Comparison of gingival and peripheral blood T cells among patients with periodontitis suggests skewing of the gingival T cell antigen receptor V beta repertoire

The present study investigated the expression of different variable regions of T cell receptor β-chain (Vβ) among functional subsets of T cells, i.e. CD45RO⁺ (activated/memory), CD4⁺ and CD8⁺in gingiva and peripheral blood of patients with periodontitis. Gingival tissue specimens (n= 25) and peripheral blood were procured from 18 patients with periodontitis during periodontal surgery or extraction. Single-cell suspensions of gingival tissues were made by enzymatic digestion. These cells were immunofluorescently labeled with a panel of monoclonal antibodies specific for 18 TCR Vβ regions, in concert with markers for various T cell subsets. The cells were then analyzed with 3-color multivariate flow cytometry. Results demonstrated that a significantly higher proportion of T cells in gingiva expressed Vβ5.2 (0.0005), Vβ6 (0.0007) and Vβ9 (0.003) regions compared to those in peripheral blood. Comparison of CD45RO⁺ (activated/memory) and CD45RO^? (naïve) subsets of gingival T cells revealed differences in the expression of TCR Vβ regions. Vβ5.2 expression was significantly higher among CD45RO⁺ gingival T cells (p= 0.004), whereas Vβ14 expression was elevated among the CD45RO^? subset relative to peripheral blood (p= 0.008). Analysis of TCR Vβ region expression among CD4⁺ and CD8⁺ subsets did not reveal any statistically significant differences between gingiva and peripheral blood, although some Vβ regions approached significance. Collectively, these results demonstrate that the T cell repertoire in the gingival compartment differs significantly from that in the peripheral blood. Furthermore, since the skewing of TCR Vβ was observed among naive, as well as activated/memory T cells, it is likely that both developmental and environmental factors are influential in shaping the gingival TCR repertoire in patients with periodontitis. Elucidation of the cause of the skewed expression of T cell receptors in gingiva can provide insights into the specificity of T cells in periodontitis.     

Memory T cell subsets in healthy gingiva and periodontitis tissues

1 Background

In the gingival sulcus, effective and balanced innate and adaptive immune responses against subgingival plaque microbiome are crucial to maintain immune homeostasis. In this study, we investigated the memory T cell subsets in healthy gingiva and periodontitis tissues.

2 Methods

Anatomical localization of T cells (CD3⁺, CD4⁺, and CD8⁺) in healthy gingiva and periodontitis tissues were examined immunohistochemically. Subsets of memory T cells from isolated gingival cells were analyzed by flow cytometry using a cocktail of monoclonal antibodies (anti‐CD69, anti‐CD103, anti‐CD45RA, anti‐CCR7, anti‐CD28, and anti‐CD95). Intracellular cytokine staining of interleukin (IL)‐17 and interferon (IFN)‐γ expression on memory T cells in periodontitis tissues was also investigated.

3 Results

We found that healthy gingiva contains two memory T cell populations; a CD69^? recirculating population and a CD69⁺ gingiva‐resident memory T cell population. CD4⁺ T cells with transitional memory (T_TM) phenotype (CD45RA^?CCR7^?CD28⁺CD95⁺) constitute the major subset within these two populations. A significant increase in the proportion of CD4⁺CD69⁺CD103^? memory T cells was observed in periodontitis tissues compared with healthy gingiva. CD4⁺ memory T cells from periodontitis tissues produced either IL‐17 or IFN‐γ whereas CD8⁺ memory T cells produced only IFN‐γ.

4 Conclusions

Our findings suggest that recirculating and gingiva‐resident memory T cells could represent an important part of the immune surveillance network in the connective tissue, maintaining periodontal homeostasis. Imbalance of subgingival bacterial communities could damage gingival barrier allowing bacterial antigens to get access to the deeper connective tissue where they activate memory T cells leading to deleterious inflammation; a hallmark of periodontitis.     

