Background: T cell mediated autoimmunity is considered to be involved in the pathogenesis of OLP. Studies demonstrate that Foxp3 transcription is significantly elevated in OLP lesions comparing with controls. This directly suggests that Foxp3+ Treg cells may participate in the pathogenesis of OLP. The crucial roles of the CD4+Foxp3+CD25+ Treg cells have been identified in a series of autoimmune and/or inflammatory diseases. Its role in the pathogenesis of OLP should not be overlooked. Sparse data are available on Foxp3+ Treg cells in OLPAim: The aim of this study was to investigate whether some of the T cells in the infiltrate of OLP are of a regulatory type.Method: By the use of labeled antibodies as specific reagents through antigen-antibody interactions immunhistochemistry was used to localize antigens in tissue sections from biopsies from twelve different patients. In this study multicolor-fluorescence was used to examine CD3, CD25, CD152 and Foxp3.Results: A fraction of median 30 % of the subepithelial T cells coexpressed Foxp3. The majority of these (median 55%, range 15%-69%) were CD25+ Treg cells. The amount of CD152+ Treg cells among CD3+Foxp3+ cells was median 31% (range 5%-67%). In addition, the exact same markers are counted for in biopsies from five patients in which the histopathological picture did not correlate with OLP/LR. The result from the histopathological analysis here did not variate signigicantly from the above described results.Conclusion: The results from this study are compared with, and meant as a compliment to the study of Koren et al. Both studys demonstrate an increased number of Treg cells compared with a control-gruop. Immunhistochemical analysis of a group of biopsies from inflammatory lesions not diagnosed OLP/LR may raise a question about the diagnostic criteriae of OLP/LR, and may also demonstrate that the Treg cell is an important target when it comes to treatment of other inflammatory disorders as well.