Characteristics and utilization of antibody measurements in clinical studies of periodontal disease

Hemophore-like proteins produced by periodontopathogens are recognized by the host immune system and react differentially with IgG antibodies

Aims

Hemophore-like proteins sequester heme from host hemoproteins. We aimed to determine whether the host immune system can recognize not only Porphyromonas gingivalis HmuY but also its homologs expressed by other periodontopathogens, and how periodontitis influences the production of respective antibodies.

Methods

The reactivity of total bacterial antigens and purified proteins with serum IgG antibodies of 18 individuals with periodontitis and 17 individuals without periodontitis was examined by enzyme-linked immunosorbent assay (ELISA). To compare IgG reactivity between groups with and without periodontitis and within the various dilutions of sera, statistical analysis was performed using the Mann-Whitney U-test and two-way ANOVA test with the post-hoc Bonferroni test.

Results

Individuals with periodontitis produced IgG antibodies reacting more strongly not only with total P. gingivalis antigens (P = 0.0002; 1:400) and P. gingivalis HmuY (P = 0.0016; 1:100) but also with Prevotella intermedia PinA (P = 0.0059; 1:100), and with low efficiency with P. intermedia PinO (P = 0.0021; 1:100). No increase in the reactivity of IgG antibodies with Tannerella forsythia Tfo and P. gingivalis HusA was found in individuals with periodontitis.

Conclusions

Although hemophore-like proteins are structurally related, they are differentially recognized by the host immune system. Our findings point to specific antigens, mainly P. gingivalis HmuY and P. intermedia PinA, whose immunoreactivity could be further investigated to develop markers of periodontitis.

Periodontitis and cardiometabolic disorders: The role of lipopolysaccharide and endotoxemia

Lipopolysaccharide is a virulence factor of gram-negative bacteria with a crucial importance to the bacterial surface integrity. From the host's perspective, lipopolysaccharide plays a role in both local and systemic inflammation, activates both innate and adaptive immunity, and can trigger inflammation either directly (as a microbe-associated molecular pattern) or indirectly (by inducing the generation of nonmicrobial, danger-associated molecular patterns). Translocation of lipopolysaccharide into the circulation causes endotoxemia, which is typically measured as the biological activity of lipopolysaccharide to induce coagulation of an aqueous extract of blood cells of the assay. Apparently healthy subjects have a low circulating lipopolysaccharide activity, since it is neutralized and cleared rapidly. However, chronic endotoxemia is involved in the pathogenesis of many inflammation-driven conditions, especially cardiometabolic disorders. These include atherosclerotic cardiovascular diseases, obesity, liver diseases, diabetes, and metabolic syndrome, where endotoxemia has been recognized as a risk factor. The main source of endotoxemia is thought to be the gut microbiota. However, the oral dysbiosis in periodontitis, which is typically enriched with gram-negative bacterial species, may also contribute to endotoxemia. As endotoxemia is associated with an increased risk of cardiometabolic disorders, lipopolysaccharide could be considered as a molecular link between periodontal microbiota and cardiometabolic diseases.

Connection between Periodontitis-Induced Low-Grade Endotoxemia and Systemic Diseases: Neutrophils as Protagonists and Targets

Periodontitis is considered a promoter of many systemic diseases, but the signaling pathways of this interconnection remain elusive. Recently, it became evident that certain microbial challenges promote a heightened response of myeloid cell populations to subsequent infections either with the same or other pathogens. This phenomenon involves changes in the cell epigenetic and transcription, and is referred to as ''trained immunity''. It acts via modulation of hematopoietic stem and progenitor cells (HSPCs). A main modulation driver is the sustained, persistent low-level transmission of lipopolysaccharide from the periodontal pocket into the peripheral blood. Subsequently, the neutrophil phenotype changes and neutrophils become hyper-responsive and prone to boosted formation of neutrophil extracellular traps (NET). Cytotoxic neutrophil proteases and histones are responsible for ulcer formations on the pocket epithelium, which foster bacteremia and endoxemia. The latter promote systemic low-grade inflammation (SLGI), a precondition for many systemic diseases and some of them, e.g., atherosclerosis, diabetes etc., can be triggered by SLGI alone. Either reverting the polarized neutrophils back to the homeostatic state or attenuation of neutrophil hyper-responsiveness in periodontitis might be an approach to diminish or even to prevent systemic diseases.

An Evaluation of the Academic Stress’ Affect on Periodontal Tissues

Background/Aim: It has been discussed over the years whether emotional stress might be a risk factor for periodontal diseases. The correlation between periodontal disease and stress can still not be explained. Our aim was to evaluate the effects of academic stress on gingival tissues in a prospective design.

Material and Methods: The study population consisted of randomly selected 40 dental students. Clinical examinations of plaque (PI), gingival (GI) and sulcus bleeding (SBI) indices, probing pocket depth (PPD) and gingival crevicular fluid flow rate were performed along with State-Trait Anxiety Inventory at three different periods of the school year. Measurements were recorded one month before the finals (1st period), during the final exams (2nd period), and two months after the final exams (3rd period).

Results: The changes in mean values of all parameters except plaque and pocket depth between the final and control terms were statistically significant. There was a significant correlation between gingival index and stress, plaque, pocket depth, and sulcus bleeding indices at 1st period. There was a significant correlation between gingival index and crevicular fluid at 2nd period. There was a significant correlation between gingival index and plaque, and sulcus bleeding indices at 3rd period.

Conclusions: The present results support the hypothesis that academic stress is a significant risk factor for gingival and periodontal inflammation.

