Epithelial Cell Apoptosis in Recurrent Aphthous Ulcers.

A recurrent aphthous ulcer (RAU) is a common inflammatory ulcerative lesion affecting oral mucosa. We studied the eventual apoptosis of epithelial cells from the point of view of ulcer and inflammation. RAU lesions and healthy mucosa samples were immunostained for caspase-3 and high-mobility group box 1 (HMGB1). DNA nicks were identified using TUNEL staining. We studied the effects of tumor necrosis factor α (TNFα) and interferon γ (IFNγ) on the toll-like receptor 2 and 4 (TLR2 and TLR4) expression of human oral SCC-25 keratinocytes. We also studied the effects of self-DNA, all-thiol-HMGB1, and disulfide-HMGB1 on epithelial cells, with or without IFNγ. At the edge of RAU lesions, all epithelial cell layers were caspase-3(+), TUNEL(+), and HMGB-1(+) and had widened intercellular spaces. In contrast, healthy epithelial cells were negative for caspase-3 and TUNEL staining. HMGB1 was seen in only the basal cell layers, and the cells retained close cell-to-cell contacts. Self-DNA increased TNF-α mRNA (P = 0.02) in SCC-25 cells. Both TNFα and IFNγ (P = 0.01) increased TLR2. Upon TNFα stimulation, SCC-25 cells lost their nuclear HMGB1 staining. HMGB1 did not increase IL-8, IL-6, or TNF-α mRNA in SCC-25 cells, which was unaffected by the presence of IFNγ. We conclude that in healthy epithelium, the most superficial cells at the end of their life cycle are simply desquamated. In contrast, RAU is characterized by top-to-bottom apoptosis such that dead cells may slough off, leading to an ulcer. Because of a lack of scavenging anti-inflammatory macrophages, apoptotic cells probably undergo secondary necrosis releasing proinflammatory danger signals, which may contribute to the peripheral inflammatory halo. This is supported by self-DNA-induced TNFα synthesis. In contrast to TLR4- and TLR2-binding lipopolysaccharide used as a positive control, disulfide-HMGB1 did not stimulate proinflammatory cytokines.

Histamine H4 receptor in oral lichen planus.

OBJECTIVES: Oral lichen planus (OLP) is an autoimmune disease characterized by a band-like T-cell infiltrate below the apoptotic epithelial cells and degenerated basement membrane. We tested the hypothesis that the high-affinity histamine H4 receptors (H4 Rs) are downregulated in OLP by high histamine concentrations and proinflammatory T-cell cytokines. MATERIALS AND METHODS: Immunohistochemistry and immunofluorescence staining, image analysis and quantitative real-time polymerase chain reaction of tissue samples and cytokine-stimulated cultured SCC-25 and primary human oral keratinocytes. RESULTS: H4 R immunoreactivity was weak in OLP and characterized by mast cell (MC) hyperplasia and degranulation. In contrast to controls, H4 R immunostaining and MC counts were negatively correlated in OLP (P = 0.003). H4 R agonist at nanomolar levels led to a rapid internalization of H4 Rs, whereas high histamine concentration and interferon-γ decreased HRH4 -gene transcripts. CONCLUSION: Healthy oral epithelial cells are equipped with H4 R, which displays a uniform staining pattern in a MC-independent fashion. In contrast, in OLP, increased numbers of activated MCs associate with increasing loss of epithelial H4 R. Cell culture experiments suggest a rapid H4 R stimulation-dependent receptor internalization and a slow cytokine-driven decrease in H4 R synthesis. H4 R may be involved in the maintenance of healthy oral mucosa. In OLP, this maintenance might be impaired by MC degranulation and inflammatory cytokines.

Increased beta 2 defensin in recurrent aphthous ulcer.

