Proteomic, miRNA and bacterial biomarker patterns in atopic dermatitis patients and their course upon anti-IL-4Rα therapy

BACKGROUND

Identification of biomarkers is required for a systems medicine approach and personalized treatment in atopic dermatitis (AD). These biomarkers may not only aid in diagnosing but also might be suitable to predict the effectiveness of targeted treatment.

OBJECTIVE

We aimed to identify proteomic, microbial and miRNA biomarkers in AD patients and investigated their course in relation to the clinical response upon anti-IL-4Rα therapy.

METHODS

Proteomic and miRNA screening was performed in AD patients in comparison to healthy controls. Differentially regulated serum proteins, miRNA and selected skin microbiota were measured consecutively in 50 AD patients before and upon systemic dupilumab treatment. A random forest classifier was used to predict the outcome of dupilumab therapy based on the initial biomarker patterns.

RESULTS

We identified 27 proteomic candidates, miRNA and three microbial strains to be dysregulated in AD. CCL17, CCL13, CCL22, E-selectin and BDNF were differently regulated and significantly associated with treatment response. In contrast, neither the microbial composition nor the miRNA pattern was associated with treatment response upon dupilumab treatment.

CONCLUSION

AD patients display defined dysregulations regarding their systemic proteomic serum profile, miRNA patterns and their skin microbiome. The proteomic profile and selected skin bacteria changed profoundly upon anti-IL-4Rα therapy which was associated with an overall clinical response. This was not seen in miRNA-related biomarkers. Our findings support the hypothesis that biomarker profiles reflect treatment responses and may in the future be used to develop a personalized medicine approach for the treatment of AD patients.

Thymic stromal lymphopoietin production induced by skin irritation results from concomitant activation of protease-activated receptor 2 and interleukin 1 pathways

BACKGROUND

Thymic stromal lymphopoietin (TSLP) mediates proallergic T helper 2-type responses by acting on leucocytes. Endogenous pathways regulating TSLP production are poorly defined.

OBJECTIVES

To uncover the mechanisms by which skin barrier disruption elicits TSLP production and to delineate the level at which individual mechanistic components may converge.

METHODS

A combination of primary keratinocytes, skin explants and in vivo strategies was employed. Murine skin was tape stripped in the presence of neutralizing antibodies or antagonists. Cells and explants were stimulated with interleukin (IL)-1 and protease-activated receptor 2 agonist (PAR-2-Ag). TSLP levels were quantified by enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction. Chromatin immunoprecipitation and promoter reporter assays were used to examine recruitment and functional activity of nuclear factor kappa B (NF-κB) at the TSLP promoter.

RESULTS

TSLP induction in mouse skin occurred in a PAR-2- and IL-1-dependent manner. This scenario was duplicated by exogenous IL-1 plus PAR-2-Ag vs. each stimulus alone. Joint activity of PAR-2 and IL-1 was also observed in human keratinocytes. The TSLP promoter was identified as the target of PAR-2/IL-1, whereby PAR-2 activation augmented the recruitment of NF-κB and transcriptional activation over IL-1 alone. Combined treatment showed activity at concentrations of IL-1 unable to elicit NF-κB activity on their own.

CONCLUSIONS

Skin barrier disruption activates the IL-1 and the PAR-2 pathways, which act in concert to activate the TSLP promoter and possibly other inflammatory genes. Awareness of this combined activity may permit a more flexible clinical management by selective targeting of either pathway individually or collectively. What's already known about this topic? Thymic stromal lymphopoietin (TSLP) is rapidly induced upon skin perturbation and mediates proallergic T helper 2-type responses by acting on leucocytes. Endogenous control of TSLP expression is poorly understood, but interleukin (IL)-1 is one regulator in the cutaneous environment In addition to IL-1, protease-activated receptor 2 (PAR-2) organizes central inflammatory pathways in the skin. What does this study add? IL-1 and PAR-2 pathways cooperate in driving TSLP production in mice and humans. Pathway integration occurs at the level of the TSLP promoter through enhanced recruitment and transcriptional activation of nuclear factor kappa B. When PAR-2 is co-stimulated, very low IL-1 levels (inactive by themselves) can induce biologically meaningful responses in the skin environment. What is the translational message? Physical skin irritation results in robust TSLP production by simultaneous activation of PAR-2 and IL-1 pathways.

Factors increasing the risk for a severe reaction in anaphylaxis: An analysis of data from The European Anaphylaxis Registry

BACKGROUND

Preventive measures to decrease the frequency and intensity of anaphylactic events are essential to provide optimal care for allergic patients. Aggravating factors may trigger or increase the severity of anaphylaxis and therefore need to be recognized and avoided.

OBJECTIVE

To identify and prioritize factors associated with an increased risk of developing severe anaphylaxis.

METHODS

Data from the Anaphylaxis Registry (122 centers in 11 European countries) were used in logistic regression models considering existing severity grading systems, elicitors, and symptoms to identify the relative risk of factors on the severity of anaphylaxis.

RESULTS

We identified higher age and concomitant mastocytosis (OR: 3.1, CI: 2.6-3.7) as the most important predictors for an increased risk of severe anaphylaxis. Vigorous physical exercise (OR: 1.5, CI: 1.3-1.7), male sex (OR: 1.2, CI: 1.1-1.3), and psychological burden (OR: 1.4, CI: 1.2-1.6) were more often associated with severe reactions. Additionally, intake of beta-blockers (OR: 1.9, CI: 1.5-2.2) and ACE-I (OR: 1.28, CI: 1.05, 1.51) in temporal proximity to allergen exposition was identified as an important factor in logistic regression analysis.

CONCLUSION

Our data suggest it may be possible to identify patients who require intensified preventive measures due to their relatively higher risk for severe anaphylaxis by considering endogenous and exogenous factors.

Serum levels of 9α,11β-PGF2 and apolipoprotein A1 achieve high predictive power as biomarkers of anaphylaxis

Anaphylaxis is a life-threatening hypersensitivity reaction. To identify biomarkers for the condition, we assessed serum levels of apolipoprotein (Apo)A and ApoE. We found a reduction of both lipoproteins in anaphylactic mice as well as in orally challenged food allergic patients. We then compared patients after acute anaphylaxis with several control groups (nonallergic, history of allergen-triggered anaphylaxis, acute cardiovascular/febrile reactions). In this unpaired setting, ApoE levels were unaltered, while ApoA1 was reduced in the anaphylactic group. Although unable to discriminate between anaphylaxis and cardiovascular/febrile reactions, ROC curve analysis revealed a reasonably high area under the curve (AUC) of 0.91 for ApoA1. Serum 9α,11ß-PGF₂ , recently identified as a suitable biomarker for anaphylaxis, outperformed ApoA1 with AUC=0.95. Intriguingly however its power further increased upon combination of both mediators reaching AUC=1_. Our data suggest that ApoA1 combined with 9α,11ß-PGF₂ represents a useful composite biomarker of anaphylaxis, achieving superior diagnostic power over either factor alone.