Regulatory T‐cell cytokines in patients with nonsegmental vitiligo

In the etiopathogenesis of vitiligo, the role of suppressor cytokines, such as transforming growth factor‐β (TGF‐β) and interleukin‐10 (IL‐10), associated with regulatory T‐cells (Treg) is not completely known. In this study, the role of Treg‐cell functions in the skin of patients with nonsegmental vitiligo was investigated. Lesional and nonlesional skin samples from 30 adult volunteers ranging in age from 18 to 36 years with nonsegmental vitiligo were compared with normal skin area excision specimens of 30 benign melanocytic nevus cases as controls. All samples were evaluated staining for forkhead box P3 (Foxp3), TGF‐β, and IL‐10 using the standardized streptavidin–biotin immunoperoxidase immunohistochemistry method. Foxp3 expression was lower in lesional vitiligo skin specimens compared to controls; it was also lower in lesional vitiligo specimens than nonlesional vitiligo specimens. IL‐10 levels were lower in lesional vitiligo specimens compared to the controls, whereas IL‐10 expression was significantly lower in lesional specimens compared with nonlesional specimens. TGF‐β expression was higher in both lesional and nonlesional skin specimens of patients with vitiligo compared to controls. TGF‐β expression was lower in lesional skin specimens than nonlesional skin specimens. In addition, there was no significant correlation between Foxp3 expression with TGF‐β and IL‐10 expressions in lesional skin specimens in the vitiligo group. In this study, results supporting the contribution of Treg cells and IL‐10 deficiency to the autoimmune process were obtained. Therefore, future studies are necessary to demonstrate the definitive role of Treg‐cell functions in the etiopathogenesis of vitiligo.     

Stimulated human melanocytes express and release interleukin‐8, which is inhibited by luteolin: relevance to early vitiligo

Vitiligo is a disorder of depigmentation, for which the pathogenesis is as yet unclear. Interleukin (IL)‐8 (CXCL8) is a key inflammatory chemokine. We investigated the regulation of IL‐8 production in human melanocytes, and the IL‐8 serum levels and skin gene expression in patients with vitiligo and in controls. Cultured melanocytes were stimulated for 24 h with tumour necrosis factor (TNF) 100 ng/mL and IL‐1β 10 ng/mL, with or without pretreatment with luteolin 50 μmol/L for 30 min, and IL‐8 release was measured by ELISA. Serum cytokines were measured by a microbead array. Skin biopsies were taken from healthy subjects (n = 14) as well as from marginal lesional and nonlesional skin from patients with vitiligo (n = 15). IL‐8 gene expression was evaluated by quantitative real time PCR. Both TNF and IL‐1β stimulated significant IL‐8 release (P < 0.01) from melanocytes, whereas pretreatment with luteolin significantly inhibited this effect (P < 0.01). IL‐8 gene expression was significantly increased in vitiligo compared with control skin (P < 0.05). IL‐8 may be involved in vitiligo inflammation. Inhibition by luteolin of IL‐8 release could be useful for vitiligo therapy.     

Role of interleukin-17 in the pathogenesis of vitiligo

Background. Skewing of the immune response towards T helper (Th)1 or Th17 and away from regulatory T cells (Tregs) and Th2 cells may be responsible for the development and progression of autoimmune disease. An autoimmune theory has been proposed in the pathogenesis of vitiligo. No previous reports have investigated alterations in IL‐17 produced by Th17 cells in lesional skin in vitiligo. Aim. To investigate the role of IL‐17 in the pathogenesis of vitiligo by assessing its levels in lesional skin and serum of patients with vitiligo compared with controls. Methods. In total, 30 patients with vitiligo and 20 controls matched for age and gender were enrolled in the study. Serum and tissue IL‐17 levels were measured by ELISA and compared between both groups for correlations with age, gender, family history, disease duration, activity of vitiligo and percentage of involved body surface area. Results. A significant difference between patients and healthy controls was found for both serum and tissue IL‐17 levels (P < 0.001 for both). Significant positive correlations were found between disease duration and IL‐17 level in both serum (r = 0.42, P = 0.02) and lesional skin (r = 0.45, P < 0.015); between extent of vitiligo and IL‐17 levels in both serum (r = 0.65, P < 0.001) and skin (r = 0.48, P < 0.05); and between the serum and the tissue IL‐17 levels in patients with vitiligo (r = 0.54, P = 0.002). Conclusions. Multiple factors have been implicated in the pathogenesis of vitiligo. The increased levels of IL‐17 we found in serum and lesional skin suggest an important role for this cytokine in the pathogenesis of vitiligo.     

