The nature of the inflammatory infiltrates in childhood gingivitis, juvenile periodontitis and adult periodontitis: immunocytochemical studies using a monoclonal antibody to HLADr

Are peri-implantitis lesions different from periodontitis lesions?

AIM

To compare histopathological characteristics of peri-implantitis and periodontitis lesions.

METHODS

A search was conducted on publications up to July 2010. Studies carried out on human biopsy material and animal experiments were considered.

RESULTS

While comprehensive information exists regarding histopathological characteristics of human periodontitis lesions, few studies evaluated peri-implantitis lesions in human biopsy material. Experimental peri-implantitis lesions were evaluated in 10 studies and three of the studies included comparisons to experimental periodontitis. Human biopsy material: the apical extension of the inflammatory cell infiltrate (ICT) was more pronounced in peri-implantitis than in periodontitis and was in most cases located apical of the pocket epithelium. Plasma cells and lymphocytes dominated among cells in both types of lesions, whereas neutrophil granulocytes and macrophages occurred in larger proportions in peri-implantitis.

EXPERIMENTAL STUDIES

placement of ligatures together with plaque formation resulted in loss of supporting tissues and large ICTs around implants and teeth. Following ligature removal, a "self-limiting" process occurred in the tissues around teeth with a connective tissue capsule that separated the ICT from bone, while in peri-implant tissues the ICT extended to the bone crest.

CONCLUSION

Despite similarities regarding clinical features and aetiology of peri-implantitis and periodontitis, critical histopathological differences exist between the two lesions.

Aspects of adaptive host response in periodontitis

OBJECTIVE

To review host response in periodontitis with respect to cellular composition of lesions, T cell receptor (TCR) gene expression, cytokine profiles of T-helper (Th) cells and autoimmune components.

MATERIAL AND METHODS

The studies included were confined to human material (biopsies, gingival crevicular fluid, blood from subjects with periodontitis).

RESULTS AND CONCLUSIONS

In periodontitis lesions, plasma cells are the most common cell type and represent about 50% of all cells, while B cells comprise about 18%. The proportion of B cells is larger than that of T cells and Th cells occur in larger numbers than T cytotoxic cells. Polymorphonuclear cells and macrophages are found in fractions of less than 5% of all cells. Lesions in aggressive and chronic forms of periodontitis exhibit similar cellular composition. Differences in disease severity, however, may reflect increases in plasma cell and B cell densities. B cells serve as important antigen-presenting cells in periodontitis. The periodontitis lesion expresses a unique TCR gene repertoire that is different from that in blood. The role of superantigens in periodontitis is unclear. There are few studies using comparative designs and unbiased quantitative methods regarding Th-1 and Th-2 cells in periodontitis. The relative dominance of B cells and plasma cells in periodontitis lesions cannot entirely be explained by enhanced Th-2 functions but maybe because of an imbalance between Th-1 and Th-2. Autoimmune reactions are evident in periodontitis lesions. The role of auto-antibodies in the regulation of host response in periodontitis, however, needs to be clarified. Auto-reactive B cells occur in larger proportions in subjects with periodontitis than in healthy controls.

Expression of HLA class II antigens in marginal periodontitis of patients with Down's syndrome

The expression of HLA Class II antigens on the surfaces of immunocompetent cells and the presence of CD1a+ cells (Langerhans cells) are important components of antigen presentation. Quantitative variations in HLA class II expression on antigen-presenting cells play a role in immune regulation. An indirect immunofluorescent technique was used on cryostat sections to reveal such differences qualitatively or quantitatively between chronic marginal periodontitis (CMP) in patients with Down's syndrome (DS) and in otherwise normal patients (NP). We found increased frequency of HLA Class II (HLA-expression on inflammatory cells and on keratinocytes of the oral gingival epithelium) in CMP of DS patients compared to sections from NP. The expression of HLA-DR was more frequent on the keratinocytes of the pocket epithelium in NP than in DS. There were significantly higher numbers of CD1a+ cells and ratios of HLA-DR+/CD1a+ cells and HLA-DP+/CD1a+ cells in the DS group compared to the NP group. Our conclusion is that there is a more pronounced inflammatory process in the gingival sites with CMP of DS patients compared to CMP in NP. The findings also indicate that there is a highly activated immune response in CMP of DS patients.