OBJECTIVES: It was hypothesized that beta 2 defensin (BD-2) is increased in RAU lesions compared with healthy controls to promote anti-microbial host defence. METHODS: RAU and control mucosa samples were subjected to quantitative real-time PCR and immunostained for BD-2, CD68, mast cell tryptase and 4-hydroxynonenal (4HNE). The effect of tumour necrosis factor-α (TNF-α) ± interleukin-17C (IL-17C), without and with vitamin K3, was studied on BD-2 expression in epithelial SCC-25 cells. RESULTS: Although BD-2 mRNA did not differ between healthy and RAU mucosa, BD-2 stained strongly in acute-phase RAU epithelium (P = 0.001). In controls, subepithelial BD-2(+) cells were mast cells and macrophages, whereas in RAU, most infiltrating leucocytes were BD-2(+) (P = 0.004). In cell culture, BD-2 was increased 124-fold by TNF-α (P < 0.0001) and 208-fold synergistically together with IL-17C (P < 0.0001). 4HNE staining of RAU epithelium was not significantly increased, and vitamin K3-induced reactive oxygen species (ROS) did not affect BD-2. CONCLUSIONS: Anti-microbial BD-2 was not affected by oxidative stress but was highly increased in the epithelial and immigrant cells in the acute-phase RAU lesions, probably in part synergistically by TNF-α and epithelial IL-17C, which are known to be induced by activation of danger-signal receptors by pathogen- and/or damage-associated molecular patterns.

Recurrent aphthous ulcers today: a review of the growing knowledge.

Recurrent aphthous ulcers represent a very common but poorly understood mucosal disorder. They occur in men and women of all ages, races and geographic regions. It is estimated that at least 1 in 5 individuals has at least once been afflicted with aphthous ulcers. The condition is classified as minor, major, and herpetiform on the basis of ulcer size and number. Attacks may be precipitated by local trauma, stress, food intake, drugs, hormonal changes and vitamin and trace element deficiencies. Local and systemic conditions, and genetic, immunological and microbial factors all may play a role in the pathogenesis of recurrent aphthous ulceration (RAU). However, to date, no principal cause has been discovered. Since the aetiology is unknown, diagnosis is entirely based on history and clinical criteria and no laboratory procedures exist to confirm the diagnosis. Although RAU may be a marker of an underlying systemic illness such as coeliac disease, or may present as one of the features of Behcet's disease, in most cases no additional body systems are affected, and patients remain otherwise fit and well. Different aetiologies and mechanisms might be operative in the aetiopathogenesis of aphthous ulceration, but pain, recurrence, self-limitation of the condition, and destruction of the epithelium seem to be the ultimate outcomes. There is no curative therapy to prevent the recurrence of ulcers, and all available treatment modalities can only reduce the frequency or severity of the lesions.

Tumor necrosis factor-alpha and its receptors, p55 and p75, in gingiva of adult periodontitis.

Tumor necrosis factor-alpha (TNF-alpha), a pro-inflammatory cytokine, can stimulate matrix metalloproteinase synthesis and osteoclastic bone resorption. We hypothesized that elevated expression of TNF-alpha and its p55 and p75 receptors (TNF-R) in gingival tissue might associate with periodontitis. Immunohistochemistry was used for the study of the localization of TNF-alpha and its p55 and p75 TNF-R in adult periodontitis (AP) gingival tissue, in comparison with that in healthy control specimens. TNF-alpha and p55 TNF-R were detected in sulcular epithelial basal cells and in monocyte/macrophages, fibroblasts, and endothelial cells in the AP gingival tissue specimens, but mainly in fibroblasts and endothelial cells in control specimens. P75 TNF-R was occasionally found in monocyte/macrophage-like cells in gingival tissue specimens. The percentage of TNF-alpha-containing cells was not increased in AP compared with controls (13.2%+/-6.1% vs. 12.8%+/-7.6%), but, due to the increased cellularity of AP samples, the number of TNF-alpha positive cells/mm2 was clearly increased (1621+/-663 vs. 664+/-191, p > 0.001). Thus, AP gingival tissue has an elevated expression of TNF-alpha and especially its p55 receptor, suggesting that TNF-alpha may contribute to tissue degradation in periodontitis.