ICAM-1-expressing pocket epithelium, LFA-1-expressing T cells in gingival tissue and gingival crevicular fluid as features characterizing inflammatory cell invasion and exudation in adult periodontitis

Activated T lymphocytes constitute a major component of inflammatory cells in the early periodontal lesion, and also appear in the gingival crevicular fluid. In an attempt to clarify the relationship between the ICAM-1 (CD54) expression of pocket epithelium in gingiva and the infiltrating lymphocyte population, we carried out an analysis of CD11a⁺ (LFA-lα), CD25⁺ (IL-2Rα) and CD4⁺ (Th) cells subjacent to ICAM-1-expressing pocket epithelia and CD11a⁺ CD25⁺CD4⁺ cells in gingival crevicular fluid (GCF). GCF was collected by crevicular washing from 16 patients with periodontitis (P group) and 3 subjects with healthy gingiva (H group). Peripheral blood (PB) was collected at the same time. Mononuclear cells were isolated by Ficoll-paque gradient centrifugation from GCF and PB. Monoclonal antibodies (mAb) to CD11a, CD25, and CD4 were used for three-color flow cytometry. Gingival biopsies were obtained from 7 patients in P group and 3 subjects in H group. Serial cryostat sections (6 μm in thickness) were prepared from each biopsy, on which a double staining was performed. The number of CD11a⁺ CD25⁺ CD4⁺ cells and the fluorescence intensity of FITC conjugated anti-CD 11a were significantly higher in GCF than in PB (p≤0.001 to p≤0.01). CD11a⁺ CD25⁺CD4⁺ cells were not detected in GCF in H group. The pocket epithelia expressed CD54 in P group, but not in H group. The number of CD11a⁺, CD25⁺ and CD4⁺cells infiltrating the connective tissue subjacent to the upper, middle and lower parts of the CD54 positive pocket epithelium (n=16) was 141±26, 38±13, 144±29 (cells/0.04 mm²), respectively, whereas in the CD54 negative pocket epithelium, it was (n=5) 9±2, 3±1, 8±3. In P group, the CD11a⁺CD25⁺CD4⁺cell number in GCF correlated with CD25⁺, CD11a⁺cells in the connective tissue subjacent to the CD54⁺pocket epithelium. These results indicate that expression of ICAM-1 in pocket epithelium is relevant to the migration of CD11a, CD25, CD4 positive cells in connective tissue subjacent to the pocket epithelium into the periodontal pocket. Assessing the relationship of our findings and other adhesion molecules would offer important clues to the understanding of T cell migration in affected gingiva.     

Dysfunction of CD4+CD25high T regulatory cells in patients with recurrent aphthous stomatitis

Background: Recurrent aphthous stomatitis (RAS) is a chronic inflammatory disease of unknown etiology characterized by recurring formation of painful oral ulcers. RAS may result from oral epithelium damage caused by T‐cell‐mediated immune response. CD4⁺CD25⁺ T regulatory (Treg) cells suppress proliferation and effector functions of other immune cells, and therefore are crucial in regulating the immune response. Methods: We tested the function of peripheral CD4⁺CD25^high Treg cells in active RAS through their ability to inhibit proliferation and cytokine production of conventional CD4⁺ T cells. We also attempted to detect the presence of FOXP3 and indoleamine 2,3‐dioxygenase (IDO) mRNA in the lesional and non‐lesional oral mucosa of RAS patients and healthy individuals using real‐time PCR assay. Results: Treg cells derived from RAS patients were less efficient in the suppression of cytokine production of CD4⁺ T effector cells than Treg cells from healthy individuals. Moreover, in RAS, Treg cells were nearly twice less potent in the inhibition of CD4⁺CD25^? T cell proliferation than in healthy donors. Furthermore, we have demonstrated the decreased proportion of CD4⁺CD25⁺FOXP3⁺ Treg cells in peripheral blood of RAS patients compared with controls. We failed to detect FOXP3 mRNA, while IDO mRNA expression was decreased in non‐lesional mucosa biopsies from RAS patients compared with ulcer biopsies or normal mucosa from healthy donors. Conclusions: These findings suggest that CD4⁺CD25^high Treg cells are both functionally and quantitatively compromised in RAS and that decreased constitutive expression of IDO in oral mucosa in RAS may lead to the loss of local immune tolerance.     