The balance between pro‐ and anti‐inflammatory cytokines is crucial in human allergic contact dermatitis pathogenesis: the role of IL‐1 family members

The interleukin (IL)‐1 family includes 11 members that are important in inflammatory processes. It includes various agonists and two antagonists, IL‐1Ra and IL‐36Ra. Our aim was to investigate whether the IL‐1 family is involved in allergic contact dermatitis (ACD). The expression of IL‐1 family members was evaluated by PCR and immunohistochemistry in the positive patch test reaction site (involved skin) and in the uninvolved skin of ACD patients. We also examined these cytokines in an ex vivo model of ACD. The antagonistic activity of IL‐36Ra was evaluated by injecting recombinant IL‐36Ra in uninvolved skin biopsies of ACD patients. IL‐1Ra and IL‐36Ra expression was quantified in mononuclear cells of nickel‐sensitized patients challenged in vitro with nickel. IL‐33 involvement in ACD was investigated by intra‐dermal injection of anti‐IL‐33 in the uninvolved skin of patients ex vivo. Results showed that IL‐1β, IL‐1Ra, IL‐36α, IL‐36β, IL‐36γ and IL‐33 expression, but not IL‐36Ra expression, was enhanced in ACD‐involved skin. Immunohistochemical analysis and ex vivo skin cultures confirmed these results. Injection of anti‐IL‐33 in ACD‐uninvolved skin inhibited IL‐8 expression, whereas IL‐36Ra inhibited IL‐36α, IL‐36β, IL‐36γ and IL‐8 expression. Nickel induced IL‐1Ra expression in lymphocytes of nickel‐sensitized patients. Hence, various IL‐1 agonists and antagonists may be involved in ACD pathogenesis.     

Study of pro‐ and anti‐inflammatory cytokine profile in the patients with parthenium dermatitis

Background: Parthenium dermatitis is a common airborne allergic contact dermatitis induced by exposures to the weed Parthenium hysterophorus. The disease manifests as itchy erythematous papules, papulovesicular and plaque lesions on exposed areas of the body. Objectives: The aim of this study was to show the alterations in pro/anti‐inflammatory cytokines in parthenium dermatitis. Methods: The study included 50 patients with parthenium dermatitis confirmed by patch testing using aqueous extracts of P. hysterophorus and 50 age‐matched healthy controls. The levels of pro‐inflammatory [tumour necrosis factor‐α (TNF‐α), interleukin (IL)‐6, IL‐8, and IL‐17] and anti‐inflammatory (IL‐4 and IL‐10) cytokines were estimated by commercially available high sensitivity enzyme‐linked immunosorbent assay (ELISA) kits. Results: All the dermatitis patients showed significantly (P < 0.001) elevated levels of TNF‐α, IL‐6, IL‐8, and IL‐17 levels as compared to healthy controls. In contrast, the anti‐inflammatory cytokine IL‐4 showed an insignificant decrease (P < 0.217) and a decrease in level of IL‐10 was statistically significant (0.001) compared with controls. Conclusions: The present study suggests the involvement of pro‐inflammatory cytokines in the pathogenesis of parthenium dermatitis. A decrease in levels of anti‐inflammatory cytokines was demonstrated, which could not downregulate pro‐inflammatory cytokines in parthenium dermatitis.     

