Cells In Atopic Dermatitis Research Articles

The Roles of Innate Immune Cells in Atopic Dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin condition characterized by recurrent eczematous lesions and severe pruritus. The economic burden and time penalty caused by the relapse of AD reduce patients' life quality. AD has complex pathogenesis, including genetic disorders, epidermal barrier dysfunction, abnormal immune responses, microbial dysbiosis of the skin, and environmental factors. Recently, the role of innate immune cells in AD has attracted considerable attention. This review highlighted recent findings on innate immune cells in the onset and progression of AD. Innate immune cells play essential roles in the pathogenesis of AD and enough attention should be given for treating AD from the perspective of innate immunity in clinics.

Investigating Vα7.2+/CD161- T Cell and MAIT Cell Profiles Using Flow Cytometry in Healthy Subjects and Subjects with Atopic Dermatitis.

This study investigates the roles of mucosal-associated invariant T (MAIT) cells and Vα7.2+/CD161- T cells in skin diseases, focusing on atopic dermatitis. MAIT cells, crucial for bridging innate and adaptive immunity, were analyzed alongside Vα7.2+/CD161- T cells in peripheral blood samples from 14 atopic dermatitis patients and 10 healthy controls. Flow cytometry and machine learning algorithms were employed for a comprehensive analysis. The results indicate a significant decrease in MAIT cells and CD69 subsets in atopic dermatitis, coupled with elevated CD38 and polyfunctional MAIT cells producing TNFα and Granzyme B (TNFα+/GzB+). Vα7.2+/CD161- T cells in atopic dermatitis exhibited a decrease in CD8 and IFNγ-producing subsets but an increase in CD38 activated and IL-22-producing subsets. These results highlight the distinctive features of MAIT cells and Vα7.2+/CD161- T cells and their different roles in the pathogenesis of atopic dermatitis and provide insights into their potential roles in immune-mediated skin diseases.

171 Deciphering dysfunctional regultory T cells in atopic dermatitis

171 Deciphering dysfunctional regultory T cells in atopic dermatitis

Evidence for a restoration of TLR2 response in epidermal dendritic cells in atopic dermatitis by topical anti-inflammatory therapy.

Evidence for a restoration of TLR2 response in epidermal dendritic cells in atopic dermatitis by topical anti-inflammatory therapy.

Type I IFN Derived from Ly6Chi Monocytes Suppresses Type 2 Inflammation in a Murine Model of Atopic Dermatitis

The roles of innate immune cells, including eosinophils, basophils, and group 2 innate lymphoid cells, in atopic dermatitis (AD) have been well-documented, whereas that of monocytes, another component of the innate immunity, remains rather poorly understood, thus necessitating the topic of this study. In addition, cytokines and cellular pathways needed for the resolution of type 2 inflammation in AD need further investigation. Using a murine AD model, we report here that (i) Ly6Chi monocytes were rapidly recruited to the AD lesion in a CCR2-dependent manner, blockade of which exacerbated AD; (ii) type I IFN production is profoundly involved in this suppression because the blockade of it by genetic depletion or antibody neutralization exacerbated AD; and (iii) Ly6Chi monocytes operate through the production of type I IFN because Ly6Chi monocytes from Irf7-null mice, which lack type I IFN production, failed to rescue Ccr2-/- mice from severe AD upon adoptive transfer. In addition, invitro studies demonstrated type I IFN suppressed basophil expansion from bone marrow progenitor cells and survival of mature basophils. Collectively, our work suggests that Ly6Chi monocytes are the first and dominant inflammatory cells reaching AD lesions that negatively regulate type 2 inflammation through the production of type I IFN.

