Autoimmunity to collagen in adult periodontal disease

Human gingival fibroblasts are a source of B cell-activating factor during periodontal inflammation

BACKGROUND

Host-modulating therapy is a possible treatment for individuals that respond poorly to conventional periodontal therapy. B cells, abundant in periodontitis lesions, require the cytokines B cell-activating factor (BAFF) and A proliferation-inducing ligand (APRIL) for survival and maturation. Although mRNA levels of BAFF and APRIL are increased in tissue from periodontitis lesions, it is unknown if periodontal resident cells express BAFF and/or APRIL during periodontal inflammation. In this study, we aim to analyze the expression of BAFF and APRIL in human gingival fibroblasts after stimulation with proinflammatory cytokines. Furthermore, we perform protein analysis in tissues and serum from periodontitis patients and healthy controls.

METHODS

Human gingival fibroblasts were cultured and stimulated with the proinflammatory cytokines' tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β). The mRNA expression of BAFF and APRIL was analyzed by real-time quantitative polymerase chain reaction (qPCR), and the protein was detected in tissue sections using immune staining. Serum levels of BAFF were analyzed with enzyme-linked immunosorbent assay (ELISA).

RESULTS

In gingival fibroblasts, TNF-α upregulated BAFF mRNA, but APRIL was unaffected. IL-1β affected neither BAFF nor APRIL expression. BAFF protein was detected in the oral epithelium and in cells of the underlying connective tissue in periodontitis tissue, and BAFF protein was increased in the serum of periodontitis patients.

CONCLUSION

Periodontal resident cells express BAFF during periodontal inflammation and participate in providing a favorable milieu for the survival and action of B cells.

Immunomodulation—What to Modulate and Why? Potential Immune Targets

Despite over 50 years of research into the immunology of periodontal disease, the precise mechanisms and the role of many cell types remains an enigma. Progress has been limited by the inability to determine disease activity clinically. Understanding the immunopathogenesis of periodontal disease however is fundamental if immunomodulation is to be used as a therapeutic strategy. It is important for the clinician to understand what could be modulated and why. In this context, potential targets include different immune cell populations and their subsets, as well as various cytokines. The aim of this review is to examine the role of the principal immune cell populations and their cytokines in the pathogenesis of periodontal disease and their potential as possible therapeutic targets.

Oral Dysbiosis and Autoimmunity: From Local Periodontal Responses to an Imbalanced Systemic Immunity. A Review

The current paradigm of onset and progression of periodontitis includes oral dysbiosis directed by inflammophilic bacteria, leading to altered resolution of inflammation and lack of regulation of the inflammatory responses. In the construction of explanatory models of the etiopathogenesis of periodontal disease, autoimmune mechanisms were among the first to be explored and historically, for more than five decades, they have been described in an isolated manner as part of the tissue damage process observed in periodontitis, however direct participation of these mechanisms in the tissue damage is still controversial. Autoimmunity is affected by genetic and environmental factors, leading to an imbalance between the effector and regulatory responses, mostly associated with failed resolution mechanisms. However, dysbiosis/infection and chronic inflammation could trigger autoimmunity by several mechanisms including bystander activation, dysregulation of toll-like receptors, amplification of autoimmunity by cytokines, epitope spreading, autoantigens complementarity, autoantigens overproduction, microbial translocation, molecular mimicry, superantigens, and activation or inhibition of receptors related to autoimmunity by microorganisms. Even though autoreactivity in periodontitis is biologically plausible, the associated mechanisms could be related to non-pathologic responses which could even explain non-recognized physiological functions. In this review we shall discuss from a descriptive point of view, the autoimmune mechanisms related to periodontitis physio-pathogenesis and the participation of oral dysbiosis on local periodontal autoimmune responses as well as on different systemic inflammatory diseases.

The emerging roles of B cells as partners and targets in periodontitis

Initial studies of periodontal disease suggested that T cell-mediated immunity against oral Gram-negative microorganisms is a key player in the pathogenesis of this inflammatory disease. Recent investigations, however, revealed that B cells are also engaged. Given their chief role in innate-like and adaptive immune responses, B cells could exert protective functions in periodontitis. However, the periodontal bacteria-specific antibody response is generally unable to halt disease progression in affected subjects, suggesting that the antibodies produced could exhibit low anti-bacterial blocking functions or opsonophagocytic potential, and/or unfavorable effects. Moreover, although microbial antigens are involved in the induction of the inflammatory responses in human adult periodontitis, endogenous antigens also may contribute to the chronicity of this common disease. Not only antibodies to self-antigens, such as collagen, are locally produced, but the autoreactivities observed in aggressive periodontitis are more severe and diverse than those observed in chronic periodontitis, suggesting that autoimmune reactivity could play a role in the tissue destruction of periodontal disease. Further support for a pathological role of B cells in periodontitis comes from the finding that B cell-deficient mice are protected from bacterial infection-induced alveolar bone loss. Studies in patients indicate that B cells and plasma cells, together with osteoclastogenic factors (RANKL and osteoprotegerin) and specific cytokines involved in their growth and differentiation (BAFF and APRIL) participate in the induction of the pathological bone loss in periodontitis. This novel insight suggests that selective targeting of B cells could represent a future therapeutic avenue for severe periodontal disease.

Regulatory T-cells Infiltrate Periodontal Disease Tissues

CD4+CD25+ regulatory T (Tr) cells are critical in regulating the immune response and thereby play an important role in the defense against infection and control of autoimmune diseases. Our previous studies demonstrated the involvement of autoimmune responses in periodontitis. The aim of this study was to identify CD4+CD25+ Tr cells in periodontitis tissues and compare them with those in gingivitis tissues. Immunohistological analysis of CD4, CD25, and CTLA-4 and the gene expression analysis of FOXP3, TGF-β1, and IL-10 on gingival biopsies revealed the presence of CD4+CD25+ Tr cells in all tissues. In periodontitis, the percentage of CD4+CD25+ Tr cells increased with increasing proportions of B-cells relative to T-cells. FOXP3, a characteristic marker for CD4+CD25+ Tr cells, TGF-β1 and IL-10 were expressed more highly in periodontitis compared with gingivitis. These findings suggest that CD4+CD25+ Tr cells and possibly other regulatory T-cell populations do exist and may play regulatory roles in periodontal diseases.

