IL10 and pemphigus vulgaris: Furthermore, there is evidence against the hypothesis that increased Treg and IL-10 levels (measured in the blood) may lead to IgG4 class switch and production of pathogenic IgG4 autoantibodies, as 1) total Treg numbers were not increased in MuSK MG (134), even decreased in pemphigus vulgaris [while Th17 T-cells were increased (135)] and 2) IL-10+ antigen-specific Tregs are only found in 17% of patients with pemphigus vulgaris, but in 80% of healthy controls, which suggests (at least in pemphigus) a protective role of Tregs and IL-10 (136).