T-regulatory cells in severe atopic dermatitis: alterations related to cytokines and other lymphocyte subpopulations

IL-4-induced decrease in both the number and CTLA-4 expression of Treg impairs suppression of Th2 type inflammation in severe atopic dermatitis

BACKGROUND

Treg plays a pivotal role in the suppression of Th2 cell and the maintenance of immune homeostasis. The precise molecular mechanism underlying the disruption of Treg suppression of Th2 cell and the promotion of Th2 type inflammation in allergic diseases remains elusive.

OBJECTIVE

This study aims to investigate the molecular mechanism underlying quantitative and functional changes of Treg in AD.

METHODS

The molecular mechanism was investigated using flow cytometry, mRNA sequencing, co-culture experiments, co-immunoprecipitation, chromatin immunoprecipitation, and bisulfite sequencing in vitro or in AD mice model and patients with AD.

RESULTS

Increased proportion of Treg was detected in mild and moderate AD. Conversely, characteristic decrease in both the number and CTLA-4 expression of Treg was relevant to serum IL-4 level in severe AD patients, which was verified under a high concentration of IL-4 treatment in vitro. The underlying mechanism is that IL-4/pSTAT6 pathway recruits DNMT1 and HDAC2 to inhibit transcriptional regulation of Foxp3 and CTLA-4 loci. High level of IL-4 impaired the suppression of Treg against Th2 cell differentiation mediated by CTLA-4, and blockade of IL-4Rα signaling in Treg restored Treg number and suppression of Th2 cell in AD model mice and patients with AD.

CONCLUSION

The number of Treg is relevant to stratification of severity and serum IL-4 level in patients with AD. Abnormal high level of IL-4 epigenetically triggers a decrease in both the number and CTLA-4 expression of Treg. The reduced expression of CTLA-4 on Treg induced by IL-4 impairs suppression of Th2 cell differentiation.

Mechanism underlying polyvalent IgG-induced regulatory T cell activation and its clinical application: Anti-idiotypic regulatory T cell theory for immune tolerance

The regulatory T (Treg) cells constitute a functionally defined subpopulation of T cells that modulate the immune system and maintain immune tolerance through suppression of the development of autoimmune responses to self-antigens and allergic reactions to external antigens. Reduction in the number or function of Treg cells has been suggested as a key immune abnormality underlying the development of autoimmune and allergic diseases. In vitro studies have demonstrated that purified polyvalent immunoglobulin G (IgG) from multiple healthy blood donors can exert immunomodulatory effects on Treg cells. Incubation of polyvalent human IgG with purified CD4+CD25high T cells increased the intracellular expression of interleukin (IL)-10. Intravenous administration of polyvalent human IgG induced significant expansions of CD4+ Foxp3+ Treg cells and clinical improvements in patients with autoimmune diseases. In human clinical trials, intramuscular administration of autologous total IgG significantly increased the percentage of IL-10-producing CD4+ Treg cells in the peripheral blood of healthy subjects and provided significant clinical improvements in patients with atopic dermatitis. These results suggest a clinical usefulness of polyvalent IgG-induced activation of Treg cells in human subjects. This review proposes a new hypothesis for immune tolerance mechanism by integrating the pre-existing "idiotypic network theory" and "Treg cell theory" into an "anti-idiotypic Treg cell theory." Based on this hypothesis, an "active anti-idiotypic therapy" for allergic and autoimmune diseases using autologous polyvalent IgG (as immunizing antigens) is suggested as follows: (1) Intramuscular or subcutaneous administration of autologous polyvalent IgG produces numerous immunogenic peptides derived from idiotypes of autologous IgG through processing of dendritic cells, and these peptides activate anti-idiotypic Treg cells in the same subject. (2) Activated anti-idiotypic Treg cells secrete IL-10 and suppress Th2 cell response to allergens and autoimmune T cell response to self-antigens. (3) These events can induce a long-term clinical improvements in patients with allergic and autoimmune diseases. Further studies are needed to evaluate the detailed molecular mechanism underlying polyvalent IgG-induced Treg cell activation and the clinical usefulness of this immunomodulatory therapy for autoimmune and allergic diseases.

