Chemokine levels in serum of children with atopic dermatitis with regard to severity and sensitization status

Atopic dermatitis and food allergy: More than sensitization

The increased risk of food allergy in infants with atopic dermatitis (AD) has long been recognized; an epidemiologic phenomenon termed "the atopic march." Current literature supports the hypothesis that food antigen exposure through the disrupted skin barrier in AD leads to food antigen-specific immunoglobulin E production and food sensitization. However, there is growing evidence that inflammation in the skin drives intestinal remodeling via circulating inflammatory signals, microbiome alterations, metabolites, and the nervous system. We explore how this skin-gut axis helps to explain the link between AD and food allergy beyond sensitization.

Distinct inflammatory markers in primary and secondary dengue infection: can cytokines CXCL5, CXCL9, and CCL17 act as surrogate markers?

Dengue fever poses a significant global health threat, with symptoms including dengue hemorrhagic fever and dengue shock syndrome. Each year, India experiences fatal dengue outbreaks with severe manifestations. The primary cause of severe inflammatory responses in dengue is a cytokine storm. Individuals with a secondary dengue infection of a different serotype face an increased risk of complications due to antibody-dependent enhancement. Therefore, it is crucial to identify potential risk factors and biomarkers for effective disease management. In the current study, we assessed the prevalence of dengue infection in and around Aligarh, India, and explored the role of cytokines, including CXCL5, CXCL9, and CCL17, in primary and secondary dengue infections, correlating them with various clinical indices. Among 1,500 suspected cases, 367 tested positive for dengue using Real-Time PCR and ELISA. In secondary dengue infections, the serum levels of CXCL5, CXCL9, and CCL17 were significantly higher than in primary infections (P < 0.05). Dengue virus (DENV)-2 showed the highest concentrations of CXCL5 and CCL17, whereas DENV-1 showed the highest concentrations of CXCL9. Early detection of these cytokines could serve as potential biomarkers for diagnosing severe dengue, and downregulation of these cytokines may prove beneficial for the treatment of severe dengue infections.

Food protein-induced allergic proctocolitis in infants is associated with low serum levels of macrophage inflammatory protein-3a

BACKGROUND

Food protein-induced allergic proctocolitis (FPIAP) is a nonimmunoglobulin (IgE)-mediated food hypersensitivity and the exact mechanisms that cause FPIAP are unknown. Chemokines play crucial roles in the development of allergic diseases.

OBJECTIVE

To examine serum levels of a group of chemokines in infants with FPIAP.

METHODS

In 67 infants with FPIAP and 65 healthy infants, we measured serum levels of mucosa-associated epithelial chemokine (MEC/CCL28), thymus-expressed chemokine (TECK/CCL25), CX3CL1 and macrophage inflammatory protein (MIP)-3a/CCL20.

RESULTS

Infants with FPIAP had a lower median value of MIP3a/CCL20 than healthy infants [0.7 (0-222) vs. 4 (0-249) pg/mL, respectively] (p < 0.001). Infants with MIP3a/CCL20 levels ≤0.95 pg/mL have 13.93 times more risk of developing FPIAP than infants with MIP3a/CCL20 levels >0.95 pg/mL. Serum MEC/CCL28, TECK/CCL25, and CX3CL1 levels were similar between the infants with FPIAP and the control group.

CONCLUSION

MIP3a/CCL20 serum levels were reduced in infants with FPIAP compared with healthy controls. Whether this finding has a role in pathogenesis remains to be determined.

A new cell line based coculture system for skin sensitisation testing in one single assay using T cells, aryl hydrocarbon receptor knockout, and co-inhibitory blockage

Established in vitro assays for regulatory testing of skin sensitisation partly suffer from only moderate sensitivity, specificity, and predictivity when testing specific groups of chemicals. This may be due to limited biomarker response in vitro in cell types that interact as crucial players of in vivo skin sensitisation pathogenesis. Here, we propose a molecular approach to overcome this limitation. In our model, we apply genome editing and blocking of immunoregulatory molecules to increase the range of biomarker modulation by sensitising chemicals. To this end, aryl hydrocarbon receptor (AhR) knockout was done by CRISPR/Cas9 technology in THP-1 cells and combined with Programmed Cell Death-Ligand (PD-L)1 blockade. AhR-knockout THP-1 in coculture with HaCaT keratinocytes showed increased CD54 expression compared to wild type cells after stimulation with 10 µmol/L dinitrochlorobenzene (DNCB) that was further enhanced by anti-PD-L1. After stimulation of AhR-knockout THP-1 with 200 µmol/L mercaptobenzothiazol or 10 µmol/L DNCB, cocultivated Jurkat T cells significantly increased expression of T cell receptor-associated CD3. No such increase was detected after prior treatment of THP-1 with 150 µmol/L of irritant sodium lauryl sulphate. Additionally, higher levels of inflammatory cytokines MIP-3α, MIP-1β, TNF-α, and IL-8 were found in supernatants of enhanced loose-fit co-culture based sensitisation assay (eLCSA) after substance treatment. Hence, eLCSA allowed to discriminate between sensitisers and non-sensitisers. Thus, inhibition of immunoinhibitory pathway signalling by combining AhR knockout and PD-L1 antibody blockage into an assay involving main acting cell types in skin sensitisation may increase sensitivity and specificity of such assays and allow potency derivation.