The expression change of RORγt,BATF, and IL‐17 in Chinese vitiligo patients with 308 nanometers excimer laser treatment

This study aims to explore the expression of RORγt, BATF, and IL‐17 in Chinese vitiligo patients with 308 nm excimer laser treatment. One hundred and sixty‐four vitiligo patients treated with 308 nm excimer laser were enrolled as Case group and 137 health examiners as Control group. Quantitative real‐time polymerase chain reaction and immunohistochemistry were conducted to detect the expressions of RORγt, BATF, and IL‐17. Expression of RORγt, BATF, IL‐17A, and IL‐17F were higher in Case group than Control group, with the diagnostic accuracy of 88.04, 87.38, 97.34, and 89.04%, respectively. Pearson correlation analysis showed a positive correlation in RORγt, BATF, IL‐17A, and IL‐17F mRNAs in vitiligo patients. Moreover, their expressions were higher in active vitiligo patients than stable ones. Besides, the expressions of RORγt, BATF, IL‐17A, and IL‐17F in vitiligo skin were significantly higher than those in non lesional skin and normal controls. After treatment, their expressions were significantly decreased. Active vitiligo and the high expressions of RORγt, BATF, and IL‐17F were the independent risk factors for the ineffectiveness of 308 nm excimer laser treatment. The expressions of RORγt, BATF, IL‐17 were significantly enhanced in vitiligo patients, which were correlated with the activity of vitiligo and 308 nm excimer laser therapeutic effects.     

Role of IL‐10 and TGF‐β in melanoma

IL‐10 and TGF‐β are immunosuppressive cytokines expressed in tumors including melanoma and, therefore, deemed major cause for failing antitumor immune responses. Re‐evaluating their role, we compared their expression by quantitative RT‐PCR in melanoma and skin of healthy individuals, tested their induction in dendritic cells and T cells co‐cultured with tumor cells, and their effects on the immune cells. Both cytokines as well as their receptors were expressed in melanoma at significantly lower levels than in healthy skin. Consequently, the expressions of IL‐10‐responsive SOCS‐3 and TGF‐β‐responsive Smad‐7 were low in tumors but high in healthy skin. T cells co‐cultured with tumor cells developed an anergic state without increased IL‐10 or TGF‐β expression. In vitro tumor‐induced immature dendritic cells produced high IL‐10 levels and less efficiently induced T‐cell proliferation. Nonetheless, they could be induced to mature, and blocking IL‐10 did not alter the capacity of the resulting mature dendritic cells to stimulate T cells. Mature dendritic cells co‐cultured with tumor cells produced increased IL‐10 but decreased TGF‐β and more efficiently induced T‐cell proliferation. The lack of correlation of IL‐10 and TGF‐β with immune deficits in situ and in vitro suggests re‐evaluating their roles in cancer.     

Increased levels of serum IL‐31 in chronic spontaneous urticaria*

Please cite this paper as: Increased levels of serum IL‐31 in chronic spontaneous urticaria. Experimental Dermatology 2010; 19: 464–466. Abstract: IL‐31 represents a novel cytokine involved in pruritic skin diseases including atopic dermatitis (AD). We, therefore, aimed at investigating IL‐31 levels in chronic spontaneous urticaria (CU). We included 46 patients with CU, 26 non‐atopic skin healthy subjects as negative and 28 patients with AD as positive controls. IL‐31 serum levels were analysed using commercial ELISA kit. IL‐31 serum levels were higher in patients with CU compared to healthy controls (P < 0.001), but lower compared to patients with AD (P < 0.001). There was no difference in IL‐31 serum levels in autologous serum skin test positive or negative CU patients and patients with infectious trigger factors including helicobacter pylori infection. IL‐31 serum levels may play a role in the pathophysiology of CU. This is supported by the finding that not all patients with CU respond to antihistamine treatment but to the treatment with immunosuppressive drugs.     

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.     

Effects of CO2 fractional laser therapy on peripheral blood cytokines in patients with vitiligo