Evaluation of interleukin-10 producing CD19+ B cells in human gingival tissue

ObjectiveThis study aimed to evaluate IL-10 producing CD19⁺ B cells and to examine the correlation between these cells and the expression levels of IL-1β, TNF-α, RANKL, and IL-10 cytokines in the gingival tissues of individuals with and without chronic periodontitis.DesignData were obtained from 20 patients with chronic periodontitis and 10 healthy controls. The gingival samples were analyzed by immunofluorescence, while real-time PCR and enzyme-linked immunosorbent assays were performed to determine cytokine levels.ResultsThe number of IL-10 producing CD19⁺ B cells and the expression levels of IL-10 were significantly higher in the inflamed gingival tissues than in the healthy tissues. A positive correlation between the expression levels of IL-10 and the number of IL-10 producing CD19⁺ B cells were observed. IL-1β, TNF-α, and RANKL expression levels were significantly elevated in diseased gingivae compared to healthy tissues, and there was a positive correlation between the expression levels of these pro-inflammatory cytokines and the number of IL-10 producing CD19⁺ B cells.ConclusionWhile IL-10 producing CD19⁺ B cells are present in the gingival tissues of patients with periodontal disease and of those with a healthy periodontium, the diseased gingival tissues had a much greater number of these cells than the healthy. The mRNA and protein levels of IL-10, IL-1β, and RANKL, as well as mRNA levels of TNF-α, were positively correlated with the number of IL-10 producing CD19⁺ B cells, which highlights the importance of these factors in the development and progression of periodontitis.     

Characterization of T lymphocyte clones derived from Porphyromonas gingivalis infected subjects

Porphyromonas gingivalis plays a major role in the pathogenesis of periodontal disease, however some individuals with P. gingivalis infection do not experience periodontal breakdown. The aim of this study was to investigate the proliferative responses of two highly defined groups of subjects and to establish and characterize peripheral blood and gingival cell T cell lines and clones from subjects from these groups, The two groups were selected on the basis of P. gingivalis in their plaque and the presence of serum anti-P. gingiralis antibodies. Both groups therefore were seen to have P. gingivalis and to have responded to it. They however differed only in their clinical susceptibility (adult periodontitis) or resistance (gingivitis) to periodontal breakdown. Dose responses of peripheral blood mononuclear cells extracted from the subjects showed a trend towards a lower response by the adult periodontitis group to P. gingivalis outer membrane (OM) antigens. Peripheral blood T cell lines and clones responsive to P. gingivalis OM were established from a high responding gingivitis subject and a low responding adult periodontitis subject. Gingival T cell lines and clones were also derived from cells extracted from the periodontal tissues of the same periodontitis subject. The majority of T cells in the peripheral blood T cell line from the gingivitis subject were CD4 while those from the adult periodontitis subject were CD8. The gingival T cell line was CD3+ve CD4-ve and CD8-ve. All lines and clones proliferated slowly to P. gingivalis OM but phytohaemagglutinin (PHA) induced an increase in DNA synthesis in those derived from the gingivitis subject with little to no effect on those established from the adult periodontitis subject. Furthermore. PHA inhibited the proliferative response of the CD8 clone derived from the adult periodontitis subject. Phenotypic analysis demonstrated that all the peripheral blood clones expressed the αβ TCR while the gingival T cell clones expressed the γδ TCR. All clones had the memory/primed CD45RO+ve phenotype and at least 80% of cells in each clone were HLA-DR + ve. A lower percent of gingival cells expressed CD45RA than the CD4 peripheral blood clones and the two CD8 clones also had a decreased CD45RA expression. The gingival T cell clones also expressed a low percent CD25 as did the CD8 clone derived from the adult periodontitis subject. The results suggest that clones derived from the gingivitis and adult periodontitis subject may be functionally different. The presence of γδ T cells in adult periodontitis remains to be confirmed and their function determined.     