Evaluation of antibody level against Fusobacterium nucleatum in the serological diagnosis of colorectal cancer

Fusobacterium nucleatum (F. nucleatum, Fn) is associated with the colorectal cancer (CRC). Fn-infection could induce significant levels of serum Fn-specific antibodies in human and mice. The objective of this study was to identify Fn-infection that elicit a humoral response in patients with CRC and evaluate the diagnostic performance of serum anti-Fn antibodies. In this work, we showed the mean absorbance value of anti-Fn-IgA and -IgG in the CRC group were significantly higher than those in the benign colon disease group and healthy control group (P < 0.001). The sensitivity and specificity of ELISA for the detection of anti-Fn-IgA were 36.43% and 92.71% based on the optimal cut-off. The combination of anti-Fn-IgA and carcino-embryonic antigen (CEA) was better for diagnosing CRC (Sen: 53.10%, Spe: 96.41%; AUC = 0.848). Furthermore, combining anti-Fn-IgA with CEA and carbohydrate antigen 19-9 (CA19-9) (Sen: 40.00%, Spe: 94.22%; AUC = 0.743) had the better ability to classify CRC patients with stages I-II. These results suggested that Fn-infection elicited high level of serum anti-Fn antibodies in CRC patients, and serum anti-Fn-IgA level may be a potential diagnosing biomarker for CRC. Serum anti-Fn-IgA in combination with CEA and CA19-9 increases the sensitivity of detecting early CRC.

Serum antibodies to periodontal pathogens are a risk factor for Alzheimer's disease

BACKGROUND

Chronic inflammation in periodontal disease has been suggested as a potential risk factor in Alzheimer's disease (AD). The purpose of this study was to examine serum antibody levels to bacteria of periodontal disease in participants who eventually converted to AD compared with the antibody levels in control subjects.

METHODS

Serum samples from 158 participants in the Biologically Resilient Adults in Neurological Studies research program at the University of Kentucky were analyzed for immunoglobulin G antibody levels to seven oral bacteria associated with periodontitis, including Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Campylobacter rectus, Treponema denticola, Fusobacterium nucleatum, Tannerella forsythia, and Prevotella intermedia. All 158 participants were cognitively intact at baseline venous blood draw. In all, 81 of the participants developed either mild cognitive impairment (MCI) or AD or both, and 77 controls remained cognitively intact in the years of follow-up. Antibody levels were compared between controls and subjects with AD at baseline draw and after conversion and controls and subjects with MCI at baseline draw and after conversion using the Wilcoxon rank-sum test. AD and MCI participants were not directly compared. Linear regression models were used to adjust for potential confounding.

RESULTS

Antibody levels to F nucleatum and P intermedia were significantly increased (α = 0.05) at baseline serum draw in the patients with AD compared with controls. These results remained significant when controlling for baseline age, Mini-Mental State Examination score, and apolipoprotein epsilon 4 status.

CONCLUSIONS

This study provides initial data that demonstrate elevated antibodies to periodontal disease bacteria in subjects years before cognitive impairment and suggests that periodontal disease could potentially contribute to the risk of AD onset/progression. Additional cohort studies profiling oral clinical presentation with systemic response and AD and prospective studies to evaluate any cause-and-effect association are warranted.

Mechanisms involved in the association between periodontal diseases and cardiovascular disease

It is now well accepted that besides the cholesterol associated mechanisms of atherogenesis, inflammation plays a crucial role in all stages of the development of the atherosclerotic lesion. This 'inflammation hypothesis' raises the possibility that through systemic elevations of pro-inflammatory cytokines, periodontal diseases might also contribute to systemic inflammation and, therefore, to atherogenesis. In fact, there is evidence that periodontal diseases are associated with higher systemic levels of high-sensitivity C-reactive protein and a low grade systemic inflammation. This phenomenon has been explained based on mechanisms associated with either the infectious or the inflammatory nature of periodontal diseases. The purposes of this article were to review (1) the evidence suggesting a role for oral bacterial species, particularly periodontal pathogens, in atherogenesis; (2) the potential mechanisms explaining an etiological role for oral bacteria in atherosclerosis; (3) the evidence suggesting that periodontal infections are accompanied by a heightened state of systemic inflammation; (4) the potential sources of systemic inflammatory biomarkers associated with periodontal diseases; and (5) the effects of periodontal therapy on systemic inflammatory biomarkers and cardiovascular risk.

Systemic inflammatory responses in progressing periodontitis during pregnancy in a baboon model

This study tested the hypothesis that pregnant female baboons exhibit increased levels of various inflammatory mediators in serum resulting from ligature-induced periodontitis, and that these profiles would relate to periodontal disease severity/extent in the animals. The animals were sampled at baseline (B), mid-pregnancy (MP; two quadrants ligated) and at delivery (D; four quadrants ligated). All baboons developed increased plaque, gingival inflammation and bleeding, pocket depths and attachment loss following placement of the ligatures. By MP, both prostaglandin E(2) (PGE(2)) and bactericidal permeability inducing factor (BPI) were greater than baseline, while increased levels of interleukin (IL)-6 occurred in the experimental animals by the time of delivery. IL-8, MCP-1 and LBP all decreased from baseline through the ligation phase of the study. Stratification of the animals by baseline clinical presentation demonstrated that PGE(2), LBP, IL-8 and MCP-1 levels were altered throughout the ligation interval, irrespective of baseline clinical values. IL-6, IL-8 and LBP were significantly lower in the subset of animals that demonstrated the least clinical response to ligation, indicative of progressing periodontal disease. PGE(2), macrophage chemotactic protein (MCP)-1, regulated upon activation, normal T cell expressed and secreted (RANTES) and LBP were decreased in the most diseased subset of animals at delivery. Systemic antibody responses to Fusobacterium nucleatum, Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Campylobacter rectus were associated most frequently with variations in inflammatory mediator levels. These results provide a profile of systemic inflammatory mediators during ligature-induced periodontitis in pregnant baboons. The relationship of the oral clinical parameters to systemic inflammatory responses is consistent with a contribution to adverse pregnancy outcomes in a subset of the animals.

