Occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in juvenile periodontitis

Prevotella: An insight into its characteristics and associated virulence factors

Prevotella species, a gram-negative obligate anaerobe, is commonly associated with human infections such as dental caries and periodontitis, as well as other conditions such as chronic osteomyelitis, bite-related infections, rheumatoid arthritis and intestinal diseases like ulcerative colitis. This generally harmless commensal possesses virulence factors such as adhesins, hemolysins, secretion systems exopolysaccharide, LPS, proteases, quorum sensing molecules and antibiotic resistance to evolve into a well-adapted pathogen capable of causing successful infection and proliferation in the host tissue. This review describes several of these virulence factors and their advantage to Prevotella spp. in causing inflammatory diseases like periodontitis. In addition, using genome analysis of Prevotella reference strains, we examined other putative virulence determinants which can provide insights as biomarkers and be the targets for effective interventions in Prevotella related diseases like periodontitis.

Salivary markers of oxidative stress and periodontal pathogens in patients with periodontitis from Santander, Colombia

Introduction:

Periodontitis affects more than 20% of the Latin American population. Oxidative markers are associated with greater progression of periodontitis; therefore, its role in pathogenesis should be studied.

Objective:

To determine the prevalence of the main oral bacteria and viruses associated with periodontitis and estimate the total antioxidant capacity and lipid peroxidation in saliva from patients with periodontitis.

Materials and methods:

We conducted systemically a cross-sectional study in 101 healthy subjects, 87 of whom had been diagnosed with periodontitis (P), according to the criteria of the Centers of Disease Control and Prevention and the American Academy of Periodontology, and 14 without periodontal pockets as controls (C). In subgingival samples, major viruses and dental pathogenic bacteria were identified using PCR techniques. The levels of total antioxidant capacity and malon-di-aldehyde (MDA) were determined by spectrophotometry in samples of unstimulated saliva.

Results:

The mean of periodontal depth pocket and clinical attachment loss in patients with periodontitis was 5.6 ± 1.7 and 6.1 ± 3.1 mm, respectively. The most prevalent microorganisms were Aggregatibacter actinomycetemcomitans (32.5%) and Porphyromonas gingivalis (18.6%). The patients from rural areas showed a higher percentage of A. actinomycetemcomitans (urban: 17.9% vs. rural: 48.9%, p=0.0018). In patients with periodontitis, the frequency of EBV, HSV1 & 2, and HCMV genes was 2.3%. Periodontitis patients had higher levels of MDA (P: 2.1 ± 1.5; C: 0.46 ± 0.3 µmol/g protein; p=0.0001) and total antioxidant capacity (P: 0.32 ± 0.2; C: 0.15 ± 0.1 mM; p< 0.0036). Oxidative markers showed no modifications due to the presence of periodontopathic bacteria.

Conclusions:

Aggregatibacter actinomycetemcomitans was the most prevalent bacteria; its presence did not modify the levels of oxidative markers in the saliva of patients with periodontitis.

Pathogen profile and MMP-3 levels in areas with varied attachment loss in generalized aggressive and chronic periodontitis

Introduction

The progression of periodontitis depends on the changes in bone and connective tissue homeostasis and the imbalance of the biofilm and the host immunoinflammatory response, particularly matrix metalloproteinases (MMP).

Aim of the study

To assess the probable relation between subgingival anaerobic flora and the expression of MMP-3 in patients with generalized aggressive periodontitis (AgP), chronic periodontitis (CP) and healthy subjects, and to evaluate these levels according to varied tissue loss severity.

Material and methods

The plaque index (PI), gingival index (GI), probing depth (PD) and clinical attachment levels (CAL) were evaluated. MMP levels obtained from gingival sulcus fluid (GCF) were measured with Enzyme Linked Immuno Assay (ELISA). The bacterial counts were determined with Parocheck^®.

Results

Higher levels of MMP-3 in patients with AgP compared to subjects with CP and healthy individuals were observed. The microorganisms responsible of possible tissue destruction in both AgP and CP are red complex bacteria. T. denticola, T. forsythia, P. intermedia and F. nucleatum show positive correlation with MMP-3 levels.

Conclusions

MMP-3 is a biomarker associated with AgP, and red complex bacteria levels are correlated with increasing periodontal tissue loss in both periodontitis forms. The diagnosis of aggressive periodontitis, or site-specific treatment strategies can be orchestrated based on the evaluation of MMP-3 and the bacterial counts in patients with periodontitis.

Association of human leukocyte antigens Class I and Class II antigens with chronic periodontitis in East India

CONTEXT

Human leukocyte antigens (HLAs) have an important role in the determination of susceptibility and resistance to periodontal diseases in humans, which may vary from population to population.

AIMS

The aim of this study was to find out the association of HLA Classes I and II genes with chronic periodontitis in East Indian population.

MATERIALS AND METHODS

In a cross-sectional study design, a total of sixty participants of chronic periodontitis (CP) (mean age: 44.12 ± 5.85) and sixty subjects of periodontal disease-free controls (NP) Periodontitis free controls (mean age 41.85 ± 7.71) were analyzed for their various HLA combinations using serologic (microlymphocytotoxicity test) method. The results are further compared with the HLA profile of 100 samples of blood donors for which periodontal status was unknown. All the data were statistically analyzed by applying Chi-square test.

RESULTS

HLA-B7 (P = 0.003), DR7 (P = 0.001), DR53 (P = 0.001), and DQ3 (P = 0.001) were identified as susceptible phenotypes to CP, whereas HLA-A1 (P = 0.010), A3 (P = 0.001), and Cw4 (P = 0.001) phenotypes were identified to be associated with disease resistance.

