Coexpression of CCR6 and CD146 (MCAM) is a marker of effector memory T-helper 17 cells

Effector memory T (T_EM) cells are a subpopulation of memory T cells that express receptors mediating migration to inflamed tissues and produce various cytokines. Effector memory T‐helper (Th)17 (Th17_EM) cells are thought to be essential for inflammation in Th17‐mediated diseases, but have not been studied in detail. To identify superior surface markers to isolate a homogeneous population of Th17_EM cells from peripheral blood, CD4⁺ T cells were isolated from the peripheral blood of healthy donors based on the expression of CCR7, CCR6 and CD146 using six‐color flow cytometry. After 4 days of culture in the presence of anti‐CD3/28 beads, intracellular cytokines were determined by flow cytometric analysis. To investigate the relevance of Th17_EM cells in Th17‐mediated disease, the frequencies of T_EM‐cell subsets in psoriasis were quantified using six‐color flow cytometry. An enzyme‐linked immunosorbent assay was performed to confirm the interleukin (IL)‐17‐producing capacity of T_EM‐cell subsets from the peripheral blood of a patient with psoriasis. CCR6⁺CD146⁺ T_EM (CD4⁺CD45RA^?CCR7^?) cells had a greater capacity to produce IL‐17 than CCR6⁺CD146^? or CCR6^?CD146⁺ T_EM cells. Although the percentage of CCR6⁺CD146⁺ cells in T_EM cells was not significantly different between patients with psoriasis and controls, three of eight patients had a higher percentage of CCR6⁺CD146⁺ T_EM cells than the mean +5 standard deviations of the controls. Coexpression of CCR6 and CD146 is a useful marker for Th17_EM cells. Increasing the number of CCR6⁺CD146⁺ Th17_EM cells in peripheral blood may facilitate estimation of systemic Th17‐cell activity in Th17‐mediated diseases.     

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‐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.     

Decrease in circulating Th17 cells correlates with increased levels of CCL17, IgE and eosinophils in atopic dermatitis

Background

Clinical significance of circulating CD4⁺ T cell subsets, including T-helper (Th)1, Th2, Th17 and regulatory T (Treg) cells, in patients with atopic dermatitis (AD) remains unclear. No previous studies have simultaneously evaluated the four T cell subset profiles in AD.

Objective

The aim of the present study was to explore whether the percentage of these four subsets of CD4⁺ T cells correlate to the severity parameters of AD patients.

Methods

Intracellular expression of interferon (IFN)-γ, interleukin (IL)-4, IL-17 and forkhead box P3 (Foxp3) in CD4⁺ T cells was evaluated in peripheral blood mononuclear cells from normal controls and patient with AD as well as with chronic eczema using a flow cytometer. Serum CCL17 levels were measured as an objective severity parameter of AD together with percentage of eosinophils and serum IgE levels.

Results

In AD patients, the number of Th1 (IFN-γ⁺) and Th17 (IL-17⁺) subsets was significantly decreased, but that of Th2 (IL-4⁺) and Treg (Foxp3⁺) subsets was similar to that of normal controls. The T cell subset profiles of patients with chronic eczema were not different with those of normal controls. The frequency of Th17cells, particularly that of the IFN-γ^negaIL-17⁺ subset, showed a significant negative correlation with CCL17, IgE and eosinophil levels in AD patients. This was, however, not the case in Th1, Th2 and Treg cells.

Conclusion

Decreased circulating Th17 cells might contribute to activity of AD.     

特应性皮炎与Th17的研究进展

特应性皮炎是一种慢性复发性、炎症性皮肤疾病,病因复杂,涉及环境、基因及免疫之间的相互作用,其中免疫因素为特应性皮炎发病的重要原因之一。Th17作为一个不同于Th1和2的CD4＋T细胞亚群,已经证实,在特应性皮炎发生发展中起重要的作用。Th17通过分泌白介素-17、21、22等细胞因子诱发炎症反应及免疫反应,参与特应性皮炎发病的免疫学机制。通过物理治疗、药物治疗等手段,可以靶向抑制Th17及相关细胞因子,对治疗特应性皮炎有一定疗效。     

Subcutaneous administration of polymerized type I collagen downregulates interleukin (IL)-17A, IL-22 and transforming growth factor-β1 expression, and increases Foxp3-expressing cells in localized scleroderma