Periodontitis in pregnancy: clinical and serum antibody observations from a baboon model of ligature-induced disease

BACKGROUND

Chronic oral infections that elicit host responses leading to periodontal disease are linked with various sequelae of systemic diseases. This report provides seminal information on the clinical and adaptive immunologic characteristics of a baboon model of ligature-induced periodontitis during pregnancy.

METHODS

Female Papio anubis were evaluated for periodontal health at baseline. Ligatures were tied around selected teeth to initiate oral inflammation and periodontitis. Then the animals were bred. At midpregnancy ( approximately 90 days), a clinical evaluation was performed, and additional ligatures were tied on teeth in the contralateral quadrants to maintain progressing periodontitis throughout pregnancy. A final clinical evaluation was done for all experimental teeth after delivery, and ligatures were removed. Serum was collected at all sampling intervals for the determination of antibody levels to a group of 20 oral bacteria. Unligated animals served as controls.

RESULTS

At baseline, 16% of animals exhibited minimal plaque and gingival inflammation without periodontal disease. The remaining baboons demonstrated varying levels of inflammation/bleeding, and approximately 20% of the population had periodontal pocketing (>3 mm). Ligated animals expressed increased levels of inflammation and increased probing depths and clinical attachment loss (AL) and could be stratified into multiple subsets postligation based upon changes in clinical parameters at midpregnancy and at delivery. Baboons were categorized into disease susceptibility groups (periodontal disease susceptibility 1 through 4) that described the extent/severity of induced disease during pregnancy. Control animals showed minimal periodontal changes during gestation. Significant differences in serum antibody to multiple oral bacteria were found in animals presenting with periodontitis at baseline and during the 6 months of ligature-induced disease. A significant correlation to antibody to P. gingivalis, which was sustained throughout ligation and pregnancy, was observed with disease presentation.

CONCLUSIONS

The clinical presentation at baseline, reflecting the natural history of oral disease in these animals, suggests individual variation that is reflected in the characteristics of the adaptive immune responses to oral bacteria. The variability in the response to ligation with resulting periodontal disease provides a model to document prospectively the relationship between oral and systemic health outcomes.

Differential gender effects of a reduced-calorie diet on systemic inflammatory and immune parameters in nonhuman primates

BACKGROUND AND OBJECTIVE

Dietary manipulation, including caloric restriction, has been shown to impact host response capabilities significantly, particularly in association with aging. This investigation compared systemic inflammatory and immune-response molecules in rhesus monkeys (Macaca mulatta).

MATERIAL AND METHODS

Monkeys on continuous long-term calorie-restricted diets and a matched group of animals on a control ad libitum diet, were examined for systemic response profiles including the effects of both gender and aging.

RESULTS

The results demonstrated that haptoglobin and alpha1-antiglycoprotein levels were elevated in the serum of male monkeys. Serum IgG responses to Campylobacter rectus, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were significantly elevated in female monkeys. While only the antibody to Fusobacterium nucleatum was significantly affected by the calorie-restricted diet in female monkeys, antibody levels to Prevotella intermedia, C. rectus and Treponema denticola demonstrated a similar trend.

CONCLUSION

In this investigation, only certain serum antibody levels were influenced by the age of male animals, which was seemingly related to increasing clinical disease in this gender. More generally, analytes were modulated by gender and/or diet in this oral model system of mucosal microbial challenge.

Severe Periodontitis Enhances Macrophage Activation via Increased Serum Lipopolysaccharide

OBJECTIVE

In periodontitis, overgrowth of Gram-negative bacteria and access of lipopolysaccharide (LPS) to circulation may activate macrophages leading to foam cell formation. We investigated whether periodontal treatment affects proatherogenic properties of low-density lipoprotein (LDL) and, thus, macrophage activation.

METHODS AND RESULTS

LDL was isolated and characterized before and after treatment from 30 systemically healthy patients with periodontitis. Production of cytokines and LDL cholesteryl ester (LDL-CE) uptake by macrophages (RAW 264.7) was determined. Baseline periodontal variables correlated positively with serum LPS and C-reactive protein concentrations, as well as macrophage cytokine production and LDL-CE uptake. LPS concentration correlated positively with serum concentration of oxidized LDL and cytokine production. Higher cytokine production and LDL-CE uptake were induced by LDL isolated from patients with elevated number of affected teeth before treatment. Patients with serum LPS concentrations above the median (0.87 ng/mL) at baseline had higher serum high-density lipoprotein (HDL) cholesterol (baseline versus after treatment, 1.30+/-0.19 versus 1.48+/-0.28 mmol/L; P=0.002) and HDL/LDL ratio (0.31+/-0.01 versus 0.34+/-0.10; P=0.048), but lower serum LPS concentration (1.70+/-0.49 versus 0.98+/-0.50 ng/mL; P=0.004) and autoantibodies to beta2-glycoprotein I (0.11+/-0.06 versus 0.09+/-0.04 ELISA units; P=0.022) after treatment.

CONCLUSIONS

Our results suggest that in systemically healthy patients, the infected/inflamed area in periodontitis is associated with macrophage activation via increased serum LPS concentration.