CONCLUSION

The HLA-B7, DR7, DR53, and DQ3 alleles may represent as risk factors for CP in Eastern Population of India, whereas HLA-A1, A3, and Cw4 may indicate to protective factors for CP of the same.

Systemic antibiotics in the treatment of periodontitis

Despite the fact that several clinical studies have shown additional benefits when certain systemic antibiotics are used as adjuncts to periodontal treatment, clear guidelines for the use of these agents in the clinical practice are not yet available. Basic questions concerning the use of systemic antibiotics to treat periodontitis remain unanswered, such as: which drug(s) should be used; which patients would most benefit from treatment; which are the most effective protocols (i.e. doses and durations); and in which phase of the mechanical therapy should the drug(s) be administered? Although not all of those questions have been directly addressed by controlled randomized clinical trials, recent concepts related to the ecology of periodontal diseases, as well as the major advances in laboratory and clinical research methods that have occurred in the past decade, have significantly broadened our knowledge in this field. This article endeavored to provide a 'state of the art' overview on the use of systemic antibiotics in the treatment of periodontitis, based on the most recent literature on the topic as well as on a compilation of data from studies conducted at the Center of Clinical Trials at Guarulhos University (São Paulo, Brazil) from 2002 to 2012.

Detection of Porphyromonas gingivalis and Treponema denticola in chronic and aggressive periodontitis patients: A comparative polymerase chain reaction study

BACKGROUND

The detection frequency of Porphyromonas gingivalis and Treponema denticola in chronic periodontitis (CP) and aggressive periodontitis (AgP) is not explored well in Indian population.

AIM

The study was undertaken to detect P. gingivalis and T. denticola in CP as well as in AgP patients using polymerase chain reaction (PCR), and to determine the relationship between the frequency of these two microorganisms and the severity of clinical periodontal parameters.

MATERIALS AND METHODS

Subgingival plaque samples were collected from ninety participants (thirty CP patients, thirty AgP patients, and thirty healthy participants) and the aforementioned two microorganisms were detected using PCR.

RESULTS

However, when CP and AgP were compared for the detection frequency of two microorganisms, no statistically significant difference was noted. A statistically significant increase in the number of bacteria-positive sites increased as the score of plaque index (PI), gingival index (GI), and clinical attachment level of CP and AgP patients increased. Coexistence of P. gingivalis and T. denticola was frequently observed in deep periodontal pockets.

CONCLUSIONS

Study findings suggest that P. gingivalis and T. denticola are significantly associated with the severity of periodontal tissue destruction. Statistically significant association exists between clinical periodontal parameters such as PI, GI, periodontal pocket depth (PPD), and clinical attachment loss and presence of both the microorganisms.

Maresin 1 Biosynthesis and Proresolving Anti-infective Functions with Human-Localized Aggressive Periodontitis Leukocytes

Localized aggressive periodontitis (LAP) is a distinct form of early-onset periodontitis linked to periodontal infection with uncontrolled inflammation and leukocyte-mediated tissue destruction. The resolution of inflammation is an active process orchestrated by specialized proresolving lipid mediators (SPMs). Since the level of the Maresin pathway marker 14-hydroxy-docosahexaenoic acid (14-HDHA) was lower in activated peripheral blood from LAP patients, we investigated the Maresin 1 (MaR1) biosynthetic pathway in these subjects and its role in regulating phagocyte functions. Macrophages from LAP patients had a lower level of expression of 12-lipoxygenase (∼30%) and reduced MaR1 (LAP versus healthy controls [HC], 87.8 ± 50 pg/10(6) cells versus 239.1 ± 32 pg/10(6) cells). Phagocytosis by LAP macrophages was reduced ∼40% compared to that of HC, and killing of periodontal pathogens, including Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, were similarly reduced. LAP neutrophils also displayed slower kinetics (∼30%) and decreased maximal phagocytosis (∼20% lower) with these pathogens than those of HC. The administration of MaR1 at 1 nM enhanced phagocytosis (31 to 65% increase), intracellular antimicrobial reactive oxygen species production (26 to 71% increase), bacterial killing of these periodontal pathogens (22 to 38% reduction of bacterial titers), and restored impairment of LAP phagocytes. Together, these results suggest that therapeutics targeting the Maresin pathway have clinical utility in treating LAP and other oral diseases associated with infection, inflammation, and altered phagocyte functions.

Host response mechanisms in periodontal diseases

Periodontal diseases usually refer to common inflammatory disorders known as gingivitis and periodontitis, which are caused by a pathogenic microbiota in the subgingival biofilm, including Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Treponema denticola that trigger innate, inflammatory, and adaptive immune responses. These processes result in the destruction of the tissues surrounding and supporting the teeth, and eventually in tissue, bone and finally, tooth loss. The innate immune response constitutes a homeostatic system, which is the first line of defense, and is able to recognize invading microorganisms as non-self, triggering immune responses to eliminate them. In addition to the innate immunity, adaptive immunity cells and characteristic cytokines have been described as important players in the periodontal disease pathogenesis scenario, with a special attention to CD4⁺ T-cells (T-helper cells). Interestingly, the T cell-mediated adaptive immunity development is highly dependent on innate immunity-associated antigen presenting cells, which after antigen capture undergo into a maturation process and migrate towards the lymph nodes, where they produce distinct patterns of cytokines that will contribute to the subsequent polarization and activation of specific T CD4+ lymphocytes. Skeletal homeostasis depends on a dynamic balance between the activities of the bone-forming osteoblasts (OBLs) and bone-resorbing osteoclasts (OCLs). This balance is tightly controlled by various regulatory systems, such as the endocrine system, and is influenced by the immune system, an osteoimmunological regulation depending on lymphocyte- and macrophage-derived cytokines. All these cytokines and inflammatory mediators are capable of acting alone or in concert, to stimulate periodontal breakdown and collagen destruction via tissue-derived matrix metalloproteinases, a characterization of the progression of periodontitis as a stage that presents a significantly host immune and inflammatory response to the microbial challenge that determine of susceptibility to develop the destructive/progressive periodontitis under the influence of multiple behavioral, environmental and genetic factors.

