This study aims to explore the mechanism of immunosuppressants combined with cord blood (IS + CBI) for severe aplastic anemia. Selecting 30 patients with SAA and all treated with IS + CBI (newly diagnosed group). 23 patients who were treated effectively (effective group) while 7 cases were treated invalidly (invalid group). Another 20 healthy individuals were selected as control group. To detect the expression levels of IL-17, IL-22 and other cytokines by ELISA method in each group. To detect the engraftment of cord blood stem cells by using short tandem repeat-polymerase chain reaction (STR-PCR) method. 1. IL-17, IL-22 and other cytokines expressions in newly diagnosed group were significantly higher than in the control group. 2. After 6 months, the level in effective group was significantly lower than pretherapy (P < 0.05).The level in invalid group had no obvious difference than pretherapy. 3. After 1 month and 3 months of treatment, a small amount of engraftment was found in effective group. After 6 months, implant rejection was showed. No effective engraftment was observed in invalid group. 1. IL-17, IL-22 cells in SAA patients increased which might positively correlated with the progression of SAA. 2. During the treatment of IS + CBI, there is a bridging mechanism between the early stage of engraftment and the advanced stage of immunosuppressant adjustment. The first 3 months after treatment, it relies on the engraftment of cord blood stem cells to promote hematopoietic recovery and 3 months later, it relies on immunosuppressants to maintain normal hematopoietic function.
Keywords: Aplastic anemia; cord blood; cytokine; interleukin-17; interleukin-22.