FoxP3(+)CD4(+), IFN-γ(+)CD4(+), and IFN-γ(+)CD8(+) cell levels in erosive and non-erosive types of oral lichen planus patients

BACKGROUND/PURPOSE: Oral lichen planus (OLP) is a localized autoimmune oral mucosal disease. This study evaluated whether different types of OLP patients including erosive OLP (EOLP), major EOLP, minor EOLP, and non-erosive OLP (NEOLP) patients had significantly higher percentages of FoxP3(+)CD4(+) or IFN-γ(+)CD4(+) cells in total CD4(+) cells, and of IFN-γ(+)CD8(+) cells in total CD8(+) cells than healthy control subjects and whether the patient's age had significant influences on these cell percentages in OLP patients. MATERIALS AND METHODS: Flow cytometry was used to count the FoxP3(+)CD4(+), IFN-γ(+)CD4(+), or IFN-γ(+)CD8(+) cell levels in 183 OLP patients (67 major EOLP, 81 minor EOLP, and 35 NEOLP patients) and 20 healthy control subjects. RESULTS: Major EOLP patients had a significantly higher FoxP3(+)CD4(+) cell percentage than health control subjects (P = 0.049) or minor EOLP patients (P = 0.008). Major EOLP patients had a significantly higher IFN-γ(+)CD4(+) or IFN-γ(+)CD8(+) cell percentage than healthy control subjects, NEOLP patients, or minor EOLP patients (all P-values < 0.01). In addition, both 61–80 year and 41–60 year OLP patients had significantly higher IFN-γ(+)CD8(+) cell percentages than healthy control subjects or 20–40 year OLP patients (all P-values < 0.005). CONCLUSION: Major EOLP patients tend to have significantly higher percentages of FoxP3(+)CD4(+), IFN-γ(+)CD4(+), and IFN-γ(+)CD8(+) cells than healthy control subjects, NEOLP patients or minor EOLP patients, suggesting that FoxP3(+)CD4(+) Treg cells are increased to modulate OLP disease activity. Increased number of IFN-γ-producing activated T cell may be involved in oral epithelial cell destruction in OLP patients.