Antigen-specific T cell balance reveals Why patients with atopic dermatitis fail to achieve immune tolerance

The number of regulatory T cells (Tregs) and how they behave in the pathogenesis of atopic dermatitis (AD) are still controversial. We identified and quantified Tregs, mite-specific Tregs, and mite-specific effector T cells (Teffs) in patients with AD and healthy controls (HCs). We collected peripheral blood and analyzed the cells using flow cytometry after stimulation with mite antigens. Mite-specific Tregs and mite-specific Teffs were recognized by the expression of CD137 and CD154, respectively. Patients with AD had more Tregs than HCs; however, when focusing on a single antigen, the ratio of mite-specific Tregs/Teffs was lower in patients with AD than in HCs. Furthermore, the mite-specific Teffs in patients with AD were more likely to produce proinflammatory cytokines interleukin (IL)-4 and IL-13. This Teff-dominant imbalance is thought to be the cause of development of atopic status in patients with AD without immune tolerance.

Immune Profiling of Dermatologic Adverse Events from Checkpoint Blockade using Tissue Cyclic Immunofluorescence

In this study, we demonstrate the utility of whole-slide CyCIF (tissue-based cyclic immunofluorescence) imaging for characterizing immune cell infiltrates in immune checkpoint inhibitor (ICI)-induced dermatologic adverse events (dAEs). We analyzed six cases of ICI-induced dAEs, including lichenoid, bullous pemphigoid, psoriasis, and eczematous eruptions, comparing immune profiling results obtained using both standard immunohistochemistry (IHC) and CyCIF. Our findings indicate that CyCIF provides more detailed and precise single-cell characterization of immune cell infiltrates than IHC, which relies on semi-quantitative scoring by pathologists. This pilot study highlights the potential of CyCIF to advance our understanding of the immune environment in dAEs by revealing tissue-level spatial patterns of immune cell infiltrates, allowing for more precise phenotypic distinctions and deeper exploration of disease mechanisms. By demonstrating that CyCIF can be performed on friable tissues, such as bullous pemphigoid, we provide a foundation for future studies to examine the drivers of specific dAEs using larger cohorts of phenotyped toxicity and suggest a broader role for highly multiplexed tissue imaging in phenotyping the immune mediated disease that they resemble.

Immune Cell Profiling of Atopic Dermatitis Patients Before and After Treatment with Halometasone Cream Wet-Wrap Therapy by Single-Cell Sequencing

Objectives

Peripheral blood immune cell profiling of atopic dermatitis patients before and after treatment by single-cell RNA sequencing technique has not been reported. To study the immune Cell Profiling of Atopic Dermatitis Patients Before and After Treatment with Halometasone Cream Wet-Wrap Therapy.

Methods

We used single cell sequencing to detect the proportion change and gene expression change of immune cells in 2 patients before and after treatment, and then used real-time PCR to confirm the mRNA level of differential genes.

Results

In this study, scRNA-seq in two patients with severe AD before and after halometasone cream wet-wrap therapy showed that in the mild severity of AD after treatment, Th2 cells were significantly decreased (41.2% vs 13.4%), Th1 and Th17 cells were increased (23.3% vs 43.7%, 2.3% vs 4.8% respectively). The proportion of Th22 cells did not change much (1.3% vs 1.9%). Tregs were significantly increased also (1.5% vs 5.0%). In the regulatory T cells, the expression of IL-27, PD-1, CD103, CTLA-4, ZNF-66, IL-β, CD7 gene was specifically increased after treatment, and CD39, P21, TOX2, CD151, CD79A, S100A12, TRAP1 gene was specifically decreased after treatment. In the TH2 cells, the expression of CD27, CD68, EZH1, RAD1, EGFR, CCR10, BCL11A, KLF4 gene was specifically increased after treatment and CCL26, CD180, IL-31, CCL22, LEF1, OX40 gene was specifically decreased after treatment.

Conclusions

These genes may be new target for further study.

Pro-Inflammatory versus Anti-Inflammatory cytokines in atopic dermatitis patients: A case control study

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disorder with significant morbidity and impairment of life quality. Prevalence is increasing around the world; therefore, intensive research is ongoing to understand the mechanisms of development of AD and offer new treatment options for AD patients.

AIMS

To investigate the association between Inflammatory (IL-17, TNF-α, IFN-γ) versus anti-Inflammatory Cytokines (IL-35, TGF-β) in AD patients.

