Similar to IgG1 findings, there were significantly lower global IgM levels [F(4, 95) = 6.6, p = 1.0E-04] described only by group (p = 3.0E-04) in MSA compared to PD (p = 0.001) and controls (p = 0.003; Figure 2F). Here, CD40LG is linked to Parkinson disease.