Severe atopic dermatitis is associated with a reduced frequency of IL-10 producing allergen-specific CD4+ T cells

Gamma-delta (γδ) T cell-derived cytokines (IL-4, IL-17, IFN-γ and IL-10) and their possible implications for atopic dermatitis development

Atopic dermatitis (AD) is a chronic disease related to skin disorders that affect individuals in their childhood and can persist or start in adulthood. Patients affected by this disease commonly show skin lesions on the body surface (mainly on the upper and lower limbs) and allergic rhinitis or asthma crises. Looking at the disease from a molecular perspective, the major cytokines involved in inflammatory skin diseases, not only AD, include IL-4, IL-17, IFN-γ and IL-10. Although they can produce these cytokines and infiltrate the affected epithelia in patients with AD, γδ T cells are still almost unexplored. In this update, we briefly discuss the involvement of IL-4, IL-17, IFN-γ and IL-10 in the pathophysiology of AD and the possible role of γδ T cells during the inflammatory process.

The translational revolution in atopic dermatitis: the paradigm shift from pathogenesis to treatment

Atopic dermatitis (AD) is the most common inflammatory skin disease, and it is considered a complex and heterogeneous condition. Different phenotypes of AD, defined according to the patient age at onset, race, and ethnic background; disease duration; and other disease characteristics, have been recently described, underlying the need for a personalized treatment approach. Recent advancements in understanding AD pathogenesis resulted in a real translational revolution and led to the exponential expansion of the therapeutic pipeline. The study of biomarkers in clinical studies of emerging treatments is helping clarify the role of each cytokine and immune pathway in AD and will allow addressing the unique immune fingerprints of each AD subset. Personalized medicine will be the ultimate goal of this targeted translational research. In this review, we discuss the changes in the concepts of both the pathogenesis of and treatment approach to AD, highlight the scientific rationale behind each targeted treatment and report the most recent clinical efficacy data.

Classifying atopic dermatitis: a systematic review of phenotypes and associated characteristics

Atopic dermatitis is a heterogeneous disease, accompanied by a wide variation in disease presentation and the potential to identify many phenotypes that may be relevant for prognosis and treatment. We aimed to systematically review previously reported phenotypes of atopic dermatitis and any characteristics associated with them. Ovid EMBASE, Ovid MEDLINE and Web of Science were searched from inception till the 12th of February 2021 for studies attempting to classify atopic dermatitis. Primary outcomes are atopic dermatitis phenotypes and characteristics associated with them in subsequent analyses. A secondary outcome is the methodological approach used to derive them. In total, 8,511 records were found. By focusing only on certain clinical phenotypes, 186 studies were eligible for inclusion. The majority of studies were hospital-based (59%, 109/186) and cross-sectional (76%, 141/186). The number of included patients ranged from seven to 526,808. Data-driven approaches to identify phenotypes were only used in a minority of studies (7%, 13/186). Ninety-one studies (49%) investigated a phenotype based on disease severity. A phenotype based on disease trajectory, morphology and eczema herpeticum was investigated in 56 (30%), 22 (12%) and 11 (6%) studies, respectively. Thirty-six studies (19%) investigated morphological characteristics in other phenotypes. Investigated associated characteristics differed between studies. In conclusion, we present an overview of phenotype definitions used in literature for severity, trajectory, morphology and eczema herpeticum, including associated characteristics. There is a lack of uniform and consistent use of atopic dermatitis phenotypes across studies.