Some microbiological, histopathological and immunohistochemical characteristics of progressive periodontal disease

The aim of the present investigation was to study the local nature of human periodontal disease by assessing the microbiota and the composition of the tissue lesions at sites with progressive attachment loss in periodontitis susceptible subjects. 300 subjects with periodontal disease were monitored for 2 years without treatment. 8 subjects lost > 2 mm of attachment at > or = 3 sites during both the first and the second 12 month interval. These 8 subjects (progressive disease group; PD) were recalled for a microbiological and histopathological examination. A group of age- and sex-matched subjects were identified who during the 2 years of monitoring exhibited gingivitis and deep pockets, but no further attachment loss. This group of 11 subjects (non-progressive disease group; NPD) served as controls. From the 8 active disease subjects, > or = 1 interproximal site which had displayed disease activity (progressive disease active; PDA) and > or = 1 contralateral site without disease progression (progressive disease inactive; PDI) were sampled. From the 11 control subjects, 1 site/subject was sampled (NPD). The total number of viable micro-organisms (TVC) in the subgingival microbiota was estimated and a series of bacterial species were identified and enumerated. The gingival tissue of the sampling site was excised and the soft tissue prepared for morphometrical and immunohistochemical analyses. No differences were observed in the subgingival microbiota of the sample sites in the subjects who exhibited disease progression (PD) when compared with the subjects with periodontally diseased but stable conditions (NPD).(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of interleukin-2 receptor and HLA-DR on lymphocyte subsets of gingival crevicular fluid in patients with periodontitis

Expression of interleukin-2 receptor (IL2R) and HLA-DR on lymphocytes of gingival crevicular fluid (GCF) was examined by two-color flow cytometric analysis. GCF from 15 patients with periodontitis was collected by crevicular washing. Mononuclear cells were isolated by Ficoll-paque gradient centrifugation from inflamed gingival tissue (GT) and peripheral blood (PB) sampled from each of the 15 patients. Lymphocyte subsets were detected by using monoclonal antibodies (mAb) of Leu 12 (CD19), Leu 4 (CD3), Leu 3a (CD4) and Leu 2a (CD8) directed to B cells, T cells, helper/inducer T cells (Th) and suppressor/cytotoxic T cells (Ts), respectively. Anti-IL2R (CD25) and anti-HLA-DR were used as lymphocyte activation markers. IL2R- or HLA-DR-positive fractions in Th, Ts and B cells were calculated. Percentage of IL2R-positive fraction in Th (IL2R+ Th) of GCF (34.0%) was significantly higher than those of GT (18.4%) and PB (13.7%). IL2R-positive fraction in B cells (IL2R+ B) of GCF was the highest among the three groups (23.9% in GCF, 12.5% in GT, 6.3% in PB). Ts did not express IL2R regardless of the origin of the samples. Compared with PB and GT, GCF showed significantly higher HLA-DR expression on Th and Ts in GCF (PB: 8.7% and 27.1%; GT: 27.9% and 50.3%; GCF: 44.7% and 65.3%). These results suggest that lymphocytes in GCF were highly activated and are related to the local host immune response in periodontitis.

The role of histopathology in the diagnosis and prognosis of periodontal diseases

The histological evaluation of surgical biopsies from affected tissues is a standard way of assessing pathological change and determining treatment in many diseases. In most forms of periodontal disease, however, this approach finds limited application. Here, we review what uses the histopathological approach has in the study and evaluation of the periodontal diseases. Current understanding of the changes in epithelial anatomy during pocket formation, the cellular composition and dynamics of the inflammatory infiltrate and the mechanisms of bone resorption and repair are reviewed from the perspective of the information available from microscopical investigation, including the uses and potential application of modern immunocytochemical methods to these questions. The usefulness of histological study of biopsy material is reassessed in the light of advances made in immunohistochemical techniques and their application to gingival inflammatory infiltrates and epithelia. Such techniques offer immediately valuable research opportunities with potential for diagnostic applications, noteably the recognition of phases of destructive activity and their differentiation from periods of effective host defence.

The composition of gingival inflammatory cell infiltrates in children studied by enzyme histochemistry

Gingival biopsies were obtained from 23 children, aged 5-11 years (8.6 +/- 1.8 years). Specimens were taken from areas of the gingiva adjacent to the teeth which were to be extracted because of caries or its sequelae and which clinically had a gingival index score of at least 1. Staining for alpha-naphthyl acetate esterase with unspecific esterase at pH 5.8 (ANAE) permitted identification of T lymphocytes, monocytes/macrophages, plasma cells and non-reactive (ANAE-negative) cells. Cells which tentatively were identified as "natural killer" (NK) cells were also observed. Differential cell counting was performed for 10 specimens, selected on the basis of the presence of a well-defined inflammatory infiltrate, clear morphology throughout and good ANAE staining. Cell counts confirmed earlier studies showing that lymphocytes predominate in the inflammatory infiltrates in childrens' gingivitis. T lymphocytes dominated particularly in the periphery of the most densely infiltrated areas. Relatively few plasma cells were seen. It was concluded that T lymphocytes dominate in the inflammatory infiltrate in childrens' gingivitis.