Serum IgG antibody response to periodontal pathogens in minority populations: relationship to periodontal disease status and progression

Differences in periodontal disease prevalence, severity, subgingival microflora and host immune response have been reported for various ethnic/racial groups, which implies that risk factors for destructive periodontal disease progression may also vary in these populations. As it is possible that these differences may be due to confounding variables other than ethnicity/race, we have measured serum IgG antibody response to six periodontal pathogens, and compared these data with microbiological, clinical and demographic parameters in three urban minority populations. The study population consisted of 23 Asiatic, 48 African-American and 37 Hispanic subjects, who were resident in the greater New York region. Clinical indices that were recorded included pocket depth, attachment level, gingival erythema, bleeding upon probing, suppuration and supragingival plaque. Attachment level measurements were taken twice at each visit, and the difference between the means of pairs of measurements taken at baseline and two months later was used to determine disease progression. Subgingival microbiological species were identified and enumerated using DNA-DNA checkerboard hybridization. Serum IgG antibody levels to Actinobacillus actinomycetemcomitans serotyopes a and b, Bacteroides forsythus, Campylobacter rectus, Porphyromonas gingivalis and Prevotella intermedia were measured by enzyme-linked immunosorbant assay (ELISA). Mean serum IgG antibody to P. gingivalis was found to be higher in the African-American group, while IgG antibody to B. forsythus was lower in the Hispanic group. However, the African-American group also had greater mean probing depth, attachment loss, number of missing teeth and numbers of individuals within the unskilled occupational group. When the data were analyzed by occupational status, mean serum IgG antibody to P. gingivalis increased from professional to skilled to unskilled groups. For the entire study population, prior disease and subsequent attachment loss were associated with elevated serum IgG antibody to P. gingivalis. Increasing pocket depth, attachment level, gingival erythema and age were also positively correlated with serum IgG antibody to P. gingivalis, but not with serum IgG antibody to the other five subgingival species. No correlation was found between whole-mouth bacterial levels and homologous serum IgG antibody levels. These results suggest that elevated serum IgG antibody to P. gingivalis reflects destructive periodontal disease status, and may be considered a risk factor for disease progression in these ethnic/racial populations. In addition, although differences in serum IgG antibody profiles to subgingival species were found among the three ethnic/racial groups, environmental and socioeconomic variables may have a greater influence on serum IgG antibody levels in these populations.

Porphyromonas gingivalis-specific IgG subclass antibody levels as immunological risk indicators of periodontal bone loss

BACKGROUND

It has been well demonstrated a positive association between the magnitude of host antibody response and periodontal disease status. Previous studies also reported that Porphyromonas gingivalis-specific IgG subclass antibodies were elevated in sera from adult periodontitis patients. However, the rôle and the association of these IgG subclass antibodies to the development of periodontal diseases are poorly understood.

AIM

The aim of present investigation was to examine the relation of serum IgG subclass antibody levels and alveolar bone loss in treated and untreated periodontitis patients.

METHODS

Serum samples were taken from 20 treated and maintained periodontitis patients (SPT patients), 30 untreated patients and 19 periodontally healthy subjects. We determined the IgG subclass antibody titers to P. gingivalis whole cells using an enzyme-linked immunosorbent assay (ELISA). Subgingival plaque samples were taken from the mesio-buccal surface of 6 randomly selected teeth of SPT patients and evaluated for the presence of P. gingivalis by immunofluorescence microscopy. Clinical measurements were also taken including full mouth intraoral radiographs to measure interproximal alveolar bone loss at baseline (BLS1) and at a 5-year recall visit in the SPT patients (BLS2).

RESULTS

Our results indicated that both patient groups had detectable levels of IgG1, IgG2, and IgG4. Significantly higher IgG1 was observed in both patient groups compared to the healthy subjects. The untreated patients also exhibited significantly elevated IgG2 response (p<0.05). The mean IgG4 level of the SPT patients was significantly higher compared to the other subject group (p<0.05). A statistically significant positive correlation between IgG2 levels and changes in bone levels (DeltaBLS: BLS2-BLS1) was seen in the SPT patients (p<0.001). SPT patients with high IgG2 and low IgG4 showed greater bone loss than those with low IgG2 and high IgG4 (p<0.05), although the mean prevalence of P. gingivalis in the 2 groups did not differ significantly.

CONCLUSION

Our data suggest that the prolonged IgG2 response after periodontal treatment may be indicative of recurrent or persistent periodontal destruction.

Antigenic specificity of gingival crevicular fluid antibody to Actinobacillus actinomycetemcomitans

Elevated antibody levels to periodontopathogens in GCF have been identified and used as support for local antibody synthesis in periodontitis. This study examined both cross-sectional and longitudinal GCF samples for the antigenic specificity of antibody in the fluid. GCF samples were collected from each tooth of 27 periodontitis patients infected with A. actinomycetemcomitans. Levels of IgG antibody in the GCF were assessed by means of an ELISA and compared with serum for determination of local elevations. A proportion of those GCF samples that exhibited significantly elevated antibody were examined by Western immunoblotting to outer membrane antigens from A. actinomycetemcomitans. Homologous sera were also examined for comparison of antibody specificities. Of the sites with elevated IgG antibody, 87% were colonized by A. actinomycetemcomitans; however, 46% of sites with A. actinomycetemcomitans infection did not have elevated antibody. Cross-sectional studies identified a 78 to 100% agreement between the antibody specificities in GCF and those in serum. Additionally, patterns of antibody reactivity in both GCF and serum in the subjects were often very distinctive. Longitudinal alterations in GCF antibody were examined in 15 patients through a monitoring interval of up to 2 years and showed a general conservation of specificities. However, 7/15 patients exhibited a definite acquisition of different antibody specificities during the monitoring. These results describe a relationship between elevated local antibody and A. actinomycetemcomitans infection. Furthermore, the antibody specificities in serum appear to reflect generally the local response to this pathogen.

