Decreased frequency of intracellular IFN-gamma producing T cells in whole blood preparations from patients with atopic dermatitis

Characterization of High and Low IFNG-Expressing Subgroups in Atopic Dermatitis

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases, with an increasing number of targeted therapies available. While biologics to treat AD exclusively target the key cytokines of type 2 immunity, Janus kinase inhibitors target a broad variety of cytokines, including IFN-γ. To better stratify patients for optimal treatment outcomes, the identification and characterization of subgroups, especially with regard to their IFNG expression, is of great relevance, as the role of IFNG in AD has not yet been fully clarified. This study aims to define AD subgroups based on their lesional IFNG expression and to characterize them based on their gene expression, T cell secretome and clinical attributes. RNA from the lesional and non-lesional biopsies of 48 AD patients was analyzed by RNA sequencing. Based on IFNG gene expression and the release of IFN-γ by lesional T cells, this cohort was categorized into three IFNG groups (high, medium, and low) using unsupervised clustering. The low IFNG group showed features of extrinsic AD with a higher prevalence of atopic comorbidities and impaired epidermal lipid synthesis. In contrast, patients in the high IFNG group had a higher average age and an activation of additional pro-inflammatory pathways. On the cellular level, higher amounts of M1 macrophages and natural killer cell signaling were detected in the high IFNG group compared to the low IFNG group by a deconvolution algorithm. However, both groups shared a common dupilumab response gene signature, indicating that type 2 immunity is the dominant immune shift in both subgroups. In summary, high and low IFNG subgroups correspond to intrinsic and extrinsic AD classifications and might be considered in the future for evaluating therapeutic efficacy or non-responders.

Prolidase deficiency, a rare inborn error of immunity, clinical phenotypes, immunological features, and proposed treatments in twins

Background

Prolidase deficiency (PD) is an autosomal recessive inborn multisystemic disease caused by mutations in the PEPD gene encoding the enzyme prolidase D, leading to defects in turnover of proline-containing proteins, such as collagen. PD is categorized as a metabolic disease, but also as an inborn error of immunity. PD presents with a range of findings including dysmorphic features, intellectual disabilities, recurrent infections, intractable skin ulceration, autoimmunity, and splenomegaly. Despite symptoms of immune dysregulation, only very limited immunologic assessments have been reported and standard therapies for PD have not been described. We report twin females with PD, including comprehensive immunologic profiles and treatment modalities used.

Case presentation

Patient 1 had recurrent infections in childhood. At age 13, she presented with telangiectasia, followed by painful, refractory skin ulcerations on her lower limbs, where skin biopsy excluded vasculitis. She had typical dysmorphic features of PD. Next-generation sequencing revealed pathogenic compound heterozygous mutations (premature stop codons) in the PEPD gene. Patient 2 had the same mutations, typical PD facial features, atopy, and telangiectasias, but no skin ulceration. Both patients had imidodipeptiduria. Lymphocyte subset analysis revealed low-normal frequency of T_reg cells and decreased frequency of expression of the checkpoint molecule CTLA-4 in CD4⁺ T_EM cells. Analysis of Th1, Th2, and Th17 profiles revealed increased inflammatory IL-17⁺ CD8⁺ T_EM cells in both patients and overexpression of the activation marker HLA-DR on CD4⁺ T_EM cells, reflecting a highly activated proinflammatory state. Neither PD patient had specific antibody deficiencies despite low CD4⁺CXCR5⁺ T_fh cells and low class-switched memory B cells. Plasma IL-18 levels were exceptionally high.

Conclusions

Immunologic abnormalities including skewed frequencies of activated inflammatory CD4⁺ and CD8⁺ T_EM cells, decreased CTLA-4 expression, and defects in memory B cells may be a feature of immune dysregulation associated with PD; however, a larger sample size is required to validate these findings. The high IL-18 plasma levels suggest underlying autoinflammatory processes.