Blood-Based Biomarkers for Eosinophilic Esophagitis and Concomitant Atopic Diseases: A Look into the Potential of Extracellular Vesicles

Eosinophilic esophagitis (EoE) is a chronic, Th2-inflammatory disease of the esophagus that can severely affect food intake. Currently, diagnosis and assessing response to treatment of EoE is highly invasive and requires endoscopy with esophageal biopsies. Finding non-invasive and accurate biomarkers is important for improving patient well-being. Unfortunately, EoE is usually accompanied by other atopies, which make it difficult to identify specific biomarkers. Providing an update of circulating EoE biomarkers and concomitant atopies is therefore timely. This review summarizes the current knowledge in EoE blood biomarkers and two of its most common comorbidities, bronchial asthma (BA) and atopic dermatitis (AD), focusing on dysregulated proteins, metabolites, and RNAs. It also revises the current knowledge on extracellular vesicles (EVs) as non-invasive biomarkers for BA and AD, and concludes with the potential use of EVs as biomarkers in EoE.

Atopic Dermatitis: Striving for Reliable Biomarkers

Atopic dermatitis (AD) is a highly heterogeneous inflammatory disease regarding both its pathophysiology and clinical manifestations. However, it is treated according to the “one-size-fits-all” approach, which may restrict response to treatment. Thus, there is an unmet need for the stratification of patients with AD into distinct endotypes and clinical phenotypes based on biomarkers that will contribute to the development of precision medicine in AD. The development of reliable biomarkers that may distinguish which patients with AD are most likely to benefit from specific targeted therapies is a complex procedure and to date none of the identified candidate biomarkers for AD has been validated for use in routine clinical practice. Reliable biomarkers in AD are expected to improve diagnosis, evaluate disease severity, predict the course of disease, the development of comorbidities, or the therapeutic response, resulting in effective and personalized treatment of AD. Among the studied AD potential biomarkers, thymus and activation-regulated chemokine/C-C motif ligand 17 (TARC/CCL17) has the greatest evidence-based support for becoming a reliable biomarker in AD correlated with disease severity in both children and adults. In this review, we present the most prominent candidate biomarkers in AD and their suggested use.

Association of the Maternal Gut Microbiota/Metabolome with Cord Blood CCL17

Chemokine (C-C motif) ligand 17 (CCL17) is a pro-allergic factor: high CCL17 levels in cord blood (CB) precede later allergic predisposition. Short-chain fatty acid (SCFA) treatment during pregnancy has been shown to protect mouse pups against allergic diseases. The maternal microbial metabolome during pregnancy may affect fetal allergic immune responses. We therefore examined the associations between CB CCL17 and gut SCFA levels in healthy pregnant Japanese women. CB CCL17 serum levels at birth, and maternal non-specific IgE levels in maternal sera at 32 weeks of gestation were measured. Maternal stool samples were collected at 12 (n = 59) and 32 (n = 58) weeks of gestation for gut microbiota analysis, based on barcoded 16S rRNA sequencing and metabolite levels. The CB CCL17 levels correlated negatively with butyrate concentrations and positively with isobutyrate at 12 weeks; CB CCL17 correlated positively with valerate and lactate at 32 weeks. Similarly, butyrate levels correlated negatively with maternal non-specific IgE levels, whereas the lactate concentration correlated positively with IgE levels. At 32 weeks, the Shannon diversity index (SDI) of Firmicutes and Proteobacteria correlated negatively with CB CCL17 levels, while those of the total microbiota correlated positively with the CB CCL17 levels. These metabolites may alter fetal immune responses. This study provides the first link between maternal metabolites during pregnancy and the risk of allergic diseases in human offspring.

Chemokines during anaphylaxis: the importance of CCL2 and CCL2-dependent chemotactic activity for basophils

Background

The role of chemokines in anaphylaxis is unclear.