Preliminary studies on the role of mast cells in the phenotype and immune activation of type 2 inflammatory cytokine release of atopic dermatitis

Objective: To investigate the role of mast cells in atopic dermatitis (AD) phenotype and the immune activation of type 2 inflammatory cytokine release. Methods: Nine AD skin samples were obtained from the Department of Dermatology, the Second Affiliated Hospital of Xi'an Jiaotong University, and nine healthy skin control samples were obtained from the surgical excision of excess normal skin by orthopedic surgery, the Second Affiliated Hospital of Xi'an Jiaotong University, which were subjected to toluidine blue staining and fluorescence staining to clarify the mast cell degranulation activation status of the AD skin lesions. We investigated whether MC903 could directly activate mast cells in vivo through the toe swelling and exudation assay in wild-type mice; we constructed the MC903-AD model using wild-type and KitW-sh/W-sh mast cell-deficient mice in order to investigate whether mast cells affected the phenotype, histopathology, and the level of type 2 inflammatory factors in AD mice; we extracted mouse peritoneal mast cells and the ability of MC903 to activate mast cells to release inflammatory mediators in vitro was explored by calcium imaging, tryptase and β-aminohexokinase release assays, and MCP-1 and CXCL-2 release assays. Results: The number of degranulated mast cells in an activated state was increased in skin lesions of AD patients compared to healthy controls, with (5.40±1.14) and (2.20±0.84), respectively (P<0.001). KitW-sh/W-sh mast cell-deficient AD mice had an attenuated phenotype with ADI scores of (5.50±1.05), compared to wild-type AD mice with (10.00±0.89) (P<0.001). The release of type 2 inflammatory factors in wild-type AD mice was higher than those in KitW-sh/W-sh mast cell-deficient AD mice, with IL-4 levels of (29.50±1.87) and (15.33±1.86) pg/mg (P<0.001), IL-13 levels were (6.32±0.25) and (3.93±0.22) pg/mg (P<0.001), IL-31 levels were (9.73±0.38) and (6.89±0.27) pg/mg (P<0.001), and TSLP levels were (206.00±4.43) and (99.00±4.86) pg/mg (P<0.001), respectively. MC903 could cause mast cell activation in wild-type mice, leading to increased swelling and exudation in the toes of mice, and MC903 could activate mast cells in vitro, leading to increased degranulation and release of inflammatory factors such as MCP-1 and CXCL-2. Conclusions: The number of activated mast cells was increased in skin lesions of AD patients than in healthy controls. KitW-sh/W-sh mast cell-deficient AD mice showed significantly reduced phenotype, histopathology, and type 2 inflammatory factor levels compared with wild-type AD mice. MC903 activates mast cells in vivo and in vitro. Mast cells play a key role in AD phenotype and immune activation.

1542 Allergen sensitization status stratifies IL-31 production by memory T cells in atopic dermatitis

1542 Allergen sensitization status stratifies IL-31 production by memory T cells in atopic dermatitis

Cytokine-Mediated Crosstalk Between Keratinocytes and T Cells in Atopic Dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by barrier dysfunction, dysregulated immune response, and dysbiosis with increased Staphylococcus aureus colonization. Infiltration of various T helper cell subsets into lesional skin and subsequent cytokine release are a hallmark of AD. Release of cytokines by both T cells and keratinocytes plays a key role in skin inflammation and drives many AD features. This review aims to discuss cytokine-mediated crosstalk between T cells and keratinocytes in AD pathogenesis and the potential impact of virulence factors produced by Staphylococcus aureus on these interactions.

Innate Lymphoid Cells in Atopic Dermatitis and Psoriasis

Innate Lymphoid Cells in Atopic Dermatitis and Psoriasis

014 C1ORF162 is specifically expressed by pathogenic Th2 cells in atopic dermatitis

Pathogenic Th2 cells are a recently described subpopulation of allergen-specific Th2 cells that are crucial mediators of type 2 immune diseases such as asthma and allergic dermatitis. Understanding the unique biology of pathogenic Th2 cells holds the promise of identifying specific and novel therapeutic targets. The gene chromosome 1 open reading frame 162 (C1ORF162) has been repeatedly identified to be specifically expressed by pathogenic Th2 cells and its expression correlates with disease severity in atopic dermatitis. Yet, its function is completely unknown. Here, we characterized the cellular expression of C1ORF162 at the mRNA and protein level in primary human T cells. RNA sequencing and qPCR analysis confirmed that both in-vivo- and in-vitro- primed Th2 express higher levels of C1ORF162 than Th1 and Th17 cells. In addition, C1ORF162 expression in Th2 cells correlated with the expression of cytokines that are specifically expressed by pathogenic Th2 cells, such as IL-9 and IL-5. These findings were confirmed at the protein level by Western Blot and FACS analysis. Initial protein localization experiments and functional analyses suggest that C1ORF162 is a perinuclear protein that is rapidly downregulated by IL-2 signaling. Finally, C1ORF162 was found to be expressed by T cells infiltrating lesional skin of atopic dermatitis. In conclusion, C1ORF162 is consistently expressed in pathogenic Th2 cells and associated with disease severity in atopic dermatitis. Future experiments aim to further define the identity and function of C1ORF162 in human Th2 cells. Based on the close association of C1ORF162 with pathogenic Th2 cells, these studies may have therapeutic implications for type 2-driven disease in the skin and beyond.

