Can serum biomarkers predict the outcome of systemic immunosuppressive therapy in adult atopic dermatitis patients?

Background: Atopic dermatitis (AD or eczema) is a most common chronic skin disease. Designing personalised treatment strategies for AD based on patient stratification is of high clinical relevance, given a considerable variation in the clinical phenotype and responses to treatments among patients. It has been hypothesised that the measurement of biomarkers could help predict therapeutic responses for individual patients. Objective: We aim to assess whether serum biomarkers can predict the outcome of systemic immunosuppressive therapy in adult AD patients. Methods: We developed a statistical machine learning model using the data of an already published longitudinal study of 42 patients who received azathioprine or methotrexate for over 24 weeks. The data contained 26 serum cytokines and chemokines measured before the therapy. The model described the dynamic evolution of the latent disease severity and measurement errors to predict AD severity scores (Eczema Area and Severity Index, (o)SCORing of AD and Patient Oriented Eczema Measure) two-weeks ahead. We conducted feature selection to identify the most important biomarkers for the prediction of AD severity scores. Results: We validated our model in a forward chaining setting and confirmed that it outperformed standard time-series forecasting models. Adding biomarkers did not improve predictive performance. Conclusions: In this study, biomarkers had a negligible and non-significant effect for predicting the future AD severity scores and the outcome of the systemic therapy.

Effect of immunosuppressive treatment on biomarkers in adult atopic dermatitis patients.

BACKGROUND: Biomarkers to objectively measure disease severity and predict therapeutic responses are needed in atopic dermatitis (AD). OBJECTIVE: Primary aim: To identify biomarkers reflecting therapeutic response in patients with AD treated systemically. Secondary aims: (i) To identify a biomarker pattern predicting responsiveness to systemic treatment. (ii) To identify differences in expression of biomarker in filaggrin gene (FLG) mutation carriers vs. non-FLG mutations carriers. METHODS: Thirty-eight severe AD patients treated with methotrexate or azathioprine participated. Serum levels of a proliferation-inducing ligand, B-cell activating factor of the TNF family, thymus and activation-regulated chemokine (chemokine (C-C motif) ligand 17) (TARC (CCl-17)), interleukin-1 receptor antagonist (IL-1RA), interleukin-1 bèta, IL-4, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12, IL-13, IL-18, IL-31, interferon gamma, tumour necrosis factor alpha, vascular endothelial growth factor (VEGF), monokine induced by interferon gamma (chemokine (C-X-C motif) ligand 9), interferon gamma-induced protein 10 (C-X-C motif chemokine Ligand 10), monocyte chemoattractant protein-1 (chemokine (C-C Motif) ligand 2), macrophage inflammatory protein-1 beta (chemokine (C-C motif) ligand 4), regulated on activation, normal T cell expressed and secreted (chemokine (C-C motif) ligand 5), Cutaneous T-cell-attracting chemokine (chemokine (C-C motif) ligand 27) (CTACK (CCL-27)), thymic stromal lymphopoietin, IL-5, interleukin-1 alpha and granulocyte-colony stimulating factor were analysed by ELISA and Luminex. The primary outcomes were differences in mean absolute change of SCORing Atopic Dermatitis (SCORAD) between groups after 12 weeks compared with baseline. Responders to treatment were defined by a SCORAD reduction in ≥50%. Buccal mucosa swabs were collected to determine FLG genotype status. RESULTS: Thymus and activation-regulated chemokine, CTACK, IL-13 and VEGF showed a significant decrease after treatment with methotrexate or azathioprine. However, no decrease in individual cytokine levels was significantly correlated with a change in any of the outcome parameters. In addition, baseline biomarker levels were not significantly different between responders and non-responders, and FLG and non-FLG mutants showed similar biomarker profiles. CONCLUSION: Thymus and activation-regulated chemokine and CTACK were confirmed as potential biomarkers. VEGF and IL-13 have a potential value as well. Biomarkers could not be used to discriminate at baseline between responders and non-responders, or FLG genotype status.

Cytokine profiles in interstitial fluid from chronic atopic dermatitis skin.

BACKGROUND: The in vivo levels of inflammatory mediators in chronic atopic dermatitis (AD) skin are not well-defined due to the lack of a non-invasive or minimally invasive sampling technique. OBJECTIVES: To investigate the cytokine milieu in interstitial fluid (ISF) collected from chronic lesional AD skin as compared to ISF from non-lesional AD skin and/or healthy donor skin. METHODS: ISF was obtained using a minimally invasive technique of creating micropores in the skin by a laser, and harvesting ISF through aspiration. We determined the levels of 33 cytokines by Luminex and ELISA in ISF and plasma from sixteen AD patients and twelve healthy individuals. In seven AD patients, we analysed the IL-13, IL-31, IL-17, IL-22 and IFN-γ production by T cells isolated from lesional skin. AD patients were genotyped for the filaggrin gene (FLG)-null mutations 2282del4, R501X, R2447X and S3247X. RESULTS: Twenty-five of 33 examined mediators were detected in the ISF. The levels of IL-1α, IL-1ß, IL-18, IL-1RA, IL-5, IL-13, IL-6, IL-8, TNF-α, RANTES(CCL-5), MIG(CXCL-9), IP-10(CXCL-10), TARC(CCL-17), VEGF and G-CSF showed significant differences between either lesional, non-lesional and/or healthy skin. IP-10 levels in ISF from lesional and non-lesional AD skin showed significant correlation with IP-10 blood levels. IP-10 also showed a significant correlation with clinical severity (SCORAD), as did IL-13. Levels of both IP-10 and IL-13 were more pronounced in patients with FLG-null mutations. Furthermore, FLG-null mutation carriers had more severe AD. CONCLUSION: The presented minimally invasive technique is a valuable tool to determine the in vivo cytokine profile of AD skin.

Interleukin-1A +4845(G> T) polymorphism is a factor predisposing to acne vulgaris.

Acne vulgaris is a common chronic inflammatory skin disease of multifactorial origin. The aim of this study was to clarify whether known polymorphisms of the interleukin-1A (IL1A) and IL1RN genes play a role in the pathogenesis of acne vulgaris. A positive association was found between the minor T allele of the IL1A +4845(G>T) single nucleotide polymorphism (SNP) and acne, whereas no association was found with respect to any alleles of the variable number of tandem repeats (VNTR) polymorphism of the IL1RN gene. The severity of inflammatory acne symptoms correlated with the percentage of individuals carrying the homozygote T/T genotype. These results may help to elucidate the molecular events leading to the development of acne.