Humoral immune responses in periodontal disease may have mucosal and systemic immune features

The humoral immune response, especially IgG and IgA, is considered to be protective in the pathogenesis of periodontal disease, but the precise mechanisms are still unknown. Immunoglobulins arriving at the periodontal lesion are from both systemic and local tissue sources. In order to understand better the local immunoglobulin production, we examined biopsy tissue from periodontitis lesions for the expression of IgM, IgG, IgA, IgE and in addition the IgG and IgA subclasses and J-chain by in situ hybridization. Tissues examined were superficial inflamed gingiva and the deeper granulation tissue from periodontal sites. These data confirm that IgM, and IgG and IgA subclass proteins and J-chain can be locally produced in the periodontitis tissues. IgG1 mRNA-expressing cells were predominant in the granulation tissues and in the gingiva, constituting approx. 65% of the total IgG-expressing plasma cells. There was a significantly increased proportion of IgA-expressing plasma cells in the gingiva compared with the granulation tissue (P < 0.01). Most of the IgA-expressing plasma cells were IgA1, but a greater proportion expressed IgA2 mRNA and J-chain mRNA in the gingival tissues (30.5% and 7.5%, respectively) than in the periodontal granulation tissues (19% and 0-4%, respectively). The J-chain or dimeric IgA2-expressing plasma cells were located adjacent to the epithelial cells, suggesting that this tissue demonstrates features consistent with a mucosal immune response. Furthermore, we were able to detect the secretory component in gingival and junctional epithelial cells, demonstrating that the periodontal epithelium shares features with mucosal epithelium. In contrast, deeper tissues had more plasma cells that expressed IgM, and less expressing IgA, a response which appears more akin to the systemic immune response. In conclusion, this study suggests that immune mechanisms involved in the pathogenesis of periodontitis may involve features of both the mucosal and systemic immune systems, dependent on tissue location.

Analysis of serum antibody responses to periodontopathogens in early-onset periodontitis patients from different geographical locations

Serum antibody specificity to oral micro-organisms was used to delineate the pathogens associated with early-onset periodontal diseases in a Turkish population. Additionally, comparison of the findings to those derived from a clinically similar US patient population described differences in bacterial specific antibody between these 2 geographic regions. Serum from 89 (LJP), 86 (RPP) and 94 (normal) subjects was analyzed (ELISA) to determine IgG antibody to 14 oral micro-organisms. All LJP patients from Turkey exhibited elevated antibody levels to A. actinomycetemcomitans (serotypes c and a significantly increased), while antibody levels to A. actinomycetemcomitans Y4 and JP2 (serotype b) were significantly higher in US LJP patients. 50% of the Turkish RPP patients also showed elevated anti-A. actinomycetemcomitans antibody, although the US RPP patients exhibited significantly higher antibody levels and frequency of elevated antibody to the A. actinomycetemcomitans serotypes. Healthy subjects and LJP and RPP patients from the US exhibited higher antibody levels to all 3 P. gingivalis serogroups compared to those from Turkey, although, the frequency of elevated antibody to the P. gingivalis serogroups was significantly higher in LJP and RPP patients from Turkey than from the US. Interestingly, 87% and 77% of the LJP patients in the Turkish population had elevated antibody responses to P. gingivalis and E. corrodens, respectively, which was not observed in the US LJP patients. These data suggested that considerable variation exists in the systemic antibody levels to periodontopathogens between these 2 countries. This supports potential differences in subgingival colonization or antigenic composition of these pathogens between patient populations from different geographical regions.

Serum antibodies reacting with subgingival species in refractory periodontitis subjects

The purpose of this investigation was to compare the levels of serum IgG antibody to 85 subgingival species in 32 refractory periodontitis, 56 successfully treated, and 33 periodontally healthy subjects. Refractory subjects showed mean full mouth attachment loss and/or >3 sites showing attachment loss >2.5 mm within 1 year after 2 treatment modalities, scaling and root planing and surgery plus systemically administered tetracycline. Successfully-treated subjects showed mean attachment level gain and no sites with attachment loss >2.5 mm, 1 year post-therapy. Periodontally healthy subjects exhibited no pocket or attachment level >3 mm, and no evidence of progressing attachment loss during 1 year of monitoring. Baseline serum was obtained from each subject and tested against 85 subgingival species, including reference strains and strains isolated from refractory subjects, using checkerboard immunoblotting. Significance of differences in levels of serum antibody among groups were sought using the Kruskal-Wallis test. Refractory subjects constituted a heterogeneous group based on their serum antibody response to subgingival species. Some individuals had antibody reactions to many subgingival species, while other subjects showed fewer or low numbers of responses. On average, refractory subjects exhibited higher numbers and levels of serum antibody reactions to a wide range of subgingival species than successfully treated or periodontally healthy subjects. Differences in serum antibody among clinical groups were more striking at higher threshold levels of antibody (>50 microg/ml and > 100 microg/ml). The data showed that a subject was 10.1 x more likely to be refractory if the subject exhibited antibody reactions with >9 subgingival species at >50 microg/ml (p<0.001, after adjusting for multiple comparisons). Serum antibody to a subset of the test species differed among the clinical groups. Porphyromonas gingivalis, Bacteroidesforsythus, and some strains isolated from refractory subjects (a novel Neisseria sp., Enterococcus faecalis, Prevotella loescheii and Prevotella oulora) elicited high serum antibody in the successfully treated and refractory subjects. High levels of serum antibody to a Microbacterium lacticum-like organism, Streptococcus oralis, Streptococcus constellatus, Actinobacillus actinonmycetemcomitans serotype c and Haemophilus aphrophilus significantly increased the likelihood of a subject being refractory to conventional periodontal therapy.

