To determine whether B cells from PB and SF of RA patients behave like those from PB of healthy donors, mononuclear cells from patients with RA were isolated and incubated in Transwells in the presence of an optimal concentration (1000 nM) of CXCL13 and CCL20 and with both chemokines in combination. Here, CXCL13 is linked to rheumatoid arthritis.