The epigenetic paradigm in periodontitis pathogenesis

Epigenome refers to “epi” meaning outside the “genome.” Epigenetics is the field of study of the epigenome. Epigenetic modifications include changes in the promoter CpG Islands, modifications of histone protein structure, posttranslational repression by micro-RNA which contributes to the alteration of gene expression. Epigenetics provides an understanding of the role of gene-environment interactions on disease phenotype especially in complex multifactorial diseases. Periodontitis is a chronic inflammatory disorder that affects the supporting structures of the tooth. The role of the genome (in terms of genetic polymorphisms) in periodontitis pathogenesis has been examined in numerous studies, and chronic periodontitis has been established as a polygenic disorder. The potential role of epigenetic modifications in the various facets of pathogenesis of periodontitis is discussed in this paper based on the available literature.

Origin of galactose-deficient immunoglobulin g in gingival crevicular fluid in periodontitis

BACKGROUND

Periodontitis is a chronic inflammatory disease initiated by a synergistic and dysbiotic microbial community that elicits a gingival inflammatory response leading to tissue breakdown. Periodontitis shares many characteristics with other chronic inflammatory diseases, including abnormal glycosylation of immunoglobulin (Ig)G. The current authors have previously demonstrated that IgG from gingival crevicular fluid (GCF) of patients with chronic periodontitis contains galactose (Gal)-deficient IgG.

METHODS

The origin of the aberrantly glycosylated IgG was determined by measuring levels of Gal-deficient IgG in GCF and serum from patients with periodontitis and non-periodontitis controls using lectin enzyme-linked immunosorbent assay. The Ig-producing cells and the proportion of cells producing Gal-deficient IgG were immunohistochemically determined in gingival tissues from patients with periodontitis by fluorescence microscopy. The results were statistically evaluated and correlated with clinical data.

RESULTS

The results indicate that GCF of patients with periodontitis had higher levels of Gal-deficient IgG compared with controls (P = 0.002). In gingival tissues, IgG was the dominant isotype among Ig-producing cells, and 60% of IgG-positive cells produced Gal-deficient IgG. Moreover, the proportion of Gal-deficient IgG-producing cells directly correlated with clinical parameters of probing depth and clinical attachment loss (AL).

CONCLUSION

These results suggest that the presence of Gal-deficient IgG is associated with gingival inflammation and may play a role in the worsening of clinical parameters of periodontitis, such as AL.

The role of osteoimmunology in periodontal disease

Periodontal disease is a pathological condition that involves inflammation of the tooth supporting structures. It occurs in response to the presence of bacterial plaque on the tooth structure. The host defense system, including innate and adaptive immunity, is responsible for combating the pathologic bacteria invading the periodontal tissue. Failure to eradicate the invading pathogens will result in a continuous state of inflammation where inflammatory cells such as lymphocytes, PMNs, and macrophages will continue to produce inflammatory mediators in an effort to destroy the invaders. Unfortunately, these inflammatory mediators have a deleterious effect on the host tissue as well as foreign microbes. One of the effects of these mediators on the host is the induction of matrix degradation and bone resorption through activation of proteases and other inflammatory mediators that activate osteoclasts.

Mesenchymal stem cells derived from inflamed periodontal ligaments exhibit impaired immunomodulation

AIM

The purpose of this study was to investigate the immunomodulatory properties of periodontal ligament stem cells derived from inflamed periodontal ligament tissues.

MATERIAL AND METHODS

Periodontal ligament stem cells were identified and isolated from healthy or inflamed periodontal ligament tissues. Peripheral blood mononuclear cells were cocultured with inflamed or healthy periodontal ligament stem cells, and T-lymphocyte proliferation was determined by incubation with carboxyfluorescein succinimidyl ester. T-helper cells (Th1/Th2, Th17) and regulatory T cells were analysed by flow cytometry. Cytokine profiles in supernatants were tested with a cytometric bead array.

RESULTS

Compared to healthy cells, inflamed periodontal ligament stem cells showed significantly diminished inhibition of T-cell proliferation. In cocultures, stimulated peripheral blood mononuclear cells showed significantly less induction of CD4+CD25+FOXP3+ regulatory T cells and IL-10 secretion in the presence of inflamed compared with healthy periodontal ligament stem cells. Furthermore, suppression of Th17 differentiation and IL-17 production by inflamed periodontal ligament stem cells was significantly lesser than by healthy cells.

CONCLUSION

This study demonstrated that inflamed periodontal ligament stem cells had markedly dysfunctional immunomodulatory properties; this may contribute to an imbalanced immune response, acceleration of osteoclastogenesis and inflammatory alveolar bone loss in periodontitis.

Autoimmune responses in periodontal diseases

Periodontal diseases are characterized by localized infections and inflammatory conditions and directly affect teeth supporting structures which are the major cause of tooth loss. Several studies have demonstrated the involvement of autoimmune responses in periodontal disease. Evidences of involvement of immunopathology have been reported in periodontal disease. Bacteria in the dental plaque induce antibody formation. Lymphocytes, cytokines and complement system are reported to have an important role in the progression of periodontal disease. The present review describes the involvement of autoimmune responses in periodontal diseases. The mechanisms underlying these responses are also discussed.

Involvement of autoimmunity in the pathogenesis of aggressive periodontitis

The aim of this study was to investigate the involvement of autoimmune reactions to native and post-translationally modified extracellular matrix components in the pathogenesis of periodontitis. Sera from individuals with aggressive periodontitis (AgP, n = 25), chronic periodontitis (CP, n = 14), and gingivitis (G, n = 18) were tested for the presence of autoantibodies against: (a) native collagen type I (CI) and collagen type III (CIII); (b) CI and CIII post-translationally modified by reactive oxygen species (ROS) of the type present during inflammation; and (c) citrullinated filaggrin-derived peptides (CCP). Autoantibodies to native and ROS-modified CI and CIII as well as autoantibodies to CCP were observed exclusively in patients with AgP and not in those with CP or G. In conclusion, autoimmune reactions to native and post-translationally modified self-antigens may play a role specifically in the pathogenesis of AgP.

Autoreactivity of serum immunoglobulin to periodontal tissue components: a pilot study

BACKGROUND

Periodontal diseases are inflammatory diseases resulting in the destruction of tissues of the periodontium. Although bacteria must be present for periodontal disease to occur, a susceptible host is also required, which is determined by genetic, environmental, and acquired factors. One such factor, autoimmunity, may play a role in the tissue destruction. Data indicate that some antibodies that occur in the gingival lesion are directed to host tissue components, such as type I collagen, although investigations of other periodontal autoimmune targets are limited.