Increased density of lymphocytes bearing gamma/delta T-cell receptors in recurrent aphthous ulceration (RAU).

Lymphocytes bearing the T-cell receptor (TCR) gamma/delta are increased in the peripheral blood of patients with recurrent aphthous ulcers (RAU) and Behcet's disease. In this study, we examined whether the density of TCR-gamma/delta bearing lymphocytes was also increased locally in RAU lesions. Ten RAU lesions from ten patients were compared with ulcer-free mucosa from sites contralateral to the lesions, and with 10 samples of clinically healthy oral mucosa taken from 10 healthy volunteers. Samples were labeled with a panel of monoclonal antibodies specific to CD3, alpha/beta TCR and gamma/delta TCR in avidin-biotin-peroxidase complex (ABC) staining. Lymphocytes expressing gamma/delta TCRs were very low in non-lesional mucosa and clinically healthy mucosa. By contrast, gamma/delta T-cells were numerous and observed in all RAU lesions especially within the epithelium, inflammatory infiltrates and at perivascular locations. The count of gamma/delta T-cells was high in connective tissue of RAU (200 +/- 126 cells/mm2) compared with connective tissue of controls (4+/-4 cells/mm2; P<0.0001) or non-lesional mucosa (5+/-7 cells/mm2). Interestingly, the density of gamma/delta T-cells was also high in the epithelium of RAU (70+/-34 cells/mm2) compared with the epithelium of non-lesional mucosa (2.8+/-06 cells/mm2; P<0.0001) or epithelium of healthy controls (1.2+/-1.5 cells/mm2; P<0.0001). Moreover, the mean percentage of gamma/delta+ T-cells among total CD3+ lymphocytes was increased in the connective tissue area from 4% and 5% in controls and non-lesional mucosa, respectively, to 19% in RAU. In epithelial areas, the average percentage was increased from 2% and 6% in controls and non-lesional mucosa, respectively, to 36% in RAU. These data showed that gamma/delta T-cells are more numerous in RAU lesions and such an increase was purely restricted to RAU inflammatory areas.

Immunolocalization of tumor necrosis factor-alpha expressing cells in recurrent aphthous ulcer lesions (RAU).

Tumor necrosis factor (TNF)-alpha is a pro-inflammatory cytokine and crucial mediator in many aspects of immunity. Although several studies have shown that recurrent aphthous ulcers (RAU) can be prevented by treatment that prevents the synthesis of endogenous TNF-alpha little is known about the location and distribution of TNF-alpha-expressing cells at disease sites. The aim of the present work is, therefore, to investigate TNF-alpha and its cellular distribution in RAU lesions compared with those in induced oral traumatic ulcers (TUs). Twelve biopsies of RAU lesions of oral mucosa were obtained from 12 patients with RAU. They were compared to a control group consisting of ten samples of induced TUs. All samples were analyzed for TNF-alpha expression by using monoclonal mouse anti-human TNF-alpha antibody in avidin-biotin-peroxidase complex (ABC) staining. Results were quantified by a semi-automatic VIDAS image analysis system. TNF-alpha immunoreactivity was contained mainly in monocyte/macrophages and lymphocytes within the mononuclear inflammatory infiltrates. TNF-alpha was often seen in mast cells and vascular endothelial cells in connective tissue lateral to the inflammatory infiltrates. Interestingly, 32%-60% of the mononuclear cells were found to be TNF-alpha immunoreactive in RAU lesions. TNF-alpha containing cells were more numerous in aphthae (188+/-46 cells/0.2 mm2) compared with controls (52+/-14 cells/0.2 mm2, P<0.001). These findings suggest that RAU lesions are characterized by high expression of TNF-alpha. Because such expression occurred in the mononuclear inflammatory cells, mast cells and vascular endothelial cells, TNF-alpha, which is a major inflammatory mediator, may contribute to the activation and recruitment of leukocytes that are found in RAU lesions.