Pimecrolimus interferes the therapeutic efficacy of human mesenchymal stem cells in atopic dermatitis by regulating NFAT-COX2 signaling

BackgroundHuman mesenchymal stem cells (hMSCs) therapy has recently been considered a promising treatment for atopic dermatitis (AD) due to their immunomodulation and tissue regeneration ability. In our previous studies, we demonstrated that hMSCs alleviate allergic inflammation in murine AD model by inhibiting the activation of mast cells and B cells. Also our phase I/IIa clinical trial showed clinical efficacy and safety of hMSCs in moderate-to-severe adult AD patients. However, hMSCs therapy against atopic dermatitis have had poor results in clinical field. Therefore, we investigated the reason behind this result. We hypothesized that drug–cell interaction could interfere with the therapeutic efficacy of stem cells, and investigated whether coadministration with pimecrolimus, one of the topical calcineurin inhibitors, could influence the therapeutic potential of human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) in AD.MethodshUCB-MSCs were subcutaneously injected to AD-induced mice with or without pimecrolimus topical application. To examine whether pimecrolimus influenced the immunomodulatory activity of hUCB-MSCs, hUCB-MSCs were treated with pimecrolimus.ResultsPimecrolimus disturbed the therapeutic effect of hUCB-MSCs when they were co-administered in murine AD model. Moreover, the inhibitory functions of hUCB-MSCs against type 2 helper T (Th2) cell differentiation and mast cell activation were also deteriorated by pimecrolimus treatment. Interestingly, we found that pimecrolimus decreased the production of PGE2, one of the most critical immunomodulatory factors in hUCB-MSCs. And we demonstrated that pimecrolimus downregulated COX2-PGE2 axis by inhibiting nuclear translocation of NFAT3.ConclusionsCoadministration of pimecrolimus with hMSCs could interfere with the therapeutic efficacy of hMSCs in atopic dermatitis, and this is the first study that figured out the interaction of hMSCs with other drugs in cell therapy of atopic dermatitis. Therefore, this study might give rise to improvement of the clinical application of hMSCs therapy and facilitate the widespread application of hMSCs in clinical field.

Production of IL-31 in CD45RO+CLA+H4R+ T Cells in Atopic Dermatitis.

IL-31 is involved in pruritus in atopic dermatitis (AD) and the pathogenesis of AD. However, the mechanism of IL-31 production is not fully understood. We sought to investigate the association between CD45RO+CLA+H4R+ T cells and IL-31 production. Immunofluorescence studies were performed retrospectively on punch-biopsy specimens from five people with AD and three healthy controls. In addition, blood samples were collected prospectively from eight patients with AD and eight healthy controls for sorting CD45RO+CLA+H4R+ T cells. There was no overlap of patients between the biopsy group and the blood sampling group. Sorted cells were stimulated with 4-methylhistamine (4MH), and the level of IL-31 was measured by an enzyme-linked immunosorbent assay. Immunofluorescence showed co-localization of H4R and IL-31 in lesional AD skin but not in normal skin of healthy controls. The proportion of CLA+H4R+ T cells among CD3+CD45RO+ lymphocytes was 18.3 ± 6.2% in patients with AD and 11.2 ± 7.6% in healthy controls. In the AD group, production of IL-31 by CD45RO+CLA+H4R+ T cells increased from 32.4 ± 13.3 pg/mL to 47.5 ± 18.7 pg/mL by 4MH stimulation after 24 h (p < 0.001). However, in the control group, production of IL-31 was 20.1 ± 10.6 pg/mL without and 22.1 ± 9.3 pg/mL with 4MH stimulation (p > 0.05). According to our study, CD45RO+CLA+H4R+ T cells are an important source of IL-31 in AD, and may be a target for treatment of IL-31-induced pruritus.

