The purpose of this project is to deeply characterize antigen-specific CD4+ T cells at the single cell level in Peripheral Blood (PB) and synovial fluids (SF) samples from RA patients. This project is centered on two aims: • Access to full alpha and beta TCR sequences. This information will allow us to clone and express recombinant TCR chains and test these TCRs in mouse models in future collaborative work. • Analyze the full transcriptome of autoreactive T cells. Evaluating the effector functions of these T cells will allow the identification of new possible targets that could be further inhibited in RA patients.