No abstract

The mucosal membrane of the oral cavity displays at times classical developmental lesions considered to be variations of normal structures rather than having disease characteristics. Of these lesions leukoedema, Fordyce granules, geographic-, fissured- and hairy tongue, median rhomboid glossitis and lingual varices were studied in 598 patients referred to the School of Dentistry, Tehran, Iran. The prevalence was studied in relation to age, gender, occupation, education, smoking habits, general health, addictions and or drug therapies. Oral developmental lesions were seen in 295 patients (49.3%). Only Fordyce granules (27,9%), fissured tongue (12,9%), leukoedema (12,5%) and hairy tongue (8,9%) had enough cases for statistical analysis. Three of these lesions increased with age but not fissured tongue. All were more common in men. After adjusting for age, the parameters education, occupation and complaints upon referral had little influence on the prevalence of the lesions. Fewer Fordyce granules were seen in oral mucosa of smoking men. Leukoedema and hairy tongue were significantly associated with smoking, leukoedema with diabetes mellitus. We conclude that there was a highly significant association between these oral lesions and age, gender and smoking. Few significant associations were found between oral lesions and general diseases.

SUMMARYWe have previously reported that the buccal mucosa can support delayed type hypersensitivity (DTH) reactions to contact sensitizers. In the present study, we show that cells isolated from the buccal epithelium are able to present soluble exogenous antigens to specific T cells. Single cell suspensions obtained by enzymatic dispersion of buccal epithelial sheets could present the native protein antigen hen-egg lysozyme (HEL) to the I-A k -restricted CD4 T-cell hybridoma specific for a.a 46-61 on HEL. T-cell activation resulted in interleukin-2 (IL-2) production which could be inhibited by anti-major histocompatibility complex (MHC) class-II antibodies of pertinent specificity. Immunohistochemical staining of whole buccal epithelial sheets revealed that all MHC II positive cells had a dendritic morphology and expressed ATPase activity, indicating that these cells represent a major antigenpresenting cell (APC) population in this tissue. Furthermore, single cell suspensions isolated from buccal epithelium (BEC) after local in vivo administration of either a native soluble protein, a synthetic dodecapeptide, or a contact sensitizer were able to activate antigen-specific T cells ex vivo. Kinetic analyses indicated that maximal APC activity in the oral epithelium occurred within 1 hr after local antigen administration, and had essentially vanished after 24 hr. Conversely, APC activity was undetectable in draining cervico-mandibular lymph node cell suspensions recovered 1 hr after local antigen injection but became manifest after 3-24 hr. These observations suggest that dendritic cells can acquire antigens in the buccal epithelium and migrate to draining lymph nodes where they present processed antigen to MHC class II-restricted T cells. This APC population may thus be a critical element in the initiation of Th1-driven DTH responses in the oral mucosa.

SUMMARYThe nature and phenotype of infiltrating cells in DTH-like reactions elicited in the murine oral mucosa have been examined by routine histological and immunohistochemical procedures. During the first few hours that followed buccal challenge with the contact sensitizer oxazolone, a discrete lymphocytic reaction was disclosed in the oral mucosa of animals previously sensitized at skin sites, but was absent in animals that had been sensitized at buccal sites. The early lymphocytic reaction in the oral mucosa of skin-sensitized animals preceded the emergence of CD11 + polymorphonuclear cells (PMN) which was most prominent 8 h after hapten challenge and invaded the whole thickness of the oral epithelium. The PMN rapidly disappeared by 24 h. In contrast, early PMN infiltration was virtually absent in specimens from animals similarly challenged but that had been sensitized at local buccal sites. Irrespective of site of initial sensitization, inflammatory reactions developed in the oral mucosa, being maximal by 24 h. At that stage, CD11 + macrophages were the predominant cell type. Both CD4 and CD8 T lymphocytes were scattered in both lamina propria and epithelium, and their numbers were raised throughout the time period studied (2-168 h). IL-2 receptor expression was maximal 16 h post-challenge, and was paralleled by increased DNA synthesis in CD4 + and CD8 + cells, as demonstrated by paired immunohistoautoradiography. Focal accumulations of mononuclear cells containing IL-2-producing cells were readily detected as early as 2-3 h following local challenge with hapten in animals primed at skin but not at buccal sites. Maximal IL-2 staining was detected at 24 h irrespective of initial sensitization site. Interferon-gamma-producing cells were detected at 8 h post-challenge and remained increased during the first 24 h. MHC class II expression was detected on few oral mucosa cells during the first 4 h following hapten challenge, being mainly confined to dendritic-like cells. Consistent with increased numbers of macrophages, MHC class II expression was most intense in specimens obtained 8-24 h after hapten challenge. Thereafter, MHC class II expression was still observed in specimens obtained as late as 72 h, but was essentially associated with patches of basal keratinocytes. Taken together, these observations support the notion that the murine oral mucosa can serve as the site of expression of locally or remotely induced DTH reactions, but also indicate that the site of initial sensitization can profoundly affect the cellular composition of inflammatory reactions subsequent to local buccal challenge.

SUMMARYWe have examined in a murine model, the potential of the oral mucosa (OM)