Kumata et al. measured TRAb-IgG and TRAb-IgM levels in the sera of 34 patients with Graves’ disease and 15 healthy controls, and noted that serum TRAb-IgM levels were significantly higher than TRAb-IgG levels, in contrast to serum total IgG levels, which were markedly higher than those of other Ig classes [65]. This evidence concerns the gene CD40LG and Graves disease.