Immune-activation in recurrent oral ulcers (ROU)

Tissue specimens from eight patients with recurrent oral ulcers (ROU) were analyzed for possible signs of active lymphocyte involvement. A total of 13 specimens were analyzed, eight (8) taken at the ulcer site and five (5) from clinically unaffected mucosa at a site opposite the ulcer. Monoclonal antibodies or heterologous antisera were applied using the avidin-biotin-peroxidase complex (ABC) or peroxidase-antiperoxidase complex (PAP) methods to visualize cell-activation-associated marker proteins. In specimens from the ulcer area, approximately 43 +/- 18% of all inflammatory cells were positive for the MHC locus II coded Ia antigen. Furthermore, markers for cycling cells, interleukin-2 (CD25, 13 +/- 6%) and transferrin (CD71, 23 +/- 14%) receptors, were frequent in the specimens studied. Staining for CD1 (5 +/- 2%) disclosed dendritic intraepithelial cells in diseased and in clinically unaffected mucosa. Mobilization of such cells is suggested by their presence in submucosa in ROU specimens, but not in clinically unaffected mucosa. The presence of CD1 cells, presumably denoting their identity as potent antigen-presenting Lagerhans' cells, and the rich presence of Ia suggest that local conditions are favorable for induction of T-cell-mediated responses. The simultaneous presence in such infiltrates of activation marker positive T-cells suggests activation de facto. This together with the rarity of activated B-cells, i.e. plasmablasts/cells containing cytoplasmic immunoglobulin, suggests active involvement of the local cells of the T-lymphocyte lineage in the pathogenesis of ROU.