METHODS

Histologic sections and extracts from periodontally healthy teeth and the associated soft tissues were probed with serum from localized aggressive periodontitis (LAgP), chronic periodontitis (CP), and periodontally healthy subjects to determine autoreactivity to components of the periodontium. Any autoreactivity observed was characterized further by mass spectrometry and enzyme-linked immunosorbent assay.

RESULTS

Autoreactivity to components of the periodontium was observed in CP and LAgP. Known autoimmune targets, such as collagen and heat shock protein, were identified along with multiple potential autoimmune targets, including members of the extracellular matrix, such as vimentin, spectrin, filamin, actin, lamin, keratin, and tubulin. Finally, it was determined that the autoreactivity observed in LAgP was more severe and diverse than that observed in CP.

CONCLUSION

These data demonstrated that autoimmune reactivity can play a role in the tissue destruction of periodontal disease but that the nature of the autoreactivity may differ based on the type and/or stage of periodontal disease.

Destructive periodontitis lesions are determined by the nature of the lymphocytic response

It is now 35 years since Brandtzaeg and Kraus (1965) published their seminal work entitled "Autoimmunity and periodontal disease". Initially, this work led to the concept that destructive periodontitis was a localized hypersensitivity reaction involving immune complex formation within the tissues. In 1970, Ivanyi and Lehner highlighted a possible role for cell-mediated immunity, which stimulated a flurry of activity centered on the role of lymphokines such as osteoclast-activating factor (OAF), macrophage-activating factor (MAF), macrophage migration inhibition factor (MIF), and myriad others. In the late 1970s and early 1980s, attention focused on the role of polymorphonuclear neutrophils, and it was thought that periodontal destruction occurred as a series of acute exacerbations. As well, at this stage doubt was being cast on the concept that there was a neutrophil chemotactic defect in periodontitis patients. Once it was realized that neutrophils were primarily protective and that severe periodontal destruction occurred in the absence of these cells, attention swung back to the role of lymphocytes and in particular the regulatory role of T-cells. By this time in the early 1990s, while the roles of interleukin (IL)-1, prostaglandin (PG) E(2), and metalloproteinases as the destructive mediators in periodontal disease were largely understood, the control and regulation of these cytokines remained controversial. With the widespread acceptance of the Th1/Th2 paradigm, the regulatory role of T-cells became the main focus of attention. Two apparently conflicting theories have emerged. One is based on direct observations of human lesions, while the other is based on animal model experiments and the inability to demonstrate IL-4 mRNA in gingival extracts. As part of the "Controversy" series, this review is intended to stimulate debate and hence may appear in some places provocative. In this context, this review will present the case that destructive periodontitis is due to the nature of the lymphocytic infiltrate and is not due to periodic acute exacerbations, nor is it due to the so-called virulence factors of putative periodontal pathogens.

Autoantibodies directed to extracellular matrix components in patients with different clinical forms of periodontitis

BACKGROUND

Periodontal disease occurs in different clinical forms, from mild and easily controllable to more aggressive inflammatory manifestations, with difficult clinical or surgical control. There is evidence that a local autoimmune reaction may participate in the onset and persistence of the aggressive forms of periodontal disease. As the underlying mechanism in this process is not fully understood, we decided to investigate whether patients bearing this form of disease presented higher levels of antibodies directed to extracellular matrix (ECM) components such as type I collagen, fibronectin, and laminin.

METHODS

Three groups of patients were selected by clinical criteria: 22 subjects with aggressive periodontitis (AgP) = group A; 18 subjects with chronic periodontitis (CP) = group B; and 10 healthy (H) volunteers without periodontal disease = group C. Autoantibody levels were evaluated in the sera of these patients using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

The levels of autoantibodies directed to ECM components (type I collagen, fibronectin and laminin) in the sera of patients with AgP and CP were shown to be statistically different (P <0.05).

CONCLUSIONS

Although the present findings suggest an involvement of autoantibodies directed to ECM components per se in the pathogeny of certain types of periodontal disease, the available data do not support the classification of the lesions as autoimmune. Nevertheless, the findings open a possibility for the development of an additional method for a differential diagnosis of the aggressive forms of periodontal disease.

Anti-Neutrophil Cytoplasmic Autoantibodies: A Renewed Paradigm in Periodontal Disease Pathogenesis?

In the past, various models including the autoimmunity model have been proposed to explain the pathogenesis of periodontal diseases. The aim of this review is to introduce the pathogenic role of anti-neutrophil cytoplasmic autoantibodies (ANCAs) in various autoimmune diseases and compare these conditions with periodontal disease to elucidate common pathogenic mechanisms. Also, a novel model to explain the pathogenesis of periodontal disease based on the concept of ANCA-associated autoimmunity is proposed. This encompasses a wide array of biochemical mediators that range from direct and indirect initiators of ANCA production and eventual release of proinflammatory mediators and free radicals, all of which have been implicated in periodontal tissue destruction in the past. In addition, specific links between the typical ANCA-associated diseases and periodontal disease are discussed. Finally, a new paradigm in the periodontal disease-associated destruction is proposed that includes the currently accepted mechanism, namely, the genetic-microbial-host interactions.

Increased infiltration of CD1d and natural killer T cells in periodontal disease tissues

BACKGROUND

Natural killer T (NKT) cells are a unique T lymphocyte subset that has been implicated in the regulation of immune responses associated with a broad range of diseases including autoimmunity, infectious diseases, and cancer. In contrast to conventional T cells, NKT cells are reactive to major histocompatibility complex (MHC) class I-like molecule CD1d. Considering the periodontitis having both aspects of infection and autoimmunity in nature, CD1d and reactive NKT cells are of particular importance.

OBJECTIVE

The aim of the present study was to examine whether the expression of CD1 isoforms and Valpha24(+) invariant NKT cells is associated with different disease entities, namely gingivitis and periodontitis.

MATERIAL AND METHODS

Immunohistochemical analysis was performed on cryostat sections of gingival tissues from 19 patients with periodontitis and eight patients with gingivitis using antibodies to CD1a, b, c, d, Valpha24(+) invariant NKT cells, CD83, CD3 and CD19.