Oral health of patients scheduled for elective abdominal aortic correction with prosthesis.

OBJECTIVE: to evaluate the frequency of potential oral foci of infection in patients scheduled for elective abdominal aortic surgery. DESIGN: prospective clinical study. MATERIALS: oral health and dentures of 50 patients (33 males and 17 females, mean age 65 years) were examined before aortic surgery. CHIEF OUTCOME MEASURES: radiographic and clinical examination with special emphasis on identifying acute and chronic oral and ontogenic conditions which may contribute to aortic prosthesis infection. RESULTS: eighty-two per cent of the patients had some oral infection foci. The mean number of remaining teeth in the cohort was 9.3, and 21% of these were potential infectious foci (62% in the patients). Twenty-six per cent of the patients suffered from oral Candida infection. Seventy-four per cent of the patients had total or partial dentures, 45% of which were ill-fitting and needed repair. CONCLUSIONS: oral infectious foci occur frequently in patients needing aortic surgery. Untreated foci may contribute to aortic prosthesis infection. Preoperative oral evaluation and elimination of intraoral infection is recommended for patients scheduled for abdominal aortic repair.

Long-term supplementation with alpha-tocopherol and beta-carotene and prevalence of oral mucosal lesions in smokers.

OBJECTIVE: To assess the effect of alpha-tocopherol and beta-carotene supplementation on the prevalence of oral mucosal lesions in smokers. DESIGN: An end-point examination of a random sample of participants in a controlled trial for 5-7 years (Alpha-Tocopherol Beta-Carotene Cancer Prevention Study) in Helsinki, Finland. SUBJECTS: A total of 409 white male cigarette smokers, aged 55-74 years who received either alpha-tocopherol (50 mg per day) or beta-carotene (20 mg per day) supplementation, both of these or placebo capsules. METHODS: Clinical examination of oral mucosae, histological examination of lesions showing leukoplakia and cytological examination of buccal epithelium. Statistical analysis using Fisher's exact test. RESULTS: No statistically significant differences were found between the study groups either in the prevalence of oral mucosal lesions or in the cells of unkeratinized epithelium. Leukoplakia was present in 24 (5.9%) of the subjects. Seven lesions showed dysplasia. CONCLUSION: The present study on oral health does not support the hypothesis that alpha-tocopherol or beta-carotene supplementation plays an essential role in preventing oral mucosal changes in smokers.

Quantitative assessment of mast cells in recurrent aphthous ulcers (RAU).

Previous studies on the frequency of mast cells (MCs) in recurrent aphthous ulcers (RAU) have yielded conflicting results. Monoclonal antibodies specific for tryptase (AA1) and anti-IgE (polyclonal antibody) were used to identify density and distribution of MCs in an immunohistochemical study of RAU (n=15), induced oral traumatic ulcers (TUs) (n=9), and control clinically healthy oral mucosa (n=15). Results were quantified by means of a VIDAS image analyzer. In all sections studied, IgE-positive cells showed similar frequency and distribution to tryptase-positive MCs. In RAU lesions, numerous tryptase-positive MCs were found in the sub-epithelial lamina propria, but MC numbers in the epithelium were low and present only in some RAU biopsies. MCs were also more numerous in RAU-inflammatory infiltrates (118+/-31 cells/mm2) than those seen in TU-inflammatory infiltrates (75+/-18 cells/mm2, P<0.001). MC activation/degranulation, as judged by diffuse extracellular tryptase staining, was a common feature within RAU-inflammatory infiltrates and at RAU-inflammatory infiltrates-connective tissue interfaces, which were often associated with connective tissue disruption. MC counts in the RAU connective tissue, lateral to the inflammatory infiltrates, were significantly greater than in the connective tissue of TUs and of control biopsies (124+/-36 vs 73+/-13 vs 69+/-21 cells/mm2, respectively; P<0.001). Overall, MCs were significantly increased in aphthae (116+/-26 cells/mm2) compared with TU lesions (72+/-11 cells/mm2, P<0.001) and controls (71+/-16 cells/mm2, P<0.001). In conclusion, MC numbers are increased in a typical topographical pattern, and the local MCs show signs of activation/degranulation suggesting active involvement of this cell type in RAU pathogenesis.