Background. Localized scleroderma (LS) is a disfiguring inflammatory autoimmune disease of the skin and underlying tissue. As in systemic sclerosis, a key feature is the presence of T cells in inflammatory lesions. Aim. To evaluate the effect of polymerized type I collagen vs. methylprednisolone (MP) in LS, and to determine the influence of this polymerized collagen (PC) on CD4+ peripheral T cells expressing interleukin (IL)‐4, IL‐17A, interferon‐γ and Forkhead box protein (Foxp)3, and on cells expressing transforming growth factor (TGF)‐β1, IL‐17A, IL‐22 and Foxp3 in the skin. Methods. In total, 16 patients with LS were treated for 3 months with monthly subcutaneous intralesional injections of 0.1 mL MP (giving a total dose of 20 mg/mL each month) and 15 patients were treated, with weekly subcutaneous intralesional injections of PC, ranging from 0.2 mL (equivalent to 1.66 mg collagen) for a lesion of 50 mm in size, up to a maximum of 1.0 mL (8.3 mg collagen) for a lesion > 100 mm in size, and followed up for a further 6 months. Skin biopsies were obtained from lesions at baseline (before treatment) and 9 months later (6 months after treatment end). Tissue sections were evaluated by histology and immunohistochemistry (IL‐17A, IL‐22, TGF‐β1 and Foxp3). CD4+ T‐cell subsets were determined in peripheral blood by flow cytometry. Results. Abnormal tissue architecture was seen in the biopsies taken from patients treated with MP, whereas the PC treatment restored normal skin architecture. PC downregulated pro‐inflammatory/profibrotic cytokine expression in peripheral cells, and upregulated the number of regulatory T cells (Tregs) in skin. PC was safe and well tolerated. Conclusions. PC is not only an antifibrotic/fibrolytic agent but also an immunomodulator biodrug that restores the balance between T helper (Th)1, Th2, Th17 and Tregs, downregulates production of pro‐inflammatory or profibrogenic cytokines (IL‐17A, IL‐22 and TGF‐β1), and renews skin architecture, without adverse effects.     

Gene–gene interactions in IL23/Th17 pathway contribute to psoriasis susceptibility in Chinese Han population

Background Psoriasis is a common chronic inflammatory skin disease. IL23/Th17 is a newly confirmed pathway in psoriasis. Objective To investigate the gene–gene interactions in IL23/Th17 pathway underlying psoriasis. Methods A total of 299 single‐nucleotide polymorphisms from 11 genes in IL23/Th17 pathway were genotyped on 1139 patients with psoriasis and 1694 controls. Multifactor dimensionality reduction and logistic regression algorithms were applied to explore the gene–gene interactions. Results We found that there were a three‐way interaction among IL21, CCR4 and TNF(χ² = 5.02(1), P = 0.025) and three pair‐wise gene–gene interactions between IL12RB1 and CCR4(χ² = 11.66(4), P = 0.0201), IL22 and CCR4 (χ² = 11.97(4), P = 0.0176), IL12RB1 and IL6 (χ² = 7.31(1), P = 0.0069) in psoriasis. Conclusions Our results might be helpful for explaining the missing heritability of the psoriasis due to epistasis and provide a deep insight into the important role of the IL23/Th17 pathway in the pathogenesis of psoriasis.     

Characterization of the T cell response in allergic contact dermatitis caused by corticosteroids

Background Delayed allergic hypersensitivity reactions have classically been described as type IV reactions, which are caused by T cells; however, the respective roles of CD4⁺ and CD8⁺ cells are yet to be defined. A central role for CD8⁺ cytotoxic T cells as effector cells has been suggested. Objectives To determine the type of T cell involved in corticosteroid allergy. Methods We analysed the kinetics of T cell recruitment and the cytokine production profile in positive patch tests of 27 corticosteroid‐sensitized patients, as compared with control sites and control subjects. Skin biopsies, collected at 8, 24 and 48 hr following drug application, were embedded in paraffin for histological and immunohistological staining, and, in some cases, also deep‐frozen for gene expression analyses. Results CD3⁺ T cells were rapidly recruited in concert with the positivity of the patch test sites. High levels of interleukin (IL)‐4, IL‐5 and, to a lesser extent, interferon‐γ suggested that both Th2 and Th1 cytokines were implicated. IL‐4 was also produced by γδ T cell receptor (TCR) lymphocytes. Conclusions This study showed that, in allergic contact dermatitis caused by corticosteroids, the inflammatory infiltrate is composed of CD3⁺ T cells with a predominant Th2 cytokine profile, among which IL‐4 is also produced by γδ TCR lymphocytes.     