RESULTS

Although all four subsets of CD1 molecules were expressed in periodontal lesions, CD1d was most abundant. CD1d expression was more frequent in periodontitis than gingivitis and increased together with increase of invariant NKT cell infiltration. Double immunohistochemical staining showed co-expression of CD1d and CD19 on identical cells and proximate infiltration of CD1d(+) and invariant NKT cells.

CONCLUSION

These findings suggest that CD1d-expressing B cells could activate NKT cells by CD1d-restricted manner and this NKT cell activation may play roles in pathogenesis of periodontal diseases.

Heterogeneity of IgG glycosylation in adult periodontal disease

Periodontal disease is a chronic inflammatory disease of bacterial etiology. In many other chronic inflammatory diseases, IgG glycans are galactose-deficient and thus capable of complement activation through the lectin pathway. In this study, we examined whether IgG in serum and gingival crevicular fluid, and IgG locally produced by plasma cells in gingiva of periodontal disease patients, display altered glycosylation. We developed a lectin-ELISA to measure levels of galactose-deficient IgG in the fluids and immunofluorescence staining to detect galactose-deficient IgG-producing cells in gingiva. Our results indicated higher levels of galactose-deficient IgG in sera and gingival crevicular fluid from periodontal disease patients, compared with levels in healthy controls. Furthermore, gingivae from periodontal disease patients exhibited infiltration of IgG-producing plasma cells; many of them contained galactose-deficient IgG in the cytoplasm. Analysis of our data suggests that IgG secreted by B-cells was aberrantly glycosylated, which resulted in the production of pro-inflammatory galactose-deficient IgG.

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.

Evidence for local production of antibodies to auto and non-self antigens in periodontal disease

Autoimmune mechanisms may contribute to periodontal disease (PD) pathogenesis; autoantibody to collagen type 1 is produced at the periodontal site and local levels are found to be higher than in serum.

OBJECTIVES

To find any evidence of autoimmune destruction in diseased periodontal tissues in patients with periodontitis. The study examines the relationship of antibodies to a self antigen collagen Type 1 and antigens from two periodontal pathogens namely Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa) and a non-oral bacterium Bacteroides fragilis (Bf) in disease sites and in serum.

MATERIALS AND METHODS

Granulomatous tissues from periodontally diseased sites and serum samples were obtained from 13 patients (15 sites) undergoing surgical therapy. Tissues were homogenized at 4 degrees C on Tris saline buffer [1 g (5 ml)-1], homogenate was centrifuged and the resultant supernatants were used in assays. Antibody to collagen and Aa, Pg and Bf in tissue eluates and serum were determined by competitive enzyme linked immunosorbant assay (ELISA) and conventional ELISA respectively using an alkaline phosphatase/p-nitrophenyl phosphate enzyme-substrate system. Sera from age and sex matched healthy subjects and pooled human serum were used as controls. Antibody (Ab) levels in tissues and serum were standardized by concomitant albumin assay.

RESULTS

Level of antibodies to collagen type 1 in tissue was significantly higher than in serum (P = 0.0001). Antibody levels in tissue to Pg were significantly higher than in serum (P = 0.0271). Ab levels to both Aa and Bf in tissues and serum were not significantly different from each other.

CONCLUSIONS

These findings confirm the process of the local production of antibodies to autoantigen namely collagen type-1 and to bacterial antigens in the granulomatous tissues housed within the periodontal lesions in patients with periodontitis.

Accumulation of human heat shock protein 60-reactive T cells in the gingival tissues of periodontitis patients

Heat shock protein 60s (hsp60) are remarkably immunogenic, and both T-cell and antibody responses to hsp60 have been reported in various inflammatory conditions. To clarify the role of hsp60 in T-cell responses in periodontitis, we examined the proliferative response of peripheral blood mononuclear cells (PBMC), as well as the cytokine profile and T-cell clonality, for periodontitis patients and controls following stimulation with recombinant human hsp60 and Porphyromonas gingivalis GroEL. To confirm the infiltration of hsp60-reactive T-cell clones into periodontitis lesions, nucleotide sequences within complementarity-determining region 3 of the T-cell receptor (TCR) beta-chain were compared between hsp60-reactive peripheral blood T cells and periodontitis lesion-infiltrating T cells. Periodontitis patients demonstrated significantly higher proliferative responses of PBMC to human hsp60, but not to P. gingivalis GroEL, than control subjects. The response was inhibited by anti-major histocompatibility complex class II antibodies. Analysis of the nucleotide sequences of the TCR demonstrated that human hsp60-reactive T-cell clones and periodontitis lesion-infiltrating T cells have the same receptors, suggesting that hsp60-reactive T cells accumulate in periodontitis lesions. Analysis of the cytokine profile demonstrated that hsp60-reactive PBMC produced significant levels of gamma interferon (IFN-gamma) in periodontitis patients, whereas P. gingivalis GroEL did not induce any skewing toward a type1 or type2 cytokine profile. In control subjects no significant expression of IFN-gamma or interleukin 4 was induced. These results suggest that periodontitis patients have human hsp60-reactive T cells with a type 1 cytokine profile in their peripheral blood T-cell pools.

The presence of local and circulating autoreactive B cells in patients with advanced periodontitis

AIM

The aim of the present investigation was to study the local (gingival) and systemic occurrence of autoreactive B cells (CD5+CD19 positive) in subjects with a high or low susceptibility to periodontitis.

MATERIAL AND METHODS

2 groups of subjects (Group A and B) susceptible to periodontitis were included. Group A consisted of 22 adult patients (7 females and 15 males, aged 24-66 years) with advanced and generalized chronic periodontitis and group B comprised 7 children (4 girls and 3 boys aged 9-13 years) with localized aggressive periodontitis. 26 periodontally healthy subjects, Group C (aged 23-80 years, mean 49.6+/-16.3), were also recruited. Assessment of clinical and radiographical characteristics of periodontal disease was performed. Gingival biopsies and peripheral blood samples were obtained and prepared for immunohistochemical analysis. Blood samples only were obtained from the periodontally healthy subjects (group C).

RESULTS

The proportion of autoreactive B cells (CD5+CD19 positive) of peripheral blood lymphocytes was about 6 times higher in group A and 4 times higher in group B than in the samples from the control subjects (group C). About 40-50% of the B cells in the peripheral blood of the periodontitis susceptible individuals expressed markers for autoreactive features while less than 15% of the circulating B cells in the subjects of group C exhibited such markers. The periodontitis lesion in the adult periodontitis patients contained a substantial number of B cells out of which about 30% demonstrated autoreactive features.