PATIENTS AND METHODS

A case control study included 40 AD patients and 20 age- and sex-matched healthy subjects. Cases were subjected to full history taking and full dermatological examination. The assessment of disease severity was conducted by using SCORAD score. Assessment of inflammatory (IL-17, TNF-α, IFN-γ) and anti-Inflammatory Cytokines (IL-35, TGF-β) was performed by using ELISA technique.

RESULTS

The mean level of TNF-α, IL-17 was statistically significantly higher in the AD cases as compared with the control group. The mean level of TGF-β, Il-35, and IFN-γ was statistically significantly lower in the Atopic dermatitis cases as compared with the control group. There was statistically significant strong positive correlation between TNF-α with SCORAD score and IL-17 while there was statistically significant strong negative correlation between TNF-α with TGF-β and IL-35. There was statistically significant strong positive correlation between IL-17 with SCORAD score and TNF-α while there was statistically significant strong negative correlation between IL-17 with TGF-β and IL-35.

CONCLUSION

The current results could be used as a clue for the utilization of inflammatory (IL-17, TNF-α, IFN-γ) versus anti-inflammatory Cytokines (IL-35, TGF-β) in AD as a diagnostic biomarker for severity of cases with Atopic dermatitis. IL-17 plays an important role in the pathogenesis of AD, and IL-17 blocker may be used as a potential future treatment of AD.

Canine memory T-cell subsets in health and disease

A more complete understanding of canine T-lymphocyte immunity is necessary for improving diagnostic and therapeutic approaches to canine diseases, developing cell-based canine immunotherapeutics, and evaluating dogs as large mammal models for comparative immunology research. The aim of this study was to utilize CD45RA (indicating antigen inexperience) and CD62L (indicating lymph node homing capability), to quantify canine memory T-cell subsets in healthy dogs and dogs with various diseases. Peripheral blood mononuclear cells (PBMCs) were prospectively collected from dogs belonging to one of four groups:dermatologic inflammation (n = 9), solid tumors (n = 9), lymphoma (n = 9), and age-/weight-matched healthy control dogs (n = 15). Dogs receiving prednisone or any other immunomodulating medication within two weeks were excluded. Flow cytometry was performed and T-cell subsets were defined as CD4+ or CD8+, and naïve (TN), central memory (CM), effector memory (EM), or terminal effector memory re-expressing CD45RA (TEMRA). T-cell subset proportions were compared between each disease group and their healthy age-/weight-matched controls using a Mann-Whitney test. Significantly increased %CD8+ TN (P = 0.036) and decreased %CD8+ TEMRA (P = 0.045) were detected in dogs with dermatologic inflammation compared to healthy controls. Furthermore, %CD4+ TN positively correlated with Canine Atopic Dermatitis Extent and Severity Index (CADESI) score within the inflammation group (ρ = 0.817, P = 0.011). No significant differences between either cancer group and their healthy controls were detected. Taken together, these data indicate that dermatologic inflammation can alter proportions of peripheral blood T-cell subsets, possibly due to the migration of antigen-specific T-cells into tissues. Furthermore, these findings support the utility of CD45RA and CD62L in characterizing clinical canine immune responses.

Autoreactive T cells and their role in atopic dermatitis

Atopic dermatitis (AD) is an itchy, non-contagious relapsing and chronic inflammatory skin disease that usually develops in early childhood. This pathology is associated with food allergy, allergic asthma, allergic rhinitis and anaphylaxis which may persist in adulthood. The underlying mechanisms of AD (endotypes) are just beginning to be discovered and show a complex interaction of various pathways including skin barrier function and immune deviation. Immune reactions to self-proteins (autoantigens) of the skin have been identified in patients with inflammatory skin diseases, such as chronic spontaneous urticaria, connective tissue disease, pemphigus vulgaris and bullous pemphigoid. IgE antibodies and T cells directed against epitopes of the skin were observed in adult patients with severe and chronic AD as well. This was associated with disease severity and suggests a progression from allergic inflammation to severe autoimmune processes against the skin. IgE-mediated autoimmunity and self-reactive T cells might accelerate the ongoing skin inflammation or might contribute to the relapsing course of the disease. However, to date, the exact mechanisms of IgE-mediated autoimmunity and self-reactive T cells in the pathophysiology of AD are still unclear. The aim of this review is to evaluate the development of (autoreactive) T cells and their response to (auto)antigens, as well as the role of the peripheral tolerance in autoimmunity in the pathophysiology of AD, including the unmet needs and gaps.

