Defective immunosuppression by AA Tregs contributed to impaired hematopoiesis in vitro. (A-B) Percentages of improvement of the numbers of CFU in presence of the supernatants obtained from the cocultured systems (AA patients, n = 6; controls, n = 6). (C) The sizes of CFU-GM, BFU-E, and CFU-Mix in presence of the cocultured supernatants from AA patients (ii,iv,vi) were significantly smaller than those from controls (i,iii,v). *P < .05; **P < .001.