BMI (beta − 0.02, p < 0.01) was associated with IgM change, diabetes was associated with IgG change (beta − 1.45, p = 0.031), which was driven by the presence of diabetes in 10 people, and previous DMT (beta = − 0.17, p = 0.049), smoking history (beta − 0.32, p = 0.002) and relapsing disease course (beta 0.22, p = 0.039) were associated with IgA change. Here, CD40LG is linked to diabetes mellitus.