Correlation of cytomegalovirus and human herpesvirus 7 with CD3+ and CD3+ CD4+ cells in chronic periodontitis patients

Thomasini RL, Bonon SH, Durante P, Costa SCB. Correlation of cytomegalovirus and human herpesvirus 7 with CD3 ⁺ and CD3 ⁺ CD4 ⁺ cells in chronic periodontitis patients. J Periodont Res 2012; 47: 114–120. © 2011 John Wiley & Sons A/S Background and Objective: Human chronic periodontitis is an inflammatory process characterized by dense accumulation of immune cells in the periodontal tissue. The periodontitis can lead to loss of teeth in the patient and the pathogenesis of this disease is not completely known. This study tested the hypothesis that chronic periodontitis‐affected sites can harbor betaherpesviruses and that viruses are linked to a profile of the inflammatory infiltrate. Material and Methods: Biopsies of periodontal tissue were taken from periodontitis‐affected patients and from healthy subjects. Immunohistochemistry was performed to count CD19⁺ B cells, CD3⁺ total T cells, T‐CD4⁺ and T‐CD8⁺ cell subsets, and PCR was performed to detect cytomegalovirus and human herpesvirus 6 and 7 in the samples. One slide of each sample was stained with Giemsa for histopathological examination and to evaluate the quality of the cellular infiltrate. Results: As expected, tissues collected from healthy subjects presented no significant level of inflammatory infiltration and were therefore excluded from immunostaining procedures. Results showed that CD19⁺ B cells were in higher number than CD3⁺ T cells in the periodontitis‐affected tissue, but this was not statistically significant. The T‐CD4⁺ lymphocyte subset was significantly higher than the T‐CD8⁺ lymphocyte subset (p = 0.004) in the samples. Cytomegalovirus and human herpesvirus 7 were found at periodontitis‐affected sites, but not in tissue collected from healthy subjects (p = 0.04 and p = 0.04, respectively). Human herpesvirus 6 was rarely detected. We found a correlation between cytomegalovirus and lower CD19⁺/CD3⁺ ratios (ratio < 0.9, p = 0.003) and between human herpesvirus 7 and lower CD19⁺/CD3⁺ ratios (ratio < 0.9, p = 0.003) and higher CD4⁺/CD8⁺ ratios (ratio > 1.1, p = 0.002). Conclusion: This study shows that cytomegalovirus and human herpesvirus 7 can be present at periodontitis‐affected sites but are uncommon at healthy periodontal sites. Moreover, our data suggest that cytomegalovirus can be related to an inflammatory infiltrate with predominance of CD3⁺ T cells, whereas human herpesvirus 7 can be associated with an infiltrate with predominance of T‐CD4⁺ cells. However, further studies are necessary to support this hypothesis. Herpesviruses could play a role in human chronic periodontitis by modulation of the T cell response.     

Alveolar Bone Resorption Induced by CD4+CD45RB High‐Density T‐Cell Transfer in Immunocompromised Mice

