GATA-3 regulates contact hyperresponsiveness in a murine model of allergic dermatitis

Daily Supplementation with Bifidobacterium longum KACC91563 Alleviates Allergic Contact Dermatitis in an Animal Model

Allergic contact dermatitis (ACD) is the most common chronic inflammatory skin disease (or immune-mediated disease), causing disruption to our psychological condition and life quality. In this study, the therapeutic properties of probiotic Bifidobacterium longum (B. longum) was investigated by using an ACD-induced animal model. For ACD induction, BALB/c mice ear and dorsal skin were sensitized with 240 µL of 1% (w/v) 2,4-dinitrochlorobenzene (DNCB) twice (3-day intervals). After a week of the first induction, the mice were re-sensitized by painting on their dorsal skin and ear with 0.4% (w/v) DNCB for a further three times (once per week). Before the ACD induction of 2 weeks and throughout the trial period, the BALB/c mice were supplemented daily with 1 mL of 1.0 × 109 CFU or 5.0 × 109 CFU B. longum using an intragastric gavage method. The ACD-induced mice without B. longum supplementation were used as a control. Results show that B. longum supplementation significantly alleviated ACD symptoms (e.g., ear swelling, epidermal damage) and immune response (e.g., reduced immune cell recruitment, serum IgE level, and cytokine production). The therapeutic efficiency of B. longum increased as the supplementation dose increased. Thus, daily supplementation with 5.0 × 109 CFU probiotic B. longum could be an effective method for the prevention and treatment of ACD.

Prominent Role of Type 2 Immunity in Skin Diseases-Beyond Atopic Dermatitis

Type 2 immunity, illustrated by T helper 2 lymphocytes (Th2) and downstream cytokines (IL-4, IL-13, IL-31) as well as group 2 innate lymphoid cells (ILC2), is important in host defense and wound healing.¹ The hallmark of type 2 inflammation is eosinophilia and/or high IgE counts and is best recognized in atopic diathesis. Persistent eosinophilia, such as seen in hypereosinophilic syndromes, leads to fibrosis and hence therapeutic Type 2 inhibition in fibrotic diseases is of high interest. Furthermore, as demonstrated in cutaneous T cell lymphoma, advanced disease is characterized by Th1 to Th2 switch allowing cancer progression and immunosuppression. Development of targeted monoclonal antibodies against IL-4Rα (eg, dupilumab) led to a paradigm shift for the treatment of atopic dermatitis (AD) and stimulated research to better understand the role of Type 2 inflammation in other skin conditions. In this review, we summarize up to date knowledge on the role of Type 2 inflammation in skin diseases other than AD and highlight whether the use of Type 2 targeted therapies has been documented or is being investigated in clinical trials. This manuscript reviews the role of Type 2 inflammation in dermatitis, neurodermatitis, IgE-mediated dermatoses (eg, bullous pemphigoid, chronic spontaneous urticaria), sclerodermoid conditions and skin neoplasms.

The Cooperative Role of CD326+ and CD11b+ Dendritic Cell Subsets for a Hapten-Induced Th2 Differentiation

Dendritic cells (DCs) play a critical role in directing immune responses. Previous studies have identified a variety of DC subsets and elucidated their context-dependent functions that parallel those of effector Th cell subsets. However, little is known about the DC subsets responsible for differentiation of Th2 cells governing allergic contact dermatitis. In this study, we sought to determine the DC subset(s) that mediate Th2 priming in hapten-sensitized mice. We induced hapten-specific Th2 differentiation by sensitizing the mice with a single application of FITC dissolved in acetone:dibutyl phthalate, and traced the immune cells responsible for inducing the Th2 differentiation process at the primary stimulation, enabling us to track Th2 priming in vivo and to delete basophils and specific DC subsets. Our analysis revealed that IL-4 was produced in vivo as early as day 3 from CD4⁺ T cells with a single application of FITC. Basophils, despite producing IL-4 1 d earlier than T cells, were found to be dispensable for Th2 differentiation. Instead, we demonstrated that CD326⁺ dermal DCs and Langerhans cells were redundantly required for FITC-induced Th2 differentiation in vivo. Moreover, the cooperation of CD326⁺ Langerhans cells and CD11b⁺ DCs differentiated naive T cells into Th2 cells in vitro. Collectively, our findings highlight at least two DC subsets that play a critical role in polarizing naive CD4⁺ T cells to Th2 cells and support a two-hit model for Th2 differentiation.

Scanning indels in the 5q22.1 region and identification of the TMEM232 susceptibility gene that is associated with atopic dermatitis in the Chinese Han population

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease. The 5q22.1 region was found to have an association with AD in our previous genome-wide association study (GWAS).

OBJECTIVE

To identify the AD susceptibility gene in 5q22.1 and observe its expression in AD tissues.

METHODS

Suggestive indels from the GWAS data were genotyped in 3013 AD patients and 5075 controls from the Chinese Han population with the SequenomMassArray system. Association, Bayesian and bioinformatics analyses were used to identify possible causal indels and genes in the 5q22.1 region. Immunohistochemistry (IHC) was performed to observe protein expression in the tissues. PLINK 1.07 software was used for all statistical analyses.

RESULTS

The genotyping and association analysis showed that six deletions and four SNPs were associated with AD (P<0.005). The rs11357450 (P_combined=7.79E-04, OR=1.39, logBayes Factor=1.29) deletion located in TMEM232 was identified to be the strongest variant. Analysis of the genetic model revealed that the dominant model best described rs11357450 (P=1.96E-03, OR=1.22; 95% CI=1.07-1.37). IHC showed that the expression of TMEM232 decreased gradually from the granular layer to the basal layer in AD, but in normal tissues, this trend was reversed. Additionally, positive cytoplasm staining was found in lymphocytes around the blood vessels in AD.

CONCLUSIONS

The study indicates that TMEM232 in the 5q22.1 region is the causal gene for AD in the Chinese Han population.