Increase in gingival inflammation under academic stress

Several correlational questionnaire studies have observed a positive relationship between psychological stress and periodontal diseases. This paper analyses the effects of academic stress on periodontal health in a prospective quasi-experimental design. 26 medical students participating in a major exam and the same number of medical students not participating in any exam throughout the study period volunteered for the study. Bleeding on probing was assessed 4 weeks prior to the exam period (baseline) and at the last day of the exam. Severe deterioration in gingival health from baseline to the last exam day were observed more frequently in exam students than in controls (p=0.014). 6 exam students but only 1 control person developed a severe gingivitis at at least one formerly healthy tooth throughout the study period. These results further support the hypothesis that psychological stress is a significant risk factor for periodontal inflammation. Future studies should examine factors mediating this relationship.

Attachment loss and serum antibody levels against autologous and reference strains of Actinobacillus actinomycetemcomitans in untreated localized juvenile periodontitis patients

Immunological data have been suggested to be a potential tool in the diagnosis, classification and monitoring of periodontal diseases. However, the role of circulating antibodies in periodontal patients is poorly understood. Patients suffering from localized juvenile periodontitis (LJP) are often reported to show high titers of serum IgG antibodies against Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans), but several affected patients do not. Most studies use well-known reference strains of the bacterium for testing against the patients' sera. The aim of the present investigation was to study the relationship between serum IgG antibody levels to autologous A. actinomycetemcomitans strains and clinical attachment loss (CAL). In addition, we wanted to assess the patients' serum titers against 4 well-known reference strains of the bacterium as well as their general potential immunoglobulin response. Intravenous blood samples were taken from 23 LJP patients and 10 healthy individuals, and autologous A. actinomycetemcomitans strains were cultured from 18 of the LJP patients. CAL was measured at 4 different sites around all present teeth and assessed as a % of teeth with at least 1 site moderately > or = 2 < 5 mm) or severely (> or = 5 mm) involved. An enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the serum titers of IgG antibodies to A. actinomycetemcomitans antigens. No significant correlation was found between serum IgG antibody titers to autologous strains and CAL. However, there was a trend that low responders had more moderately affected teeth than had high responders and patients with undetectable A. actinomycetemcomitans levels, which is in agreement with a hypothetically protective role of the antibodies. The total counts of immunoglobulin assessed in all participants showed that the predominant class was IgG and the reference group displayed significantly less (p < 0.05) IgG and IgG1 counts than the LJP patients. Both the reaction pattern against reference and autologous strains varied widely. We conclude that the specific antibody response against A. actinomycetemcomitans shows a weak correlation to clinical attachment levels in LJP patients.

[Oral manifestations in patients with systemic lupus erythematosus]

Forty-six patients with systemic lupus erythematosus underwent thorough dental examination to determine the frequency and severity of oral lesions and periodontal diseases. According to clinical criteria, disease was classified as severe (n = 26) or less severe (n = 20). The overall rate of mucosal involvement in the studied patients was 48%-from 54% in patients with severe disease, 40% in those with less severe disease. Patients with severe disease were found to have a higher rate of tooth loss and an increased rate of gingival inflammation. The severity of periodontal lesions correlated with alterations in the immunoglobulin pattern, particularly with an increase in gamma-immunoglobulins. Thus it is suspected that complex immunodysregulation in combination with immunosuppressive therapy is responsible for the high rate of oral and periodontal lesions in patients with systemic lupus erythematosus.

Gingival fibroblast cytokine profiles in Actinobacillus actinomycetemcomitans-associated periodontitis

Within the in vivo environment human gingival fibroblasts (HGF) may be challenged with bacteria or bacterial products. This interaction may result in the release of cytokines which are directly or indirectly involved in connective tissue and bone catabolism, such as interleukin (IL)-1 beta, IL-6, and IL-8. Our investigation has tested the hypothesis that HGF from Actinobacillus actinomycetemcomitans (Aa)-infected patients with rapidly destructive forms of periodontitis, such as localized juvenile periodontitis (LJP), respond to Aa challenge with an exaggerated secretion of IL-1 beta, IL-6, and IL-8. We have compared the in vitro profiles of these cytokines by Aa-challenged HGF obtained from 2 healthy subjects, 2 Aa-infected, slowly progressing adult periodontitis (AP) patients and 2 LJP patients. HGF were challenged throughout a 48-hour period with formalinized whole bacterial cells, and culture supernatants were analyzed for cytokine content using RIA. No differences were noted in the IL-1 beta secretion levels among the different HGF cultures. Although basal (unchallenged) IL-6 and IL-8 production was similar in all HGF cultures, HGF from the two LJP patients responded to Aa challenge with a more rapid IL-6 and a more pronounced IL-8 secretion than healthy or AP HGF. We also tested the ability of human serum antibodies against Aa to moderate the Aa-elicited HGF cytokine secretion by adding human serum, with normal or elevated antibody content. Both sera appeared to have an upregulating effect on IL-6 and IL-8 secretion. Depletion of 95% of the anti-Aa antibody from serum by absorption did not affect its activity. Based on the response of HGF from two LJP patients, we propose that Aa-induced pathology in LJP may be modulated by stimulation of rapid and/or exaggerated secretion of cytokines with potential catabolic effects, although studies with a larger group of LJP patients are needed to further test this hypothesis. Furthermore, serum antibodies against this microorganism do not appear to have a neutralizing effect in cytokine-eliciting HGF-Aa interactions.

