ARG1 and myeloid sarcoma: 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.