Factor XIIIa-positive dendrocytes are increased in number and size in recurrent aphthous ulcers (RAU).

The factor XIIIa-positive (FXIIIa+) cell is a potent antigen-presenting cell, which has been described as increasing in numbers in various chronic inflammatory conditions. The purpose of this study was to investigate the distribution and frequency of FXIIIa+ cells in acute recurrent aphthous ulcer (RAU) lesions compared with induced traumatic ulcer (TU) lesions and with clinically healthy oral mucosa. Samples were labeled with polyclonal rabbit anti-human FXIIIa antibodies in avidin-biotin-peroxidase complex (ABC) staining. Most of the FXIIIa-immunoreactive cells in TUs and normal mucosa were spindle-shaped, whereas a relatively large, dendritic-like cell was predominant in RAU lesions. FXIIIa+ cells were quite frequent within mononuclear cell-rich inflammatory cell infiltrates and in perivascular areas in RAU lesions. In contrast, FXIIIa+ cells were not found in mucosal epithelium or in the neutrophil-rich areas. RAU mononuclear cell-rich inflammatory cell infiltrates appeared to have greater numbers of positively stained cells than the TU-inflammatory cell infiltrates (199 +/- 67 vs 110 +/- 31 cells/mm2, P < 0.001). Overall, FXIIIa+ dendrocytes were increased in numbers, and apparently also in size, in RAU lesions (274 +/- 68/mm2) as compared to controls (177 +/- 74/mm2, P < 0.01), and to TU lesions (183 +/- 50 mm2, P < 0.01). Interestingly, relatively high numbers of FXIIIa+ dendrocytes were also found in deep connective tissue in RAU sections compared with TUs (281 +/- 80 vs 166 +/- 57, P < 0.01). The characteristic changes in the size and shape of individual FXIIIa+ cells, their typical distribution and increase in frequency in RAU lesions indicate active involvement in the local pathogenic mechanisms. Localization to perivascular areas/inflammatory cell infiltrates would be compatible with a role in antigen presentation.

Doxymycine-cyanoacrylate treatment of recurrent aphthous ulcers.

OBJECTIVE: This study addressed the efficacy of singularly applied topical doxymycine in the pain relief treatment of recurrent aphthous stomatitis. STUDY DESIGN: Thirty-one patients with recurrent aphthous lesions were examined and divided randomly in two groups. Experimental group (n = 15) received a topical application of doxymycine and controls (n = 16) received calcii gluconase in the same manner. Medications were covered by isobutyl cyanoacrylate (Iso-Dent). Application was made only once during the recurrent aphthous ulcer episode. RESULTS: Patients recorded their pain level on a visual analog scale for 10 days during healing. Pain decreased more rapidly in the experimental group, and a statistically significant difference (p < 0.05) in the pain intensity was found from the second to the seventh day after application of doxymycine. CONCLUSIONS: In recurrent aphthous ulcers, singular treatment of topical doxymycine-cyanoacrylate relieves the pain intensity remarkably for 6 days after a 1 day latency period. Topical doxymycine treatment further exerts potential to directly prevent tissue destruction and to indirectly suppress host inflammatory reaction.

Cathepsin G in gingival tissue and crevicular fluid in adult periodontitis.

