ITP patients had less histone acetylation within the CTLA4 gene. ChIP-Seq used the H3K27-specific antibodies to capture DNA fragments of the CTLA4 gene in human PBMCs and then used qPCR to amplify the captured fragments. Relative expression of the CTLA4 gene can reflect the acetylation level of histone H3K27. (A) DNA ultrasonic broken image. Healthy controls (ctrl1-4), and ITP patients’ (ITP1-6) chromatin were broken into 200- to 500–bp fragments with ultrasonic agarose gel to detect fragment size, and the ultrasonic broken DNA samples were quantified. (B) Location of primers 1 to 5 within the human CTLA4 gene. (C) ITP patients had less acetylated H3K27 expression in the CTLA4 gene compared with that in the control group, as assessed by qPCR. (D) PBMCs were collected for ChIP-Seq to detect the acetylation level of histone H3K27 in the CTLA4 gene. ITP patients treated with chidamide had significantly more acetylated H3K27 than did those without chidamide treatment.