Effects of Hyperbaric Oxygen Therapy in Children with Severe Atopic Dermatitis

In the course of atopic dermatitis (AD), the overactivity of the immune system, associated with predominant Th2 lymphocyte responses, is observed, which leads to an increased inflammatory reaction. Cases of a severe course of atopic dermatitis lead to the search for new therapeutic options. The aim of this study was to assess the effects of hyperbaric oxygen therapy (HBOT) treatment for severe cases of AD in children. A total of 15 children with severe AD underwent therapy. The influence of HBOT on the clinical course of AD and immunomodulatory effect of the therapy was analyzed by the SCORAD and objective SCORAD (oSCORAD) scales and by determining the serum concentration of immunological parameters (blood: nTreg lymphocytes, CD4+CD25highCD127-FOXP3+, NKT lymphocytes CD3+, CD16/56+, and serum: total IgE, cytokines IL-4, IL-6, and IL-10, before and after the 30-day treatment cycle). The study showed a significant effect of the therapy on the improvement of the skin condition. In all children, a reduction in the extent and intensity of skin lesions, reduction of redness, swelling, oozing/crusting, scratch marks and skin lichenification after HBOT was observed. Patients also reported a reduction in the intensity of pruritus and an improvement in sleep quality after therapy. In all children, a statistically significant decrease in the serum level of IgE was observed. However, no statistically significant changes in the blood levels of IL-4, IL-6 and IL-10, as well as the percentage of CD4⁺CD25^highCD127⁻FOXP3⁺ Treg and NKT lymphocytes, were found. In conclusion, the use of hyperbaric therapy has a positive impact on treatment results in children with a severe course of atopic dermatitis.

Increased Frequency of CTLA-4 and PD-1 Expressing Regulatory T Cells and Basophils With an Activating Profile in Infants With Moderate-to-Severe Atopic Dermatitis Hypersensitized to Food Allergens

Background: Infants with severe atopic dermatitis (AD) may be sensitized to foods that have not been introduced into their diet, posing a risk for developing an immediate hypersensitivity reaction on the first exposure to the food to which they are sensitized. The aim of this work was to perform an analysis of the sensitization profile in infants with moderate-to-severe AD and to identify cellular and molecular markers for food allergy (FA). Methods: Blood samples from healthy donors and children with moderate-to-severe AD were studied. Specific IgE to several allergens were determined using ImmunoCAP FEIA system and ISAC technology. Furthermore, using flow cytometry-based studies, basophils and regulatory T (Treg) cells were phenotypically characterized. Results: 90% of children with AD were sensitized to food antigens before introducing them into the diet, and 100% developed FA. Phenotypic analysis showed a significantly higher percentage of CTLA-4 and PD-1 expressing Treg cells in AD patients than in healthy controls. Basophils from patients exhibited a marked reduction in the expression of CD300a, higher expression of FcεRI and CXCR4, and to some extent higher expression of CD63 and CD300c. Conclusions: Infants with moderate-to-severe AD are at high risk of being sensitized to food allergens. Therefore, to avoid allergic reactions, broad-spectrum sensitization studies are necessary before introducing complementary diet. Increased expression of CTLA-4 and PD-1 suggests greater suppressive potential of Treg cells in infants with AD than healthy controls. Furthermore, our results suggest a role for CD300 molecules on circulating basophils as possible biomarkers for FA susceptibility.

Pathophysiology and Management of Atopic Dermatitis: A Laconic Review

Conclusion:

Atopic Dermatitis (AD) is long-lasting degenerating skin disease with a characteristic phenotype and stereotypically spread skin lesions. The AD results due to a complex interface among genetic factors, host’s surroundings, pharmacological anomalies and immunological factors. In previous decades, researchers had shown marked interest due to increased prevalence in developed countries. In this review, basics along with the advances in pathogenesis and management of AD have been discussed. The immunological factors i.e. Innate Lymphoid Cells, IL-22 and Toll-like receptors have an important role in the pathogenesis. The proactive topical therapy by skincare, topical glucocorticosteroids and calcineurin inhibitors have improved effect in the management of AD. The human monoclonal antibody-based systemic drug (Duplimab) is a considerable advancement in the management of AD. Other monoclonal antibody-based drugs (Lebrikizumab, Tralokinumab, Apremilast and Nemolizumab) are in different phases of clinical trials. A better understanding of genetics and immunoregulatory cascade will lead to the development of efficacious drugs and better management therapy preventing the relapse of flares and improved life quality of AD patients.

