CD40LG and systemic lupus erythematosus: SLE patients showed a significant increase in the CD40L-expressing monocytes (Katsiari et al., 2002), and recombinant CD40L induces the production of total IgG in B cells of SLE patients (Harigai et al., 1999), while CD40L overexpression triggers lupus-like autoimmune disease (Higuchi et al., 2002; Wang et al., 2003).