AB0068 Distribution of blood dendritic cell subsets in patients with rheumatoid arthritis, spondyloarthritis and psoriatic arthritis treated with etanercept

Objectives Dendritic cells play a pivotal role in the initiation of innate and adaptive immune responses in host reaction to microbial infection as well as in autoimmune pathology. DC subsets in peripheral blood consist of myeloid DC 1 (MDC1), plasmocytoid DC (PDC), and myeloid DC2 (MDC2) that differ in their expression of Toll-like receptor repertoire and cytocine expression upon stimulation. Several inflammatory diseases have been reported to have altered DC subsets distribution such as Sjögren’s, Lupus erythematosus, Hepatitis and HIV Infection. Little data exist about the impact of TNF-blocking agents on peripheral blood DC subsets. Methods 38 patients with active rheumatic disease (16 rheumatoid arthritis (RA), 14 spondylarthritis (SPA), 8 psoriatic arthritis (PSA)) requiring TNF-blocking therapy due to insuffient disease control under DMARD therapy were prospectively followed for 12 weeks after initiation of etanercept treatment (timepoints: 0,week 2, 6,and 12). Peripheral blood dc subsets were evaluated by flow cytometry using the different expression of BDCA antigens (Milthenyi KIT). Prednisolon dose was