High loading-dose of dupilumab resulted in rapid disease control in pediatric patients with atopic dermatitis

Background

The real-world experience of dupilumab in Chinese is limited, and the initial loading dose has not yet been deeply explored in patients aged <6 years.

Objective

To explore the efficacy and safety of dupilumab in Chinese patients with moderate-to-severe atopic dermatitis and investigate the effect of higher loading dose for disease control in patients aged <6 years.

Methods

A total of 155 patients were divided into three groups according to age: <6 years, 6-11 years, and >11 years. Among patients aged <6 years, 37 patients received a high loading dose of 300 mg for body weight <15kg or 600 mg for body weight ≥15kg, and another 37 patients received a standard loading dose of 200 mg for body weight <15kg or 300 mg for body weight ≥15kg. Multiple physicians and patient-reported outcome measures were evaluated at baseline and 2, 4, 6, 8, 12, and 16 weeks after dupilumab treatment.

Results

The proportion of patients showing an improvement of ≥75% in the Eczema Area and Severity Index was 68.0% (17/25), 76.9% (10/13), and 62.5% (25/40) in the aged <6, 6-11, and >11 years groups, respectively, at week 16. After increasing the loading dose, 69.6% (16/23) of patients aged <6 years achieved 4-point improvement in Pruritus Numerical Rating Scale at week 2, compared with 23.5% (8/34) of patients receiving standard loading dose (P < 0.001). Obesity (odds ratio=0.12, 95% confidence interval: 0.02-0.70) was predictive of a poor response to dupilumab treatment, while female (odds ratio=3.94, 95% confidence interval: 1.26-12.31) predicted good response at week 16. The change of serum C-C motif ligand 17(CCL17/TARC) could reflect the response to dupilumab (r = 0.53, P = 0.002 in EASI) among patients aged <18 years. No major adverse events were reported during the treatment.

Conclusions

Dupilumab was effective and well-tolerated in Chinese patients with atopic dermatitis. The increased loading dose helped achieve rapid pruritus control in patients aged <6 years.

[Epigenetic modification as a therapeutic approach for B-cell lymphoma]

Genes that regulate immunological activities are transiently suppressed by epigenetic modification during the germinal center reaction of B cells and reactivated when B cells exit the germinal center. Mutations of EZH2 and other epigenetic modifier genes are frequently involved in the pathogenesis of follicular lymphoma and lead to silencing of the genes necessary for exiting the germinal center. Tazemetostat, an EZH2 inhibitor, has been approved for the treatment of follicular lymphoma with EZH2 gain-of-function mutations in Japan. Tazemetostat restores the expressions of MHC and CD58 in lymphoma cells and synergistically enhances the immune reactions of T and natural killer cells against lymphoma cells. Tazemetostat also induces lymphoma cells to secrete CCL17/TARC and enhances T-cell migration. CD58 and CCL17 are known to play central roles in the formation of T-cell-rich tumor microenvironment of Hodgkin lymphoma. We found that tazemetostat enhances the expression of genes overexpressed in Hodgkin/Reed-Sternberg cells. Epigenetic modifiers and new molecular targeted therapies are expected to provide new insights into the pathogenesis of lymphoma and mechanisms determining the histology of lymphoma.

Development of an Electrochemical CCL17/TARC Biosensor toward Rapid Triage and Monitoring of Classic Hodgkin Lymphoma

A point-of-care blood test for the detection of an emerging biomarker, CCL17/TARC, could prove transformative for the clinical management of classic Hodgkin lymphoma (cHL). Primary care diagnosis is challenging due to nonspecific clinical presentation and lack of a diagnostic test, leading to significant diagnostic delays. Treatment monitoring encounters false-positive and negative results, leading to avoidable chemotherapy toxicity, or undertreatment, impacting patient morbidity and mortality. Here, we present an amperometric CCL17/TARC immunosensor, based on the utilization of a thiolated heterobifunctional cross-linker and sandwich antibody assay, to facilitate novel primary care triage and chemotherapy monitoring strategies for cHL. The immunosensor shows excellent analytical performance for clinical testing; linearity (R² = 0.986), detection limit (194 pg/mL), and lower and upper limits of quantitation (387-50 000 pg/mL). The biosensor differentiated all 42 newly diagnosed cHL patients from healthy volunteers, based on serum CCL17/TARC concentration, using blood samples collected prior to treatment intervention. The immunosensor also discriminated between paired blood samples of all seven cHL patients, respectively, collected prior to treatment and during chemotherapy, attributed to the decrease in serum CCL17/TARC concentration following chemotherapy response. Overall, we have shown, for the first time, the potential of an electrochemical CCL17/TARC biosensor for primary care triage and chemotherapy monitoring for cHL, which would have positive clinical and psychosocial implications for patients, while streamlining current healthcare pathways.

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.