Methods

We prospectively recruited 49 patients presenting to the emergency department with an acute episode of anaphylaxis and 28 healthy subjects. We measured serum levels of the chemokines CCL2, CCL5, CCL7, CCL8, CCL11, CCL13, CCL17, CCL21, CCL22, CCL24, and CCL26, tryptase, the absolute number of circulating basophils, monocytes, lymphocytes, and PMNs, and whole blood FCER1A, CPA3 and HDC gene expression at two time points: during the anaphylactic episode and in convalescent samples collected approximately 3 months later. We then investigated the in vitro chemotactic activity of chemokines induced during anaphylaxis for the in vitro migration of the corresponding cells.

Results

Only CCL2 chemokine levels were significantly increased in anaphylaxis samples (median 514 pg/ml) compared to convalescent samples (284 pg/ml, P < 0.0001) and healthy subjects (279 pg/ml, P < 0.0001); there was no significant difference in any of the other chemokines. There was a significant positive correlation between the rates of increase of serum CCL2 (median [range]: 106.0% [− 44.7% to 557.4%]) and tryptase (133.8% [− 6.6% to 893.4%]; r = 0.68, P < 0.0001) and between the acute concentration of serum CCL2 and the acute concentration of serum tryptase (r = 0.77, P < 0.0001). The number of circulating basophils, but not other blood cells, significantly decreased during anaphylaxis (median 5.0 vs. 19.1 cells/µl in convalescent samples; P < 0.0001); a decrease in whole-blood gene expression of basophil markers (P ≤ 0.0018) confirmed these changes. Anaphylactic serum enhances the in vitro migration of basophils via CCL2-dependent chemotactic activity; in contrast, no CCL2-dependent chemotactic activity was observed for convalescent samples.

Conclusions

Our findings imply an important and specific role for CCL2-mediated chemotactic activity in the pathophysiology of human anaphylaxis.

Plasma thymus and activation‐regulated chemokine (TARC) as diagnostic marker in pediatric Hodgkin lymphoma

Pediatric classical Hodgkin's lymphoma (cHL) is characterized by Hodgkin Reed‐Sternberg cells located in an inflammatory microenvironment. Blood biomarkers result from active crosstalk between these cells. One promising biomarker in adult cHL patients is “thymus‐and‐activation‐regulated chemokine” (TARC). The objectives of this study were to define normal TARC values in non‐cHL children and to investigate and correlate pretherapy TARC as diagnostic marker in pediatric cHL. In this multicenter prospective study, plasma and serum samples were collected of newly diagnosed cHL patients before start of treatment (n = 49), and from randomly selected non‐cHL patients (n = 81). TARC levels were measured by enzyme‐linked immunosorbent assay. The non‐cHL patients had a median plasma TARC value of 71 pg/mL (range: 18‐762), compared to 14 619 pg/mL (range: 380‐73 174) in cHL patients (P < .001). TARC values had a high discriminatory power (AUC = .999; 95% confidence interval, .998‐1). A TARC cutoff level of 942 pg/mL maximized the sum of sensitivity (97.9%) and specificity (100%). TARC plasma levels were associated with age, treatment level, bulky disease, B‐symptoms, and erythrocyte sedimentation rate. TARC was found to be a highly specific and sensitive diagnostic marker for pediatric cHL. This noninvasive marker could be of great value as screening test in the work‐up for pediatric patients with lymphadenopathy.

Association between atopic dermatitis and serious cutaneous, multiorgan and systemic infections in US adults

BACKGROUND

Atopic dermatitis (AD) is associated with barrier disruption, immune dysregulation, and immunosuppressing treatments that can increase the association with an unusual number of infections.

OBJECTIVE

To determine whether adults with AD have an unusually large number of serious infections and related outcomes.

METHODS

Data from the 2002 to 2012 National Inpatient Sample were analyzed, including an approximately 20% sample of all US hospitalizations (n = 72,108,077 adults). Prevalence of serious infections in hospitalized patients with vs without AD, length of stay, cost of care, and inpatient mortality secondary to serious infections were determined.

