Rapid allergen‐induced interleukin‐17 and interferon‐γ secretion by skin‐resident memory CD8⁺ T cells

Abstract

SummaryBackground. Skin-resident memory T (T RM ) cells are associated with immunological memory in the skin. Whether immunological memory responses to allergens in the skin are solely localized to previously allergen-exposed sites or are present globally in the skin is not clear. Furthermore, the mechanisms whereby T RM cells induce rapid recall responses need further investigation. Objectives. To study whether contact allergens induce local and/or global memory, and to determine the mechanisms involved in memory responses in the skin. Methods. To address these questions, we analysed responses to contact allergens in mice and humans sensitized to 2,4-dinitrofluorobenzene and nickel, respectively. Results. Challenge responses in both mice and humans were dramatically increased at sites previously exposed to allergens as compared with previously unexposed sites. Importantly, the magnitude of the challenge response correlated with the epidermal accumulation of interleukin (IL)-17A-producing and interferon (IFN)--producing T RM cells. Moreover, IL-17A and IFN-enhanced allergen-induced IL-1 production in keratinocytes. Conclusions. We show that sensitization with contact allergens induces a strong, longlasting local memory and a weaker, temporary global immunological memory response to the allergen that is mediated by IL-17A-producing and IFN--producing CD8 + T RM cells.

Short contact with nickel causes allergic contact dermatitis: an experimental study

“…The elicitation threshold by a single occlusive nickel exposure on skin with a defective barrier has generally been found to be reduced compared with an intact barrier . Furthermore, skin sites with previous allergic nickel dermatitis have been shown to have a local allergen‐specific memory and a reduced threshold for elicitation of dermatitis . The results of this study are in line with our previous finding that nickel‐allergic individuals report dermatitis after relatively short direct contact with metallic items (21·4% after 10 min of contact) .…”

Nickel allergy in a Danish population 25 years after the first nickel regulation

“…Another explanation for patients reporting eczema after short direct skin contact may concern local memory T cells in the skin. In a recent study, we showed the existence of distinct local memory in 10 patients with nickel contact allergy . The patients were patch tested with nickel or pet.…”

Nickel allergy and allergic contact dermatitis: A clinical review of immunology, epidemiology, exposure, and treatment

“…Recently, skin‐resident memory T cells have been harvested from skin with previous nickel dermatitis and a lowered elicitation threshold for nickel exposure. These cells have been shown to lead to a specific “local skin memory” for nickel, even though the immunological mechanisms are not fully elucidated . Although new discoveries have been made in the field in recent years, there is still a lack of understanding of the immunological mechanisms underlying the disease.…”

“…Furthermore, a flare of dermatitis at sites of previous allergic nickel dermatitis has been shown both after systemic and after cutaneous nickel exposure at other sites (Figure B). More recently, a specific “local skin memory” has been described for nickel . In addition to dermatitis flare‐up, systemic nickel exposure may lead to generalized dermatitis, vesicular hand eczema, flexural eczema, and the “baboon syndrome.”…”