Mechanism of pathogenesis of imiquimod‐induced skin inflammation in the mouse: A role for interferon‐alpha in dendritic cell activation by imiquimod

Topical application of imiquimod (IMQ), a Toll‐like receptor (TLR)7 ligand, can induce and exacerbate psoriasis, a chronic inflammatory skin disorder. In a mouse model of IMQ‐induced psoriasis‐like skin inflammation, T‐helper (Th)17 cells and interleukin (IL)‐17/IL‐22‐producing γδ‐T cells have been shown to play a pivotal role. However, the mechanisms of induction of the Th17 pathway and development of psoriasis‐like skin inflammation by IMQ treatment remain unclear. In this study, we investigated pathogenic mechanisms of IMQ‐induced psoriasis‐like skin inflammation in mice. We first confirmed that, together with an increase in IL‐17 and IL‐22 production, application of IMQ to mouse skin induced the expression of cytokines required for activation of the Th17 pathway, and pro‐inflammatory mediators involved in the pathology of psoriasis. Analysis of Tlr7^?/? mice demonstrated that most of the in vivo effects of IMQ were mediated via TLR7. In an in vitro study using plasmacytoid dendritic cells (DCs), IMQ induced production of interferon (IFN)‐α, IL‐23, IL‐6 and tumor necrosis factor (TNF)‐α. Furthermore, when we analyzed in vitro‐generated bone marrow‐derived DCs with features similar to TNF‐α and inducible nitric oxide synthase (iNOS)‐producing DCs, IL‐23, IL‐6, IL‐1β, TNF‐α and iNOS/NO production was weakly induced by IMQ alone and further enhanced after co‐stimulation with IMQ and IFN‐α. These in vitro effects of IMQ were also mediated via TLR7 and the synergistic effect of IMQ, and IFN‐α was suggested to be caused by upregulation of TLR7 expression by IFN‐α. These results demonstrate part of the mechanism by which the Th17 pathway and psoriasis‐like skin inflammation are induced by IMQ and IFN‐α in a mouse model.     

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.     

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.     

Attenuation of contact hypersensitivity by cell‐permeable heat shock protein 70 in BALB/c mouse model

 In contact hypersensitivity (CHS), multiple cells, inflammatory mediators and cytokines are known to be involved in the regulation of the immune response. Previously, we revealed the reactive oxygen species generation by 2, 4, 6‐trinitrobenzene sulphonic acid (TNBS) in vivo, followed by heat shock protein 70 (Hsp70) carbonylation and the exogenous antioxidant role of cell‐permeable Hsp70. Here, we demonstrate the role of Hsp70 using cell‐permeable Hsp70 in the mouse CHS model. Pretreatment of cell‐permeable Hsp70: (i) suppressed ear swelling; (ii) down‐regulated phosphorylated p38, but up‐regulated phosphorylated extracellular signal‐regulated kinase; (iii) increased population of CD4⁺CD25⁺Foxp3⁺ T cells; (iv) decreased secretion of tumor necrosis factor‐α (TNF‐α), IL‐12, interferon‐γ and IL‐2 and (v) but up‐regulated IL‐4 and transforming growth factor beta (TGF‐β) in the lymph nodes. In conclusion, cell‐permeable Hsp70 attenuates CHS through modulation of MAPK pathway and regulation of Th1, Th2 and regulatory T cells.     

Impaired T‐cell‐dependent protection against Leishmania major infection in HIV‐positive patients is associated with worsened disease outcome

Cutaneous leishmaniasis (CL) patients coinfected with HIV are known to show a more severe, prolonged course of disease; the immunological basis is not known. We now assessed clinical features, sera and skin biopsies of HIV⁺ and HIV^? patients with CL to identify drivers of increased susceptibility to Leishmania. CL lesion numbers, surface, and healing duration were significantly increased in HIV⁺ as compared to HIV^? patients (2.5, 14 and >4‐fold, respectively). Patients with HIV infection exhibited lower serum Leishmania‐specific IgG levels and decreased IL‐6 and IL‐8. Most importantly, dramatically decreased numbers of CD4⁺ T cells (approximately eightfold), but not CD8⁺ cells, together with fewer CXCR3⁺ Th1 cells, fewer Foxp3⁺ effector/regulatory T cells, and reduced levels of IFN‐γ expression were found in lesional skin. Our findings suggest that compromised CD4⁺ T‐cell responses may be responsible for worsened disease outcome leading to defects in parasite elimination in the absence of sufficient numbers of IFN‐γ‐producing Th1 cells.     

