A further study demonstrated that low-dose HDAC inhibitor can modulate CTLA-4 expression to facilitate the natural production of Foxp3+ Treg cells and restore the suppressive function of Treg cells via the regulation of histone H3K27 acetylation in immune thrombocytopenia (ITP). This evidence concerns the gene FOXP3 and autoimmune thrombocytopenic purpura.