Efficacy, Safety, and Immunomodulatory Effect of the Intramuscular Administration of Autologous Total Immunoglobulin G for Atopic Dermatitis: A Randomized Clinical Trial

Purpose

The management of patients with atopic dermatitis (AD) is often difficult. We hypothesized that repeated intramuscular administration of autologous total immunoglobulin G (IgG) could induce clinical improvement in patients with AD through immune modulation. This clinical trial was conducted to evaluate the efficacy, safety, and immunomodulatory effect of the intramuscular administration of autologous total IgG in patients with AD.

Methods

In this randomized, double-blind, placebo-controlled trial, 51 adolescent and adult patients with moderate-to-severe AD were randomized to receive 8 weekly intramuscular administrations of autologous total IgG 50 mg (n = 26) or saline (n = 25) over a 7-week period and were followed up to week 16. Changes in the clinical severity score (Eczema Area and Severity Index), affected body surface area, patient-reported Dermatology Life Quality Index (DLQI) score, laboratory biomarkers, and incidence of adverse events from baseline to week 16 were assessed.

Results

The intramuscular administration of autologous total IgG, compared with saline, decreased the clinical severity score (−64.8% vs. −20.3%, P < 0.001), reduced the affected body surface area (−53.9% vs. −19.1%, P < 0.001), improved the DLQI score (−35.4% vs. −14.4%, P = 0.015), increased serum interleukin-10 and interferon-γ levels (P = 0.011 and P = 0.003, respectively), and reduced the incidence of AD exacerbation (11.5% vs. 48.0%, P = 0.004) from baseline to week 16. No serious adverse events were observed.

Conclusions

The intramuscular administration of autologous total IgG provided clinical improvements and a systemic immunomodulatory effect in adolescent and adult patients with moderate-to-severe AD without significant side effects.

Trial Registration

Clinical Research Information Service Identifier: KCT0001597

Correlation of Blood FoxP3+ Regulatory T Cells and Disease Activity of Atopic Dermatitis

Objectives

To investigate CD4+CD25+FoxP3+ T regulatory cells (Tregs) in the peripheral blood of patients with atopic dermatitis (AD) and its correlation with disease severity.

Methods

Blood samples from 79 AD patients before and after four-week conventional treatment were collected. Cell counts of CD4+CD25+FoxP3+Tregs, CD4+CD25+FoxP3-T effector cells (Teffs), and CD4+IL-10+Tregs were analyzed by flow cytometry. Serum levels of IL-4, IL-10, IL-12, IL-13, IFN-γ, and TGF-β were measured by ELISA.

Results

The pretreatment cell count of CD4+CD25+FoxP3+Tregs positively correlated with disease severity in all patients (P < 0.0001). However, when that correlation was rechecked based on the treatment response, a much stronger correlation of that was found in those patients with remission after treatment, while no correlation of that was found in patients without remission. Both the cell count and proportions of peripheral CD4+CD25+FoxP3+Tregs and CD4+CD25+FoxP3-Teffs reduced significantly after treatment in patients with remission, but remained unchanged in patients without remission. The cell count and proportion of CD4+IL-10+Tregs did not change after treatment in both groups. In patients with remission, serum levels of IL-4 and IL-13 significantly reduced (all P < 0.05); IL-12 and IFN-γ levels increased significantly (all P < 0.05); IL-10 and TGF-β levels remained unchanged after treatment. None of those cytokine levels changed in patients without remission.

Conclusions

CD4+CD25+FoxP3+Tregs is associated with AD development and severity in some patients but not in others. AD maybe divided into CD4+CD25+FoxP3+Treg-associated subtype, which CD4+CD25+FoxP3+Treg is parallel to the activity of AD, and nonassociated subtype, which CD4+CD25+FoxP3+Treg is not related. This subgroup difference may contribute partly to the nonidentical markers that have been found in AD and should be studied further.

