The involvement of interdigitating (antigen-presenting) cells in the pathogenesis of rheumatoid arthritis

Macrophage like cells expressing high concentrations of HLA-DR antigen have been identified in situ within the synovium of patients with rheumatoid arthritis. The characteristics of these cells have been determined using immunohistological analysis and combined cytochemical techniques. It was found that the majority (greater than 80%) of these cells were interspersed within the perivascular lymphocytic infiltrates occurring in the synovium. These cells did not stain with antisera against surface immunoglobulin or any Mc Abs to T lymphocyte markers. Further combined staining demonstrated that the HLA-DR + ve cells did stain with an anti-monocyte monoclonal (FMC-17), but could not be stained with a Mc Ab against C3b receptors. The interfacing of cytochemical reactions for acid phosphatase (ACP) and adenosine triphosphatase (ATPase) with immunofluorescence staining for HLA-DR demonstrated that these cells were ACP - ve ATPase + ve. This analysis led to the conclusion that the HLA-DR + ve cells found in abundance in the rheumatoid synovium expressed identical characteristics to the interdigitating cells of the normal lymph node paracortex. The possible significance of the presence of large numbers of such antigen presenting cells in the rheumatoid synovium is discussed.

A radiographic study of chronic periodontitis in 15 year old Queensland children

A retrospective study was carried out to determine the frequency of early periodontal bone loss in 15 year olds as seen in bite-wing radiographs. A total of 468 radiographs of 15 year olds was examined, 246 from 1970-74 and 222 from 1978-80. The alveolar bone crest on the mesial and distal of the first permanent molar teeth was examined for radiographic evidence of early chronic periodontitis. The condition of the adjacent proximal tooth surfaces was also recorded. No significant difference was found between the two groups; 39% of the 1978-80 and 43% of the 1970-74 group showed radiographic evidence of early chronic periodontitis (P less than 0.05). Males and females showed a similar frequency of periodontal disease levels. The mesial interproximal space of the first molars had significantly higher frequencies of radiographic evidence of chronic periodontitis than the distal interproximal spaces in the two groups examined. Fewer proximal restorations with overhangs were noted in the 1978-80 group, however more proximal subgingival calculus was found in this group than the 1970-74 group.

Association between plaque accumulation and Langerhans cell numbers in the oral epithelium of attached gingiva

After gingival health had been achieved in four subjects they were instructed to cease all oral hygiene measures. At 0, 8 and 21 days Plaque and Gingival Indices were recorded and gingival biopsies were removed from the buccal aspect of a first molar. Frozen sections of the gingival oral epithelium were stained for ATPase and 5'-nucleotidase to determine the number of Langerhans cells in a defined cross-sectional area. It was found that, as plaque accumulated, there was a statistically significant increase in the number of Langerhans cells in oral epithelium, particularly in the stratum spinosum. These results indicate that dental plaque can elicit a response in Langerhans cells located in the oral epithelium of the gingiva.

Histological assessment of periodontally involved cementum

Contamination of periodontally involved cementum by bacterial substances such as lipopolysaccharide (LPS) is considered a major reason for root planing. The purpose of the present study was to investigate the presence and location of lipid and polysaccharide within involved cementum as compared with uninvolved cementum. Frozen sections were prepared from the decalcified roots of 36 periodontally diseased and two control teeth. Serial sections were stained for either lipid (Oil-Red-O) or polysaccharide (Alcian Blue - PAS) and also with haematoxylin & eosin (H & E) or Huberstone's gram stain. Specimens of involved and uninvolved cementum were then examined under the light microscope for assessment of differences. Involved cementum from 12 of the periodontally diseased teeth exhibited strongly PAS-positive stained processes penetrating 3-7 mum into the surface of cementum from overlying plaque. Such processes were not observed in uninvolved cementum, suggesting a possible bacterial origin. Lipid granules were noted in only one involved specimen where they were situated up to 10 mum beneath the cemental surface. Similar granules were observed within plaque deposits but never in uninvolved cementum, again suggesting a possible bacterial origin. H & E and gram-stained specimens revealed the presence of microbial deposits in surface defects and within defects at the cemento-dentinal junction (CDJ), as well as penetration of micro-organisms into cementum in the absence of any surface defects. The results indicate that although lipid and polysaccharide of possible bacterial origin may be present within the 10 mum surface zone of involved cementum, the finding of microbial deposits down to the level of the CDJ suggests that all periodontally involved cementum should be removed during root planing, in order to achieve a root surface free of bacterial contamination.

