Regulatory T cells in CIDP and the inhibitory effect of rapamycin on them.

We aim to investigate the proportion and function of regulatory T (Treg) cells, as well as mTORC activity in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients. Peripheral blood mononuclear cells (PBMCs) from 15 CIDP and healthy controls (HC) were collected. Treg and responsive T (Tresp) cells were isolated. The inhibition rate of Treg cells was analyzed with and without rapamycin. The percentage of CD4 + CD25highFoxP3+ Tregs was higher in CIDP than in HCs (median 3.06 % vs 1.98 %, P = 0.014). The suppressive function of CIDP Tregs was normal compared with that of HCs. The activity of mTORC1 and mTORC2 revealed by pAKT and p4EBP1 in Treg cells was not significantly different between CIDP and HC. The percentage of Treg cells showed no difference in the presence or absence of rapamycin, while the suppressive function of CIDP and HC Tregs was dramatically diminished in the presence of rapamycin. The percentage of P-akt in Tregs was also reduced in the presence of rapamycin. In conclusion, the percentage and suppressive function of Tregs were not impaired in CIDP patients. The presence of rapamycin had no effect on the percentage of Treg cells but could reduce the suppressive function of CIDP and HC Tregs, possibly by reducing P-Akt.