Vitiligo is a disease pathologically characterized by specific damage to melanocytes. The aim of this study was to explore the mechanism underlying CO2 fractional laser treatment of vitiligo by detecting the levels of Th1 cytokines (IL‐2 and IFN‐γ), Th2 cytokines (IL‐4 and IL‐10), and Th17 cytokines (IL‐17 and IL‐23) in peripheral blood. Twenty five vitiligo patients were enrolled in this study and were treated with a CO2 fractional laser four to eight times. The cytokines of 25 vitiligo patients and 20 healthy volunteers were measured by enzyme‐linked immunosorbent assay. After CO2 fractional laser therapy, six cases were cured, and the apparent efficiency was 72.0% (18/25), while the efficiency was 92.0% (23/25). Before CO2 fractional laser therapy, IL‐2 and IFN‐γ levels in vitiligo patients were higher than those in the control group, but the difference was not statistically significant (p > .05). IL‐4, IL‐10, IL‐17, and IL‐23 levels were also higher in vitiligo patients than those in the control group (p < .05). After treatment, IL‐2 and IFN‐γ levels in vitiligo patients were lower than before treatment, but the difference was not statistically significant (p > .05), while IL‐4, IL‐10, IL‐17, and IL‐23 levels were significantly lower compared with before treatment (p < .05). The results show that CO2 fractional laser treatment has a good curative effect in the treatment of vitiligo.     

Analysis of interleukin-10 levels in lesions of vitiligo following treatment with topical tacrolimus

Background Vitiligo is an acquired dermatological condition that is characterized by depigmentation of patches of skin. It is relatively common, occuring in about 0·38–0·50% of the general population, and can engender significant cosmetic disfigurement and psychological sequelae in the affected individual. Recent studies demonstrate that topical tacrolimus (Protopic^®; Astellas, Markham, ON, Canada) is efficacious in the treatment of vitiligo. We propose that the successful treatment of vitiligo with topical tacrolimus involves the unique immunosuppressive actions of the T lymphocyte T‐helper (Th) 2 cytokine, interleukin (IL)‐10. Objectives We aimed to monitor clinical changes in lesions of vitiligo treated with topical tacrolimus 0·1% ointment and quantify IL‐10 cytokine levels in nonvitiliginous skin, as well as lesions of vitiligo before and following topical tacrolimus therapy. Methods Clinical evaluation of lesions of vitiligo on the basis of surface area and follicular repigmentation under Wood’s lamp was performed in 20 enrolled adult patients. Biopsy specimens were obtained from nonvitiliginous skin, as well as lesions of vitiligo before and following topical tacrolimus therapy. Specimens were processed and analysed for expression of IL‐10 using the method of enzyme‐linked immunosorbent assay. Results A statistically significant mean ± SEM decrease in vitiligo lesion size of 41·0 ± 5·2% was observed following 3 months of treatment. A pattern of follicular repigmentation was noted by the third month of treatment for all patients completing the study. In addition, there was a statistically significant difference between IL‐10 expression in vitiligo lesions following treatment for 3 months with topical tacrolimus compared with untreated vitiligo lesions (P = 0·017) and normal skin (P = 0·004). Conclusions These results confirm that topical tacrolimus is an effective treatment for vitiligo. We propose that topical tacrolimus increases IL‐10 expression in vitiligo lesions, and thereby inhibits melanocyte destruction triggered by unchecked Th1 pathways in vitiligo.     

Th17 cytokines interleukin (IL)-17 and IL-22 modulate distinct inflammatory and keratinocyte-response pathways

Background Psoriasis vulgaris is an inflammatory skin disease mediated by Th1 and Th17 cytokines, yet the relative contribution of interferon (IFN)‐γ, interleukin (IL)‐17 and IL‐22 on disease pathogenesis is still unknown. Objectives In this study, we sought to identify the cytokines produced by skin‐resident T cells in normal skin, localize the receptors for these cytokines, and examine how these cytokines alter gene expression profiles of the cells bearing cognate receptors. Methods We used intracellular cytokine staining and flow cytometry to evaluate T cell cytokine production, and immunohistochemistry and double‐label immunofluorescence to localize cytokine receptors in skin. Gene array analysis of cytokine‐treated keratinocytes was performed using moderated paired t‐test controlling for false discovery rate using the Benjamini–Hochberg procedure. Results We demonstrate that T‐helper cells producing IL‐17, IL‐22 and/or IFN‐γ, as well as the cells bearing cognate cytokine receptors, are present in normal human skin. Keratinocytes stimulated with IL‐17 expressed chemokines that were different from those induced by IFN‐γ, probably contributing to the influx of neutrophils, dendritic cells and memory T cells into the psoriatic lesion. In contrast, IL‐22 downregulated genes associated with keratinocyte differentiation and caused epidermal alterations in an organotypic skin model. Conclusions Our results suggest that the Th17 cytokines IL‐17 and IL‐22 mediate distinct downstream pathways that contribute to the psoriatic phenotype: IL‐17 is more proinflammatory, while IL‐22 retards keratinocyte differentiation.     