An unusual form of chronic gingivitis: an ultrastructural, histochemical, and immunologic investigation

Gingival tissue from a patient suffering from an unusual form of gingivitis, previously described as plasma cell gingivitis, has been subjected to ultrastructural, histochemical, and immunologic investigation. Macrophages and T-lymphocytes infiltrated the oral epithelium where a dissecting type of injury was produced, predominantly in the lower spinous layer. Interkeratinocyte junctions were disrupted and collections of isolated desmosomes were observed in the intercellular spaces. It is postulated that the primary lesion in this atypical gingivitis lies in the epithelium and that the plasma cell infiltrate in the connective tissue is secondary to this. No allergen could be identified, and over a period of 7 years the condition has shown a tendency to resolve spontaneously.

Bacterial endotoxin: a role in chronic inflammatory periodontal disease?

A review of current information was undertaken examining suggested roles for bacterial endotoxin in periodontal disease. Evidence for the presence of endotoxin in plaque, gingival crevicular fluid and periodontally involved cementum is discussed. The biological effects of endotoxin are numerous, and its abilities to induce tissue inflammation, resorb rat foetal bone, activate the complement pathway, stimulate macrophages and activate immune responses are examined in relation to the suggestion that endotoxin is an important factor in the pathogenesis of periodontal disease.

Identification of cells expressing T and p28,33 (Ia-like) antigens in sections of human lymphoid tissue

A method has been developed for identifying human lymphocyte populations in tissue sections using hetero-antisera to T cells and to the B cell associated Ia-like, p28,33 polypeptide complex. The differential topographical localisation of T and B cells is revealed by simultaneous staining with antibodies tagged with different fluorochromes; this approach also identifies a small population of T cells bearing Ia-like antigens. Preliminary studies on lymphomatous tissue suggests this approach will be of value in the study of malignancy and cellular infiltration in disease.

Conversion of a stable T-cell lesion to a progressive B-cell lesion in the pathogenesis of chronic inflammatory periodontal disease: an hypothesis

Changes in the host's immunological response or, alternatively, changes in the oral microflora have been implicated as possible mechanisms by which a stable lesion of chronic inflammatory periodontal disease may become a progressive lesion leading to tissue destruction and tooth loss. It has recently been established that the progressive lesion in humans can be unequivocally considered as a B-cell response. Circumstantial evidence exists which suggests that the stable lesion is in fact a T-cell-mediated mechanism. An hypothesis is presented to explain the change from a stable to a progressive state in terms of a shift from a predominantly T-cell lesion to one involving large numbers of B-cells. Mechanisms of this shift in cell populations are considered together with a discussion of possible means of preventing such a shift.

The immunopathogenesis of progressive chronic inflammatory periodontal disease

Natural, humoral and cellular immune mechanisms have all been implicated in the pathogenesis of chronic inflammatory periodontal disease. However, confusion still exists as to the role played by each of these immunological mechanisms. Recently, characterization of the cell types within the progressive lesion has been established, in which four recognizable zones were described. Immediately subjacent to the epithelium lining the periodontal pocket both polymorphonuclear leukocytes (PMN's) and macrophages were seen, while cells deeper in the tissues had the morphological appearance of lymphocytes. The majority of these lymphocytes had a B-cell phenotype although a few T-cells and macrophages were found. On the advancing front of the lesion the cells had the morphological appearance of plasma cells, the majority of which contained IgG. Other cells found in this region had the morphology of plasma cells yet contained no cytoplasmic immunoglobulin, but they did contain substantial amounts of lysosomal enzymes. Similar cells have previously been described in periodontal disease; their frequent association with fibroblasts may suggest that they are important in the pathogenesis. Deposits of IgG and fibrin were found in the fibrous tissue band surrounding the lesion. These results are reviewed and, although the zones described were not anatomically distinct, by describing the lesion in this way it was possible to establish a convenient model to explain the immunopathogenesis of progressive chronic inflammatory periodontal disease. In this respect, progressive chronic inflammatory periodontal disease in man should be considered as a B-cell lesion.