Long-wavelength ultraviolet A (UVA-1) phototherapy for the treatment of patients with atopic dermatitis

One of the methods of therapy for atopic dermatitis is long-wavelength ultraviolet therapy A (UVA-1- therapy). This review aims to provide the mechanisms of action of UVA-1-therapy an overview about the effectiveness of UVA-1-therapy in patients with atopic dermatitis taking into account factors that can affect the effectiveness of treatment radiation dose, skin phototype of patients, concomitant drug therapy. The available data on a decrease in the severity of atopic dermatitis as a result of the course of UVA-1-therapy and on a decrease in the severity of itching in patients are presented. The data on the rate of onset of the therapeutic effect of UVA-1-therapy and the duration of its maintenance are considered. The safety of UVA-1-therapy is discussed, and the most frequent undesirable effects a feeling of warmth, fever, itching, hyperpigmentation, are given. The possibility of developing side effects requiring discontinuation of treatment is assessed. The data obtained indicate the effectiveness and safety of the UFA-1-radiation in the treatment of patients with moderate-to-severe atopic dermatitis.

Role of antimicrobial peptides in atopic dermatitis

Host defense peptides (HDPs) or antimicrobial peptides (AMPs) are short cationic amphipathic peptides of divergent sequences, which are part of the innate immune system and produced by various types of cells and tissues. The predominant role of HDPs is to respond to and protect humans against infection and inflammation. Common human HDPs include defensins, cathelicidin, psoriasin, dermcidin, and ribonucleases, but these peptides may be dysregulated in the skin of patients with atopic dermatitis (AD). Current evidence suggests that the antimicrobial properties and immunomodulatory effects of HDPs are involved in AD pathogenesis, making HDPs research a promising area for predicting disease severity and developing novel treatments for AD. In this review, we describe a potential role for human HDPs in the development, exacerbation, and progression of AD and propose their potential therapeutic benefits.

Cytokine Gene Polymorphisms in Saudi Patients With Atopic Dermatitis: A Case-Control Study

The cause of atopic dermatitis (AD) is multifactorial and a number of genes including cytokines have been involved. We genotyped 315 subjects for polymorphisms in TNF-α and TNF-β and IL-10 genes. Patients had significantly higher frequency of GA genotype of TNF-α (−308 G/A) than healthy controls. Patients with AD and controls had similar distribution of A and G alleles. Genotype AA was found in 7.11% of controls while completely absent in cases. The frequencies of genotypes GG and AA of TNF-β (+252 A/G) polymorphism were higher whereas the frequency of genotype GA was significantly lower in patients than the controls. The frequencies of genotypes GG and AA of IL-10 (1082 G/A) polymorphism were significantly increased whereas genotype GA was decreased in patients than the controls. It is concluded that TNF-α (−308 G/A), TNF-β (+252 A/G), and IL-10 (−1082 G/A) polymorphisms are linked with the susceptibility of AD in Saudis and can be a risk factor.

IgG from atopic dermatitis patients induces IL-17 and IL-10 production in infant intrathymic TCD4 and TCD8 cells

INTRODUCTION

Our group recently demonstrated that IgG modulates αβT cell cytokine production during the maturation process in the human thymus. The effects of this modulation are IgG repertoire dependent and can exert a systemic and long-term impact.

OBJECTIVE

To investigate whether IgG from atopic dermatitis (AD) patients can modulate cytokine production of infant intrathymic TCD4 and TCD8 cells in vitro.

METHODS

Thymic tissues were obtained from newborn children from nonatopic mothers, and thymocytes were cultured for 6 days with purified IgG from AD patients or with intravenous immunoglobulin (IVIG) or mock conditions as controls. Cells were gated as double positive T cells (TDP^- CD4⁺ CD8⁺ ), TCD4 cells (CD4⁺ CD8^- ), or TCD8 cells (CD4^- CD8⁺ ), and intracellular levels of IL-17A, IFN-γ, TNF-α, IL-4, IL-10, and TGF-β were evaluated by flow cytometry.

RESULTS

Compared to mock and IVIG culture conditions, IgG of AD individuals induced in vitro intracellular production of IL-17 and IL-10 by intrathymic TDP, TCD4, and TCD8 cells of infants. TGF-β was also detected at a higher frequency in response to AD IgG in TDP and TCD8 cells compared to mock and IVIG cultured conditions. An opposite effect was detected upon IFN-γ production in TCD4 cells, such that AD IgG reduced IFN-γ production compared to production under mock conditions but not under IVIG conditions.

