Purpose: Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease mediated by Th2 cells in acute phase. Type 2 innate lymphoid cells (ILC2s) have a role in initiating Th2 response. We investigated whether ILC2s are involved in the skin inflammation in a murine model of AD-like skin induced by Aspergillusfumigatus (Af).
Method: We applied Afcrude extract (40µg) to the dorsal skin of BALB/c mice 5 times a week repeatedly with an interval of 2weeks. Clinical score and transepidermal water loss (TEWL) were assessed and histology was examined. The levels of interferon (IFN)-γ, IL-13, IL-17 in skin draining lymph node (LN) and immunoglobulin E (IgE) in serum were measured using ELISA. The mRNA expressions of IL-25, IL-33, thymic stromal lymphopoietin (TSLP) in the skin were measured using Real-Time PCR.The ILC2s of Lin- CD25+ IL-33R+cells in the skin and LN were analyzed using flow cytometry.
Result: The clinical score and TEWL increased in mice applied with Af(Afgroup), compared with control group. Histologic findings showed that epidermal and dermal thickness, and eosinophilic and mast cell infiltration in the skin of Afgroup. The levels of total IgE were increased in the serum of Af group. Moreover, Afgroup showed increased levels of IL-13 in the supernatant from culture of skin draining LN stimulated with Af. The populations of Lin- CD25+ IL-33+cells were increased in the skin of Af group. The mRNA expression of IL-33 was increased in the skin of Afgroup.
Conclusion: This study suggests that innate type 2 response to Af may have a role in Th2-mediated skin inflammation in a murine model of AD-like skin lesions induced by Af.