IFN-γ Reduces Epidermal Barrier Function by Affecting Fatty Acid Composition of Ceramide in a Mouse Atopic Dermatitis Model

IFN-γ is detected in chronic lesions of atopic dermatitis (AD); however, its specific role remains to be elucidated. An impaired stratum corneum barrier function is a hallmark of AD, and it is associated with a reduction in ceramides with long-chain fatty acids (FAs) in the stratum corneum. FA elongases, ELOVL1 and ELOVL4, are essential for the synthesis of these ceramides, together with ceramide synthase 3 (CerS3). We have previously shown that IFN-γ, but not other cytokines, induced the downregulation of these enzymes in cultured keratinocytes. Our aim was to investigate the in vivo role of IFN-γ in the lesional skin of AD by analyzing mouse dermatitis models. The local mRNA expression of IFN-γ increased in mite fecal antigen-induced AD-like dermatitis in NC/Nga mice but not in imiquimod-induced psoriasis-like dermatitis in BALB/c mice. The mRNA expression of ELOVL1 and ELOVL4 significantly decreased in AD-like dermatitis, whereas ELOVL1 increased in psoriasis-like dermatitis. The expression of CerS3 increased slightly in AD-like dermatitis, but it increased by 4.6-fold in psoriasis-like dermatitis. Consistently, the relative amount of ceramides with long-chain FAs decreased in AD-like dermatitis but not in psoriasis-like dermatitis. These results suggest that IFN-γ in the lesional skin may reduce ceramides with long-chain FAs by decreasing the expression of ELOVL. Thus, IFN-γ may contribute to the chronicity of AD by impairing barrier function.

Evaluation of Potential Disease-Mediated Drug-Drug Interaction in Patients With Moderate-to-Severe Atopic Dermatitis Receiving Dupilumab

This open‐label drug–drug interaction study assessed whether blockade by dupilumab of interleukin (IL)‐4 and IL‐13 signaling affects the pharmacokinetics of drugs metabolized by cytochrome P450 (CYP450) enzymes. The pharmacokinetics of five CYP450 substrates given orally (midazolam, omeprazole, S‐warfarin, caffeine, and metoprolol, metabolized by CYP3A, CYP2C19, CYP2C9, CYP1A2, and CYP2D6, respectively) were evaluated before and 28 days after initiation of dupilumab treatment (subcutaneous 300 mg weekly) in 14 patients with moderate‐to‐severe atopic dermatitis. Dupilumab had no clinically relevant effects on the pharmacokinetics of CYP450 substrates, provided substantial clinical benefit, and was generally well tolerated. Only one serious adverse event was reported, an episode of systemic inflammatory response syndrome that resolved after treatment was discontinued. In summary, blockade of IL‐4/IL‐13 signaling in patients with type 2 inflammation does not appear to significantly affect CYP450 enzyme activities; the use of dupilumab in atopic dermatitis patients is unlikely to influence the pharmacokinetics of CYP450 substrates.

The translational revolution and use of biologics in patients with inflammatory skin diseases

Psoriasis and atopic dermatitis (AD) are common inflammatory skin diseases characterized by immune-mediated inflammation and abnormal keratinocyte differentiation. Although T-cell infiltration characterizes both diseases, T-cell polarization differs. Psoriasis is currently the best model for translational medicine because many targeted therapeutics have been developed and testing of targeted therapeutics has cemented psoriasis as IL-23/TH17 polarized. In patients with AD, although therapeutic development is approximately a decade behind that in patients with psoriasis, there is now active development and testing of targeted therapeutics against various immune axes (TH2, TH22, and IL-23/TH17). These clinical trials and subsequent molecular analyses using human samples will be able to clarify the relative roles of polar cytokines in patients with AD.

Investigation of cytokine levels and their association with SCORAD index in adults with acute atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease with increasing frequency over the last decades, especially in adults. Cytokines orchestrate atopic skin inflammation. Objectives  The aim of this study was to compare serum levels of cytokines in adult patients with acute AD (AD1) with other groups of AD patients and controls and investigate the possible association between such cytokines and disease severity.

METHODS

We measured cytokine levels using flow cytometry in 21 adult patients with acute AD, 12 adults with chronic AD, 10 children with acute AD and 10 healthy adults.

RESULTS

Flow cytometry analysis of cytokines revealed that interleukin 10 (IL-10), IL-6, interferon γ (IFN-γ) and IL-4 levels were significantly decreased in AD1 group compared with controls, whereas IL-2 and tumour necrosis factor (TNF) did not differ. Comparison of AD1 group with adults chronic phase group showed that IgE, eosinophil and IL-2 levels remained unaltered, whereas IL-10, IL-6, IFN-γ, IL-4 and TNF were significantly decreased. SCORAD and IgE levels were significantly increased, IL-10, IL-6 and IFN-γ were decreased and TNF, IL-2, IL-4 and eosinophil levels remained unchanged in AD1 group compared with children acute phase group. Within AD1 group correlation analysis revealed that IgE and TNF levels were significantly associated with AD severity. Coefficient of determination analysis revealed that TNF and IgE levels could explain 49.14% and 35.28% of the variance of SCORAD.

