A1.32 An imbalance between inflammatory and regulatory T-cell subsets in LYMPH node biopsies during the earliest phases of rheumatoid arthritis

Background and Objective Recently, we showed increased T cell activation in lymph node biopsies of early rheumatoid arthritis (RA) patients. We hypothesise that different lymph node T-cell subsets are involved in the regulation of immune responses during the earliest phases of RA. Materials and Methods We included 11individuals with arthralgia without any evidence of arthritis who were positive for IgM rheumatoid factor (IgM-RF) and/or anti-citrullinated protein antibodies (ACPA; RA risk group), 18 DMARD naïve early arthritis patients (ACR/EULAR 2010 criteria: 3 undifferentiated arthritis and 15 RA; disease duration less than 1 year) and 10 seronegative healthy controls. All study subjects underwent ultrasound-guided inguinal lymph node (LN) biopsy sampling. Gene expression profiling of whole LN biopsies (10 controls and 8 ACPA positive early arthritis patients) was performed using the Illumina array platform. Gene Set Enrichment Analyses (GSEA) was used to search for significant enrichment of immunological gene sets representing certain classes of cell subsets. In all other study subjects T-helper (Th)1, cytotoxic T-cell (Tc)1, Th2, Tc2, Th17, Tc17 and regulatory T-cells (Treg) were analysed by multi-colour flow cytometry. Results First we investigated whether gene expression profiles of lymph node biopsies from ACPA positive early arthritis patients (n = 8) are different from seronegative controls (n = 10). A false discovery rate of