035 Expansion of bacterial phosphatidylglycerol reactive CD4+ T cells in atopic dermatitis

035 Expansion of bacterial phosphatidylglycerol reactive CD4+ T cells in atopic dermatitis

Keratinocytes: innate immune cells in atopic dermatitis.

The skin is a unique immune organ that constitutes a complex network of physical, chemical and microbiological barriers against external insults. Keratinocytes are the most abundant cell type in the epidermis. These cells form the physical skin barrier and represent the first line of the host defense system by sensing pathogens via innate immune receptors, initiating anti-microbial responses and producing various cytokines, chemokines and anti-microbial peptides, which are important events in immunity. A damaged epidermal barrier in atopic dermatitis allows the penetration of potential allergens and pathogens to activate keratinocytes. Among the dysregulation of immune responses in atopic dermatitis, activated keratinocytes play a role in several biological processes that contribute to the pathogenesis of atopic dermatitis. In this review, we summarize the current understanding of the innate immune functions of keratinocytes in the pathogenesis of atopic dermatitis, with a special emphasis on skin-derived anti-microbial peptides and atopic dermatitis-related cytokines and chemokines in keratinocytes. An improved understanding of the innate immunity mediated by keratinocytes can provide helpful insight into the pathophysiological processes of atopic dermatitis and support new therapeutic efforts.

Vitamin D3-Induced Promotor Dissociation of PU.1 and YY1 Results in FcεRI Reduction on Dendritic Cells in Atopic Dermatitis.

Atopic dermatitis (AD) is a severe inflammatory skin disease. Langerhans cells and inflammatory dendritic epidermal cells (IDEC) are located in the epidermis of AD patients and contribute to the inflammatory processes. Both express robustly the high-affinity receptor for IgE, FcεRI, and thereby sense allergens. A beneficial role of vitamin D3 in AD is discussed to be important especially in patients with allergic sensitization. We hypothesized that vitamin D3 impacts FcεRI expression and addressed this in human ex vivo skin, in vitro Langerhans cells, and IDEC models generated from primary human precursor cells. We show in this article that biologically active vitamin D3 [1,25(OH)2-D3] significantly downregulated FcεRI at the protein and mRNA levels of the receptor's α-chain, analyzed by flow cytometry and quantitative RT-PCR. We also describe the expression of a functional vitamin D receptor in IDEC. 1,25(OH)2-D3-mediated FcεRI reduction was direct and resulted in impaired activation of IDEC upon FcεRI engagement as monitored by CD83 expression. FcεRI regulation by 1,25(OH)2-D3 was independent of maturation and expression levels of microRNA-155 and PU.1 (as upstream regulatory axis of FcεRI) and transcription factors Elf-1 and YY1. However, 1,25(OH)2-D3 induced dissociation of PU.1 and YY1 from the FCER1A promotor, evaluated by chromatin immunoprecipitation. We show that vitamin D3 directly reduces FcεRI expression on dendritic cells by inhibiting transcription factor binding to its promotor and subsequently impairs IgE-mediated signaling. Thus, vitamin D3 as an individualized therapeutic supplement for those AD patients with allergic sensitization interferes with IgE-mediated inflammatory processes in AD patients.