RESULTS

The prevalence of serious infections expressed as a percentage (95% confidence interval) was higher in adults hospitalized with than in those without AD (42.1% [41.6-42.6] vs 25.4% [25.2-25.6]; P = .0002). In logistic regression models with multiple predictors (multivariable logistic regression models), AD was associated with 32 of 38 infections examined. Associated cutaneous infections included eczema herpeticum (odds ratio [95% confidence interval] adjusted for other predictors: 67.93 [47.93-96.28]), erysipelas (11.15 [9.47-13.1]), and cellulitis (4.53 [4.42-4.64]). Associated respiratory infections included aspergillosis (1.51 [1.21-1.88]) and tuberculosis (1.57 [1.41-1.76]). AD was associated with extracutaneous, multiorgan, and systemic infections, including infectious arthropathy (2.01 [1.84-2.20]), endocarditis (1.25 [1.12-1.39]), encephalitis (1.65 [1.40-1.96]), and methicillin-resistant Staphylococcus aureus infections (3.29 [3.17-3.42]). Patients with AD hospitalized with vs without any serious infection had an increased geometric mean cost of inpatient care ($8,273 [8,126-8,423] vs $7,179 [7,052-7,307]) and length of stay (5.3 days [5.2-5.3] vs 3.9 [3.9-4.0]; P = .0002), with $11 to $228 million excess annual costs from hospitalization with serious infections in adults with AD.

CONCLUSION

Adults with AD had increased cutaneous, respiratory, multiorgan, and systemic infections, which were associated with a considerable cost burden.

Systemic and stratum corneum biomarkers of severity in infant atopic dermatitis include markers of innate and T helper cell-related immunity and angiogenesis

Background

Biomarkers of atopic dermatitis (AD) are largely lacking, especially in infant AD. Those that have been examined to date have focused mostly on serum cytokines, with few on noninvasive biomarkers in the skin.

Objectives

We aimed to explore biomarkers obtainable from noninvasive sampling of infant skin. We compared these with plasma biomarkers and structural and functional measures of the skin barrier.

Methods

We recruited 100 infants at first presentation with AD, who were treatment naive to topical or systemic anti‐inflammatory therapies, and 20 healthy children. We sampled clinically unaffected skin by tape stripping the stratum corneum (SC). Multiple cytokines and chemokines and natural moisturizing factor were measured in the SC and plasma. We recorded disease severity and skin barrier function.

Results

Nineteen SC and 12 plasma biomarkers showed significant differences between healthy and AD skin. Some biomarkers were common to both the SC and plasma, and others were compartment specific. Identified biomarkers of AD severity included T helper 2‐skewed markers [interleukin (IL)‐13, CCL17, CCL22, IL‐5]; markers of innate activation (IL‐18, IL‐1α, IL1β, CXCL8) and angiogenesis (Flt‐1, vascular endothelial growth factor); and others (soluble intercellular adhesion molecule‐1, soluble vascular cell adhesion molecule‐1, IL‐16, IL‐17A).

Conclusions

We identified clinically relevant biomarkers of AD, including novel markers, easily sampled and typed in infants. These markers may provide objective assessment of disease severity and suggest new therapeutic targets, or response measurement targets for AD. Future studies will be required to determine whether these biomarkers, seen in very early AD, can predict disease outcomes or comorbidities.

What's already known about this topic?

Atopic dermatitis is a clinically heterogeneous condition with multiple clinical manifestations and a complex pathogenesis.

Systemic biomarkers of severity have been identified in adults, but are less well defined in children.

Biomarkers from the skin compartment have been based on biopsies to date.

What does this study add?

Noninvasive sampling can detect clinically relevant biomarkers in AD skin.

These biomarkers may be useful for disease stratification, and provide insights into the pathogenesis of infant AD.

Innate immune activation is important in the epidermis in infantile AD.

What is the translational message?

Noninvasive biomarkers can yield significant insights into infantile AD.

They identify innate activation, the T helper 2 pathway and angiogenesis as important pathways in this condition.

Respond to this article

Linked Comment:Hijnen. Br J Dermatol 2019; 180:455–456.

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Exploring Immune Development in Infants With Moderate to Severe Atopic Dermatitis

Background

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in infancy with a complex pathology. In adults, the clinical severity of AD has been associated with increases in T helper cell type (Th) 2, Th22, and Th17 serum markers, including high levels of CC chemokine ligand (CCL) 17 and CCL22 chemokines.

Objective

To explore the possible association between serum chemokine levels and AD severity in infants with moderate-to-severe AD and elevated immunoglobulin E (IgE).

Subjects and methods

Serum samples (n = 41) obtained from a randomized, double-blind, and clinical dietary intervention study were used to study biomarkers in infants with AD. Baseline- and post-intervention samples (4 months) were used, six chemokines and nine ratios thereof were analyzed using Luminex and correlated to AD severity. In the initial study, the infants were randomized to receive extensively hydrolyzed whey-based formula without (control) or with short-chain galacto-oligosaccharides/long-chain fructo-oligosaccharides (9:1) and Bifidobacterium breve M-16V (active).