Background: The aims of this study are to determine whether the antigen‐inexperienced (naive, CD45RB high‐density) T‐cell (CD4⁺CD45RB^High T‐cell) transfer model is associated with alveolar bone resorption, to elucidate the local osteogenic/adipogenic potential of alveolar bone marrow stromal cells (ABCs) from T‐cell–transferred animals, and to investigate the systemic osteogenic potential by transplanting human periodontal ligament stem cells (hPDLSCs) into these animals. Methods: CD4⁺CD45RB^High and CD4⁺CD45RB^Low (antigen‐experienced [memory, CD45RB low‐density]) T cells were sorted and transferred into severe combined immunodeficiency (SCID) mice to induce inflammatory bowel disease–like syndrome (n = 8). hPDLSCs were transplanted into T‐cell–transferred SCID mice to examine ectopic cementum formation 8 weeks after T‐cell transfer. The mandibles and tibias of these mice were retrieved for microcomputed tomography (micro‐CT), histomorphometric analysis, and isolation of ABCs 16 weeks after T‐cell transfer. The in vitro osteogenic and adipogenic potentials of the ABCs were evaluated. Results: Histologic and micro‐CT analysis revealed that the transfer of CD4⁺CD45RB^High T‐cell subset was sufficient for alveolar bone resorption and affected the osteogenic/adipogenic potential of ABCs. Furthermore, it was found that CD4⁺CD45RB^High T‐cell–transferred animals have decreased systemic osteogenic potential, as evidenced using the in vivo ectopic hPDLSC transplantation model. Conclusion: CD4⁺CD45RB^High T‐cell transfer induced both alveolar bone resorption and reduced systemic osteogenic potential, with a concomitant downregulation of the osteogenic potential of ABCs.     

Role of distinct CD4+ T helper subset in pathogenesis of oral lichen planus

Oral lichen planus (OLP) is one of the most common chronic inflammatory oral mucosal diseases with T‐cell‐mediated immune pathogenesis. In subepithelial and lamina propria of OLP local lesions, the presence of CD4⁺ T helper (CD4⁺ Th) cells appeared as the major lymphocytes. These CD4⁺ T lymphocytes can differentiate into distinct Th cell types such as Th1, Th2, Treg, Th17, Th22, Th9, and Tfh within the context of certain cytokines environment. Growing evidence indicated that Th1/Th2 imbalance may greatly participate into the cytokine network of OLP immunopathology. In addition, Th1/Th2 imbalance can be regulated by the Treg subset and also greatly influenced by the emerging novel CD4⁺ Th subset Th17. Furthermore, the presence of novel subsets Th22, Th9 and Tfh in OLP patients is yet to be clarified. All these Th subsets and their specific cytokines may play a critical role in determining the character, extent and duration of immune responses in OLP pathogenesis. Therefore, we review the roles of distinct CD4⁺ Th subsets and their signature cytokines in determining disease severity and susceptibility of OLP and also reveal the novel therapeutic strategies based on T lymphocytes subsets in OLP treatment.     

Expression of CD14, CD16 and CD45RA on monocytes from periodontitis patients

BACKGROUND AND OBJECTIVE: Peripheral blood monocytes are a heterogeneous population, with phenotypes that change on activation or differentiation. Most of the monocytes express lipopolysaccharide (LPS) receptor, CD14 intensely, and do not express Fc gamma receptor III, CD16 (CD14++CD16- monocytes). But monocytes expressing CD16 with reduced CD14 (CD14+CD16+ monocytes) increase in inflammatory diseases as well as sepsis and bacteremia in hemodialysis patients. CD45RA is expressed on activated monocytes, and is regarded as an activation marker of peripheral blood monocytes. The purpose of this study was to determine the phenotypic and functional alteration of monocytes in periodontitis patients. METHODS: Peripheral blood was collected from 33 aggressive periodontitis patients (22 females, 11 males), 55 chronic periodontitis patients (35 females, 20 males) and 30 healthy subjects (16 females, 14 males), and the expression of CD14, CD16 and CD45RA on monocytes was determined using flow cytometry. The production of interleukin-6 (IL-6) by CD16+ and CD16- monocytes stimulated with LPS from Escherichia coli and Actinobacillus actinomycetemcomitans was also examined using flow cytometry. RESULTS: The percentage of CD14+CD16+ monocytes was significantly increased in chronic periodontitis patients. Percentage of monocytes expressing CD45RA was significantly increased in aggressive periodontitis patients compared to healthy subjects. CD16+ and CD16- monocytes produced IL-6 in response to LPS from E. coli and A. actinomycetemcomitans, and the percentage of IL-6 producing cells was higher in CD16+ monocytes than CD16- monocytes, suggesting that CD14+CD16+ monocytes represent a hyper-reactive phenotype. CONCLUSIONS: The present study demonstrated that CD14+CD16+ monocytes and CD45RA+ monocytes were increased in chronic and aggressive periodontitis, respectively. These findings suggest that alteration of monocytes in periodontitis patients could be evaluated by monitoring the surface expression of CD14, CD16 and CD45RA on monocytes.     