CONCLUSIONS

These data indicate that serum IgE and TNF levels correlate with AD severity and that serum cytokines are downregulated in AD1 group. Further studies are clearly needed to elucidate cytokines' role in adults with AD.

Persulphate challenge in female hairdressers with nasal hyperreactivity suggests immune cell, but no IgE reaction

PURPOSE

The aim of this study was to examine the effects of persulphate on the nasal mucosa and on the immune cells in hairdressers suffering from bleaching powder associated rhinitis (BAR) versus subjects with rhinitis not previously exposed to bleaching powder.

METHODS

Fifteen hairdressers (S) with BAR, 14 without symptoms (WS) and 12 atopics (A) with rhinitis but without exposure to bleaching powder were studied. Each performed a nasal challenge with persulphates. Effect parameters were symptom score, acoustic rhinometry, albumin in nasal lavage, subpopulations of lymphocytes in blood and specific serum antibodies.

RESULTS

The S group had a post-challenge increase in nasal symptoms and nasal lavage albumin. The A group reacted to a lesser intent. The S and A groups showed an increase in Th1 cells. An HLA class II cell expression was noticed in both groups of hairdressers. No evidence of a type 1 reaction (immediate type) to persulphate was noticed.

CONCLUSIONS

Persulphate challenge affects hairdressers with BAR, but also atopics. The reaction may be driven by a Th1 cell activation.

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.

Asthma in patients with atopic dermatitis

OBJECTIVE

This cross-sectional study was designed to estimate the frequency of asthma in patients with atopic dermatitis (AD), and its related factors.

METHODS

The study population consisted of 236 patients with AD who were referred to Children Medical Center in 1997-2002 and their diagnosis was based on Hanifin & Rajka criteria. Severity of AD was categorized based on Severity Scoring of Atopic Dermatitis (SCORAD) index. Asthma was diagnosed with medical history and clinical examination (three or more episodes of wheezing and/or dyspnea and/or cough after 1 year old). The patients were divided in two groups according to having or not having asthma.

RESULTS

The mean age of patients with AD was 38.67+/-2.68 month and the mean age at onset of asthma was 20+/-2.5 month. The frequency of asthma in AD patients was 27.5%. The mean of SCORAD in nonasthmatic patients was 52.27 +/- 2.52 and in asthmatic patients was 56.2+/- 4.2 (P= 0.4). The mean of duration of breastfeeding in asthmatic patients was 12.2+/-1.6 month and in non-asthmatic patients was 11.16+/-6.3 month (P = 0.87). There was no significant difference between asthmatic patients and others in serum IgE levels (P = 0.65) and blood eosinophil count. (P = 0.49).

CONCLUSION

These results confirmed that development of asthma in patients with AD is more than normal population and AD can be a significant predisposing factor to developing asthma but the causative factors are not clear.

Elevated allergen-induced IL-13 secretion predicts IgE elevation in children ages 2-5 years

It is unclear if early immune responses to allergens, specifically Th1 and Th2 cytokine production, predict later immune responses, including increased IgE levels. In a group of children (n = 151) with a parental history of allergy or asthma followed from ages 2 through 5 years, we examined IL-13, IL-4, and IFN-gamma secretion by peripheral blood mononuclear cells in response to phytohemagglutinin (PHA), and to dust mite (Der f 1), cockroach (Bla g 2), and cat (Fel d 1) allergens in relation to elevated IgE. Elevated IgE was defined either as a positive IgE-specific response to at least one allergen (dust mite, cockroach, cat, and ovalbumin) or as an elevated total IgE level above a specified cut-off value. In multivariate logistic regression models including 181 observations made between the age of 2 through 5 years and accounting for repeated measures, we found an association between increased IL-13 secretion in response to Der f 1 and elevated IgE (odds ratio [OR] = 1.21, 95% confidence interval [CI] = 1.09-1.34). Age did not modify this relationship. No association was found between allergen-induced IFN-gamma secretion and IgE production. Among the group of children with measurements made at age 4-5 (n = 70), IL-13 in response to Der f 1 (p = 0.046), and IL-4 in response to PHA (p = 0.04) were increased among children with elevated IgE. In a smaller subset of children with measurements made at both age 2-3 and age 4-5 (n = 36), IL-13 levels at age 2-3 were also significantly increased in response to Der f 1 (p = 0.01) and Fel d 1 (p = 0.002) among those with elevated IgE at age 4-5. In a group of children ages 2-5 years, there is an association between IL-13 and elevated IgE.