CONCLUSION

IgG of AD patients can stimulate cytokine production in infant thymocytes and thus resembles the peripheral profile observed in adults. These findings suggest a novel mechanism that can contribute to AD pathogenesis.

Strategies targeting the IL-4/IL-13 axes in disease

IL-4 and IL-13 are pleiotropic Th2 cytokines produced by a wide variety of different cell types and responsible for a broad range of biology and functions. Physiologically, Th2 cytokines are known to mediate host defense against parasites but they can also trigger disease if their activities are dysregulated. In this review we discuss the rationale for targeting the IL-4/IL-13 axes in asthma, atopic dermatitis, allergic rhinitis, COPD, cancer, inflammatory bowel disease, autoimmune disease and fibrotic disease as well as evaluating the associated clinical data derived from blocking IL-4, IL-13 or IL-4 and IL-13 together.

Atopic dermatitis patients carrying G allele in -1082 G/A IL-10 polymorphism are predisposed to higher serum concentration of IL-10

INTRODUCTION

Atopic dermatitis (AD) is a chronic skin inflammatory disease in which Th2-derived cytokines play an essential role. Aim of the study was to assess interleukin 4, 10 and 13 (IL-4, IL-10 and IL-13) serum concentrations in AD patients and to correlate the values with the occurrence of genotypes of selected polymorphisms in genes encoding these cytokines.

MATERIAL AND METHODS

Seventy-six AD patients (mean age 11.4 years) and 60 healthy controls were enrolled in the study. Blood samples were analyzed for IL-4, IL-10 and IL-13 concentrations with ELISA assay and genotyping for -590C/T IL-4, -1082A/G IL-10 and -1055C/T IL-13 polymorphisms with PCR-RFLP.

RESULTS

The obtained results revealed statistically higher serum concentration of IL-10 and IL-13 in AD patients when compared to healthy controls (10.30 pg/ml vs. 8.51 pg/ml for IL-10 and 5.67 pg/ml vs. 4.98 pg/ml for IL-13). There were no significant differences between AD patients and controls in regard to IL-4 serum level (5.10 pg/ml vs. 7.1 pg/ml). Analyzing the association between level of the examined cytokines and genotype polymorphisms -590 C/T for the IL-4 gene, -1082 A/G for the IL-10 gene and -1055 C/T for the IL-13 gene, we found a statistically higher IL-10 serum level among carriers of the G allele in the -1082 G/A IL-10 polymorphism both in AD and control groups. We did not find any significant differences between serum level of IL-4 and IL-13 in regard to genotype occurrence in examined polymorphisms: -590 C/T for the IL-4 gene and -1055 C/T for the IL-13 gene.

CONCLUSIONS

The obtained results confirm the genetic background of IL-10 synthesis in the Polish population.

IL-10 suppresses IL-17-mediated dermal inflammation and reduces the systemic burden of Vaccinia virus in a mouse model of eczema vaccinatum

Individuals with atopic dermatitis (AD) are susceptible to a severe, potentially fatal, systemic infection and inflammatory response following exposure to Vaccinia virus (VV). IL-10 acts both as an inducer of Th2 responses and as a regulator of T cell activation. It has been shown to limit skin inflammation elicited by contact sensitizers. AD exacerbations have been associated with decreased IL-10 function. We used IL-10(-/-) mice to test the role of the cytokine in VV immunity. They exhibited larger primary lesions and increased cutaneous neutrophil infiltration compared to wild-type (WT) counterparts. This was associated with enhanced production of IL-17A, IL-17F and CXCL2. Paradoxically, despite intact adaptive immune responses, tissue viral burdens were increased in IL-10(-/-) mice. These findings suggest that IL-10 is important in limiting skin inflammation induced by VV and that abnormal IL-17-driven neutrophil recruitment at the primary infection site in the skin results in increased systemic viral dissemination.