CONCLUSION

It is suggested that both circulating and local B cells in periodontitis susceptible individuals have a higher propensity to autoreactive properties than B cells of patients with a low susceptibility to periodontitis.

Human fibroblasts ubiquitously express glutamic acid decarboxylase 65 (GAD 65): possible effects of connective tissue inflammation on GAD antibody titer

BACKGROUND

Type 1 diabetes is caused by a destruction of pancreatic beta cells due to autoimmunity. Autoantibody against glutamic acid decarboxylase (GAD) 65 expressed in pancreatic beta cells is widely used as a predictive marker for pancreatic destruction. In this study, we hypothesized that if certain cells in periodontal tissues could express GAD, then it may influence GAD antibody titer.

METHODS

We used: 1) reverse transcription-polymerase chain reaction (PCR) analysis to detect GAD 65 mRNA in various cells; 2) nucleotide sequencing analysis to confirm that amplified PCR product is the gene encoding GAD; and 3) Western blotting to determine the expression of GAD 65 protein in human gingival fibroblasts. Immunohistochemical staining of GAD 65 protein in normal and inflamed gingiva was performed to examine the potential influence of periodontal inflammation on GAD 65 expression. GAD antibody titer in sera of periodontal patients as well as healthy subjects was measured to determine if periodontal patients could develop autoantibody against GAD 65.

RESULTS

Cultured human gingival, periodontal, and dermal fibroblasts and mesangial cells expressed GAD mRNA. Nucleotide sequencing analyses confirmed the amplified PCR product as GAD 65. Western immunoblotting analyses and immunohistochemical staining revealed that the GAD 65 protein was expressed in vitro and in vivo. The expression of GAD 65 in inflamed tissue was higher than that in normal tissues. Two of 62 periodontal patients without diabetes showed an increased antibody titer against GAD 65, while none of the systemically healthy subjects showed an increased antibody titer against this antigen.

CONCLUSIONS

We concluded that periodontal inflammation may result in higher levels of GAD and influence GAD antibody titer, and, hence, affect diabetic diagnosis based upon GAD antibody production.

Elevated proportion of natural killer T cells in periodontitis lesions: a common feature of chronic inflammatory diseases

Although periodontitis is a chronic inflammatory disease caused by a group of so-called periodontopathic bacteria, autoimmune mechanisms have also been implicated in the disease process. Recently, a unique subset of lymphocytes designated natural killer (NK) T cells expressing the Valpha24JalphaQ invariant T cell receptor (TCR) has been reported to have a regulatory role in certain autoimmune diseases. Therefore, we investigated the proportion of the invariant Valpha24JalphaQ TCR within the Valpha24 T cell population in periodontitis lesions and gingivitis lesions using single-strand conformation polymorphism methodology. NK T cells were identified with a specific JalphaQ probe whereas the total Valpha24 TCR was identified using an internal Calpha probe. NK T cells were a significant proportion of the total Valpha24 population both in periodontitis lesions and to a lesser extent in gingivitis lesions but not in the peripheral blood of either periodontitis patients or nondiseased controls. Using immunohistochemistry, some of Valpha24(+) cells in the periodontitis lesions seemed to associate with CD1d(+) cells, which are specific antigen-presenting cells for NK T cells. Although the mechanism underlying the elevation of NK T cells in periodontitis and in gingivitis lesions remains unclear, it can be postulated that NK T cells are recruited to a play regulatory role in the immune response to bacterial infection.

Epitope mapping of heat shock protein 60 (GroEL) from Porphyromonas gingivalis

Porphyromonas gingivalis, a putative pathogen in human periodontal disease, possesses a 60-kDa heat shock protein (hsp60, GroEL). The GroEL homologs are known to be key molecules in auto-immune reactions because of the sequence similarity with human hsp60. In this study, B-cell epitopes on P. gingivalis GroEL (PgGroEL) were analyzed by both Western immunoblotting with truncated PgGroEL and by the multi-pin synthetic peptide approach. To examine auto-antibody production in periodontitis patients, Western immunoblotting with human gingival fibroblasts was performed. Deletion mutants were constructed from the cloned PgGroEL gene (P. gingivalis groEL), and four C-terminal truncated PgGroEL and one N-terminal truncated PgGroEL were prepared from the deletants. Sera from periodontitis patients reacted with all truncated PgGroEL used in this study. The results suggest that the B-cell epitopes were overlaid throughout PgGroEL. To determine the detailed locations of the B-cell epitope, 84 decapeptides covering the entire PgGroEL were synthesized and the serum IgG response to the peptides was examined. Epitope mapping using the synthetic peptides confirmed that the B-cell epitopes were overlaid throughout the length of PgGroEL and revealed that highly conserved peptides between PgGroEL and human hsp60 were recognized by the serum antibodies. Immuno-reactivity against human gingival fibroblasts was examined with sera from 30 periodontitis patients and 10 periodontally healthy subjects. IgG antibody against the 65-kDa antigen in human gingival fibroblasts (same molecular mass as human hsp60) was detected in two patients. Although IgG production against human hsp60 may be rare case in periodontitis patients, the results of epitope mapping demonstrated the potential of PgGroEL to cause the cross-reactions with human hsp60.

Elevated humoral immune response to heat shock protein 60 (hsp60) family in periodontitis patients

The presence of antibodies to the 60-kD human and Porphyromonas gingivalis GroEL hsp60 in the sera and inflamed gingival tissues of periodontitis patients was examined. In order to obtain the antigens, recombinant plasmids carrying human hsp60 and P. gingivalis GroEL genes were constructed and expressed as histidine-tagged recombinant proteins. Immunoreactivities of these proteins were confirmed by MoAbs specific to mammalian hsp60 and cross-reactive with both mammalian and bacterial hsp60. Western blot analysis clearly demonstrated that the number of periodontitis patients showing a positive response to P. gingivalis GroEL was higher than the number of periodontally healthy subjects. Furthermore, anti-P. gingivalis GroEL antibody was detected in all samples of gingival tissue extracts. For human hsp60, a higher frequency of seropositivity was found in the periodontitis patients than in the healthy subjects. In addition, the periodontitis patients demonstrated stronger reactivity compared with the healthy subjects. Quantitative analysis of serum antibodies by ELISA also demonstrated that the levels of antibodies in the sera of patients were significantly higher than those of control subjects. In the gingival tissue extracts, seven out of 10 patients demonstrated a positive response to human hsp60 and tso of these demonstrated strong positivity. Affinity-purified serum antibodies to human hsp60 and P. gingivalis GroEL from selected patients reacted with P. gingivalis GroEL and human hsp60, respectively, suggesting cross-reactivity of antibodies. These results suggest that molecular mimicry between GroEL of the periodontopathic bacterium P. gingivalis and autologous human hsp60 may play some role in immune mechanisms in periodontitis.