Results

31 Infants up to 11 months of age, with an objective-SCORAD score (oSCORAD) ≥ 20 and elevated total-IgE and/or specific-IgE levels were included. In time, the median oSCORAD decreased in both groups by −8 (control, p < 0.05; active, p < 0.01). Irrespective of dietary intervention, several changes in Th2 chemokines (CCL17 and CCL22), inflammatory chemokine (CCL20), and the Th1 chemokine, CXC chemokine ligand (CXCL) 9, were detected over time. Overall CCL17 correlated to oSCORAD (r = 0.446, p < 0.01). After 4 months of dietary intervention, CXCL9 was higher (p < 0.01) in the active group compared with control [active, 2.33 (1.99–2.89); controls, 1.95 (1.77–2.43) log 10 median (range)]. In addition, a reduction in Th2/Th1 chemokine ratios for CCL17/CXCL9, CCL22/CXCL9, CCL20/CXCL10, and CCL20/CXCL11 was detected associated with the active intervention.

Conclusion

While this study is small and exploratory in nature, these data contribute to immune biomarker profiling and understanding of AD in infants.

Food allergy and atopic dermatitis: Prediction, progression, and prevention

The rising burden of allergic diseases in childhood requires a compelling need to identify individuals at risk for atopy very early in life or even predict the onset of food allergy and atopic dermatitis since pregnancy. The development and clinical phenotypes of atopic diseases in childhood depend on a complex interaction between genetic and environmental factors, such as allergen exposure, air pollution, and infections. Preventive strategies may include avoidance measures, diet supplements, and early complementary food introduction. Overall, the management of allergic diseases has been improving to date toward a patient's tailored approach. This review will cover the current understanding of risk factors, prediction, and management of food allergy and atopic dermatitis in childhood and discuss how these may contribute to the modification of the natural history of food allergy and atopic dermatitis.

Hydrogen water ameliorates the severity of atopic dermatitis-like lesions and decreases interleukin-1β, interleukin-33, and mast cell infiltration in NC/Nga mice

OBJECTIVES

To examine the effect of hydrogen water (HW) on the severity of atopic dermatitis (AD) and elucidate the underlying pathophysiological mechanisms.

METHODS

For this experimental study between March 2015 and December 2015, NC/Nga mice characterized by mild AD severity were given either HW (n=11) or purified water (PW) (n=9) ad libitum; specific-pathogen-free mice (n=9) were used as AD-free control. Atopic dermatitis severity score and transepidermal water loss (TEWL) were examined at baseline (0 week), and after 4 weeks of HW/PW treatment. Levels of serum thymus and activation-regulated chemokine (TARC) and cytokines in the AD lesion were measured by ELISA; and mRNA expression of TARC  and aquaporin (AQP-3) genes in the skin was examined by real-time polymerase chain reaction. Results: Mice treated with HW for 4 weeks demonstrated a significant decrease in the AD severity score compared with PW-treated mice (p less than 0.01). Hydrogen water administration also significantly reduced TEWL and serum TARC levels (p less than 0.01), infiltration of mast cells (p less than 0.05), and secretion of the proinflammatory cytokines interleukin (IL)-1β and IL-33 (p less than 0.05) in skin lesions compared with PW. However, no difference was observed between PW and HW groups in interferon-γ secretion and expression of AQP-3 and TARC genes. Conclusion: Hydrogen water suppressed inflammation in AD mice, leading to amelioration of disease severity, which suggests the therapeutic potential of HW in AD treatment.

β-Carotene Concentration and Its Association with Inflammatory Biomarkers in Spanish Schoolchildren

AIM

To examine the correlation between inflammatory biomarkers and plasma β-carotene levels in children.

METHODS

A total of 564 Spanish schoolchildren aged 9-12 were observed and studied. Plasma β-carotene levels were assessed by HPLC. A β-carotene level <4.83 µg/dL (0.09 µmol/L) was considered deficient. Plasma tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured by immunoenzyme assays. Serum high-sensitivity C-reactive protein (hs-CRP) was tested by immunonephelometry.

RESULTS

Subjects who were β-carotene-deficient (23.1% of the studied children) had higher IL-6 levels than subjects with normal β-carotene concentrations. The log-IL-6 and log-hs-CRP concentrations, but not the log-TNF-α level, were strongly and inversely related to the plasma log-β-carotene level (taking into account log-age, energy intake, log-triglycerides, gender, log-body mass index, log-β-carotene intake, energy from lipids and cholesterol as covariables). When the 3 inflammatory biomarkers were introduced into the regression model along with the corresponding covariables, only the log-IL-6 level was related to the plasma log-β-carotene level (β = -0.505 ± 0.078; p < 0.001).

CONCLUSIONS

Inflammatory status, in particular IL-6 levels, appears to be negatively associated with plasma β-carotene levels in schoolchildren.