Finally, RA lymphocytes stimulated by the polyclonal B cell activator Epstein-Barr virus (EBV), produced less IgM than controls after 1 week and showed increasing IgM production between 14 and 21 days, whereas, in normal lymphocytes, IgM production decreased during this period (Irving et al., 1985). Here, CD40LG is linked to rheumatoid arthritis.