Circulating immune complex studies on patients with oral lichen planus.

To investigate the role of systemic factors such as age, diabetes, and hypertension in the formation of subepithelial immune deposits in oral lichen planus (OLP) we performed circulating immune complex CIC determinations by polyethylene glycol precipitation in sera of patients with OLP, diabetes mellitus, and hypertension and in sera of healthy control subjects. We examined patients with leukoplakia as a control group with oral keratosis but no OLP. Forty percent of the OLP patients were suffering from diabetes, hypertension, or both. The occurrence of CIC positivity was higher in the OLP group with diabetes than in the group with OLP only. However, we could not find CIC positivity in our control patients with diabetes. The almost equal distribution of hypertension among, patients with OLP who tested positive for CIC and those who tested negative does not seem to support the hypothesis that this factor causes the CIC positivity in OLP. The same applies to other assumed factors such as age, medication, dental foci, or metal framework. In summary, we support the idea that CIC positivity may be the consequence of lichen itself, but diabetes and hypertension contribute to the development of erosive OLP lesions.

The decreased antibacterial activity of oral polymorphonuclear leukocytes coincides with the occurrence of virus-carrying oral lymphocytes and epithelial cells.

Patients suffering from periodontitis or periodontosis were selected for the study. Further subdivision of these groups was based on the presence or absence of herpes and/or adenoviruses in their oral lymphocytes and epithelial cells. The phagocytic and bactericidal activities of oral leukocytes isolated from the same individuals were compared with virus carriage. In the periodontitis group, 60.5%, and in the periodontosis group 61.5% of patients carried viruses, while this was established only in 21.1% of control cases. On the other hand, emigration and sulcular gathering of the less viable polymorphonuclear leukocytes was elevated but their phagocytotic activity was decreased among periodontitis patients. Bactericidal capacity was significantly lowered among those subjects who carried viruses in their cells, as compared with virus-free persons, especially in the periodontitis group. The functions of the polymorphonuclear leukocytes accumulated in the sulcus gingivalis may be modified by mediators released from the virus-carrying cells. These mediators could achieve a greater concentration locally, and the damaged leukocytes would not be able to eliminate the microbes continuously so that the accumulation of bacterial products, among them endotoxins, could lead to periodontal inflammation.

The colonization and establishment of invading bacteria in periodontium of ligature-treated immunosuppressed rats.

The morphologic features and pattern of bacterial invasion of the periodontal tissue in ligature-induced periodontal defects of immunosuppressed rats were studied. Silk ligatures were placed circumferentially on the maxillary left second molar of 24 Sprague-Dawley rats. The treatment group (14 rats) received Cytoxan (75 mg/kg) the day after ligature placement and at Day 4. The control group (10 rats) received no medication. All animals were sacrificed on Day 8 and the maxillae processed for light and electron microscopy. Only ligated sites in immunosuppressed animals exhibited bacterial invasion. Invading bacteria consisted of microcolonies of Gram-negative and Gram-positive coccoid cells and rods located near the tissue surface. Each microcolony consisted of morphologically homogeneous microorganisms. The deeper sites revealed a diffuse invasion of Gram-negative rods which appeared morphologically similar. Other features associated with invasion were complete destruction of epithelial tissue next to the ligature and the lack of inflammatory cells in the gingival region. These findings, when compared to those of other reports of tissue penetration by bacteria, point to the necessity of differentiating between bacterial invasion of gingival tissues, associated with penetration of tissues by proliferating bacteria, and bacterial translocation, a situation in which bacteria are passively carried into the tissues, for example by mechanical manipulation immediately before or during biopsy taking, or possibly during processing for histology.

Pathomorphologic features of the ulcerative stage of oral aphthous ulcerations.

Macroscopic, histopathologic, and immunohistochemical features of eight 1- to 7-day-old minor (Mikulicz) aphthae, one herpetiform ulcer, and one ulcer from a patient with Behcet's syndrome were studied. In addition to light and electron microscopy, methods included the peroxidase-antiperoxidase (PAP) technique to disclose binding of IgA, IgG, IgM, Clq, and C3. Observations revealed the presence and distribution of extravasates of erythrocytes at and around the ulcers, extravascular neutrophilic granulocytes undermining the oral epithelium of the ulcer margin, the presence of numerous macrophages loaded with phagolysosomes containing debris of neutrophilic granulocytes, particular pathomorphologic features of a Behcet lesion and a herpetiform lesion, and the occurrence in diseased and normal oral mucosa of particular stratum spinosum cells binding nonselectively all immune components tested in this study, probably by leakage and passive diffusion of serum proteins. The observations fit the concept of immune complex vasculitis being essential in the pathogenesis of oral aphthous ulcerations.

Bacterial invasion of oral tissues of immunosuppressed rats.

The periodontia of immunosuppressed rats were examined by light and electron microscopy. Bacterial invasion was noted in the periodontal tissues of septicemic ligature-treated animals. Invading bacteria consisted of gram-negative rods which were morphologically similar to the Pseudomonas aeruginosa strain isolated from the mouth of one of the septicemic animals.

Absorption of viruses into oral lymphocytes and decreased antibacterial activity of oral polymorphonuclear leukocytes.

Antibacterial activity of the oral polymorphonuclear leukocytes and in vitro virus absorption by oral lymphocytes was studied in two patient groups and in controls. A slight decrease of phagocytosis was observed in those control cases and periodontitis patients where orolymphocytes and oral epithelial cells had absorbed viruses, but in the same subjects the bactericidal effect was significantly weaker. Periodontosis patients with a defect of polymorphonuclear cells did not exhibit such a difference. As in similar subjects the antibacterial activity was more frequently weak when their orolymphocytes carried latent viruses, the results suggest that certain individuals are prone to carry latent viruses in their lymphocytes. Lymphokines released from these carrier cells and concentrated locally might damage phagocytic leukocytes, resulting in serious local inflammation.

Stereologic analysis of leukocyte infiltration in oral ulcers of developing Mikulicz aphthae.

Biopsy specimens of 1- to 7-day-old oral ulcers from patients with minor (Mikulicz), herpetiform, and Behcet's aphthae and of nonulcerated oral mucosa of aphthous patients were subjected to a quantitative, stereologic, electron microscopic analysis of the connective tissue infiltrate residing both at the center of and lateral to the ulcers. The data representing volume fractions and the numerical density of cellular and other infiltrate components demonstrated that (1) the infiltrate under the epithelium lateral to the ulcer is different from that at the ulcer's center, (2) at both sites, composition of the gross infiltrate does not change with age of the ulcer, (3) a large population of leukocytes (about 18% in the lateral and 23% in the central region) belong to the monocyte/macrophage series, (4) blast-forming T-lymphocytes are consistently present, blast-forming B-lymphocytes and plasma cells are very rare, and (5) mast cells are several times more numerous than in normal mucosa. In a comparison of the infiltrates of Mikulicz aphthae with those of herpetiform and Behcet's ulcers, it appears that the pathogenesis of the various oral ulcerations may well be diverse.