Elevated NK-cell transcriptional signature and dysbalance of resting and activated NK cells in atopic dermatitis

Altered quantities, activity, and composition of natural killer (NK) cells in blood as well as expression changes of genes involved in NK-cell function in skin lesions of patients with atopic dermatitis (AD) were recently reported. We sought to comprehensively analyze cutaneous NK-cell transcriptomic signatures in AD, and to examine changes under treatment. We analyzed NK-cell signatures in skin transcriptome data from 57 patients with moderate to severe AD and 31 healthy controls. In addition, changes after 12 weeks of systemic treatment (dupilumab n= 21, cyclosporine n= 8) were analyzed. Deconvolution of leucocyte fractions was conducted. Immunofluorescence staining of NK cells was performed on paraffin-embedded skin sections. Immunofluorescence staining revealed a relatively high abundance of both NK cells and CD3+CD56+ cells in lesional as compared with nonlesional and healthy skin. Lesional and to a lesser extent nonlesional skin showed a strong upregulation of NK-cell markers together with a dysbalanced expression of inhibitory and activating receptors, which was not reverted under treatment. Digital cytometry showed a decrease in activated and an increase in resting NK cells in both lesional and nonlesional skin, which was reverted by both treatment with dupilumab and cyclosporine. The NK-cell transcriptomic signature remained upregulated after treatment, but there was a shift on the qualitative level, indicating a compositional change in NK-cell subsets toward CD56bright NK cells. Lesional AD skin shows a NK-cell dysregulation, which despite clinical improvement under systemic therapy was only partially reverted, and which may represent a yet underappreciated disease mechanism.

JAK1/2 inhibition impairs the development and function of inflammatory dendritic epidermal cells in atopic dermatitis

Janus kinase (JAK) inhibitors are a new class of therapeutic compounds for dermatological diseases. In atopic dermatitis (AD), data of clinical phase III trials show rapid improvement of pruritus and significant reduction of inflammation within the first weeks with a favorable safety profile. However, their mode of action in AD is not fully understood. In our study, we investigate the effect of different JAK inhibitors on cell differentiation, phenotype, and function of inflammatory dendritic epidermal cells (IDECs). We analyzed the JAK expression in IDEC from exvivo skin and invitro generated IDECs using flow cytometry and PCR. Further, we studied invitro the effect of different JAK inhibitors on IDEC cell differentiation, phenotype, and maturation. IDECs express JAK1 and JAK2 exvivo and invitro. We found that JAK1 and JAK2 were upregulated during the differentiation from monocytes to IDECs. Conversely, JAK2 inhibition by ruxolitinib (JAK1/2 inhibitor) or BMS-911543 (JAK2 inhibitor) abrogated the differentiation from monocytes into IDECs. Differentiated IDECs can redifferentiate into a more monocyte-like phenotype in the presence of ruxolitinib or BMS-911543. Furthermore, we showed that concomitant inhibition of JAK1/2 rather than blocking JAK1 or JAK2 alone, impaired maturation and the release of proinflammatory cytokines on lipopolysaccharide stimulation. Our results suggest that inhibition of JAK1/2 impairs IDEC differentiation and function. We provide new insight into the mode of action of JAK inhibitors in AD and highlight the role of JAK1/2 inhibitors for the treatment of patients with AD.

Characterization of CD19+ CD24hi CD38hi B cells in Chinese adult patients with atopic dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Human interleukin-10+ B cells (B10 cells) is one of regulatory B cells and is enriched in CD19+ CD24hi CD38hi B cells. A little is known about these cells in atopic dermatitis. To study CD19+ CD24hi CD38hi B cells and their clinical significance in Chinese adult patients with atopic dermatitis. Thirty-two adult patients with AD and nineteen healthy controls were enrolled. Peripheral blood mononuclear cells (PBMCs) were isolated and stained with fluorescein-conjugated monoclonal antibodies for CD19, CD24, CD27, CD38 and Annexin V. The stained PBMCs were analysed by flow cytometry. B10 cells were prepared by stimulating PBMCs with CpG, LPS and CD40L followed by restimulation with phorbol12-myristate 13-acetate (PMA) and ionomycin. Serum IL-10, B-cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL) levels were measured by using the ELISA. Apoptosis and proliferation of CD19+ CD24hi CD38hi B cells were measured by flow cytometry. 4/P-signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase 1/2 (Erk) phosphorylation were also studied. The number of CD19+ CD24hi CD38hi B cells in patients with AD was similar to that in healthy controls. However, B10 cells were decreased in patients with AD. The proportion of B10 cells was negatively associated with blood basophil counts but not associated with disease activity. CD19+ CD24hi CD38hi B cells from AD patients were more susceptible to apoptosis upon stimulation with CpG, LPS and CD40L. B cells from AD patients showed lower STAT3 and Erk phosphorylation. CD19+ CD24hi CD38hi B cells were unchanged in atopic dermatitis while B10 cells were decreased. The increased B-cell apoptosis, decreased STAT3 and Erk phosphorylation might contribute to these changes.

