Under hypoxic conditions that mimic the microenvironment of the inflamed joint, however, RA-derived B cells secreted significantly higher IL-6 and TNF when stimulated through the BCR (P = 0.0003, P = 0.007, respectively) with or without additional TLR stimulation (P = 0.0007, P = 0.03, respectively) (Figure 4, A–C). Here, BCR is linked to rheumatoid arthritis.