Comparative Study of the Effect of 5,6-Dihydroergosterol and 3-epi-5,6-dihydroergosterol on Chemokine Expression in Human Keratinocytes

5,6-Dihydroergosterol-glucose is an organic synthetic derivative of spinasterol-glucose, which has potent anti-inflammatory activity. We previously synthesized alpha and beta anomers of DHE-glycosides and compared their inhibitory activity on CCL17 and CCL22 mRNA expression induced by TNF-α/IFN-γ in activated HaCaTs. Recently, we synthesized a new type of DHE-glycosides, 3-epi-5,6-dihydroergosterol(3-epi-DHE)-glycosides, and compared its inhibitory activity on mRNA expression levels of CCL17 and CCL22 in TNF-α/IFN-γ-induced HaCaT. DHE-Xly did not affect TNF-α/IFN-γ induced CCL17 and CCL22 mRNA expression in HaCaTs, however, 3-epi-DHE-Xly strongly inhibited TNF-α/IFN-γ induced CCL17 and CCL22 mRNA expression levels in human keratinocytes. These results provide important clues for development of chronic dermatitis treatment via inhibition of chemokine expression using DHE derivatives.

CCL17/TARC and CCR4 expression in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare, highly aggressive neuroendocrine skin cancer. In more than 80% of the cases, Merkel cell polyomavirus (MCPyV) is a causal factor. The oncogenic potential of MCPyV is mediated through its viral oncoproteins, large T antigen (LT) and small t antigen (sT). To investigate the role of cytokines in MCC, a PCR array analysis for genes encoding inflammatory cytokines and receptors was performed on MCPyV-negative and MCPyV-positive MCC cell lines, respectively. We detected an increased expression of CCL17/TARC in the MCPyV-positive MKL2 cell line compared to the MCPyV-negative MCC13 cell line. Transfection studies in MCC13 cells with LT expression plasmid, and a luciferase reporter plasmid containing the CCL17/TARC promoter, exhibited stimulated promoter activity. Interestingly, the ectopic expression of CCL17/TARC upregulated MCPyV early and late promoter activities in MCC13 cells. Furthermore, recombinant CCL17/TARC activated both the mitogen-activated protein kinase and the NF-κB pathways. Finally, immunohistochemical staining on human MCC tissues showed a strong staining of CCL17/TARC and its receptor CCR4 in both LT-positive and -negative MCC. Taken together, CCL17/TARC and CCR4 may be a potential target in MCC therapy providing MCC patients with a better overall survival outcome.

Allergic inflammation is augmented via histamine H4 receptor activation: The role of natural killer cells in vitro and in vivo

BACKGROUND

Natural Killer cells (NK cells) are identified as pivotal mediators in allergic skin diseases and accumulate in lesions of atopic dermatitis (AD) patients. Histamine levels are increased in these lesions and histamine is involved in chemotaxis in dendritic cells and NK cells.

OBJECTIVE

The aim of this study was to determine if the histamine H4 receptor (H4R) mediates NK cell chemotaxis and whether it influences interplay between NK cells and dendritic cells during the early phase of allergic inflammation.

METHODS

Chemotactic function of the H4R as well as the influence of the H4R on the cytokine profile of an NK cell-dendritic cell co-culture was studied in vitro. The effect of H4R activation on NK cell migration, NK cell-dendritic cell interaction and cytokine levels in the skin was further characterized in the murine TDI model of allergic dermatitis. Additionally, the impact of the H4R on dermal NK cells was determined in the ovalbumin (OVA)- induced allergic dermatitis model, comparing wild type and H4R knockout mice.

RESULTS

The selective H4R agonist ST-1006 induced NK cell chemotaxis in vitro, which was inhibited with the H4R antagonist JNJ7777120. In vivo, mice treated with TDI plus ST-1006 topically onto the ear, showed significantly enhanced ear swelling and an increased number of NK cells compared to just allergen challenged ears. CCL17 levels in the ear were also significantly increased 8h after allergen challenge. Histology revealed that the main source for increased CCL17 were dendritic cells. These effects could be blocked using the H4R antagonist JNJ7777120. In the chronic model of allergic dermatitis, OVA induced NK cell migration into lesional skin sites. The number of NK cells was lower in OVA-sensitized H4R knockout mice compared to wild type mice.

CONCLUSIONS

These results identify the H4R as a new target controlling NK cell migration and NK cell-dendritic cell interaction in the skin during early allergic inflammation. These results further suggest that blocking the H4R in the skin might be beneficial in diseases like AD.

Epidemiology of atopic dermatitis in Japan

Atopic dermatitis (AD) is a common, chronic or chronically relapsing, severely pruritic and eczematous skin disease. AD is the second most frequently observed skin disease in dermatology clinics in Japan. Prevalence of childhood AD is 12-13% in mainland Japan; however, it is only half that (~6%) in children from Ishigaki Island, Okinawa. Here, we summarize the prevalence, incidence and spontaneous regression of AD and the relation of AD to other allergic diseases from previous reports. We also refer to our recent findings from a population cohort study on Ishigaki Island, Okinawa.