AB018. Myeloid dendritic cells (mDCs) are major producers of interferon-beta in dermatomyositis and increased numbers of mDCs are found in hydroxychloroquine nonresponders
التفاصيل البيبلوغرافية
العنوان:
AB018. Myeloid dendritic cells (mDCs) are major producers of interferon-beta in dermatomyositis and increased numbers of mDCs are found in hydroxychloroquine nonresponders
BACKGROUND: Dermatomyositis (DM) is an autoimmune disease affecting skin, skeletal muscle, and lungs. Pathogenesis is considered largely driven by interferon-beta (IFN-beta) and involves CD4+ cells and dendritic cells (DCs). (I) Quantify inflammatory cells and IFN-beta in skin; correlate with Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) scores. (II) Identify DC type contributing to refractoriness to hydroxychloroquine (HCQ). (III) Compare IFN-beta production by mDCs vs. pDCs in DM. METHODS: (I) DM skin biopsies evaluated for cells and cytokines using IHC from 12 patients with moderate-severe skin disease at baseline and after 12 weeks of therapy. (II) IHC performed on skin biopsies to compare myeloid DC (mDC) and pDC expression in HCQ-responders vs. -nonresponders. (III) Flow cytometry performed on PBMCs from 5 healthy controls and 5 DM patients. RESULTS: (I) CD4+ cells, macrophages, mDCs, and TRM cells were the most populous in DM skin, followed by CD8+ cells, mast cells, and pDCs. Change in CD4+ and CD8+ cells/HPF significantly correlated with change in CDASI scores (r=0.82, P