The immune modulation of B-cell responses by Porphyromonas ginginvalis and interleukin-10

BACKGROUND

Polyclonal B-cell activation induced by periodontopathic bacteria has been cited as being important for elevated numbers of B cells, but the role of bacteria in the pathogenesis of periodontal disease remains unknown. In this study, we used an in vitro model to investigate the activation of immune cells by the periodontopathic bacterium Porphyromonas gingivalis in healthy subjects.

METHODS

Peripheral blood mononuclear cells (PBMC) or purified subsets of lymphocytes were stimulated with sonicated extracts of P. gingivalis for 24 hours. Cells were harvested and monitored for expression of CD69 by flow cytometry. Cytokine production (IL-10, IL-12, and IL-15) in P. gingivalis-stimulated PBMC cultures was measured by ELISA. To identify IL-10 producer cells, a cell depletion experiment was used and confirmed by the ability of the purified cell population to produce IL-10. To evaluate the effect of P. gingivalis and IL-10, the proliferative response of purified B cells was assessed by [3H] thymidine uptake.

RESULTS

PBMC cultured with P. gingivalis led to a large number of activated B and natural killer (NK) cells as monitored by CD69 expression. When positively sorted cells were used, the bacterium itself could directly activate only B cells but not NK cells, alphabeta, and gammadelta T cells. Measurement of B-cell regulatory cytokine production in P. gingivalis-stimulated PBMC cultures revealed a large amount of IL-10 but no detectable IL-12 or IL-15; the major producing cells were monocytes, not B cells or alphabeta T cells. When IL-10 was added to B cells in the presence of bacteria, significantly increased B-cell proliferative responses were observed.

CONCLUSIONS

These results suggest that P. gingivalis, both directly and indirectly via macrophage IL-10, may play an important role in polyclonal B-cell activation associated with periodontal disease.

Depressed responsiveness of peripheral blood mononuclear cells to heat-shock proteins in periodontitis patients

The extensive homology between human and bacterial heat shock proteins (HSPs) may play a role in autoimmune reactions in periodontitis. Thus, we questioned whether peripheral blood mononuclear cell (PBMC) proliferative responses to HSPs are different between periodontitis patients and control subjects with gingivitis. The proliferative responses of PBMCs of patients (n = 10) and controls (n = 12) to recombinant mycobacterial HSP60 (MycHSP60) and HSP70 (MycHSP70), as well as recombinant human HSP60 (HumHSP60) and HSP70 (HumHSP70), were investigated. In addition, the proliferative responses to Candida albicans and purified protein derivatives of Mycobacterium (PPD) were included. Mean responses to HumHSP60, MycHSP60, and HumHSP70 were significantly lower for patients compared with controls. The responses to MycHSP70 showed a similar trend. However, when Candida and PPD were used as antigens, there was no difference in responses of the PBMCs between the periodontitis patients and controls. The level of IFN-gamma in the supernatants of the cells stimulated with HSPs was lower in the patients compared with controls. This concurs with the current hypothesis that periodontitis patients have a depressed Th1 response. Furthermore, we found that with an increasing estimated subgingival bacterial load, periodontitis patients mount a decreasing immune response to HSPs, while the controls showed a positive correlation between these two parameters. From these findings, we speculate that poor reactivity to HSPs may be a susceptibility factor for destructive periodontal disease and may need to be considered in the pathogenesis of this condition.

Induction of anti-thymocyte/T lymphocyte antibodies in mice injected with lipopolysaccharides from periodontopathic bacteria

We examined the levels of anti-thymocyte/T lymphocyte autoantibody (ATA) in the serum of mice injected intraperitoneally with lipopolysaccharides (LPS) from periodontopathic bacteria; Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Capnocytophaga ochracea, and non-oral Escherichia coli. All of the LPS induced IgM-ATA. Among these, LPS from C. ochracea induced the highest level of IgM-ATA, whereas that of P. gingivalis induced the lowest. The peritoneal T lymphocytes of mice injected with LPS were bound by IgM-ATA. Peritoneal B-1 (CD5+B) cells stimulated by each LPS produced much more IgM-ATA than splenic B-2 (CD5-B) cells, suggesting that B-1 cells might be responsible for the production of these antibodies. Serum of mice injected with C. ochracea and F. nucleatum LPS showed cytotoxicity against thymocytes in the presence of rabbit complements. Binding and cytotoxicity were confirmed by IgM purified from serum of the mice injected with C. ochracea LPS. Furthermore, serum of mice treated with C. ochracea, F. nucleatum or A. actinomycetemcomitans LPS inhibited the proliferation of thymocytes. However, purified IgM from the serum of mice treated with C. ochracea LPS failed to produce the same inhibition. Our results suggest that LPS from certain species of periodontopathic bacteria can induce IgM-ATA in the serum and these antibodies may modulate the local immune network in periodontal tissues.

Presence of activated B-1 cells in chronic inflamed gingival tissue

B-1 cells are physically and functionally unique B cells that produce polyreactive natural antibody. This study examined the activation of B-1 cells in inflamed gingival tissue. Serum IgG antibodies to phosphorylcholine, E. coli LPS, DNA, and some commensal bacteria were examined in adult periodontitis patients and healthy subjects. In addition, the proportion of B-1a (CD20+CD5+) cells and the amount of IL-6 and IL-10 in the inflamed gingival tissues were examined. The serum levels of IgG antibodies to phosphorylcholine, E. coli LPS, and commensal bacteria were significantly higher in the adult periodontitis patients than the healthy subjects. The proportion of B-1a cells and the amount of IL-6 and IL-10 were significantly higher in the inflamed gingival tissues than in peripheral blood from the healthy subjects. These results suggest the activation of B-1 cells in the inflamed gingival tissue of adult periodontitis patients, and that B-1 cells may serve as the first line of defense by producing polyreactive antibodies to phosphorylcholine, LPS, and commensal bacteria.