Increased circulating Th17 frequencies and serum IL‐22 levels in patients with acute generalized exanthematous pustulosis

Background/Objective Acute generalized exanthematous pustulosis (AGEP) is a diffuse pustular disorder that usually begins in intertriginous folds with widespread erythema. The causes in the majority of the cases are drugs. T cells and interleukin (IL)‐8 play roles in the development of AGEP, but the mechanism remains to be elucidated. We investigated the involvement of Th17 cells and their cytokine IL‐22 in the pathogenesis. Methods Three patients with AGEP were enrolled in this study. The percentages of IL‐17⁺ Th17 cells, interferon γ⁺ T cells and IL‐4⁺ T cells were measured in the patients’ peripheral blood lymphocytes by intracellular cytokine staining and flow cytometry. The concentration of IL‐22 in the sera was measured by enzyme‐linked immunosorbent assay. Results The percentages of Th17 cells were markedly higher in all three patients than healthy control individuals. The frequencies of interferon γ⁺ T cells were slightly high in the patients compared with the control, and there was no definite tendency in IL‐4⁺ T‐cell frequencies. The concentration of IL‐22 was remarkably high in all patients when compared with normal subjects with levels under detection. Conclusion Th17 cells and their produced cytokine IL‐22 were elevated in the peripheral blood of patients with AGEP. As IL‐17 and IL‐22 cooperatively stimulate keratinocytes to produce IL‐8, IL‐8 may contribute to the accumulation of neutrophils in the lesional epidermis of AGEP.     

Primary human keratinocytes efficiently induce IL‐1‐dependent IL‐17 in CCR6+ T cells

Abstract: Keratinocytes and activated T cells interact in skin inflammation by virtue of chemokines and cytokines. T cell‐derived IL‐17 has been described to play an important role in the course of psoriatic inflammation. In this study, we addressed how keratinocytes influence the secretion of IL‐17 in autologous T cell subsets. We found that a co‐culture of autologous keratinocytes and T cell‐receptor‐stimulated T cells markedly enhanced the production of IL‐17. Besides the importance of direct cell contact, this effect was mainly mediated by IL‐1 and could be blocked by the IL‐1 antagonist anakinra. An additional increase in IL‐17 production by IL‐23 was only seen in the presence of IL‐1, which thus plays a permissive role for the action of IL‐23. Importantly, co‐culture of keratinocytes with CCR6+ CD4+ T cells that are enriched for Th17 cells resulted in significantly higher IL‐17 production compared to co‐culture with CD4+ T cells.     

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.     

Expression of interleukin-17 is correlated with interferon-α expression in cutaneous lesions of lupus erythematosus

Background. Type I interferon (IFN) has been reported to have an important role in the development of cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE). A new subset of CD4+ T cells, T helper (Th)17 cells, also plays a role in the development of autoimmunity. Aim. To investigate expression of interleukin (IL)‐17 and IFN‐α in different CLE subsets, and their associations with the pathogenesis of LE. Methods. Skin tissue samples from 33 cases, including chronic discoid LE (n = 24), acute (A)CLE (n = 4), subacute CLE (n = 1) and lupus panniculitis (n = 4) were collected for immunohistochemistry. Expression of IL‐6, IL‐17A, IFN‐α, IFN‐γ, myxovirus protein (Mx)A and transforming growth factor (TGF)‐β was assessed in these samples. Results. All LE specimens had staining for IL‐6 and TGF‐β in the infiltrated inflammatory cells. IL‐17A staining was seen in 84.8% of specimens, and IFN‐α or MxA was seen in 93.9%. TGF‐β expression in ACLE was significantly greater than that in both chronic cutaneous (CC)LE and in lupus panniculitis (P = 0.02 for both). Expression of IL‐17A was positively associated with expression of IFN‐α and MxA (Spearman’s ρ = 0.56 and 0.39, respectively). In addition, the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) correlated positively with expression of IFN‐α and MxA (ρ = 0.40 for both), whereas there was no correlation with IL‐17A expression. Conclusions. Two major cytokines, IL‐17A and IFN‐α, may play roles in the pathogenesis of CLE. Their patterns of expression positively correlated with each other.     

