CD40LG and rheumatoid arthritis: Ishiguro et al. also revealed that treatment with IGU plus MTX significantly declined the rheumatoid factor (33%, P < 0.001), and immunoglobulins, such as IgA, IgM, and IgG levels (P < 0.001) at 24 weeks in patients with RA, but these measures have no significantly change in the MTX group [20].