The presence, localization and activities of cathepsin G in gingival tissue specimens and crevicular fluid (GCF) from 9 adult periodontitis patients and 6 controls with clinically healthy periodontium were studied by use of avidinbiotin-peroxidase complex method, Western and dot blotting, and spectrophotometric activity assay. In contrast to healthy gingival tissue specimens, gingival tissue specimens collected from adult periodontitis patients contained inflammatory cells in lamina propria, beneath the oral sulcular epithelium, 10-50% of which were cathepsin G positive polymorphonuclear neutrophilic leukocytes (PMNs) and monocyte/macrophage-like cells. Cathepsin G activities were increased in adult periodontitis GCF when compared to periodontally healthy controls' GCF (p < 0.05). In adult periodontitis GCF, Western blotting disclosed free cathepsin G but also clear complexes of cathepsin G with its predominant endogenous inhibitor alpha 1-antichymotrypsin (alpha 1-ACT). The present results demonstrate that part of the cathepsin G, despite the presence of increased concentrations of alpha 1-ACT, was in an uncomplexed, free and functionally active form. Our results suggest that GCF cathepsin G reflects the disease process in adjacent inflamed gingiva and also increased host response to microbiota and/or dental plaque in the periodontitis lesions. Cathepsin G may contribute to periodontal tissue destruction directly and indirectly, via proteolytic activation of latent neutrophil procollagenase (promatrix metalloproteinase-8 [proMMP-8]).

Effect of tetracyclines on collagenase activity in patients with recurrent aphthous ulcers.

Human neutrophil-type (MMP-8) and fibroblast-type (MMP-1) interstitial collagenase, and their inhibition by tetracyclines in saliva from patients with recurrent aphthous ulcers (RAU) or aphthae, were studied by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and enzymological analyses. In the salivary specimens obtained from patients with aphthae, collagenase was found in endogenously active form and was predominantly of MMP-8 type. Topical rinsing treatment with chlortetracycline (Aureomycin) alleviated the discomfort caused by the lesions but did not reduce salivary collagenase amounts; however in vitro, doxycycline inhibited salivary collagenase totally.

Innervation of recurrent aphthous ulcers.

Specimens from nonkeratinized oral mucosa were obtained from diseased and clinically healthy mucosa from 7 patients with minor recurrent aphthous ulcers. The innervation of the specimens was visualized using antibodies to neuron-specific intermediate cytoskeletal neurofilament fiber, the cytoplasmic protein gene product 9.5 and a 38 kDa integral membrane protein of synaptic vesicles applied in avidin-biotin-peroxidase staining. Mapping with these 3 antibodies revealed dense and basically similar pattern of innervation in the specimens of the clinically healthy oral mucosa. In recurrent aphthous ulcers, all 3 general markers disclosed peripheral nerve fibers also in the lesions, apart from the necrotic area, among the inflammatory cells without signs of retraction from the diseased area. Synaptophysin staining suggested that these peripheral nerve fibers in the inflammatory areas still contained synaptic vesicles. Accordingly, they were shown to contain substance P and calcitonin gene-related peptide, which are known to be released upon stimulation of the nerve and can exert potent paracrine actions, possibly on the local inflammatory cells as suggested by a close spatial relationship between neuropeptide-containing nerves and inflammatory cells.

Long-lasting allergic patch test reaction caused by gold.

Allergic contact dermatitis caused by gold is rare, and only isolated cases have been reported. Patch testing with gold may cause a long-lasting reaction. The purpose of this study is to describe a well-studied case of gold allergy caused by dental gold crowns. A gold-sensitized patient and a non-sensitized control subject were examined using patch tests, immunohistochemistry, electron microscopy and blast transformation reactions. Sodium thiosulfate, auranofin and sodium thiomalate gave positive patch test reactions. Immunohistochemistry and electron microscopy were performed from biopsies taken from allergic patch test reactions caused by gold sodium thiosulfate 1 day and 17 days after applying the patches, from normal skin and from a 17-day-old allergic patch test reaction caused by ammonium persulfate. Down-regulation had taken place by 17 days in the allergic ammonium persulfate reaction, but not in the 17-day allergic gold test reaction. The patient reacted to all but one of the gold-induced blast transformation tests, sodium chloroaurate being non-inductive. The non-sensitized control subject did not exhibit any reactions. In conclusion, gold sodium thiosulfate, gold sodium thiomalate and auranofin can be used as patch test substances for gold allergy, though long-lasting allergic patch test reactions may develop. In vitro gold salt induced blast transformation is an alternative test for gold allergy. The slow down-regulation of the allergic patch test reactions needs to be studied further.