Filaggrin null mutations are associated with altered circulating Tregs in atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a complex pathogenesis. Although regulatory T cells (Tregs) have previously been studied in AD, their role remains controversial, likely owing to patient heterogeneity. Thus, we recruited adult AD patients and age‐matched healthy controls, and assessed their filaggrin (FLG) genotype, serum IgE level, and eczema area and severity index (EASI). We found increased proportions of all circulating Treg subpopulations in AD patients. Moreover, we show positive correlations between circulating Tregs and serum IgE FLG null mutations limited the expansion of both memory and effector Tregs and enhanced that of recently thymus‐emigrated Tregs. Furthermore, proportions of circulating Th2‐ or Th17‐Tregs but not Th1‐Tregs were increased in AD patients, and accentuated by FLG null mutations, thereby mimicking the immune deviation observed in Th cell populations. Moreover, ICOS⁺ Tregs showed reduced production of interleukin‐10, suggesting impaired immunosuppression in AD. The level of demethylation of FOXP3i1, which reflects the stability of FOXP3 expression, was similar in the blood and skin of AD patients and healthy controls. Overall, these results show that Tregs may participate into AD pathogenesis and that FLG null mutations exert further modifications on specific subpopulations of circulating Tregs.

The effect of an ex vivo boosted immune cell therapy on canine atopic dermatitis: an open, uncontrolled pilot study

BACKGROUND

Canine atopic dermatitis (cAD) is associated with an imbalance between multiple T lymphocytes and cytokines. Ex vivo boosted immune cell (EBIC) therapy is the sequential administration of ex vivo cultured and activated lymphocytes to patients to improve immune function.

OBJECTIVE

This pilot study aimed to assess the safety of EBIC therapy and demonstrate its efficacy as a novel treatment for cAD.

ANIMALS

Ten dogs with AD.

METHODS AND MATERIALS

The phenotypes of the immune cells before and after ex vivo culture were analysed by flow cytometry. EBICs (1.0-5.0 × 10⁸ cells/animal) were administered to dogs every two weeks, with a total of six injections. The cAD extent and severity index (CADESI)-03 and pruritus scores were calculated to evaluate the efficacy of EBIC therapy for cAD. For safety assessment, regular blood examination was conducted, and any adverse events recorded. The serum levels of interleukin (IL)-4, IL-10, IL-31 and interferon-gamma (IFN-γ) were evaluated.

RESULTS

The cells expanded by an average of 57.52-fold and the proportions of CD8⁺ cells and IFN-γ-producing cells significantly increased after ex vivo culture. Sequential EBIC therapy improved CADESI-03, and pruritus scores significantly. After stopping treatment the improvement rates increased for the CADESI score and were maintained for the pruritus score. There were no significant changes in cytokine levels. No significant adverse events were observed.

CONCLUSIONS AND CLINICAL SIGNIFICANCE

EBIC therapy is a safe and efficient treatment for cAD. This therapy could correct the immunological imbalance in dogs with AD by infusing activated T lymphocytes.

The role of regulatory T cells and genes involved in their differentiation in pathogenesis of selected inflammatory and neoplastic skin diseases. Part II: The Treg role in skin diseases pathogenesis

Regulatory FOXP3+ T cells (Tregs) constitute 5% to 10% of T cells in the normal human skin. They play an important role in the induction and maintenance of immunological tolerance. The suppressive effects of these cells are exerted by various mechanisms including the direct cytotoxic effect, anti-inflammatory cytokines, metabolic disruption, and modulation of the dendritic cells function. The deficiency of Treg cells number or function are one of the basic elements of the pathogenesis of many skin diseases, such as psoriasis, atopic dermatitis, bacterial and viral infections. They also play a role in the pathogenesis of T cell lymphomas of the skin (cutaneous T cell lymphomas - CTCL), skin tumors and mastocytosis. Here, in the second part of the cycle, we describe dysfunctions of Tregs in selected skin diseases.

