P031 In both rheumatoid and psoriatic arthritis naive CD4+ T lymphocytes are predisposed to differentiate towards TH17 cells and have characteristic cytokine profiles

Introduction The Th17 helper T lymphocytes represent a subset of T cells that produce inflammatory cytokines. Increased Th17 cell differentiation has been observed in rheumatoid arthritis (RA) and in psoriatic arthritis (PsA). IL-17 induced inflammation promotes osteoclast differentiation which is contributes to the bone and join destruction in RA. In addition IL-17 and IL-22 are co-expressed by Th17 cells which redounds the psoriatic plaque formation in PsA. Objectives In this present work we studied Th17 cell differentiation in RA and PsA. Methods Blood samples from healthy donors, RA and PsA patients were collected. CD45RO- (naive) and CD45RO+ (memory) T cells were isolated from PBMC by magnetic separation. Naive T cells were stimulated with anti-CD3, anti-CD28 and with goat anti-mouse IgG antibodies and treated with TGFβ, IL-6, IL-1β and IL-23 cytokines and with anti-IL-4 antibody. IL-17A and IL-22 production were measured by ELISA, RORC and TBX21 expression were analysed by qPCR and flow cytometry. CCR6, CCR4 and CXCR3 expression were determined by flow cytometry. Cell viability was monitored by impendance-based cell analyzer (CASY-TT). Results RORC, TBX21, CCR6 and CCR4 expression of memory T cells of healthy individuals (but not RA or PsA patients) were increased (p Conclusions The naive CD4 T-lymphocytes are predisposed to differentiate to Th17 cells and the in vitro Th17-cell differentiation is profoundly altered in both RA and PsA. Disclosure of interest None declared