Aberrant histone modification and inflammatory cytokine production of peripheral CD4+ T cells in patients with oral lichen planus

BACKGROUNDS: To investigate alterations in histone modification and histone deacetylases (HDACs) in patients with oral lichen planus (OLP), and to evaluate correlations with inflammatory cytokine production. METHODS: Global histone H3/H4 acetylation and HDAC activity in CD4+ T cells from 23 patients with OLP and 10 healthy control subjects were examined using spectrophotometry. The mRNA levels of eight members of four classes of HDAC genes were measured by real‐time quantitative polymerase chain reaction. Forty cytokines involved in inflammation were examined with a cytokine array. The correlation between histone modification and cytokine production was analyzed. RESULTS: Global histone H3 hypo‐acetylation was observed in OLP patients. Patients with OLP had significantly higher HDACs activity,and higher HDAC6 and HDAC7 mRNA level compared with the controls. Of the 40 cytokines in the cytokine array, eight were significantly increased in OLP patients: interleukin (IL)‐4, IL‐8, IL‐1ra, tumor necrosis factor receptor II (TNFR II), macrophage inflammatory protein 1b (MIP‐1b), fibrosis‐associated tissue inhibitors of metalloproteinase 1 (TIMP)‐1, monocyte chemotactic protein 1 (MCP‐1), and eotaxin‐2. In the OLP group, the acetylation level of histone H3 was negatively correlated with IL‐4 and MCP‐1 production, and the expression of HDAC6 mRNA was positively correlated with MCP‐1 production. In the non‐erosive subgroup, acetylation of histone H3 was negatively correlated with IL‐4, IL‐16, and TIMP‐2 production. In the erosive OLP subgroup, the expression of HDAC7 mRNA was positively correlated with MIP‐1a production. CONCLUSION: Aberrant histone modification of CD4+ T cells in peripheral blood could occur in OLP patients, and possibly affects inflammatory cytokine production.