Tu1510 LYMPHOCYTIC GASTRITIS AND ASSOCIATION WITH ATOPIC SYMPTOMS: A CASE SERIES

Lymphocytic gastritis is rare, characterized by >25 intraepithelial lymphocytes per 100 epithelial cells, specifically CD8+ T-cells. Prevalence has been reported as <0.3%. Little is known about the pathophysiology, however up to 80% may be found with Helicobacter pylori infections or celiac disease. Endoscopically, the gastric mucosa is classically described as nodular with hypertrophied rugae, with or without erosions and plaques. Lymphocytic gastritis is a histologic diagnosis and when encountered, clinical management is ill-defined. We sought to identify clinical characteristics of this disease. Patients with histological diagnosis of lymphocytic gastritis were identified from January 2007 to August 2019 at our tertiary-care, medical center. Each patient’s chart was reviewed. Demographic information, medical history and outcomes, medications, endoscopic findings, and pathologic results were recorded. Serologic tests for human immunodeficiency virus (HIV) were reviewed. Serologic or duodenal biopsies were used to screen for celiac disease. Twenty-six patients were identified with lymphocytic gastritis. Fifty percent were male and age ranged from 2 years to 77 years, averaging 49 years at time of upper endoscopy. Atopy (e.g. asthma, allergies, or eczema) was noted in 46% of patients. Five (19%) patients had history of autoimmune disorders. The most common indications for upper endoscopy included abdominal pain (30%) and anemia (23%). Fifteen percent of the patients had concomitant Helicobacter pylori infections based on gastric biopsies. Low proportions of patients were tested for celiac disease (50%) and HIV (26.9%); none were positive. Endoscopically, 75% had erythema and erosions and only 20% demonstrated the classically described nodular mucosa. Histologically, lymphocytic gastritis was commonly seen with chronic inflammation (65.4%). Among the 11 patients with duodenal biopsies, 36.4% had increased lymphocytes in the duodenum. Nearly half of the patients in our case series were noted to have atopy. Although lymphocytes are not typically associated with atopic illnesses, there are several studies elucidating the roles of CD4+ and CD8+ T cells in relation to eosinophils and mast cells in atopic dermatitis and asthma. Current management revolves around symptom control, however, further studies are needed to evaluate the implications of this pathological finding.Demographic information, clinical history, endoscopic findings, and pathologic results of patients diagnosed with lymphocytic gastritis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

The Th2 cytokine IL-4 mediates loss of skin γδT cells in atopic dermatitis

Abstract Atopic dermatitis (AD) is a common Th2-biased chronic inflammatory skin disease. Major clinical manifestations include erythema, severe itchiness, and dry skin that impose a burden on patients and impairs their quality of life. Extensive research has been conducted to identify possible underlying mechanisms and develop therapeutic approaches. γδT cells, an understudied T cell population, play important roles in maintaining skin integrity in both human and mice. They are among the first responders to epithelial wounding and are a source of keratinocyte/fibroblast growth factors that promote wound repair. Hence, we wanted to investigate their behavior during wounding in an AD-like environment. Using a mouse model, we observed that γδT cell numbers are drastically decreased in atopic skin. Multiple factors contribute to this decrease, including insufficient activation, less proliferative capacity and increased cell death. These changes in γδT cell function are IL-4 dependent. Administration of IL-4 to wild type (WT) mice resulted in significant loss of γδT cells, and Il4−/− mice in the AD model showed numbers of γδT cells similar to WT controls. We further observed that the levels of keratinocyte/fibroblast growth factors are lower in AD animals, suggesting that loss of γδT cells could compromise re-epithelialization and repair following wounding. Collectively, our data indicate that in an atopic environment, γδT cells decrease drastically in an IL-4 dependent fashion, which may contribute to the aberrant wound healing process in AD animals.