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.     

Role of IL‐17A receptor blocking in melanocyte survival: A strategic intervention against vitiligo

Cytokines regulate immune response and inflammation and play an important role in depigmentation process of an autoimmune disease, vitiligo. We sought to determine how inflammatory cytokines influence the progression of vitiligo, and based on that, we develop a logical therapeutic intervention using primary melanocyte culture. Melanocytes were cultured and exposed to IL‐17A, IL‐1β, IFN‐γ and TGF‐β for 4 days. Melanocytes proliferation, tyrosinase assay and melanin content were measured. Real‐Time PCR was used to analyse mRNA expression of genes specific for melanocytes growth and pigmentation. Anti‐IL‐17A receptor antibody was used to block IL‐17A receptors expressed on melanocytes. Protein expression of MITF and TYR was assessed by immunofluorescence and Western blotting. A gradual decline in the melanocyte population, melanin content and tyrosinase activity was observed after different cytokine treatment. The expression of MITF and its downstream genes after blocking with anti‐IL‐17RA, an increased melanin content, increased expression of TYR, MITF along with its downstream genes, and cell proliferation was observed.     

SLE患者外周血单个核细胞中IL-6 IL-10表达研究

目的 探讨系统性红斑狼疮（ＳＬＥ）患者中Ｔｈ２型细胞因子ｍＲＮＡ的表达。方法 用逆转录－多聚酶链反应（ＲＴ－ＰＣＲ）法检测了１０例正常人和１５例活动期ＳＬＥ患者外周血单个核细胞（ＰＢＭＣ）中白介素６（ＩＬ－６）和白介素１０（ＩＬ－１０）ｍＲＮＡ表达的水平。结果 与正常相比,活动期ＳＬＥ患者ＰＢＭＣ中ＩＬ－６和ＩＬ－１０ｍＲＮＡ的表达水平均增高（均Ｐ〈０．０１）。结论 ＳＬＥ患者中Ｔｈ２型细胞因子Ｉ     

Epidermal growth factor receptor tyrosine kinase inhibitors induce CCL2 and CCL5 via reduction in IL‐1R2 in keratinocytes

Please cite this paper as: Epidermal growth factor receptor tyrosine kinase inhibitors induce CCL2 and CCL5 via reduction in IL‐1R2 in keratinocytes. Experimental Dermatology 2010; 19 : 730–735. Abstract: Epidermal growth factor receptor tyrosine kinase (EGFR‐TK) is a transducer of mitogenic signals, and is involved in the pathogenesis and progression of a number of cancers, including non‐small cell lung cancer (NSCLC). Gefitinib is an EGFR‐TK inhibitor that is clinically used to treat NSCLC; however, this drug frequently causes adverse effects, including skin eruptions. The mechanism underlying these skin reactions is elusive, although it is assumed that they are caused by the inhibition of EGFR‐TK signalling in epidermal and adnexal cells. In this article, we demonstrate by immunocytochemistry that the skin lesions of patients treated with oral gefitinib had higher expression of CCL2 and CCL5 compared to normal human epidermis. Further, PD153035, a gefitinib prototype, induced CCL2 and CCL5 mRNA and protein expression in HaCaT and HSC‐1 keratinocyte cell lines with or without interleukin‐1 (IL‐1) treatment in vitro. PD153035 also reduced the levels of interleukin‐1 receptor 2 (IL‐1R2), an IL‐1 decoy receptor. Moreover, we demonstrate that reduction in IL‐1R2 by RNA interference increased IL‐1‐mediated CCL2 and CCL5 mRNA and protein expression. Taken together, our data strongly suggest that IL‐1‐mediated signalling is activated to induce the high expression of CCL2 and CCL5 via reduction in IL‐1R2 in the skin lesions caused by gefitinib.