Evaluation of Immune Indices and Serum Vitamin D Content in Children with Atopic Dermatitis

The influence of vitamin D on allergic diseases, including atopic dermatitis, is linked to the presence of vitamin D nuclear receptors in immune cells. The present study seeks to determine the possible relationship between serum vitamin D content and immune indices in children with atopic dermatitis. The study was conducted in 19 children with atopic dermatitis. The control consisted of 17 age-matched healthy children. A single significant finding was a distinctly lower number of serum regulatory T cells in atopic dermatitis compared with controls (p < 0.00001). There were no appreciable differences between the two groups concerning the immunological indices such as the phenotypes: CD3, CD4, CD8, CD4/CD8, CD19, CD16/56, natural killer T cells, and anti-CD3 human leukocyte antigen - antigen D related cell surface receptor (HLA-DR3), or the percentage of lymphocytes, eosinophils, and the IgE level. We also revealed an inverse association between the serum vitamin D and the percentage of CD8+ cells (p < 0.05; r = 0.62) in atopic dermatitis. In conclusion, the results point to a regulatory role of T cells in the pathogenesis of atopic dermatitis, but fail to substantiate the influence of vitamin D on the course of the disease.

Upregulation of CD47 in Regulatory T Cells in Atopic Dermatitis

PURPOSE

Regulatory T (Treg) cells are key modulators in the immune system. Recent studies have shown that atopic dermatitis (AD) patients have higher numbers of Treg cells; however, little is known about the specific phenotype and function of Treg cells in AD.

MATERIALS AND METHODS

To identify differentially expressed proteins in peripheral induced Treg cells in AD and naturally derived Treg cells in normal controls, CD4⁺CD25⁺ Treg cells were isolated from thymus tissue of normal mice and the spleens of AD mice. Membrane proteins were extracted, and quantitative proteomics labeling with Tandem Mass Tags (TMT) was performed, followed by one-dimensional liquid chromatography/tandem mass spectrometry analysis.

RESULTS

Using TMT labeling, we identified 510 proteins, including 63 membrane proteins and 16 plasma membrane proteins. CD47 was one of the upregulated proteins in Treg cells in AD spleens. Although CD47 was expressed in all CD4⁺ and CD8⁺ T cells, a significantly higher expression of CD47 was observed in the Treg cells of AD mice and AD patients than in those of normal mice and healthy controls. Furthermore, Treg cells from the spleen showed a significantly higher expression of CD47 than those from the thymus.

CONCLUSION

We found that CD47 is highly expressed in the Treg cells of AD mice, particularly in the spleen. Based on our results, we propose that CD47(high) Treg cells are likely induced Treg cells and that upregulated CD47 in the Treg cells of AD patients may play a role in the increased population of Treg cells in AD.

Lymphocyte subpopulations and Treg cells in dogs with atopic dermatitis receiving ciclosporin therapy: a prospective study

BACKGROUND

Canine atopic dermatitis (CAD) is a chronic dermatological disease partly due to dysregulation of the immune system. Inappropriate activation of CD4(+) lymphocytes could favour and promote the allergic response. An inadequate activation system of regulatory T cells (Tregs) is suspected to be a key immunological feature of the allergic response in atopic dogs.

HYPOTHESIS/OBJECTIVES

To evaluate the difference in the CD4/CD8 lymphocyte ratio and the percentage of Tregs in healthy dogs, in a breed predisposed to CAD, and in dogs affected by CAD before and during therapy with ciclosporin (CsA). Additionally to assess the improvement in pruritus and skin lesions during therapy with CsA, and to compare this with CD4/CD8/Treg values.

ANIMALS

Ten atopic dogs of different breed, sex and age, ten healthy dogs and ten English bulldogs were included.

METHODS

Peripheral blood from all dogs was tested using flow cytometry to assess the CD4/CD8 ratio and percentage of Tregs. For atopic dogs, sampling was repeated after 30 and 90 days of therapy with CsA.

RESULTS

The CD4/CD8 ratio was not significantly different between the three groups. The Treg percentage was higher, but not statistically significant, in atopic dogs compared with controls. Therapy with CsA led to clinical improvement; it was not associated with statistically significant differences in haematological variables.

CONCLUSION AND CLINICAL IMPORTANCE

This study suggests that Tregs may be involved in the pathogenesis of CAD and that ciclosporin therapy does not affect the circulating lymphocyte subpopulations.

