The role of pDC in the RA pathogenesis is dual: on one hand in synovial tissues pDC via the secretion of type I IFNs contribute to local inflammation, although at lower extend as compared to myDC (Pettit et al., 2000; Takakubo et al., 2008); on the other hand, pDC could play a role in activating B cells via the expression of B cell-activating factor (Lebre et al., 2008), leading to antibody production, which sustain tissue damage. Here, PDC is linked to rheumatoid arthritis.