Putative periodontal pathogens, antibody titres and avidities to them in a longitudinal study of patients with resistant periodontitis

OBJECTIVE

To study changes in antibody titres and antibody avidities to putative periodontal pathogens in patients with resistant periodontitis and to compare these findings with the result of culture of these pathogens.

SUBJECTS AND METHODS

Patients meeting strict clinical criteria in whom periodontal therapy had failed to prevent disease progression were studied microbiologically and immunologically over a 75-week period. Particular reference was made to the isolation of Actinobacillus actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) together with changes in antibody titres and avidities to these organisms between baseline examination and week 75.

RESULTS

Pg was eliminated following antibiotic treatment but metronidazole and amoxycillin therapy failed to remove Aa in all cases. Antibody avidities to these pathogens were higher in patients than in matched controls but no change in avidity was noted during the course of treatment. Most antibody titres were not significantly higher in patients than in controls.

CONCLUSIONS

Continued disease progression characterised these patients who, nevertheless, mounted an immune response to the periodontal pathogens but this appeared to be inadequate to stop the disease.

Host response assessment in recurring periodontitis

Data derived from periodontitis patients have provided support for a relationship between the distribution of selected members of the periodontopathic microbiota and antibody levels to the intact bacteria in both serum and GCF. These data are consistent with the systemic antibody as a reflection of the host response to an infectious process associated with an episode of disease activity. The purpose of this report is to address the concept that the host antibody responses may help to elucidate the specific etiologic agents and be used to model the risk for future periodontal disease progression in recurring periodontitis. These findings from one study in adult periodontitis patients indicated that elevations in certain antibody specificities are most closely associated with patients exhibiting a risk of disease recurrence. Furthermore, analysis of the frequency of antibody elevations suggested that patients capable of maintaining elevated antibody to these pathogens post-treatment, may be indicative of an individual at less risk. A 2nd investigation was implemented to address questions concerning host-parasite interactions in A. actinomycetemcomitans-associated recurring periodontitis. The results showed distinctive characteristics of local and systemic antibody responses and A. actinomycetemcomitans infection in patients with varying extents of recurrent disease. These longitudinal studies developed evidence for the potential of local and/or systemic antibody responses as indicators of periodontal disease recurrence.

Longitudinal dynamics of infection and serum antibody in A. actinomycetemcomitans periodontitis

OBJECTS

This report describes one of the first prospective studies delineating the relationship between infection, host antibody responses and disease exacerbations and remissions in a distinct subset of periodontitis patients infected with A. actinomycetemcomitans.

DESIGN

The design of this longitudinal study included visits for each patient approximately every 2 months for up to 3 years.

SUBJECTS AND METHODS

Subjects (n=51) included 16 adult periodontitis (AP) and 11 early-onset periodontitis (EOP) patients with elevated serum IgG antibody to A. actinomycetemcomitans and infection with this microorganism, 12 AP patients with normal levels of anti-Aa antibody, and 12 normal subjects. MEASUREMENT OUTCOMES: Clinical parameters included a gingival index, plaque index, bleeding on probing, pocket depth, and attachment level. Disease activity was defined as loss of attachment during the monitoring intervals. Serum IgG, IgM and IgA antibody to A. actinomycetemcomitans Y4 (serotype b) was quantitated using an ELISA. Subgingival plaque samples were examined for A. actinomycetemcomitans using colony immunoblotting. Human serum IgG antibody specificities to outer membrane antigens (OMA) of A. actinomycetemcomitans Y4 were determined using Western immunoblotting.

RESULTS

A. actinomycetemcomitans-infected AP patients had a higher frequency of teeth infected when compared to the EOP patients. However, the EOP patients exhibited a trend for higher levels of A. actinomycetemcomitans in those teeth that were infected. Active disease patients demonstrated a significantly greater frequency of infected sites, as well as significant elevations in the proportions of A. actinomycetemcomitans. Both EOP and AP groups showed significantly elevated IgG, IgM and IgA antibody to A. actinomycetemcomitans when compared to a periodontally normal group. The level of IgG antibody was significantly elevated in A. actinomycetemcomitans-positive patients with active disease, while IgA antibody was decreased in a number of the active group patients. Plaque samples derived from active sites showed a clear and significant increase in A. actinomycetemcomitans that occurred from 2-6 months prior to the identification of disease activity. Approximately 70% of the active disease patients showed an increase in IgG antibody level by 2-4 months prior to disease activity. Studies of the antigen reactivity patterns of serum IgG indicated that antibody to antigens of 65, 58, 48, 29 and 24 kDa were more frequent in patients who showed active disease, while those patients with the greatest frequency of active disease appeared to show a general decrease in the recognition of the A. actinomycetemcomitans OMA.

CONCLUSIONS

It appears that A. actinomycetemcomitans infection relates to a particular type of disease with accompanying antibody responses that reflect periods of active disease. The dynamics of A. actinomycetemcomitans infection and the level and specificity of systemic antibody responses to this pathogen support an important contribution of the immune response to managing this infection.