Microbiology of aggressive periodontitis

For decades, Aggregatibacter actinomycetemcomitans has been considered the most likely etiologic agent in aggressive periodontitis. Implementation of DNA-based microbiologic methodologies has considerably improved our understanding of the composition of subgingival biofilms, and advanced open-ended molecular techniques even allow for genome mapping of the whole bacterial spectrum in a sample and characterization of both the cultivable and not-yet-cultivable microbiota associated with periodontal health and disease. Currently, A. actinomycetemcomitans is regarded as a minor component of the resident oral microbiota and as an opportunistic pathogen in some individuals. Its specific JP2 clone, however, shows properties of a true exogenous pathogen and has an important role in the development of aggressive periodontitis in certain populations. Still, limited data exist on the impact of other microbes specifically in aggressive periodontitis. Despite a wide heterogeneity of bacteria, especially in subgingival samples collected from patients, bacteria of the red complex in particular, and those of the orange complex, are considered as potential pathogens in generalized aggressive periodontitis. These types of bacterial findings closely resemble those found for chronic periodontitis, representing a mixed polymicrobial infection without a clear association with any specific microorganism. In aggressive periodontitis, the role of novel and not-yet-cultivable bacteria has not yet been elucidated. There are geographic and ethnic differences in the carriage of periodontitis-associated microorganisms, and they need to be taken into account when comparing study reports on periodontal microbiology in different study populations. In the present review, we provide an overview on the colonization of potential periodontal pathogens in childhood and adolescence, and on specific microorganisms that have been suspected for their role in the initiation and progression of aggressive forms of periodontal disease.

Acquisition of oral microbes and associated systemic responses of newborn nonhuman primates

The acquisition and development of the complex oral microbiome remain ill defined. While selected species of oral bacteria have been examined in relation to their initial colonization in neonates, a more detailed understanding of the dynamics of the microbiome has been developed only in adults. The current investigation used a nonhuman primate model to document the kinetics of colonization of the oral cavities of newborns and infants by a range of oral commensals and pathogens. Differences in colonization were evaluated in newborns from mothers who were maintained on an oral hygiene regimen pre- and postparturition with those displaying naturally acquired gingivitis/periodontitis. The results demonstrate distinct profiles of acquisition of selected oral bacteria, with the transmission of targeted pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, being passed on primarily from mothers with gingivitis/periodontitis. This colonization resulted in defined patterns of systemic antibody responses in the infants. The significant relative risk measures for infection with the pathogens, as well as the relationship of oral infection and blood serum antibody levels, were consistent with those of the newborns from mothers with gingivitis/periodontitis. These findings indicate that the early acquisition of potentially pathogenic oral bacterial species might impact the development of mucosal responses in the gingiva and may provide an enhanced risk for the development of periodontitis later in life.

Sustained mitogen-activated protein kinase activation with Aggregatibacter actinomycetemcomitans causes inflammatory bone loss

Aggregatibacter actinomycetemcomitans is a gram-negative facultative capnophile involved in pathogenesis of aggressive forms of periodontal disease. In the present study, we interrogated the ability of A. actinomycetemcomitans to stimulate innate immune signaling and cytokine production and established that A. actinomycetemcomitans causes bone loss in a novel rat calvarial model. In vitro studies indicated that A. actinomycetemcomitans stimulated considerable production of soluble cytokines, tumor necrosis factor-α, interleukin-6 and interleukin-10 in both primary bone marrow-derived macrophages and NR8383 macrophages. Immunoblot analysis indicated that A. actinomycetemcomitans exhibits sustained activation of all major mitogen-activated protein kinase (MAPK) pathways, as well as the negative regulator of MAPK signaling, MAPK phosphatase-1 (MKP-1), for at least 8 h. In a rat calvarial model of inflammatory bone loss, high and low doses of formalin-fixed A. actinomycetemcomitans were microinjected into the supraperiosteal calvarial space for 1-2 weeks. Histological staining and micro-computed tomography of rat calvariae revealed a significant increase of inflammatory and fibroblast infiltrate and increased bone resorption as measured by total lacunar pit formation. From these data, we provide new evidence that fixed whole cell A. actinomycetemcomitans stimulation elicits a pro-inflammatory host response through sustained MAPK signaling, leading to enhanced bone resorption within the rat calvarial bone.

The highly leukotoxic JP2 clone of Aggregatibacter actinomycetemcomitans in localized and generalized forms of aggressive periodontitis

OBJECTIVE

To investigate the presence of A. actinomycetemcomitans, including the highly virulent JP2 clone, in young adult patients with aggressive periodontitis, and associate the findings with the two forms of the disease.

MATERIALS AND METHODS

Seventy Moroccan subjects with aggressive periodontitis, aged less than 35 years, were recruited. Among these, 41 had LAgP and 29 had GAgP. Plaque samples were collected from periodontal pockets and examined using a PCR that detects the presence of A. actinomycetemcomitans and which differentiates between JP2 and non-JP2 genotypes of the bacterium.

RESULTS

total of 58 (83%) from the 70 AgP patients were positive for A. actinomycetemcomitans, among whom 77% were positives for the JP2 clone. The JP2 clone was detected in 34 (83%) of the LAgP patients compared to 20 (69%) of the GAgP patients (p = 0.17). Fourteen (20%) of the patients harbored non-JP2 genotypes of A. actinomycetemcomitans, although most of these patients (10/14) also harbored the JP2 clone.

