Low-dose chidamide enhanced CTLA4 expression in splenocytes from active ITP mice and in CD4⁺CD25⁺Foxp3⁺ Treg cells from PBMCs from ITP patients. (A) Low-dose chidamide enhanced CD4⁺CTLA4⁺ T cell numbers and percentages in splenocytes from active ITP mice. (B) Low-dose chidamide enhanced CTLA4 expression in CD4⁺CD25⁺FOXP3⁺ Treg cells in PBMCs from ITP patients. *P < .05, **P < .01.