Initial serum antibody titer to Porphyromonas gingivalis influences development of antibody avidity and success of therapy for chronic periodontitis

This study assessed the effect of periodontal therapy on specific serum antibody concentration, expressed as titer, and antibody binding strength, expressed as relative avidity. The immune responses to Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans were investigated. Antibody titer was assayed by enzyme-linked immunosorbent assay (ELISA) and relative avidity was measured by thiocyanate elution in 17 adult periodontitis patients before and after therapy. Immunoglobulin G (IgG) avidities (expressed as thiocyanate molarity) to P. gingivalis increased from 1.01 to 1.38 M (P = 0.05) and IgA titers (expressed as ELISA units [EU]) increased from 89 to 237 EU (P = 0.012). There were no significant changes in avidity to A. actinomycetemcomitans, but the titer of all three immunoglobulin classes increased significantly (P < 0.03). More specifically, when patients were divided into subgroups which had originally been either IgG seropositive (i.e., having an IgG titer to this organism > 2 times the control median) or seronegative for P. gingivalis, only patients who were initially seropositive showed a significant increase in antibody avidity (P = 0.026; mean difference, 0.69 M). Patients who were originally seropositive in terms of IgG and IgA titer to P. gingivalis had demonstrably better treatment outcomes in terms of a reduced number of deep pockets and sites which bled on probing (P < 0.05). These findings suggest that periodontal therapy affects the magnitude and quality of the humoral immune response to suspected periodontopathogens, that this effect is dependent on initial serostatus, and that initial serostatus may have a bearing on treatment outcome.

Antigen specificity of serum antibody in A. actinomycetemcomitans-infected periodontitis patients

We hypothesized that serum antibody with selected antigen specificities would relate to infection and disease in the patients and, thus, describe the characteristics of potential protective antibody. This study used serum samples from 24 periodontitis patients with subgingival infection and elevated serum IgG antibody to A. actinomycetemcomitans to define the antigenic specificities of IgG, IgM, IgA, and IgG1-4 antibody to A. actinomycetemcomitans strain Y4 outer membrane antigens (OMA). Uniform IgG antibody (> 70% of the patients) was noted to antigens with M(r) of 65, 38, 29, and 17 kDa. Both IgA and IgM specificities reflected those shown for IgG in each patient. IgG1 and IgG2 antibody reacted with several OMA bands in each patient, while IgG3 antibodies were directed to numerous OMA bands in many patients and represented the most broad-based response. The IgG4 response patterns were limited to a few OMA bands. We noted a prominent occurrence of IgG reactions with OMA bands that were characteristic for individual patients. The frequency of responses to OMA of higher M(r) (i.e., > 80 kDa) and to the 34-, 31-, and 24-kDa antigens was positively related to the total IgG antibody levels. Antibody reactive with OMA bands at 65-, 38-, 29-, 17-, 15-, and 11-kDa antigens was detected in patients with few to many teeth infected with A. actinomycetemcomitans. Furthermore, patients with a high percentage of teeth with > or = 6 mm pockets had a decreased frequency of responses to the high-M(r) antigens (i.e. > 90 kDa) as well as to the 58-kDa antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Subgingival distribution of A. actinomycetemcomitans in periodontitis

This investigation developed an experimental design that (1) detailed the distribution of A. actinomycetemcomitans in subgingival plaque related to the level of serum antibody to this pathogen; (2) used broad based subgingival plaque sampling to allow a definition of the distribution of A. actinomycetemcomitans infection in periodontitis patients; (3) described the distribution of A. actinomycetemcomitans serotypes in patients and within sites; and, (4) assessed how this infection impacted upon local clinical symptoms of disease. We noted a significant positive relationship between the level of IgG anti-A. actinomycetemcomitans antibody and the frequency of teeth infected until nearly 13 teeth demonstrated an infection. Furthermore, the results showed a generally negative relationship between the antibody level and the burden of A. actinomycetemcomitans in the infected sites. Interproximal sites associated with first molar teeth were the predominant sites for subgingival colonization; incisors were also frequently infected in this population. The first molar teeth also exhibited the greatest level of A. actinomycetemcomitans, while the incisors demonstrated a high level of A. actinomycetemcomitans in individual sites. The results clearly indicated the majority of the sites sampled were colonized by a single serotype of A. actinomycetemcomitans. We detected A. actinomycetemcomitans nearly 2 x times more frequently and a significant increase in the proportion of A. actinomycetemcomitans was found in samples obtained from teeth with bleeding on probing. The results also showed a significant trend for both pocket depth and attachment levels to be related to the presence and proportion of A. actinomycetemcomitans in the subgingival plaque. These findings detail the microbiological, immunological and clinical characteristics of a unique subset of periodontitis patients that appear to exhibit disease associated (caused?) with A. actinomycetemcomitans infection irrespective of clinical categorization. The results support a unique distribution of this microorganism in the subgingival ecology that is related to active host immune responses and clinical presentation of the tooth.

Unusual gingival enlargement with rapidly progressive periodontitis. Report of a case

A 15-year-old female patients suffered from recurrent unusual enlargement of the gingiva together with rapidly progressive alveolar bone loss. The enlarged gingiva completely covered her anterior teeth and protruded from the mouth. Marked inflammatory edematous tissue, which predominantly contained plasma cells, was observed in the connective tissue. Rapidly progressive alveolar bone loss was observed radiographically. The serum antibody titer to Porphyromonas gingivalis, measured by ELISA, was much higher than that in healthy individuals. The diagnosis was unusual gingival enlargement with rapidly progressive periodontitis. Conventional periodontal therapy, including plaque control, scaling, root planing, and surgical removal of the soft tissue, did not produce complete healing of the gingival lesion, although recurrence of gingival enlargement and further loss of the periodontal attachment level were well controlled. After the periodontal treatments, the serum antibody titer to P. gingivalis decreased to normal levels. This unusual gingival enlargement was considered due to systemic factors that exaggerated the gingival response to local irritation and altered the usual clinical features of chronic gingivitis; local plaque irritation produced the extensive and recurrent enlargement of the gingiva. Under these circumstances, infection or overgrowth of periodontopathic bacteria, including P. gingivalis, might occur and the alveolar bone loss would then advance very rapidly.