Serum Th1/Th2 and macrophage lineage cytokines in leprosy; correlation with circulating CD4+ CD25highFoxP3+ T‐regs cells

Not only macrophages, T‐helper (Th)1 and Th2, but also CD4⁺ CD25^highFoxP3⁺ regulatory T cells (T‐regs) are involved in immune response to Mycobacterium leprae. We aimed to evaluate serum interleukin (IL)‐1β and IL‐12p70 (macrophage cytokines), interferon‐γ (IFN‐γ) (Th1 cytokine), IL‐4 (Th2 cytokine) and circulating CD4⁺ CD25^highFoxP3⁺ T‐regs, in untreated leprosy patients. Forty three patients and 40 controls were assessed for the mentioned cytokines using ELISA. Patients were assessed for circulating T‐regs using flow cytometry. Patients were subgrouped into tuberculoid (TT), pure neural leprosy (PNL), borderline cases, lepromatous (LL), type 1 reactional leprosy (RL1) and erythema nodosum leprosum (ENL). Serum IL‐12p70, IFN‐γ and IL‐4 were significantly higher in patients versus controls (P < 0.05). Serum IL‐4 was highest in LL and lowest in RL1 (P = 0.003). Serum IL‐1β levels was significantly higher in multibacillary versus paucibacillary patients (P = 0.006). Significantly higher T‐regs levels was detected in TT, RL1 and PNL, while the lowest levels in ENL(P < 0.001), with significant differences versus controls (P < 0.05). FoxP3 expression% was significantly lower in PNL than other patients and controls (P < 0.05). T‐regs/T‐effs was lowest in ENL(P < 0.05). IFN‐γ correlated positively with T‐regs but negatively with IL‐1β (P = 0.041&0.046 respectively), which correlated positively with T‐effs%( P = 0.05). IL‐4 correlated positively with T‐regs FoxP3 expression% (P = 0.009). We concluded that: Circulating T‐regs were increased in TT, RL1 and PNL patients, known of relatively high cell‐mediated immunity. This finding was supported by low FoxP3 expression (in PNL) and correlation between T‐regs count and IFN‐γ level. Overproduction of IL‐4 in LL may infer liability to develop ENL, with disease progression and immune hyperactivation, marked by deficient T‐regs and increased T‐regs FoxP3 expression%. IL‐1β probably has a pro‐inflammatory role in multibacillary patients as correlated with T‐effs%.     

Biomarkers of alopecia areata disease activity and response to corticosteroid treatment

Alopecia areata (AA) is a common inflammatory disease targeting the anagen‐stage hair follicle. Different cytokines have been implicated in the disease profile, but their pathogenic role is not yet fully determined. We studied biopsies of pretreatment lesional and non‐lesional (NL) scalp and post‐treatment (intra‐lesional steroid injection) lesional scalp of 6 patchy patients with AA using immunohistochemistry and gene expression analysis. Immunohistochemistry showed increases in CD3⁺, CD8⁺ T cells, CD11c⁺ dendritic cells and CD1a⁺ Langerhans cells within and around hair follicles of pretreatment lesional scalp, which decreased upon treatment. qRT‐PCR showed in pretreatment lesional scalp (compared to NL) significant increases (P < 0.05) in expression of inflammatory markers (IL‐2, IL‐2RA, JAK3, IL‐15), Th1 (CXCL10 and CXCL9), Th2 (IL‐13, CCL17 and CCL18), IL‐12/IL‐23p40 and IL‐32. Among these, we observed significant downregulation with treatment in IL‐12/IL‐23p40, CCL18 and IL‐32. We also observed significant downregulation of several hair keratins in lesional scalp, with significant upregulation of KRT35, KRT75 and KRT86 in post‐treatment lesional scalp. This study shows concurrent activation of Th1 and Th2 immune axes as well as IL‐23 and IL‐32 cytokine pathways in lesional AA scalp and defined a series of response biomarkers to corticosteroid injection. Clinical trials with selective antagonists coupled with cytokine‐pathway biomarkers will be necessary to further dissect pathogenic immunity.