Distribution of immunoglobulin isotypes including IgA subclasses in adult, juvenile, and rapidly progressive periodontitis

The plasma cell population in gingival biopsies from 3 groups of patients with adult, juvenile, and rapidly progressive periodontitis was characterized with respect to the distribution of individual immunoglobulin isotypes, including IgA subclasses, by paired immunofluorescence staining. The median ratios of IgG:IgA plasma cells in gingival connective tissue from the 3 groups were 2.7 (range 2.0-6.5), 3.0 (1.4-6.2), and 2.0 (1.2-4.0), respectively. Cells staining for intracellular IgM were found in low numbers in all biopsies (range 0.3-6.3% of all plasma cells). No statistically significant differences were observed between the 3 patient groups. In all 3 groups, the IgA plasma cell population was predominantly of the IgA1 isotype. One function of IgA seems to be to dampen inflammatory side-effects of other immune effector systems. The demonstrated predominance of IgA1 plasma cells indicates that the majority of IgA produced locally in gingivae of patients with periodontal diseases is susceptible to the IgA1-specific proteases excreted by important members of the disease-associated subgingival microflora. This may be an important factor in the apparently uncontrolled inflammation and tissue degradation taking place in the marginal periodontium during active periodontal disease.

Histological characteristics associated with suppurating periodontal pockets

The purpose of this study was to characterize histologically the gingival lesion associated with suppuration in advanced periodontitis. Thirty-three bleeding, suppurating (S) and 23 bleeding, nonsuppurating (NS) interproximal biopsies were obtained from nine patients and processed for light microscopy. Pocket depths (mean +/- SD) were 6.7 +/- 1.6 mm (S) and 5.4 +/- 2.2 mm (NS). Six-micron serial sections were stained with (1) hematoxylin/eosin and (2) van Gieson. Quantitative cell types were determined by a grid intersection counting technique at x 1000. Volumetric analysis of collagen-poor (inflammation) areas was conducted using a computer biometric system that revealed three histologic patterns: Type I sites showed mild to moderate inflammation (less than 50% infiltrate, S = 15, NS = 20); Type II sites showed intense inflammation (greater than 50% infiltrate, S = 17, NS = 3); and only one (S) site had a large connective tissue abscess (Type III). The mean percentage of collagen-poor area was significantly larger in suppurating (42.1 +/- 25.5%) versus nonsuppurating (27.7 +/- 20.4%) sites (P = 0.02). In both S and NS sites, plasma cells (means = 66%) and lymphocytes (means = 27%) predominated in the inflammatory infiltrates. Histologically, suppuration appeared to be associated with increased gingival inflammation and a slight increase in connective tissue neutrophils.

In situ lymphocyte subpopulations from active versus stable periodontal sites

The purpose of this study was to evaluate lymphocyte subset densities and distributions within gingival biopsies from active sites (greater than or equal to 2 mm clinical attachment loss within three months of biopsy) versus clinically similar but stable or healthy sites. Small interproximal gingival biopsies representing at least one of each of the above categories were obtained from each of 20 periodontal maintenance patients. Serial cryostat sections displaying a cross section of the gingiva were labeled with monoclonal antibodies for (1) pan T cells, (2) T cytotoxic/suppressor cells, (3) T helper/inducer cells and (4) pan B cells and were developed using an avidin-biotin-peroxidase system. Lymphocyte populations were enumerated in repeatable fields from the sulcular, middle and oral one-third of each section. Relative proportions of the same lymphocyte subsets were analyzed in peripheral blood samples from the same patients using direct immunofluorescence. Pan B cells were significantly more prevalent in infiltrates from active sites than in stable (P less than 0.05) or healthy (P less than 0.01) sites. The T/B cell ratio was also significantly lower in active than stable biopsies (P less than 0.05), and in active biopsies versus blood (P less than 0.05). The T helper/T suppressor cell ratio did not vary significantly between blood and any gingival tissue disease group or location, but a trend toward lower relative numbers of T helper cells in the sulcular infiltrates of active sites was noted. These results support the premise that active periodontal sites display elevated B cell populations and abnormal immune regulation possibly involving the T helper cell subset.

Cellular aspects of and effects on the gingiva in children with Down's syndrome during experimental gingivitis

In a previous experimental gingivitis study, it was shown that in children with Down's syndrome (DS), gingival inflammation started earlier, was more extensive and developed faster, than in normal healthy control children. In both groups, the start of the process was accompanied by an acute inflammatory response and an increase of the infiltrated connective tissue area (ICT). The purpose of the present study was to investigate how these facts were reflected at a cytological level. The study was carried out in 8 DS and 8 matched control children. Their ages ranged from 5-10 years. A "normal" healthy gingiva was attained after strict oral hygiene procedures. During a period of 21 days in which oral hygiene was abolished, gingival biopsies were taken on days 0, 7, 14, and 21. In both groups, junctional epithelium (JE) and ICT contained low numbers of polymorphonuclear leucocytes (PMNs). The start of the inflammation (day 7 for the DS and day 14 for the control children) was marked by a significant positive correlation between the numbers of PMNs in the JE and the ICT, and a significant increase of the numbers of PMNs in ICT. In ICT, a concomitant decrease in collagen fibre density was observed. In the control group, the decrease correlated with the numbers of PMNs in ICT, which suggests that this collagen breakdown is caused by PMN products. After the initial decrease, the collagen fibre density remained fairly constant in this group throughout the study. In the DS group, there was a tendency to a further decrease in the ICT3 area, correlated with the numbers of PMNs in ICT.(ABSTRACT TRUNCATED AT 250 WORDS)