Case study of patients with type 1 diabetes mellitus showed a significant increase in the level of IgA (by +82.7%, p < 0.001) and IgG (+ 35.2%, p < 0.001), but a decrease in the level of IgM (by −6.7%, p < 0.001) and the described phenomenon is poorly explainable concerning to diabetes mellitus [76,78]. Here, CD40LG is linked to diabetes mellitus.