Collagenase and stromelysin in recurrent aphthous ulcers (RAU).

Six patients with recurrent aphthous ulcers were studied for the presence of matrix metalloproteinases (MMP) 1, 3, and 8 in the lesions and in the clinically unaffected control mucosa obtained from the opposite side. MMP-type specific antisera were applied in the avidin-biotin-peroxidase complex staining method. Neutrophil-type collagenase (MMP-8) was found intracellularly in the connective tissue under the necrotized epithelium, and also laterally to the ulcer in association with the basement membrane. Fibroblast-type collagenase (MMP-1) and stromelysin (MMP-3) were found in the epithelial cells adjacent to the ulcerous lesion. They were found also in the endothelium of capillary blood vessels and postcapillary venules and also in some macrophage- and fibroblast-like mononuclear cells in the lamina propria laterally to the ulcer. A small number of MMP-1 and MMP-3 positive cells were noted in the control biopsies obtained from the clinically uninvolved control mucosa. These findings suggest regional differences in the distribution of the two main collagenases, implying distinct roles in tissue destruction and remodeling.

Peripheral nerves and mast cells in normal buccal mucosa.

The topographical distribution and relation to mast cells of PGP 9.5 (protein gene product 9.5, a major cytoplasmic neuron-specific protein with ubiquitin C-terminal hydrolase activity) and neurofilament (intermediate neuron-specific cytoskeletal filaments) in normal human buccal mucosa was studied in five healthy volunteers. Morphometric analysis disclosed the densest innervation to be in the middle layers of the lamina propria, with a mean number of 5.9-6.1 PGP 9.5 and/or neurofilament-immunoreactive nerve fiber profiles per one mm2. In contrast, the mean mast cell number decreased from 110/mm2 to 46/mm2 from superficial to deep lamina propria, being 69-72/mm2 in the most densely innervated middle layers. Only 16-17% of all fiber profiles contained substance P and 51-54% calcitonin gene-related peptide (CGRP). Finally, analysis of the spatial relationship between nerve fiber profiles and mast cells in a double staining procedure disclosed no preferential neuron-effector associations. All these findings suggest that such a relationship does not exist between peripheral nerves and mast cells in normal buccal mucosa.

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.

Distribution of adhesion receptors in recurrent oral ulcers.

When activated under physiologic or pathologic conditions leukocytes adhere to one another or to other cell types. Adhesion receptors mediate these interactions. In the study reported here, the distribution of the adhesion receptors LFA-1 (CD11a/CD18), ICAM-1 (CD54), CD2 and LFA-3 (CD58) in recurrent oral ulcers (ROU) were studied. Nine tissue specimens from five female patients (mean age 33 yr, age range 21-40 yr) with ROU were studied using the avidin-biotin-peroxidase complex (ABC) method. The main mononuclear cell infiltrations were in lamina propria (LP) and the epithelium next to the basement membrane (BM), laterally to the ulcers. In this area, ICAM-1 was strongly expressed in capillaries and in postcapillary venules. LFA-1, LFA-3 and CD2 were expressed in 65 +/- 1.1%, 70 +/- 16% and 80 +/- 1%, respectively, of all mononuclear cells. The findings indicate that LFA-1/ICAM-1 and CD2/LFA-3 interactions may play roles in cell to cell adhesion events in ROU.