036 T cells in resolved allergic contact dermatitis drive inflammation and MMP-12–driven tissue modulation

Pathogenic memory T cells are implicated in the local relapse of allergic contact dermatitis (ACD), vitiligo and psoriasis. Here we investigate how resident initiate relapses response to allergen Methylisothiazolinone (MI). MI–related ACD was sampled two months years after resolution disease. were activated skin explants with MI or pan T-cell agonist OKT-3. Epidermis analysed by RNAseq, Nanostring multiplex methods. Metalloproteinase 12 (MMP-12)–induction ACD–related cytokines assessed primary keratinocytes fibroblasts a humanized xenograft mouse model used. Ex vivo activation resolved induced chemokines involved immune cell recruitment tissue remodeling, including collagenase MMP-12. In cytokine stimulation, human had capacity overexpress release Local injections MMP-12 ACD–associated resulted degradation Collagen IV–rich basement membrane separating epidermis dermis redistribution within skin. Resident induce MMP-12–driven remodeling that facilitates cells. Our findings emphasize potential for topical eradication promote deep remission relapsing inflammatory dermatoses.