The Drinking Effect of Hydrogen Water on Atopic Dermatitis Induced by Dermatophagoides farinae Allergen in NC/Nga Mice

Hydrogen water (HW) produced by electrolysis of water has characteristics of extremely low oxidation-reduction potential (ORP) value and high dissolved hydrogen (DH). It has been proved to have various beneficial effects including antioxidant and anti-inflammatory effects; however, HW effect on atopic dermatitis (AD), an inflammatory skin disorder, is poorly documented. In the present study, we examined the immunological effect of drinking HW on Dermatophagoides farinae-induced AD-like skin in NC/Nga mice. Mice were administered with HW and purified water (PW) for 25 days. We evaluated the serum concentration of pro-inflammatory (TNF-α), Th1 (IFN-γ, IL-2, and IL-12p70), Th2 (IL-4, IL-5, and IL-10), and cytokine expressed by both subsets (GM-CSF) to assess their possible relationship to the severity of AD. The serum levels of cytokines such as IL-10, TNF-α, IL-12p70, and GM-CSF of mice administered with HW was significantly reduced as compared to PW group. The results suggest that HW affects allergic contact dermatitis through modulation of Th1 and Th2 responses in NC/Nga mice. This is the first note on the drinking effect of HW on AD, clinically implying a promising potential remedy for treatment of AD.

Tumor necrosis factor-α, monocyte chemoattractant protein-1 and intercellular adhesion molecule-1 increase during the development of a 2,4-dinitrofluorobenzene-induced immediate-type dermatitis in rats

BACKGROUND

Due to the steadily increasing incidence of atopic dermatitis, there is a great medical need for new therapies and improved animal models.

OBJECTIVE

To provide more detailed analysis of a Sprague-Dawley rat dermatitis model.

METHODS

Sprague-Dawley rats were actively sensitized by intraperitoneal injections of dinitrophenylated ovalbumin (DNP-OVA) plus alum. Skin reactions were elicited by repeated epicutaneous challenge with 2,4-dinitrofluorobenzene (DNFB).

RESULTS

The ear thickness exhibited a significant increase from the first challenge. A relatively steep increase in ear thickness was observed at the fifth DNFB application. After the fifth DNFB application, total serum immunoglobulin (Ig) E and IgG1 levels reached a plateau at 1 h compared with the normal group. The peak production of tumor necrosis factor (TNF)-α and monocyte chemoattractant protein (MCP)-1 was found at 1 h, while that of intercellular adhesion molecule (ICAM)-1 was found at 24 h. Infiltration of CD4+ T cells, CD8+ T cells, eosinophils and mast cells increased in the skin lesion.

CONCLUSIONS

The indices such as thickness and inflammatory cell infiltration in the lesional skin were increased by repeated hapten application; TNF-α, MCP-1 and ICAM-1 increased with the development of the dermatitis.

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

The changes in lymphocyte subpopulations in atopic dermatitis (AD) concern also T-regulatory cells. We investigated the expression of various surface receptors on CD3⁺CD4⁺CD25^highFoxP3⁺ T-regulatory cells and the activation CD28⁺ receptor and the inhibitory CD152⁺ receptor on helper/inducer as well as cytotoxic/suppressor T cells. Peripheral blood lymphocytes of 15 AD patients and 20 healthy subjects were analyzed by flow cytometry using monoclonal antibodies. The concentrations of IL-6, IL-10 and TGF-β were determined in the serum and the supernatant of ConA-stimulated CD4⁺ lymphocytes. In AD patients the percentage of CD4⁺CD25^highFoxP3⁺ as well as CD3⁺CD8⁺ cells increased, which positively correlated with SCORAD index (r = 0.55, p = 0.03). The concentrations of IL-10 in the CD4⁺ lymphocyte culture supernatants and the concentrations of TGF-β in the sera and the supernatant negatively correlated with the severity of AD (p < 0.01, r = −0.63; p < 0.02, r = −0.64 and p < 0.03, r = −0.58, respectively), whereas the serum concentration of IL-6 correlated positively (p < 0.003, r = 0.71). The regulatory cells expressed more CD62L and CD134 surface markers but less CD95. Reduced expression of the apoptotic CD95 receptor suggests that survival time of these cells is prolonged. Since CD62L and CD134 were upregulated, the enhanced modulatory effect of CD4⁺CD25^highFoxP3⁺ cells seemed to be suggested, which may result in increased co-expression of CD28/CD152 on both CD4⁺ and CD8⁺ subpopulations.