Local and systemic TCR V gene expression in advanced periodontal disease

The aim of the present investigation was to study the expression of specific alpha/beta 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 V alpha/beta gene repertoire dominated by Vbeta 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 V alpha/Vbeta expression in peripheral blood samples of subjects with periodontal disease does not differ from that of healthy individuals, and (ii) the periodontitis lesion expresses a unique TCR repertoire in which the Vbeta 17 gene dominates.

Polyclonal B cell activators and in vitro induction of auto-antibody reactive with collagen

Cells producing autoantibodies are known to be present in chronically inflamed periodontal tissues. In sites of chronic inflammation, polyclonal B cell activators (PBA) are known to exhibit adjuvant activity when combined with foreign antigens. These results prompted an examination of PBA in eliciting an antibody response to an autoantigen (i.e. collagen type I). Rat lymphocytes were stimulated with rat collagen (type I), microbial PBA (LPS) or the combination of LPS plus rat collagen in vitro. Anti-collagen antibody-forming cells (AFC) were enumerated using an ELISPOT assay. Collagen or LPS alone elicited few anti-collagen AFC but the addition of LPS to collagen resulted in a substantial adjuvant effect and yielded maximal responses to collagen. Comparisons of anti-collagen AFC from short-term immunized (2-6 wk after booster), non-immunized and long-term immunized (3-4 months after booster) animals were performed. It revealed that cells from recently immunized rats were significantly easier to activate than the other 2 groups. The adjuvant effect of microbial PBA may be important in anti-collagen antibody production and thus the localization of PBA in periodontal pockets may explain why anti-collagen AFC are restricted to the chronically inflamed periodontal tissues.

Standardization of measurement of immunoglobulin-secreting cells in human peripheral circulation

A sensitive, and at times the most sensitive, measurement of human vaccine immunogenicity is enumeration of antibody-secreting cells (ASC) in peripheral blood. However, this assay, which is inherently capable of measurement of the absolute number of antigen-specific ASC, is not standardized. Thus, quantitative comparison of results between laboratories is not currently possible. To address this issue, isotype-specific ASC were enumerated from paired fresh and cryopreserved mononuclear cell (MNC) preparations from healthy adult volunteers resident in either the United States (US group) or Egypt (EG group). Analysis of fresh cells from US volunteers revealed mean numbers of ASC per 10(6) MNC of 617, 7,738, and 868 for immunoglobulin M (IgM), IgG, and IgA, respectively, whereas EG volunteers had 2,086, 7,580, and 1,677 ASC/10(6) MNC for the respective isotypes. Cryopreservation resulted in a slight reduction in group mean IgM, IgG, and IgA ASC (maximum reduction in group mean, 14%), but in no instance were results obtained with cryopreserved cells significantly lower than those obtained with fresh cells. To determine if cryopreservation affected the number of bacterial antigen-specific ASC detected, cells from a group of US adult volunteers who received a single oral dose of a mutated Escherichia coli heat-labile enterotoxin (LT(R192G)) were tested. There was no significant difference (P > 0.05) in the number of antigen-specific IgA or IgG ASC detected between fresh and cryopreserved MNC. The results support the views that ASC assays can be standardized to yield quantitative results and that the methodology can be changed to make the test more practical.

Interleukin-10 promotes anti-collagen antibody production in type I diabetic peripheral B lymphocytes

Previous studies have shown that type I diabetes (IDDM) increases the risk of developing periodontitis by 2-3-fold. IDDM patients exhibit destruction of the pancreatic beta cells, most probably caused by an autoimmune reaction. Evidence is accumulating to support the role of the autoimmune response in periodontal pathogenesis. A cytokine, interleukin (IL)-10, has been reported to selectively promote the expansion of a B lymphocyte lineage (CD5/LY1/B1) which has the propensity for secreting high levels of autoantibody. Therefore, the purpose of this project was to evaluate IL-10 production, percentage of CD5 B cells and the frequency of anti-collagen secreting cells in peripheral blood mononuclear cells of age, gender and race matched IDDM patients and controls. IL-10 production was evaluated by an ELISA using the supernatant of adherent peripheral blood cells cultured for 24 h in the presence of Porphyromonas gingivalis lipopolysaccharide (LPS). In 8 of 31 patients, IL-10 levels were significantly increased in IDDM compared to controls and a higher percentage of CD5 B cells was also observed by flow cytometry. In addition, these patients exhibited a higher frequency of anti-collagen secreting cells as elucidated by an ELISPOT. Moreover, treatment with a neutralizing anti-IL-10 antibody diminished the anti-collagen antibody response by 70%. These findings support the concept that a subset of IDDM patients possess an extremely robust IL-10 response following exposure to Gram-negative LPS, which could predispose them to the development of periodontitis through a heightened autoimmune mechanism.

Effects of cyclosporine A on plasma cells in experimental gingivitis in dogs

The aim of the present investigation was to evaluate the effect of Cyclosporine A (CsA) on the inflammatory lesion formed in the gingival tissues during de novo plaque formation. 5 beagle dogs were used. On day 0, all teeth of the 5 dogs were scaled and polished. A 6-week period of plaque control including daily tooth cleaning with toothbrush and dentifrice was initiated. A clinical examination regarding plaque and gingivitis was performed, and the plaque control measures were abandoned on the right side of mandible. 3 weeks later, the clinical examination was repeated, samples of subgingival plaque harvested and biopsies obtained from the 3rd and 4th right mandibular premolar regions. The tooth cleaning measures on the left side of the mandible were terminated at this interval. During the following 3 weeks, the animals formed plaque in the lower left premolar regions, and received, 1 x daily, a subcutaneous injection of CsA. At the end of this 2nd plaque formation period (test), the clinical examination was repeated, subgingival plaque was sampled and biopsies from the 3rd and 4th left mandibular premolar regions harvested. The biopsies were prepared for histometric and morphometric analyses. The clinical and histological examinations demonstrated that plaque formation resulted in a gingival lesion (ICT) which, in the 2 periods, had similar size and apical extension. The ICT formed during the CsA administration period, however, harbored an increased number of plasma cells and a reduced macrophage density than the control lesion. It is suggested that CsA administration may result in a Th-2 (T-helper 2-cell) dependent activation of B-lymphocytes.