CONCLUSIONS

The presence of the JP2 clone of A. actinomycetemcomitans is strongly associated with both LAgP and GAgP in young adults in Morocco. This implies that treatment of AgP in this population should include microbiological screening and aim at eradication of the bacterium when present.

Occurrence of Actinobacillus actinomycetemcomitans in patients with chronic periodontitis, aggressive periodontitis, healthy subjects and children with gingivitis in two cities of the state of São Paulo, Brazil

The aim of this study was to determine the frequency of isolation of Actinobacillus actinomycetemcomitans (Aa) in 100 patients with chronic periodontitis, 14 patients with aggressive periodontitis, 142 pre-school children with gingivitis and 134 periodontally healthy subjects. Samples of subgingival plaque were taken using sterilized paper points introduced into periodontal pockets or gingival crevice for 60 seconds and inoculated on TSBV agar, which was incubated under anaerobiosis at 37°C, for 4 days. Microbial identification was performed through biochemical methods and morphocellular and morphocolonial analysis. Aa was detected in 40.3% of healthy subjects, 68% of patients with chronic periodontitis, 92.86% of patients with aggressive periodontitis and 40.14% of children with gingivitis. The rate of recovery of Aa in the tested human groups proved to be higher than previously reported and in agreement with participation of this facultative anaerobe as a member of native microbiota of the periodontium and its relation with aggressive and chronic periodontitis in Brazil.

Microbiological profile of untreated subjects with localized aggressive periodontitis

AIM

The microbial profile of localized aggressive periodontitis (LAgP) has not yet been determined. Therefore, the aim of this study was to evaluate the subgingival microbial composition of LAgP.

MATERIAL AND METHODS

One hundred and twenty subjects with LAgP (n=15), generalized aggressive periodontitis (GAgP, n=25), chronic periodontitis (ChP, n=30) or periodontal health (PH, n=50) underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analysed for their content of 38 bacterial species using checkerboard DNA-DNA hybridization.

RESULTS

Red complex and some orange complex species are the most numerous and prevalent periodontal pathogens in LAgP. The proportions of Aggregatibacter actinomycetemcomitans were elevated in shallow and intermediate pockets of LAgP subjects in comparison with those with GAgP or ChP, but not in deep sites. This species also showed a negative correlation with age and with the proportions of red complex pathogens. The host-compatible Actinomyces species were reduced in LAgP.

CONCLUSION

A. actinomycetemcomitans seems to be associated with the onset of LAgP, and Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Campylobacter gracilis, Eubacterium nodatum and Prevotella intermedia play an important role in disease progression. Successful treatment of LAgP would involve a reduction in these pathogens and an increase in the Actinomyces species.

Yeast diversity in the oral microbiota of subjects with periodontitis: Candida albicans and Candida dubliniensis colonize the periodontal pockets

The term periodontitis encompasses several polymicrobial infectious diseases, of multifactorial etiology, with chronic and aggressive forms. In spite of the etiopathogenic differences between these two forms of the disease, few studies have analyzed the subgingival colonization by yeast. The objective of this investigation was to analyze the composition of the yeast microbiota present in the mucosa and subgingival sites of healthy individuals and patients with aggressive and chronic periodontitis. For this, samples were recovered from these two locations and the yeast recovered identified by phenotypic and genotypic methods. Patients with chronic periodontitis showed significant differences in relation to the other groups with respect to carrier status (69.2% versus 35.7% of healthy individuals; [chi(i)(2) test; p=0.014]), the total number of isolated colony forming units or CFU (mean and ranges 281.6 (0-6048) [K-W(2)=6.998; p=0.03]), the Simpson diversity index (I) in site b (I(b)=0.344 versus healthy subjet and aggresive periodontitis where I=0 [multiple t-test comparisons with the Bonferronni correction, p<0.05]), and the species profile. Interestingly, in spite of the varied profiles of the species present in the mucosa of the three groups analyzed we noted that only C. albicans and C. dubliniensis were capable of colonizing the periodontal pockets in patients with chronic periodontitis, while only C. albicans was identified in the subgingiva of healthy individuals and patients with aggressive periodontitis.

Prevalence and distribution of principal periodontal pathogens worldwide

BACKGROUND

Detailed genetic analysis of bacteria has demonstrated an unanticipated genetic diversity within species, which often reveals evolutionary lineages that are disproportionately associated with infection. There is evidence that some evolutionary lineages of bacteria have adapted to particular ethnic groups.

AIM

This review analyzes to what extent observed differences in periodontal disease prevalence among ethnically or geographically distinct populations may be explained by restricted host adaptation of clones of principal periodontal pathogens.

RESULTS

Carriage rates of several putative periodontal pathogens and particular subsets of these species vary between ethnic groups. Few of these differences can, with the limited information available, be directly related to differences in periodontal disease prevalence. Asian populations are regularly colonized with Actinobacillus actinomycetemcomitans serotype c with questionable pathogenic potential. Conversely, the JP2 clone of A. actinomycetemcomitans has enhanced virulence and causes significantly higher prevalence of aggressive periodontitis in adolescents whose descent can be traced back to the Mediterranean and Western parts of Africa. Some genetically distinct types of Porphyromonas gingivalis are more associated with disease than others, but additional work is required to relate this to clinical differences.

CONCLUSIONS

Studies that take into account differences linked to the genetics of both patients and potential pathogens are likely to give better insight into the aetiology of periodontal diseases.

