Heterogeneous IL-9 Production by Circulating Skin-Tropic and Extracutaneous Memory T Cells in Atopic Dermatitis Patients.

Interleukin (IL)-9 is present in atopic dermatitis (AD) lesions and is considered to be mainly produced by skin-homing T cells expressing the cutaneous lymphocyte-associated antigen (CLA). However, its induction by AD-associated triggers remains unexplored. Circulating skin-tropic CLA+ and extracutaneous/systemic CLA- memory T cells cocultured with autologous lesional epidermal cells from AD patients were activated with house dust mite (HDM) and staphylococcal enterotoxin B (SEB). Levels of AD-related mediators in response to both stimuli were measured in supernatants, and the cytokine response was associated with different clinical characteristics. Both HDM and SEB triggered heterogeneous IL-9 production by CLA+ and CLA- T cells in a clinically homogenous group of AD patients, which enabled patient stratification into IL-9 producers and non-producers, with the former group exhibiting heightened HDM-specific and total IgE levels. Upon allergen exposure, IL-9 production depended on the contribution of epidermal cells and class II-mediated presentation; it was the greatest cytokine produced and correlated with HDM-specific IgE levels, whereas SEB mildly induced its release. This study demonstrates that both skin-tropic and extracutaneous memory T cells produce IL-9 and suggests that the degree of allergen sensitization reflects the varied IL-9 responses in vitro, which may allow for patient stratification in a clinically homogenous population.

Efficacy of dimethyl fumarate treatment for moderate-to-severe plaque psoriasis: presentation extracts from the 29th EADV virtual congress, 29-31 October 2020.

Background: The 29th EADV Virtual Congress took place between the 29th-31st of October 2020. On October 29th, there was a Session on systemic treatment in which Professors Ulrich Mrowietz and Mar Llamas-Velasco presented the latest research on the efficacy of dimethyl fumarate (DMF) treatment for moderate-to-severe plaque psoriasis (BRIDGE and DIMESKIN 1 studies, respectively). The accepted DMF abstract from Professor Matthias Augustin, on the SKILL study, is also presented here. Results: Data from either prospective interventional (BRIDGE) or non-interventional (DIMESKIN 1, SKILL) studies among patients with moderate-to-severe psoriasis showed that DMF provides a positive efficacy profile in all four body regions included in the Psoriasis Area and Severity Index assessment (head and neck, trunk, upper and lower extremities) and a particularly interesting profile (strong efficacy) in the head and neck region. These findings may be of special interest to patients with scalp psoriasis who have been using topical therapies for a long time. Patient-reported outcomes (quality of life, pruritus) also improved during the 24 weeks of DMF treatment. The safety profile of DMF was similar to the previously described with fumaric acid esters. Conclusions: In summary, these results confirm the favorable efficacy and safety profile of DMF in long-term treatment.