Limiting dilution analysis of proliferating and cytotoxic lymphocytes in the peripheral blood and tumours of oral cancer patients

Frequencies of proliferating and cytotoxic lymphocytes from the peripheral blood and tumour tissue of oral cancer patients and healthy individuals were monitored using limiting dilution analysis. Significantly lower precursor frequencies of proliferating lymphocytes were observed in the peripheral blood and tumour tissue of oral cancer patients. A high frequency of natural killer (NK) cells but low cytotoxic T lymphocytes (CTL) was observed in the peripheral blood compartment of oral cancer patients as compared to healthy individuals. A marked reduction in both NK and CTL frequencies in the tumour tissue compared to the peripheral blood was observed. In the tumour tissues, increased percentages of activated CD4⁺ lymphocytes as compared to CD8⁺ lymphocytes were observed. Our results suggest that impaired proliferative and cytotoxic potential of tumour infiltrating lymphocytes may play an important role in the escape of tumour cells from the immune system.     

Local and systemic TCR V gene expression in advanced periodontal disease

Abstract. The aim of the present investigation was to study the expression of specific α/β T cell receptor (TCR) gene products in relation to some microbiological and immunological features of advanced destructive periodontitis, 21 individuals with advanced periodontal disease (diseased group) and 16 age- and sex-matched healthy subjects (healthy group) were recruited. Following a clinical examination of the diseased group, the 3 deepest interproximal sites in the upper and lower premolar- or molar segments (i.e., 12 sites in each individual) were selected for further analysis. Samples from the subgingival microbiota were obtained from the pocket of the selected sites and were prepared for a microbiological examination. The gingival tissue at one of the selected sites was also biopsied. Each excised soft tissue specimen was divided into 2 equal portions. One portion of the biopsy was prepared for histometric and morphometric analyses. The 2nd portion was snap frozen and prepared for immunohistochemical analysis, A sample of peripheral blood was obtained from each individual of the diseased and the healthy group and prepared for immunohistochemical analysis. The selected sites of the diseased group harbored varying numbers of microorganisms which have been associated with periodontal disease. The excised gingival tissue contained inflammatory lesions with substantial numbers of lymphocytes and plasma cells including T- and B-cells and a TCR Vα/β gene repertoire dominated by Vβ 17. The TCR profile of the lesion, however, differed markedly from that of the circulating blood of the diseased subjects. While only minor differences were observed between the blood samples of the diseased and the healthy subjects regarding the TCR genes, CD5, HLA-DR and CD5+CD19 positive cells occurred in higher proportions in the blood samples of the subjects susceptible to periodontal disease than in healthy controls. It may be suggested that (i) TCR Vα/Vβ expression in peripheral blood samples of subjects with periodontal disease does not differ from that of healthy individuals, and (ii) the periodontal lesion expresses a unique TCR repertoire in which the Vβ 17 gene dominates.     

Activated lymphocyte subsets in adult periodontitis.