Periodontal profile and presence of periodontal pathogens in young African-Americans from Salvador, Ba, Brazil

This cross-sectional study evaluated the periodontal status and the presence of periodontopathogens in 132 young, black ethnic subjects who live in Salvador/Bahia-Brazil and have never smoked. Periodontal Probing Depth (PPD), Clinical Attachment Level (CAL), Plaque Index (PI) and Gingival Index (GI) were measured and analyzed by ANOVA and Wilcoxon tests (p<0.05) according to gender and age. The presence of A.actinomycetemcomitans, P.gingivalis, E.corrodens and F.nucleatum was determined by PCR and was analyzed by ANOVA, Wilcoxon, Student-t tests (p<0.05). Mean values of PPD and CAL were 2.18 and 1.0mm, respectively. Clinical parameters did not show differences between subjects of varying gender and age. The microbial prevalence was observed to be 95.45% for E.corrodens followed by F.nucleatum with 68.18%, A.actinomycetemcomitans with 45.45% and P gingivalis with 40.9%. An association between the presence of pathogens and gender and age was not observed (p<0.05). PPD, CAL and PI were not associated with P.gingivalis; however, GI appeared in higher frequencies among subjects without P.gingivalis. In this young, black ethnic, Brazilian population, a high percentage (96.96%) of subjects harbored at least one selected periodontal pathogen, but most subjects showed a healthy periodontal status. Further investigations are required to evaluate the actual influence of the presence of these bacterial species.

Subgingival microbiota of periodontally untreated Mexican subjects with generalized aggressive periodontitis

BACKGROUND AND AIM

Specific microbial profiles that may distinguish between generalized aggressive-periodontitis (GAgP) and generalized chronic-periodontitis (GCP) have, to date, not been described. The purpose of the present study was to describe the subgingival microbial composition of Mexican subjects with GAgP and compare it with that of individuals with GCP and periodontal health (PH).

MATERIAL AND METHODS

Seventy-seven subjects with GAgP (n=19), GCP (n=39) and PH (n=19) were selected. Clinical measurements included plaque accumulation, gingival erythema, bleeding on probing, suppuration, pocket depth and attachment level. Up to 28 subgingival plaque samples were obtained from each subject and analysed using the checkerboard DNA-DNA hybridization technique.

RESULTS

GAgP and GCP subjects harboured significantly higher levels and/or proportion of Porphyromonas gingivalis, Tannerella forsythia (levels: p<0.001, proportion: p<0.01), Prevotella nigrescens (p<0.05 levels) and "red" complex species (p<0.001 proportion) than PH subjects. All GAgP subjects were carriers of P. gingivalis and P. nigrescens. No significant differences in any of the 40 microbial species tested were detected between GAgP and GCP subjects.

CONCLUSIONS

Our results revealed that the microbial differences between GAgP and GCP subjects were only discrete and none of the bacterial species tested seemed to specifically differentiate the subgingival microbial profile of either periodontitis group.

Immunoglobulin G subclass antibody profiles in Porphyromonas gingivalis-associated aggressive and chronic periodontitis patients

BACKGROUND/AIMS

The immunoglobulin G (IgG) antibody response is considered to be protective and beneficial for the control of periodontal lesions. This study analysed IgG subclass antibody levels of Porphyromonas gingivalis in patients with both aggressive periodontitis (AgP) and chronic periodontitis (CP).

METHODS

Subgingival plaque and peripheral blood samples were collected from patients with localized AgP (n = 13), generalized AgP (n = 28) and generalized CP (n = 27) and from 14 periodontally healthy controls. P. gingivalis was identified in subgingival pockets using a polymerase chain reaction. Simultaneously, serum IgG subclass antibody against P. gingivalis whole cells/P. gingivalis fimbriae were measured using enzyme-linked immunosorbent assay.

RESULTS

P. gingivalis was frequently detected in periodontitis patients. Anti-P. gingivalis whole cell IgG1 was elevated in all P. gingivalis-positive patients in the three periodontitis groups. Although increased anti-P. gingivalis IgG1 was also observed in the bacterium-positive healthy controls, the level was lower than that found in the three periodontitis groups. Levels of IgG1, IgG2, IgG3 and IgG4 to P. gingivalis did not differ among bacterium-positive patients in the three periodontitis groups; a significant increase of IgG2 level was not observed in localized AgP. Anti-fimbriae IgG subclass levels of IgG1, IgG2 and IgG4 did not differ among bacterium-positive subjects in all groups, while the anti-fimbriae IgG3 level in generalized CP was significantly higher than that in localized and generalized AgP.

CONCLUSIONS

P. gingivalis infection elicited an IgG subclass antibody response in both periodontitis patients and healthy subjects, while higher anti-P. gingivalis IgG1 levels were found in the three periodontitis groups compared with the healthy control group.

The transmission of anaerobic periodontopathic organisms

The oral microbial flora is unique, and available evidence indicates that it is passed vertically from parents to children. In this investigation, we used a chairside assay for the N-benzoyl-DL-arginine-2-naphthylamide (BANA)-sensitive enzyme found in Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythensis, to determine the prevalence of these BANA-positive species in young children and their caregivers. We predicted that if the BANA enzyme was found in plaque samples of children, it would also be present in the plaque samples of the caregivers. Forty-four percent of 150 children had at least one plaque sample positive for the BANA enzyme. If the caregiver was BANA-positive, the odds of the child also being BANA-positive was 35 times more than for a child with a BANA-negative caregiver, after adjustment for the child's age and papillary bleeding score (PBS). Other significant predictors were the PBS of children (p < 0.001), a history of periodontal disease, and the ages of the caregivers (p < 0.001).

Prevalence of periodontal pathogens in Brazilians with aggressive or chronic periodontitis

OBJECTIVES

Previous studies suggest differences between geographically and racially distinct populations in the prevalence of periodontopathic bacteria as well as greater periodontal destruction associated with infection by highly leucotoxic Actinobacillus actinomycetemcomitans. The present study examined these hypotheses in Brazilians with aggressive or chronic periodontitis.

