For cultured cells from HCs and CIS (but not MS patients), ARG1 associated positively only with TGFB mRNA levels; this supported an ARG‐TGFB inter‐relationship with Treg induction (Table 2).26 However, in PBMCs from MS patients, this link may be impaired because of ARG1 intrinsic changes described above. This evidence concerns the gene TGFB1 and in situ carcinoma.