Atopic dermatitis results in intrinsic barrier and immune abnormalities: implications for contact dermatitis

Atopic dermatitis (AD), as well as irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD), are common skin diseases. These diseases are characterized by skin inflammation mediated by activated innate immunity or acquired immune mechanisms. Although AD, ICD, and ACD can be encountered in pure forms by allergists and dermatologists, patients with AD often present with increased frequency of ICD and ACD. Although a disturbed barrier alone could potentiate immune reactivity in patients with AD through increased antigen penetration, additional immune mechanisms might explain the increased susceptibility of atopic patients to ICD and ACD. This review discusses cellular pathways associated with increased skin inflammation in all 3 conditions and presents mechanisms that might contribute to the increased rate of ICD and ACD in patients with AD.

Th2 Cytokines and Atopic Dermatitis

Atopic dermatitis (AD), a chronic relapsing inflammatory skin disease, is increasing in prevalence around the world. Intensive research is ongoing to understand the mechanisms involved in the development of AD and offer new treatment options for patients suffering from AD. In this review, we highlight the importance of allergic Th2 responses in the development of the disease and summarize relevant literature, including genetic studies, studies of human skin and mechanistic studies on keratinocytes and mouse models of AD. We discuss the importance of the skin barrier and review recent findings on the pro-Th2 cytokines TSLP, IL-25, and IL-33, notably their ability to polarize dendritic cells and promote Th2 responses. After a brief update on the contribution of different T-cell subsets to AD, we focus on Th2 cells and the respective contributions of each of the Th2 cytokines (IL-4, IL-13, IL-5, IL-31, and IL-10) to AD. We conclude with a brief discussion of the current gaps in our knowledge and technical limitations.

Phenotypic analysis of perennial airborne allergen-specific CD4+ T cells in atopic and non-atopic individuals

BACKGROUND

Accumulating evidence suggests that T cells play an important role in the pathogenesis of atopic dermatitis (AD); yet, little is known of the differentiation status of CD4+ T cells specific for common environmental allergens, such as the major cat allergen, Fel d 1.

OBJECTIVE

To determine the frequency, differentiation phenotype and function of circulating Fel d 1-specific CD4+ T cells in adult individuals with severe persistent AD in comparison with healthy controls.

METHODS

Using HLA class II tetrameric complexes based on a HLA-DPB1*0401-restricted Fel d 1 epitope, ex vivo and cultured T cell frequency and phenotype were analysed in individuals with AD and healthy controls. Cytokine secretion was measured by ex vivo and cultured IL-4 and IFN-γ ELISpots.

RESULTS

Ex vivo Fel d 1-specific DPB1*0401-restricted CD4+ T cells in both atopics and non-atopics express high levels of CCR7, CD62L, CD27 and CD28, placing the cells largely within the central memory subgroup. However, the functional phenotype was distinct, with greater IL-4 production from the cells derived from atopics, which correlated with disease severity.

CONCLUSIONS AND CLINICAL RELEVANCE

Circulating Fel d 1-specific DPB1*0401-restricted CD4+ T cells in both atopic and non-atopic donors maintain a central memory phenotype; however in atopics, the cells had greater Th2 effector function, compatible with a disease model of altered antigen delivery in atopic individuals.