Intracellular production of IL-2, IL-4, IFN-gamma, and TNF-alpha by peripheral blood CD3+ and CD4+ T cells in children with atopic dermatitis

The role of the type-2 T helper (Th2) cell-mediated immune response in the immunopathogenesis of atopic dermatitis (AD) is well documented. Whether polarized immunoresponse is confined to antigen-specific T cells or is distributed among all T cell subsets is still controversial. We investigated frequencies of interleukin-2 (IL-2), IL-4, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) producing CD3(+) and CD4(+) T cells in peripheral blood from children with atopic dermatitis and healthy subjects with and without in vitro stimulation. Children with severe AD had a significantly lower percentage of CD4(+) T cells spontaneously expressing IL-4 compared with healthy controls (p <0.01). Polyclonal stimulation significantly increased cytokine production in both AD patients and healthy individuals. Frequencies of CD3(+) and CD4(+) producing IL-2, IL-4, IFN-gamma, and TNF-alpha after in vitro stimulation with phorbol-12-myristate 13-acetate (PMA) + ionomycin were comparable in the AD and control groups. In response to PMA/ionomycin, children with AD and asthma symptoms had a significantly lower percentage of CD3(+) T cells producing TNF-alpha. We failed to demonstrate evidence of an imbalance with respect to type-2 cytokine productions in children with AD. Comparable induction of Th1 and Th2 cytokines in polyclonally stimulated peripheral CD3(+) and CD4(+)T cells from AD patients and controls puts into question the polarized Th2 immune response as a general characteristic of T cells in children with atopic dermatitis.

Down-regulation of interferon-gamma parallels clinical response to selective leukocyte apheresis in patients with inflammatory bowel disease: a 12-month follow-up study

BACKGROUND & AIMS

Pilot studies have indicated a therapeutic role for an apheresis device (Adacolumn) that selectively adsorbs leukocytes in patients with inflammatory bowel diseases. It may also exert immunoregulatory effects contributing to its clinical efficacy. This study aimed to correlate the clinical response to leukocyte apheresis with the expression of key cytokines in mucosal tissue, in peripheral leukocytes, and in plasma.

METHODS

Ten patients (seven with Crohn's disease and three with ulcerative colitis, median age: 31 years) with mild to moderately chronic activity were recruited to an open study. Patients were refractory to or had a relapse despite conventional treatment including azathioprine. Leukocyte apheresis was performed once a week for five consecutive weeks. Clinical efficacy was assessed on week 7 and after 12 months. Colonoscopy with multiple biopsies was performed at the start of the study and after 7 weeks for semiquantitative immunohistochemical analyses of cytokines. Cytokine levels in blood and the proportion of cytokine producing CD4+ and CD8+ lymphocytes were determined.

RESULTS

The apheresis procedures were well tolerated and no major adverse events were encountered. The median clinical activity score decreased from 12 to 7 on week 7 (P=0.031, n=9) and to 4 after 12 months (P=0.004, n=9). Five patients were in clinical remission at the 12th month. Tissue interferon (IFN)-gamma-positive T-cells decreased in clinical responders (P=0.027) after apheresis. In parallel, significantly lower levels of IFN-gamma-producing lymphocytes were detected in peripheral blood. IFN-gamma-positive cells in pretreatment biopsies completely disappeared or decreased in posttreatment biopsies sampled on week 7 in responders (P=0.027) and appeared to predict the maintenance of long-term remission or response after 12 months.

CONCLUSIONS

Leukocyte apheresis is a novel and safe nonpharmacological adjunct therapy that may prove useful in steroid refractory or dependent patients when conventional drugs have failed. Down-regulation of IFN-gamma in mucosal biopsies and in peripheral leukocytes may be a predictive marker for sustained, long-term response.

