Abstract: Abstract: Objective To investigate the regulatory effect of cord blood derived-multipotent stem cells (CB-SCs) on peripheral blood lymphocytes (LCs) of patients with Alzheimer’s disease (AD) and to explore the therapeutic potential of CB-SCs for AD. Methods CB-SCs were isolated from human cord blood. Lymphocytes were isolated from the peripheral blood of patients with AD. Then, after the two cell populations co-cultured with or without phytohaemagglutinin-P (PHA-P) for 3 days, the levels of cytokines in the supernatant were detected with the ELISA test, the proportions of T-cell subsets were determined by the flow cytometric analysis. Results 1) CB-SCs showed an inhibitory effect on lymphocyte proliferation and gathers induced by the PHA-P; 2) Compared with the control group, the level of the pro-inflammatory factor IL-1 was dramatically decreased (P<0.05), while the release of the anti-inflammatory factors IL-4 and IL-10 were significantly increased (P<0.01) in the CB-SCs co-cultured group. 3) The ratio of CD4+/CD8+T cells in the CB-SCs co-cultured group was significantly lower than that in the control group (P<0.01). 4) Compared with the control group, the proportion of regulatory T cells (Tregs) in the CD4+ T cells was higher in the CB-SCs co-cultured group without the stimulation of PHA-P (P<0.01), while the anti-inflammatory proteins expressed in the Tregs was at a higher level with the stimulation of PHA-P. Conclusions CB-SCs can regulate lymphocytes of patients with Alzheimer’s disease in vitro, which was mainly displayed with the increased proportion of Tregs subset and enhanced anti-inflammatoty function of Tregs.

Key words: stem cells, Alzheimer’s disease (AD) , immune-modulatory, cytokines, regulatory T cells.