Anti-IL5 decreases the number of eosinophils but not the severity of dermatitis in Sharpin-deficient mice

Sharpin-deficient (Sharpin(cpdm)) mutant mice develop a chronic eosinophilic dermatitis. To determine the efficacy of eosinophil-depletion in chronic inflammation, Sharpin(cpdm) mice were treated with anti-IL5 antibodies. Mice treated with anti-IL5 had a 90% reduction of circulating eosinophils and a 50% decrease in cutaneous eosinophils after 10 days compared with sham-treated littermates. Reducing the number of eosinophils resulted in increased severity of alopecia and erythema and a significant increase in epidermal thickness. Skin homogenates from mice treated with anti-IL5 had decreased mRNA expression of arylsulfatase B (Arsb), diamine oxidase (amiloride-binding protein 1, also called histaminase; Abp1) and Il10, which are mediators that eosinophils may release to quench inflammation. Skin homogenates from mice treated with anti-IL5 also had decreased mRNA expression of Il4, Il5, Ccl11, kit ligand (Kitl) and Tgfa; and increased mRNA expression of Tgfb1, Mmp12 and tenascin C (Tnc). In order to further decrease the accumulation of eosinophils, Sharpin(cpdm) mice were crossed with IL5 null mice. Il5(-/-), Sharpin(cpdm)/Sharpin(cpdm) mice had a 98% reduction of circulating eosinophils and a 95% decrease in cutaneous eosinophils compared with IL5-sufficient Sharpin(cpdm) mice. The severity of the lesions was similar between IL5-sufficient and IL5-deficient mice. Double mutant mice had a significant decrease in Abp1, and a significant increase in Tgfb1, Mmp12 and Tnc mRNA compared with controls. These data indicate that eosinophils are not essential for the development of dermatitis in Sharpin(cpdm) mice and suggest that eosinophils have both pro-inflammatory and anti-inflammatory roles in the skin of these mice.

Probiotics for the treatment or prevention of atopic dermatitis: a review of the evidence from randomized controlled trials

Probiotics are defined as live microorganisms which, when administered in adequate amounts, confer a health benefit on the host. To synthesize the evidence for the effectiveness of probiotics in the treatment or prevention of atopic dermatitis (AD) in children, we reviewed the results of 13 relevant randomized (placebo)-controlled trials (RCTs), 10 of which evaluated probiotics as treatment and 3 for prevention of AD. The main outcome measure in 9 RCTs was the change in SCORAD (SCORing Atopic Dermatitis). Four RCTs suggested that there was a statistically significant decrease in SCORAD after probiotic administration to infants or children with AD for 1 or 2 months compared with that after placebo, while in two RCTs SCORAD was significantly reduced after treatment with lactobacilli only in children with IgE-associated AD. In four of these six RCTs, clinical improvement was associated with a change in some inflammatory markers. In three RCTs, the change in SCORAD was not statistically significant between probiotic- and placebo-treated children, although in one of these trials SCORAD was significantly lower after probiotic than with placebo treatment in food-sensitized children. In most RCTs, probiotics did not cause a statistically significant change in interferon-gamma, interleukin-4, tumor necrosis factor-alpha, eosinophil cationic protein or transforming growth factor-beta compared with placebo. Regarding the effectiveness of probiotics in the prevention of AD, in two RCTs, infants at high risk for atopy who received probiotics developed AD significantly less frequently during the first 2 years of life than infants who received placebo. In these studies, mothers were administered Lactobacillus rhamnosus GG with or without other probiotics perinatally, followed by treatment of the infants with the same probiotics for the first 6 months of life. However, in another trial, neither the frequency nor the severity of AD during the first year of life were significantly different between infants with atopic mothers who received L. acidophilus for the first 6 months of life compared with infants who received placebo.Probiotics, especially L. rhamnosus GG, seem to be effective for the prevention of AD. They were also found to reduce the severity of AD in approximately half of the RCTs evaluated, although they were not found to change significantly most of the inflammatory markers measured in the majority of the RCTs evaluated. More RCTs need to be conducted to elucidate whether probiotics are useful for the treatment or prevention of AD.