The activation state of T and B lymphocytes in the peripheral blood of periodontitis patients may be a reflection of disease activity. We have utilized 2- and 3-color flow cytometric analyses using a new chromophore, peridinin chlorophyll A protein, and conventional dyes, fluorescein isothiocyanate and phycoerythrin, conjugated to monoclonal antibodies against activated lymphocyte surface markers to measure blood lymphocyte subsets from 18 periodontitis patients and 16 periodontally healthy control subjects. Two-color flow cytometric analysis demonstrated that the frequency of CD4+ and CD5+ T cells, CD20+ B cells, and CD16+ NK (natural killer) cells were increased in periodontitis patients. Of particular interest, CD4+ activated "memory" T cells, CD5+ B cells, and CD56+ NK effector cells were increased significantly in periodontitis patients (p less than 0.05). While the relationship of lymphocyte activation to periodontal disease activity remains unclear, there may be potential for using 2- and 3-color flow cytometry to subcategorize periodontitis patients into high- and moderate-risk groups.     

Detection of, and anti-collagen antibody produced by, CD5-positive B cells in inflamed gingival tissues

This study was performed to investigate the frequency and distribution of CD5-positive (CD5+) B cells in inflamed gingival tissues using flow cytometric and immunohistochemical analyses. The ability of CD5+ B cells to produce anti-type I collagen antibody was also examined. CD5+ B cells expressed "low" fluorescence intensity in the peripheral blood of both healthy subjects and patients with adult periodontitis. However, in inflamed gingival tissues the intensity of this surface marker was high. The percentage of B cells bearing CD5 surface marker was statistically higher in gingiva than in peripheral blood obtained from both the patients and healthy subjects. These CD5+ B cells were observed in gingival subepithelial connective tissues from the bottom to the middle of the periodontal pocket. This area showed destruction of collagen fibers and dense cell infiltrations. Anti-collagen IgG antibody level in patients' gingival crevicular fluids (GCF) was higher than that in sera from healthy subjects, and slightly higher than in autologous sera. IgM anti-collagen antibody in GCF was lower than in autologous sera and in sera from healthy subjects. EBV-transformed CD5+ B cells produced considerably more IgM and IgG antibody to collagen than CD5- B cells. Therefore CD5+ B cells may contribute to the pathogenesis of inflamed gingival tissues.     

Dendritic cells and their role in periodontal disease

T cells, particularly CD4⁺ T cells, play a central role in both progression and control of periodontal disease, whereas the contribution of the various CD4⁺ T helper subsets to periodontal destruction remains controversial, the activation, and regulation of these cells is orchestrated by dendritic cells. As sentinels of the oral mucosa, dendritic cells encounter and capture oral microbes, then migrate to the lymph node where they regulate the differentiation of CD4⁺ T cells. It is thus clear that dendritic cells are of major importance in the course of periodontitis, as they hold the immunological cues delivered by the pathogen and the surrounding environment, allowing them to induce destructive immunity. In recent years, advanced immunological techniques and new mouse models have facilitated in vivo studies that have provided new insights into the developmental and functional aspects of dendritic cells. This progress has also benefited the characterization of oral dendritic cells, as well as to their function in periodontitis. Here, we provide an overview of the various gingival dendritic cell subsets and their distribution, while focusing on their role in periodontal bone loss.     

Presence of activated eosinophils, high IgE and sCD23 titers in gingival crevicular fluid of patients with adult periodontitis

