To evaluate which monocyte population contributes to cytokine production in RA patients, isolated mononuclear cell populations of RA patients and healthy controls were stimulated in vitro with synthetic and viral TLR2 agonists, LTA and EBV particles [33] and with TLR9 agonists, CpG and EBV DNA [30]. This evidence concerns the gene TLR9 and rheumatoid arthritis.