Abnormal histone acetylation of CD8+ T cells in patients with severe aplastic anemia.

Severe aplastic anemia (SAA) is a rare autoimmune disease characterized by severe pancytopenia and bone marrow failure, which is caused by activated T lymphocytes. In the present study, we evaluated histone H3 acetylation levels of bone marrow CD8+ T cells in SAA patients, and analyzed its correlation with clinical condition parameters. We found that the percentages of CD8+ T cell histone H3 acetylation in patients with untreated SAA, recovering SAA (R-SAA) and normal control, were 1.21 ± 0.08, 1.05 ± 0.36, and 1.00 ± 0.41, respectively, with no significant statistical differences. However, the amount of CD8+ T cell histone H3 acetylation from untreated SAA was 176.21 ± 32.22 μg/mg protein, which was significantly higher than that of complete response (CR)-SAA (104.29 ± 62.06 μg/mg protein) and normal control (133.94 ± 56.27 μg/mg protein) (P < 0.05) groups. Moreover, histone H3 acetylation amount of CD8+ T cell was significantly and negatively correlated with absolute neutrophil count, proportion of reticulocytes, ratio of CD4+ to CD8+ T cell in peripheral blood, and percentage of bone marrow erythroid (P < 0.05). To some extent, it also negatively correlated with hemoglobin level, platelet count, percentage of bone marrow granulocyte, and megakaryocyte count. Abnormal histone H3 acetylation of CD8+ T cells may thus play a role in the immune pathogenesis of SAA.