MATERIALS AND METHODS

Clinical, radiographical, and microbiological assessments were performed on 25 aggressive periodontitis and 178 chronic periodontitis patients including 71 males and 132 females, 15-69 years of age.

RESULTS

The prevalence of Porphyromonas gingivalis was similar to that of other South American populations. The prevalence of A. actinomycetemcomitans and its highly leucotoxic subgroup was higher in Brazilians. Highly leucotoxic A. actinomycetemcomitans was more prevalent in aggressive periodontitis (chi2=27.83) and positively associated with deep pockets (>6 mm, chi2=18.26) and young age (<29 years, chi2=18.68). Greater mean attachment loss was found in subjects with highly leucotoxic A. actinomycetemcomitans than in subjects with minimally leucotoxic (p=0.0029) or subjects not infected (p=0.0001).

CONCLUSION

These data support the hypothesis of differences between populations in the prevalence of periodontopathic bacteria and of greater attachment loss in sites infected with highly leucotoxic A. actinomycetemcomitans. Detection of highly leucotoxic A. actinomycetemcomitans in children and adolescents may be a useful marker for aggressive periodontitis.

Characteristics of Periodontal Microflora in Acute Myocardial Infarction

BACKGROUND

Periodontitis has been linked to increased risk of cardiovascular diseases. Systemic reactions associated with cardiovascular events may depend on characteristics of the subgingival microflora in periodontitis. Our objectives were to compare the numbers of cultivable bacteria, composition of subgingival microflora and clonal distribution of Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) in two groups of patients with generalized chronic periodontitis (GCP), one with an acute myocardial infarction (AMI-GCP) and the other one without AMI (non-AMI-GCP).

METHODS

In all, 150 dentate individuals were screened for suitability to this study. Subgingival bacterial samples were collected from 11 AMI-GCP and 11 non-AMI-GCP patients who had been selected using strict inclusion criteria in an attempt to exclude confounding factors and to increase comparability of periodontal conditions by matching for periodontal probing depths and attachment levels. Culture methods were used to determine the total viable counts and occurrence and proportions of six periodontal bacterial species and yeasts. Polymerase chain reaction (PCR) technique was used to detect A. actinomycetemcomitans and Porphyromonas gingivalis (P. gingivalis). Intraspecies characterization of A. actinomycetemcomitans included serotyping and genotyping.

RESULTS

The mean proportions of P. gingivalis (P = 0.05) and Tannerella forsythensis (T. forsythensis) (P = 0.01) were significantly lower, but the numbers of Micromonas micros (M. micros) and A. actinomycetemcomitans were up to nine times higher and the mean total number of cultivable bacteria per sample higher (P <0.01) in AMI-GCP than in non-AMI-GCP.

CONCLUSION

The findings that no target subgingival species were overrepresented but the total bacterial number was higher in AMI-GCP than non-AMI-GCP patients may provide support to the hypothesis that elevated numbers of bacteria in close vicinity to sterile parenteral area present a risk for systemic health.

The Relationship BetweenPorphyromonas gingivalisInfection and Local and Systemic Factors in Children

BACKGROUND

Porphyromonas gingivalis (P. gingivalis) is a major pathogen related to periodontitis. There are few reports on the prevalence and effect of P. gingivalis in children. The purpose of the present study was to describe in children the level of DNA-P gingivalis in subgingival plaque and the IgG serum reactivity to P. gingivalis (IgG-Pg), and examine their relationship to demographic, systemic, and oral variables.

METHODS

Thirty-four children, aged 1.83 to 13.42 years, were included in the study; 16 with no systemic disease and 18 with systemic conditions. The demographic data for caries incidence, plaque and gingival indices, probing depth, and alveolar bone height were recorded. The IgG-Pg and DNA-Pg levels were determined by enzyme-linked immunosorbent assay and DNA-DNA hybridization, respectively. The relationships between the IgG-Pg and DNA-Pg values to the demographics, oral parameters, and systemic conditions were examined.

RESULTS

IgG-Pg was evident in 53% of the children and DNA-Pg in 47%. IgG-Pg values significantly correlated positively with age, plaque index, and bone height. DNA-Pg values had statistically significant positive correlations with age. IgG-Pg and DNA-Pg values correlated with probing depth among children with systemic diseases. Neither the IgG-Pg nor the DNA-Pg values had a significant correlation to systemic conditions. Multiple regression analyses indicated that only age remained significantly related to IgG-Pg and DNA-Pg values.

CONCLUSIONS

P. gingivalis can be found in significant levels in the plaque of young children and elicits an immune reaction that increases with age and may be related to incipient signs of periodontal disease. Plaque DNA-Pg and serum IgG-Pg levels correlate significantly.

Periodontal epidemiology: towards social science or molecular biology?

Terms such as 'molecular epidemiology' and 'genetic epidemiology' have been coined to depict the change from 'traditional epidemiology', concerned with disease determinants at the community or society level, over to 'modern epidemiology', which is concerned with determinants operating at the individual level or even below, i.e. at the organ, tissue, cell, or molecular level. In this commentary, we point out to the limitations of this development and suggest that more emphasis is placed on making the presumed causal disease models explicit, when investigating the relationship between putative determinants and disease. Understanding the disease processes at the micro-level is insufficient for understanding disease at the individual level; and disease patterns at the population level cannot be understood unless it is realized that individuals exist in a variety of contexts that cannot be reduced to individual attributes.

Prevalence of periodontopathic bacteria in aggressive periodontitis patients in a Japanese population

BACKGROUND

Actinobacillus actinomycetemcomitans is considered a major etiologic agent of aggressive periodontitis. Other periodontopathic bacteria such as Porphyromonas gingivalis are also suspected of participating in aggressive periodontitis, although the evidence is controversial. The aim of the present study was to investigate the prevalence of periodontopathic bacteria and to clarify the microbiological features of aggressive periodontitis in Japanese patients.