Staphylococcus aureus skin colonization in atopic dermatitis children is associated with decreased IFN-gamma production by peripheral blood CD4+ and CD8+ T cells

Atopic dermatitis (AD) is a chronic inflammatory skin disorder, which is associated with an increased expression of Th2 cytokines with concomitant decrease in IFN-gamma production by circulating CD4+ and CD8+ T cells. The skin of patients with AD is often colonized by Staphylococcus aureus, which may reflect in changes in immunological parameters. The aim of the study was flow cytometric measurement of some peripheral blood lymphocyte subsets expressing naive/memory marker (RA/RO) and activation marker (CD25) as well as intracellular production of IFN-gamma by peripheral blood CD4+ and CD8+ T cells from varied severity AD children and determine the impact of S. aureus skin colonization on cytokines profiles. There was a significant increase in the percentage of CD4+ and CD8+ T cells producing IL-4 and IL-13 and decrease in the percentage of CD4+ and CD8+ T cells producing IFN-gamma upon in vitro stimulation with phorbol 12-myristate 13-acetate and ionomycin in children with AD compared to healthy ones. The absolute number of CD4+ and CD8+ T cells expressing memory marker CD45RO was elevated as compared with controls. The severity of AD was positively correlated with the percentage of lymphocyte subsets: CD45RO+, CD4+CD45RO+, and the percentage of CD3+ and CD4+ expressing CD25 as well as the number of S. aureus on the skin. In conclusion, both CD4+ and CD8+ memory T cells are involved in the immunopathogenesis of AD. S. aureus skin colonization is related with disease severity and changes in expression of CD45RO and CD25 on T cells. A decrease in the percentage of CD4+ and CD8+ T cells producing IFN-gamma in AD children may explain propensity for skin infection.

The novel tellurium immunomodulator AS101 inhibits interleukin-10 production and p38 MAPK expression in atopic dermatitis

The immunomodulator, AS101, inhibits production of IL-10, IL-4 and expression of p38 MAPK, while increasing production of IFNgamma and IL-2. Together with its excellent clinical safety profile in humans, suggests a potential therapeutic use for AD.

Different profiles of IL-10+IFN-gamma-IL-4-CD4+ T cells in the peripheral blood in atopic and non-atopic asthmatics

BACKGROUND

The impaired production of interleukin (IL) 10 from regulatory T cells has been proposed as a causal mechanism of asthma. Although IL-10-producing (IL-10+) T cells are detectable in the peripheral blood, their significance in the pathophysiology of asthma remains uncertain.

OBJECTIVES

This study aimed to investigate the profile of circulating IL-10+CD4+ T cells in atopic and non-atopic asthma.

METHODS

Atopic and non-atopic asthmatics were divided into a mild and severe group. Their peripheral blood mononuclear cells (PBMCs) were stimulated with anti-CD3 and anti-CD28 antibodies and then processed for triple cytokine flow cytometry directed to IL-10, interferon (IFN) gamma and IL-4.

RESULTS

IL-10+CD4+ cells were exclusively detected in the IFN-gamma-IL-4- population. In atopic asthma, the frequency of IL-10+IFN-gamma-IL-4-CD4+ cells in the severe group was significantly lower than that in the mild group. The frequency of IL-10+IFN-gamma-IL-4-CD4+ cells in the severe group was not significantly different from that in the mild group of those with non-atopic asthma. The frequency of IL-4+IFN-gamma-IL-10-CD4+ cells (Th2) was significantly higher in the group with mild atopic asthma than in that with mild non-atopic asthma. IFN-gamma+IL-4-IL-10-CD4+ cells (Th1) did not differ between groups, irrespective whether the subjects suffered from atopic or non-atopic asthma.

CONCLUSIONS

IL-10+CD4+ cells in PBMCs may be distinct from Th1 or Th2 and likely have the profile of regulatory T cells. The differential association of IL-10+IFN-gamma-IL-4-CD4+ cells with clinical severity between atopic and non-atopic asthma implies that its pathophysiological significance may differ among asthma phenotypes.