Methods: PBMC were isolated from reticular and erosive OLP patients and healthy individuals by density gradient centrifugation. Expressions of T-bet and GATA-3 mRNA in the PBMCs were detected by the real-time quantitative polymerase chain reaction. Results: When all OLP patients were regarded as a whole group, T-bet mRNA level was significantly increased (P<0.01) while no statistical difference in GATA-3 mRNA level was found in OLP patients, compared with heathy controls. In addition, the ratio of T-bet/GATA-3 mRNA expression in OLP patients was significantly higher (P<0.05). When the patients were divided into erosive group and reticular group, however, only T-bet mRNA level (P<0.01) and the ratio of T-bet/GATA-3 mRNA expression from reticular OLP patients were significantly higher than those in control group (P<0.05). Neither T-bet nor GATA-3 mRNA level, nor the ratio of T-bet/GATA-3 mRNA expression in PBMC from erosive OLP patients showed statistical difference.Conclusion: Patients with OLP have increased level of T-bet mRNA and the higher T-bet/GATA-3 mRNA ratio, indicating a predominant role of Th1-type immune response in pathogenesis of OLP. Different gene expression patterns of T-bet and GATA-3 may indicate different immunoregulatory mechanisms in different forms of OLP.
Key words: Oral lichen planus; Th1; Th2; T-bet; GATA-3