Our previous studies showed that the expression of CD23 on polymorphonuclear leukocytes (PMNLs) in gingival crevicular fluid (GCF) from adult periodontitis (AP) patients was higher than in autologous peripheral blood (PB). Percentages of eosinophils in GCF PMNLs ranged between 6 and 14%. The purpose of the present studies was to increase understanding of the potential role of eosinophils and their products, including CD23, in periodontal disease. We analysed the eosinophil fraction in GCF and PB by flow cytometry using monoclonal antibodies to CD23b (BB10), eosinophil cationic protein (ECP) in stored and secretory forms (EG1 and EG2), and CD67 (80H3). Simultaneously, we measured IgE and soluble CD23 titer and GCF and serum by ELISA. Flow cytometric analysis of BB10, EG2 and 80H3 binding showed that GCF eosinophils from AP were activated. A large BB10⁺ EG2⁺ cellular fraction was detected in GCF from AP whereas it was very low in autologous serum (9.30±2.460 vs 0.16±0.10, p>0.001). GCF from gingivitis patients exhibited no flow cytometric evidence for the presence of BB10+ EG2+ cells. BB10+ EG1+ cells, or inactivated eosinophils rated lower in GCF than in PB both in gingivitis and periodontitis patients (0.45±0.63 vs 1.83±0.96 and 0.15±0.30 vs 1.30±0.20, p>0.05. respectively). IgE titer in AP patients reached 1208.1 ±421.2 IU/ml in GCF while only 49.1 ±50.4 in sera. Soluble CD23 in GCF reached 236.1 ±81.3 ng/ml in GCF and 5.6±1.8 ng/ml in sera. GCF of gingivitis patients, however, contained no detectable sCD23. Thus. GCF from AP patients displayed a high rate of activated eosinophils secreting ECP. while GCF of gingivitis patients did not. These results suggest that ECP-secreting activated eosinophils are relevant to the pathology of adult periodontitis.     

Involvement of vascular endothelial growth factor, CD44 and CD133 in periodontal disease and diabetes: an immunohistochemical study

Aim: The aim of this study was to investigate the relationship between expression of angiogenic and regeneration markers and periodontal disease in subjects with/without diabetes mellitus.
Material and Methods: Immunohistochemical detection of vascular endothelial growth factor (VEGF), CD44 and CD133 was performed in 16 samples each of (1) healthy gingiva from non-diabetic subjects (controls), (2) gingiva from non-diabetic subjects with periodontitis, (3) gingiva from subjects with type 1 diabetes and periodontitis, (4) gingiva from subjects with type 2 diabetes and periodontitis.
Results: Diseased gingivae from patients with diabetes and periodontitis had greater clinical measures of periodontal disease than those with periodontitis only. VEGF expression was significantly enhanced in epithelial and endothelial cells from patients with periodontitis compared with controls ( p <0.05). Epithelial CD44 expression was strong in all groups, while CD44 was significantly enhanced ( p <0.05) in connective tissue cells from both diabetic groups. Epithelial and endothelial CD133 expression was comparable in all patients except those with type 2 diabetes and periodontitis, where it was not detected. Stromal CD133 expression was significantly lower in patients with type 2 diabetes and periodontitis and was increased in periodontitis patients ( p <0.05).
Conclusions: The involvement and high expression of VEGF, CD44 and CD133 in periodontal disease may predict a greater regeneration capacity of gingival tissue.     

High numbers of T cells in gingiva from patients with human immunodeficiency virus (HIV) infection

A quantitative, immunohistologic evaluation of CD3⁺, CD4⁺and CD8⁺ cells was carried out on gingival biopsies from 25 HIV-infected persons with gingivitis or periodontitis and 13 HIV-seronegative persons with periodontitis. CD3⁺ T cells were found in all biopsies. CD8⁺ cells were significantly more numerous and the CD4⁺/CD8⁺ ratio was significantly decreased in the gingival connective tissue of the HIV⁺ patients (P < 0.05). The number of CD4⁺ lymphocytes subjacent to the pocket epithelium was moderately lower in the HIVH patients as compared to the HIV⁺ patients (P < 0.05). HIV⁺ patients with a history of necrotizing periodontal disease had fewer CD4⁺ cells subjacent to the oral gingival epithelium than patients without such disease (P < 0.05). The general HIV-related changes in T lymphocyte numbers were therefore reflected in inflamed gingival tissues. HIV⁺ patients had, however, significantly higher CD4⁺/CD8⁺ ratios in gingiva than in peripheral blood (P < 0.05), indicating that CD4⁺ T cells are actively recruited to gingiva, even in cases of extreme CD4⁺ T lymphocytopenia.