Immunohistochemical study of gamma delta T cells in human gingival tissues

The distribution and the density of gamma delta T cells in human gingival tissues were examined immunohistochemically in biopsy samples obtained from 20 subjects. Few gamma delta T cells were observed in gingival tissue free from inflammatory cell infiltration, but were found, albeit in low numbers, in association with inflammatory cell infiltration, especially T cells. This relationship with T cells was confirmed statistically. The ratios of gamma delta T cells to T cells in the epithelia and in the connective tissue were calculated in the sections in which more than 500 CD3-positive cells were identified. Seven of eight such epithelial specimens showed a ratio of less than 1% and one less than 2% (mean +/- SD; 0.8% +/- 0.4). In the connective tissue, 8 of 13 such specimens showed less than 1%, three less than 2%, one 3%, and one 7% (1.4% +/- 1.9). These results suggest that basically gamma delta T cells are not resident cells in the gingival epithelium such as comprise the first defense line against exogenous irritation. They may play some role in the pathogenesis of periodontal disease collaborating with alpha beta T cells in the inflammatory response.

Massive gingival enlargement and alveolar bone loss: report of two cases

We present two cases of massive gingival enlargement and osteolysis of alveolar bone in a 30-year-old female and a 36-year-old male. The etiology could not be established in either case. Histologically, both lesions contained hyperplastic fibrous connective tissue and intense plasma cell infiltrates. Both patients responded well to extensive gingivectomy, extraction of all teeth, and alveoplasty.

Cloning, characterization, and antigen specificity of T-lymphocyte subsets extracted from gingival tissue of chronic adult periodontitis patients

Chronic periodontitis is characterized by dense infiltrations of B and T lymphocytes within the gingival connective tissue. Distinct anaerobic gram-negative bacteria as well as autoimmunity to collagen have been reported to play a role in the etiology and the pathogenesis of this disease. Here we describe the cloning and characterization of CD4+ and CD8+ T lymphocytes isolated from inflamed gingival tissue obtained from four patients with chronic periodontitis. Clones were raised with phytohemagglutinin and interleukin-2 and tested for proliferation in response to whole-cell antigens of Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, human collagen type I, and two bacterial heat shock proteins. CD4+ T-cell clones reactive with collagen type I were obtained from all four patients. Eighty percent of these clones had phenotypes resembling the mouse type 2 T helper (Th) phenotype, i.e., they produced high levels of interleukin-4 and low levels of gamma interferon. No collagen-type-I-reactive CD8+ clones were obtained. Bacterial-antigen-reactive CD4+ and/or CD8+ T-cell clones were also obtained from each patient, and the majority of the clones showed a Th0-like cytokine pattern and produced equal amounts of interleukin-4 and gamma interferon. Although most clones were reactive with P. intermedia, it seems that the immune response is not strictly directed against this particular microorganism, as clones reactive with one of the other bacteria were also obtained from two patients. We propose that collagen-specific CD4+ Th2-like T cells contribute to the chronicity of periodontitis but that their modes of activation might be controlled by Th0-like T cells specific for periodontitis-associated bacteria.

Clinical and laboratory studies on a patient with early onset periodontitis and her family members. A case report

Extensive clinical, microbiological, hematological, and immunological studies were performed on a patient with early onset periodontitis (EOP) and two other members of the family. The proband, a 27-year-old female, had early onset periodontitis and a high level of serum rheumatoid factors (RF) with no diagnosable medical disease. Her mother had lost all her teeth at the age of 50 because of advanced periodontitis, while her elder sister was unaffected by periodontitis. Neither the proband's periodontally-affected mother nor her unaffected sister exhibited a detectable level of RF. In this study, we examined: 1) serum immunoglobulin G (IgG) antibody titers against putative periodontal pathogenic bacteria; 2) peripheral neutrophil functions; 3) phenotypic analyses of peripheral lymphocyte subpopulations; and 4) peripheral lymphocyte functions (T cell proliferative activity, ability of cytokine [interleukin (IL)-2, tumor necrosis factor-alpha, interferon-gamma, IL-6 and IL-8] and IgG and IgM productivity). High antibody titers to Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Campylobacter rectus were detected in the sera of the proband, as were high serum antibody titers to P. gingivalis in the mother and to C. rectus in the unaffected sister compared to the non-periodontitis affected subjects. The proband also showed enhanced neutrophil chemotaxis; a high percentage of pan-B cells; and high productivity of IL-6, IgG, and IgM compared to individuals who were not periodontally affected. The mother showed slightly low helper/induced T cells (Th/i) suppressor/cytotoxic T cells (Ts/c) ratios due to the elevated count of Ts/c, and high IFN-gamma productivity compared to control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Specific antibodies and their potential role in periodontal diseases

Periodontal diseases are thought to result from inflammatory responses to bacterial challenges in the gingival crevicular area. Antibodies are a major host-protective mechanism in many bacterial infections. Consequently, the antibody responses to suspected periodontal pathogenic bacteria have been extensively measured as to their relationship to diseases and specificity for suspected pathogens associated with progressing disease sites. Recently, studies on the bacterial immunogen characterization, antibody-subclass identification, and antibody biological capabilities have been reported. Although increased antibody levels to certain suspected periodontal pathogens were associated with periodontal diseases in humans, little evidence exists as to the role of these antibodies in the infectious process. In vivo experiments in animals indicated that specific antibodies against certain suspected periodontal pathogens were associated with suppression of bacterial colonization, limiting the spread of infection, and a decrease in alveolar bone loss. However, in vitro as well as in vivo experiments suggested that phagocytic cells are required for efficient bactericidal activity of antibodies and that the presence of other sensitized immune cells may either have inhibited or enhanced the infectivity of certain periodontal pathogens. Possible explanations for the observed inconsistencies are presented and the potential for utilization of specific anti-periodontal pathogen responses in the understanding and prevention of diseases is discussed.

The possible relationship between mercury from dental amalgam and diseases. I: Effects within the oral cavity

Mercury is released from dental amalgams, and therefore it is necessary to consider the biological and clinical consequences of such exposure. Intraorally, it would appear as though mercury can cause hypersensitivity/toxic reactions resulting in lichen planus lesions, and may play a major role in the pathogenesis of gingivitis, periodontitis and periodontal disease.