Foxp3(+) regulatory T cells are expanded in severe atopic dermatitis patients

Regulatory T cells (Tregs) are known to play critical roles in homeostasis and immune responses in the skin. Whether Treg frequencies are altered in atopic dermatitis (AD) patients has been addressed by several studies, leading to conflicting results. The detection of Tregs by FOXP3 expression may lead to false-positive results as activated T cells without regulatory function may transiently upregulate this transcription factor. In contrast, measurement of the DNA methylation status of a region within the FOXP3 locus that is selectively demethylated only in bona fide Tregs (Treg-specific demethylated region, TSDR) represents a reliable method to quantify Tregs. Here, we measured circulating Treg frequencies of adult patients and detected a positive correlation with disease severity. Subsequent surface marker analysis revealed higher frequencies of CD45RA(+) CCR7(-) tissue-homing Tregs in the patient group with a tendency of reduced expression of CD39 compared with healthy donors, a marker for the highly suppressive TREM subtype.

Circulating CD4(+) CD25(high) FoxP3(+) T-regulatory cells in patients with atopic dermatitis after narrowband-ultraviolet B phototherapy

BACKGROUND

Previous studies showed controversial results regarding CD4(+) CD25(high) FoxP3(+) T-regulatory cells (Tregs) in atopic dermatitis (AD) and effect of therapy.

METHODS

Circulating CD4(+) CD25(high) FoxP3(+) Tregs were assessed by flow cytometry in 20 controls and 20 patients with AD at baseline and after narrowband ultraviolet B with assessment of disease severity.

RESULTS

Patients showed higher pretreatment T-effector cells (Teffs) (%) and lower pretreatment Tregs FoxP3 expression% than controls (P = 0.003 and 0.01, respectively). Mild AD showed a lower Tregs/Teffs ratio compared to controls (P = 0.013), while moderate group showed higher Teffs%, and lower Tregs FoxP3 expression% and Tregs/Teffs compared to controls (P = 0.016, 0.007, and 0.009 respectively). The severe group had higher Tregs% and Teffs%, yet with a lower Tregs FoxP3 expression% compared to controls (P < 0.001, P = 0.043, P = 0.044, respectively). There was significant reduction of severity after narrowband ultraviolet B (P = 0.007), with overall significant elevation of Tregs FoxP3 expression% in patients (P = 0.004). All patients' post-treatment laboratory findings were statistically matched to each other and to controls whatever their previous severity or therapeutic response. The improvement of severity score correlated with the change in both Tregs% and Tregs/Teffs.

CONCLUSIONS

Significant reduction in AD disease severity is correlated with the change in Tregs% and Tregs/Teffs.

Oral administration of Lactobacillus delbrueckii subspecies bulgaricus OLL1073R-1 suppresses inflammation by decreasing interleukin-6 responses in a murine model of atopic dermatitis

The oral intake of Lactobacillus spp. can provide beneficial effects to the host by modulating the immune response. Atopic dermatitis (AD) is an allergic inflammatory disease mediated by various immune responses. In this study, we examined the effect of a Lactobacillus strain, Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 (OLL1073R-1), on AD development in a murine model of AD that was developed by the topical application of mite antigen in NC/Nga mice. The oral intake of heat-killed OLL1073R-1 cells inhibited both the development of dermatitis and the elevation of an acute inflammation marker, serum amyloid A. Another bacterial strain, Lactobacillus rhamnosus OLL2984, exerted no inhibitory effects on dermatitis. The oral intake of heat-killed OLL1073R-1 cells also attenuated secretion of IL-6 from lymph node cells in response to mite antigen and reduced IL-6 levels in inflamed tissues, such as auricles. Production of IFN-γ or IL-4 was not influenced by OLL1073R-1 intake. We also found that inhibition of IL-6 signaling by gp130-Fc (a fusion protein consisting of the extracellular portion of glycoprotein 130 fused to the Fc region of human IgG1) markedly decreased the severity of dermatitis in NC/Nga mice. Moreover, secretion of IL-6 by lymph node cells was augmented in NC/Nga mice compared with that in BALB/c mice. These results indicate that IL-6 plays an essential role in the development of dermatitis in the NC/Nga mouse model of AD, and that OLL1073R-1 inhibits dermatitis, at least in part, by suppressing the IL-6 response.