the supernatant was measured by enzyme‐linked immunosorbent assay (ELISA), and the increase calculated. Results Response was positive in 27 (21.43%) of the 126 drugs. Statin was the only drug with a positive response in 80% of those cases. Nine of 20 patients (45.0%) had complete resolution after discontinuation of the drug; 6 (30.0%) who replaced one drug by another statin had partial or no resolution; and 5 (20.0%) had no resolution despite cessation of statins of all kinds. Conclusion A positive INF‐γ release test was found in patients who developed skin reactions while taking statins; the test’s reliability was strengthened by prompt improvement following elimination of the suspected drug in the majority of patients.     

Interleukin (IL)-17F and IL-17E are related to fibrosis and vasculopathy in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune disease that causes fibrosis and vasculopathy of the skin and internal organs against a background of autoimmune abnormalities. In recent years, the importance of the interleukin (IL)-17 family for inflammatory diseases has received much attention, but autoimmune diseases have not yet been fully explored. As for SSc, there is also no unified perspective on the involvement of the IL-17 family in its development, and few studies have been conducted linking IL-17F and IL-17E particularly to the disease severity. In the present study, we examined the correlation between serum IL-17F and IL-17E levels and disease severity in SSc patients. Moreover, the expression of the receptors for these cytokines, IL-17RB and IL-17RC, in skin tissues obtained by skin biopsy was examined by immunohistochemistry. Both cytokines were significantly elevated in the sera of patients with diffuse cutaneous SSc patients compared with healthy controls. Serum IL-17F levels correlated with modified Rodnan total skin thickness score, a semiquantitative measure of skin sclerosis, percent predicted forced vital capacity, percent predicted carbon monoxide lung diffusion capacity and serum levels of Krebs von den Lungen-6 and surfactant protein-D, serological markers of interstitial lung disease. Serum IL-17E levels were significantly correlated with percent predicted forced vital capacity and serum Krebs von den Lungen-6 levels. Serum levels of IL-17F and IL-17E also correlated with the prevalence of digital ulcers, and serum IL-17F levels were associated with elevated right ventricle systolic pressure values. In addition, IL-17RC and IL-17RB expression was increased in the skin tissues of diffuse cutaneous SSc patients. These results suggested that IL-17F and IL-17E could be involved in fibrosis and vasculopathy in SSc through their respective receptors in the affected organ tissues.     

IL6 −174G>C polymorphism is associated with an increased risk of psoriasis but not response to treatment

Interleukin‐6 (IL‐6) is implicated in the pathogenesis of psoriasis as well as in its treatment efficacy. The aim of this study of 406 patients with psoriasis and 203 healthy controls was to evaluate the association between the IL6 ?174G>C (rs1800795) polymorphism and psoriasis susceptibility, as well as treatment efficacy. The frequency of genotype GG (33.7% vs 20.7%; P = 0.00022; OR = 0.51, 95% confidence interval 0.34–0.76) and of allele G (56.2% vs 46.8%; P = 0.0023) was significantly higher in the psoriasis group compared with controls. No polymorphism variants were associated with better response to topical or combined topical/narrow‐band ultraviolet B (NB‐UVB) treatment. We conclude that the IL6 ?174G>C polymorphism can be a marker of susceptibility to psoriasis, with an almost twofold increased risk of the disease in individuals carrying the GG genotype; however, it was not associated with treatment response to topical and/or NB‐UVB therapy.