The histopathogenesis of acute ulcerative gingivitis

The present study was a preliminary histological and immunofluorescent investigation of the edge of the ulcer in acute ulcerative gingivitis. The results of this study show that the lesion is dominated by polymorphonuclear leukocytes, with plasma cells present in the deeper parts. The epithelium on the edge shows widening of the intercellular spaces with destruction of the epithelial cells, accompanied by a heavy infiltrate of PMNs. Both IgG and C3 could be demonstrated between these epithelial cells, although the present study could not establish whether this represented immune complex deposition. The histopathogenesis of AUG therefore seems to involve a PMN infiltration of the epithelium, with subsequent destruction of the epithelium, probably due to the release of hydrolytic enzymes. The presence of the PMNs within the epithelium may involve direct bacterial chemotaxis and/or the activation of complement via the classical or alternative pathways.

Cytochemical identification of T and B cells in situ in mouse lymphoid tissue and lymph nodes from the rat, gerbil and cat

The use of enzymes as markers of T or B cells in tissue sections has been studied in mouse lymphoid tissue and lymph nodes from the gerbil, rat and cat. Lymphocytes in the T-cell areas of murine lymph nodes and spleen contained discrete dots of non-specific esterase and N-acetyl-beta-D-glucosaminidase (beta-glucosaminidase) activity, with weak acid phosphatase activity. Lymphocytes in the B-cell areas lacked this discrete staining. Cortical thymocytes contained slight esterase activity while medullary thymocytes were strongly positive for both esterase and beta-glucosaminidase. Lymphocytes with a T-cell staining pattern were only occasionally seen in lymph nodes from Nude (nu/nu) mice. ATPase staining was restricted to lymphocytes in the B-cell areas; weak 5'-nucleotidase staining was only present in a frew lymphocytes in both T- and B-cell areas. Blast cells stimulated by in vivo injection of ConA or PHA in the mouse showed strong discrete enzyme activity for non-specific esterase and beta-glucosaminidase. Lipopolysaccharide-stimulated blast cells and cells within germinal centres lacked this discrete staining. Comparison of lymph nodes from the gerbil, rat and cat suggested at least on enzymes as a T-cell marker in each species although considerable variation in staining profiles was seen in the different species.

Enzyme differentiation of lymphocyte subpopulations in sections of human lymph nodes, tonsils and periodontal disease

Five enzymes have been studied to differentiate between T and B lymphocytes in sections of human lymph nodes, tonsils and chronic inflammatory periodontal disease. The presence of acid phosphatase, beta-glucuronidase N-acetyl-beta-glucosaminidase, non-specific esterase and fluoride-resistant esterase activity was determined histochemically. The results indicate that cells in the B area of both lymph nodes and tonsils are negative for enzyme activity, while those in the T area show a single intense granule of activity. These enzymes were unable to differentiate between T blasts, B blasts and plasma cells in the sections studied. The majority of the lymphoid cells in the lesions of chronic inflammatory periodontal disease are enzyme-negative and probably of B-cell origin.

CPQ validity: the relationship between children's personality questionnaire scores and teacher ratings

Scores on the Children's Personality Questionnaire (CPQ) were correlated with scores from rating scale items selected by a panel of raters measuring the same behavior as a CPQ scale. Data were obtained on a normal sample of school children in grades three to six and on two referred groups, underachievers and children with behavior or social problems. The teachers of the children were asked to complete two rating scales on each child. Correlations between rating scale scores and CPQ scores suggest that, in general, the CPQ does not measure the traits it purports to measure.

The possible pathogenesis of gingival recession. A histological study of induced recession in the rat

Stages in the pathogenesis of gingival recession were observed in rats in which pocketing had been induced by replacement of natural incisors with dental implants. Suitable conditions were thus created on the palatal aspect of the implant sockets for recession to occur. The recession process was examined at intervals by taking transverse serial sections. In the epithelial and connective tissues deep to the receding margin, morphological changes were seen which apparently lead to cleft formation and recession. These appeared to be associated with mononuclear cell infiltration of the connective tissue. The study suggests that gingival recession involves a localized inflammatory process which causes breakdown of connective tissue and leads to proliferation of the epithelium into the site of connective tissue destruction. Proliferation of the epithelial cells into the connective tissue brings about a subsidence of the epithelial surface, which is manifest clinically as recession.