The disease progression in the keratin 14 IL-4-transgenic mouse model of atopic dermatitis parallels the up-regulation of B cell activation molecules, proliferation and surface and serum IgE

We have previously characterized the keratin 14 interleukin-4-transgenic (IL-4-Tg) mouse model of atopic dermatitis as a chronic pruritic inflammatory skin disease typified by skin infiltration of inflammatory cells and early up-regulation of Th2 cytokines and late surge of Th1 cytokines. In the present study, we examined the involvement of B cells. Systematic examinations of the following immunological parameters on B cells were carried out in non-Tg control mice and in IL-4-Tg mice at before disease onset and early and late disease stages so that we could determine the immunological sequence of events leading to the disease development: surface expressions of IA/IE, activation and costimulatory molecules, proliferation under LPS or IgM stimulation, quantification of cell surface and serum IgE, IgG1, and IgG2a. Our results showed that as the disease progresses from before onset to early disease and to late disease, there is a parallel increase in surface markers of B cell activation (IA/IE, CD44, CD69, CD80 and CD86), in B cell proliferation, and in cell surface and serum IgE. Significant increases of Th2-driven serum IgG1 and IgE in early disease was followed by significant increase of Th1-driven IgG2a in late disease. Importantly the significant increases of activation molecule (IA/IE), proliferation (to LPS), and surface IgE on B cells of the IL-4-Tg mice precedes the up-regulation of serum IgE and disease onset. These data suggest that activated B cells may play a role in atopic dermatitis disease development by up-regulating serum IgE concentration, which serves as a marker of disease onset.

Allergen challenge alters intracellular cytokine expression

The pathophysiology of asthma is complex and engages cascades of events in the cytokine network. We, therefore, investigated the impact of bronchial allergen challenge in humans on the cytokine profile of circulating lymphocytes. Peripheral blood samples from 10 patients with allergic asthma were collected before and 24 h after allergen provocation. Patients who mounted a late-phase reaction were designated dual responders opposite to single responders. Whole blood cells were stimulated by mitogen and intracellular interleukin (IL)-4 and interferon (IFN)-gamma were detected by flow cytometry. The allergen challenge induced a decrease in IL-4+CD4+ cells in the patients (P = 0.05), and a significant decrease (P < 0.05) in IFN-gamma+CD4+ cells was noted in single, but not dual, responders. In addition, there was a significant difference (P < 0.01) with respect to the changes in the IFN-gamma+CD4+ cells comparing dual and single responders. No corresponding changes were observed in CD8+ cells. The data suggest a possible on-going traffic of IFN-gamma and IL-4+CD4+ lymphocytes into the bronchial mucosa in relation to an allergen challenge and generate the hypothesis that a difference exists between single and dual responders in this respect. Because the CD4+IFN-gamma-producing cells have the capacity to downregulate the T-helper type 2 response, a reduced capacity in this aspect might contribute to the pathophysiology in dual responders.

T cell epitope-specific defects in the immune response to cat allergen in patients with atopic dermatitis

Atopic dermatitis (AD) is often associated with high titer IgE antibodies (ab) to allergens, and IL-10-mediated regulation of IFN-gamma has been proposed to contribute to this IgE ab production. However, the relevance of IL-10 and IFN-gamma to IgE associated with AD has not been examined in the context of an allergen-specific system. Analysis of PBMC responses in vitro showed deficient T cell proliferation to overlapping IL-10- (peptide (P) 2:1) and IFN-gamma- (P2:2) inducing chain 2 major epitopes of cat allergen (Fel d 1) in cultures from sensitized AD patients (mean IgE to cat=20.9 IU/ml). Diminished IFN-gamma induction by Fel d 1 and P2:2, along with elevated peptide-induced IL-10 (except for P2:1) was observed in PBMC cultures from AD subjects compared with non-AD (sensitized and non-sensitized) subjects. Neither T cell proliferation nor IFN-gamma production to chain 2 epitopes could be restored by anti-IL-10 mAb in cultures from sensitized AD subjects. Moreover, allergen avoidance was associated with a paradoxical decrease in both IL-10 and IFN-gamma in peptide-stimulated PBMC from these subjects. Control of IFN-gamma production to chain 2 epitopes by IL-10 may be relevant to sensitization status. Development of high titer IgE ab in AD could reflect a failure of this mechanism.