METHODS

Subgingival plaque was collected from 50 aggressive periodontitis (AgP) patients (localized 10, generalized 40). Samples from 35 generalized chronic periodontitis (CP) patients and 18 healthy subjects were examined as controls. Plaque samples were examined using culture and polymerase chain reaction (PCR) method.

RESULTS

The prevalence of A. actinomycetemcomitans was relatively low in the localized (20%) and generalized (17.5%) AgP patients, with no significant difference observed in detection frequencies between AgP and the control groups (CP 8.6%, healthy 0%). On the other hand, Tannerella forsythensis (formerly Bacteroides forsythus), Campylobacter rectus, P. gingivalis, and Treponema denticola were frequently detected in localized as well as generalized aggressive periodontitis patients. The prevalence and proportion of P. gingivalis correlated with severity of clinical attachment loss in both localized and generalized aggressive periodontitis.

CONCLUSIONS

T. forsythensis, C. rectus, P. gingivalis, and T. denticola were the predominant periodontopathic bacteria of aggressive periodontitis patients in Japan. Although A. actinomycetem- comitans was also detected in AgP patients, the prevalence of this bacterium was much lower than that of P. gingivalis.

Expression of endothelins and their receptors in cells from human periodontal tissues

OBJECTIVE

The present study investigated the presence of ET-1 in gingival crevicular fluid (GCF) from patients with periodontitis, and the expression of endothelins (ETs) and their receptors mRNA in cultured cells from human periodontal tissues.

BACKGROUND

ET was originally discovered as a potent vasoconstrictive peptide from endothelial cells. It has been reported that ETs are produced by various cells besides endothelial cells. ETs are related to inflammatory and sclerotic lesions, such as arteriolosclerosis and hepatic cirrhosis. Therefore, ETs may be involved in periodontal disease. However, the roles of ETs in development and progression of periodontal disease are not clear.

METHODS

ET-1 released from the cultured cells was measured by enzyme-linked immunosorbent assay. mRNA expressions for ETs and their receptors were examined by reverse transcription-polymerase chain reaction and Northern blotting analysis.

RESULTS

ET-1 levels in GCF from patients with periodontitis were higher than those from healthy subjects. Human gingival keratinocytes (HGK) expressed mRNA for ETs and their receptors, ET-Ar and ET-Br. ET-1 mRNA expression and ET-1 peptide production from HGK were enhanced by interleukin-1beta and tumor necrosis factor-alpha.

CONCLUSIONS

These results suggest that ET-1 plays a significant role in periodontal disease.

Three case reports of aggressive periodontitis associated with Porphyromonas gingivalis in younger patients

The terms 'early onset periodontitis' (EOP) and 'juvenile periodontitis' (JP) were replaced by that of 'aggressive periodontitis' in a recent international workshop for the classification of periodontal diseases and conditions. The chief etiologic agent for aggressive periodontitis is considered to be Actinobacillus actinomycetemcomitans in localized juvenile periodontitis. Porphyromonas gingivalis is also mentioned as the etiologic agent of the aggressive periodontitis, although to date its role remains questionable. This communication describes three cases of aggressive periodontitis found to be associated with P. gingivalis but not A. actinomycetemcomitans by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Our findings clarify the role of P. gingivalis as an etiologic agent in this type of periodontitis and confirm its inclusion in the current definition of aggressive periodontitis.

Subgingival microbiota of Brazilian subjects with untreated chronic periodontitis

BACKGROUND

Different periodontopathogenic microbiota have been associated with periodontal diseases in several populations. The present investigation determined the subgingival microbiota of untreated chronic periodontitis Brazilians using the checkerboard DNA-DNA hybridization technique.

METHODS

Twenty-five periodontitis patients (mean age, 41 +/- 2; mean probing depth [PD], 3.3 +/- 0.2; mean attachment level [AL], 3.6 +/- 0.2) with no history of previous periodontal therapy and a control group of 14 healthy subjects (mean age, 34 +/- 0.6; mean PD, 1.8 +/- 0.2; mean AL, 1.7 +/- 0.1) were selected. Measurements of PD, AL, bleeding on probing, plaque accumulation, and suppuration were recorded at 6 sites/tooth. Subgingival plaque samples were obtained from 4 sites in each tooth/subject in both groups. The presence and levels of 41 subgingival species were determined in 4,032 plaque samples using whole genomic DNA probes and the checkerboard method.

RESULTS

Periodontal pathogens, as well as some unusual species (E. faecalis, E. coli and Bartonella sp.), were detected significantly more often and/or in higher levels in the periodontitis group (P < 0.05). Most species were more frequently detected in interproximal sites. B. forsythus, P. gingivalis, E. nodatum, and F. nucleatum ss vincentii showed a significant positive correlation with mean PD and AL (P < 0.05).

CONCLUSIONS

The subgingival microbiota of Brazilians with untreated chronic periodontitis were complex, including high proportions of periodontopathogens commonly found in other populations, as well as some unusual species.

Periodontal disease as a specific, albeit chronic, infection: diagnosis and treatment

Periodontal disease is perhaps the most common chronic infection in adults. Evidence has been accumulating for the past 30 years which indicates that almost all forms of periodontal disease are chronic but specific bacterial infections due to the overgrowth in the dental plaque of a finite number of mostly anaerobic species such as Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola. The success of traditional debridement procedures and/or antimicrobial agents in improving periodontal health can be associated with the reduction in levels of these anaerobes in the dental plaque. These findings suggest that patients and clinicians have a choice in the treatment of this overgrowth, either a debridement and surgery approach or a debridement and antimicrobial treatment approach. However, the antimicrobial approach, while supported by a wealth of scientific evidence, goes contrary to centuries of dental teaching that states that periodontal disease results from a "dirty mouth." If periodontal disease is demonstrated to be a risk factor for cardiovascular disease and stroke, it will be a modifiable risk factor since periodontal disease can be prevented and treated. Since the antimicrobial approach may be as effective as a surgical approach in the restoration and maintenance of a periodontally healthy dentition, this would give a cardiac or stroke patient and his or her physician a choice in the implementation of treatment seeking to improve the patient's periodontal condition so as to reduce and/or delay future cardiovascular events.

Occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in progressive adult periodontitis

BACKGROUND

Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia are the major periodontal bacteria species in most forms of progressive periodontitis in Scandinavia and the United States. The occurrence of periodontal pathogens appears to be different in subjects of different ethnic origin, and geographical factors may influence the distribution of these species.

METHODS

The occurrence of A. actinomycetemcomitans, P. gingivalis, and P. intermedia was determined using a DNA probe in progressive adult periodontitis in Chileans. Sixty patients (mean age 43.6 +/- 8 years) who had not previously received any type of periodontal therapy were selected. Bleeding on probing, probing depth, and clinical attachment level measurements were made with an automated probe. Patients were monitored at 2-month intervals until at least 2 sites exhibited > or =2 mm attachment loss. Two subgingival plaque samples from active sites were taken in 56 subjects and matched with 2 plaque samples from inactive sites in the same individuals.

RESULTS

P. gingivalis was found in 75% of active sites and in 59.7% of inactive sites in 96% of the patients (P = 0.022). P. gingivalis at high levels of detection was significantly more frequent in active sites (48.2%) than in inactive sites (31.2%) (P = 0.014). A. actinomycetemcomitans was detected in 6.25% of active sites and in 12.5% of inactive sites in 11.6% of patients. P. intermedia was found in 33% of patients and at a significantly higher proportion in active sites (49.1%) than in inactive sites (30.3%) (P = 0.006). There was a significantly higher proportion of inactive sites (34.8%) than active sites (19.6%) without any of the 3 pathogens (P = 0.016). Bleeding on probing was significantly more associated with active sites with high levels of P. gingivalis and with active sites with P. intermedia than with inactive sites.

CONCLUSIONS

A high prevalence of P. gingivalis and P. intermedia was found in adult periodontitis, and the occurrence of these bacteria appears to be higher in Chileans than in other populations. No apparent association exists between A. actinomycetemcomitans and progressive adult periodontitis in Chileans.

Human herpesviruses and Porphyromonas gingivalis are associated with juvenile periodontitis

BACKGROUND

Although herpesviruses have been associated with adult periodontitis, their relationship with juvenile periodontitis (JP) has not been established. This case-control study examined possible associations between JP and pathogenic bacteria, the human cytomegalovirus (HCMV), and the Epstein-Barr type 1 virus (EBV-1).

METHODS

Subjects were participants in a larger survey of schoolchildren in North-Central Jamaica. Subgingival plaque samples from 15 subjects with JP, 20 with incipient periodontitis (IP), and 65 randomly-selected healthy controls were assayed for Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans using a 16S rRNA polymerase chain reaction (PCR) identification method, and for HCMV and EBV-1 using nested PCR identification.

RESULTS

Strong bivariate associations were found between JP and P. gingivalis (odds ratio [OR] = 12.7; 95% CI = 2.6, 61.4), HCMV (OR = 10.0; 95% CI = 2.7, 36.3), and A. actinomycetemcomitans (OR = 8.0; 95% CI = 2.3, 27.5), but not EBV-1. In multivariate analyses, P. gingivalis remained a significant explanatory variable (OR = 7.8; 95% CI = 1.5, 40.9); however, the associations were marginal for HCMV (OR = 4.6; 95% CI = 0.9, 22.7), and non-significant for A. actinomycetemcomitans (OR = 2.0; 95% CI = 0.4, 9.7). The associations with JP and the extent of attachment loss were even stronger when both P. gingivalis and HCMV were detected together. P. gingivalis (OR = 3.9; 95% CI = 1.3, 12.0) and EBV-1 (OR = 3.3; 95% CI = 1.0, 10.3) were the only significant explanatory variables in the multivariate analysis of IP.

CONCLUSIONS

P. gingivalis is the strongest and most stable indicator of periodontitis in Jamaican adolescents. Co-infection with P. gingivalis and HCMV appears to be particularly deleterious to periodontal health.

Activation of arachidonate release and cytosolic phospholipase A2 via extracellular signal-regulated kinase and p38 mitogen-activated protein kinase in macrophages stimulated by bacteria or zymosan

The mitogen-activated protein kinases (MAP kinases), extracellular signal-regulated kinase (ERK) and p38, can both contribute to the activation of cytosolic phospholipase A2 (cPLA2). We have investigated the hypothesis that ERK and p38 together or independent of one another play roles in the regulation of cPLA2 in macrophages responding to the oral bacterium Prevotella intermedia or zymosan. Stimulation with bacteria or zymosan beads caused arachidonate release and enhanced in vitro cPLA2 activity of cell lysate by 1.5- and 1.7-fold, respectively, as well as activation of ERK and p38. The specific inhibitor of MAP kinase kinase, PD 98059, and the inhibitor of p38, SB 203580, both partially inhibited cPLA2 activation and arachidonate release induced by bacteria and zymosan. Together, the two inhibitors had additive effects and completely blocked cPLA2 activation and arachidonate release. The present results demonstrate that ERK and p38 both have important roles in the regulation of cPLA2 and together account for its activation in P. intermedia and zymosan-stimulated mouse macrophages.

No association with HLA-DQB1 in European Caucasians with early-onset periodontitis

Periodontitis is a chronic inflammatory disease of the supporting tissues of the teeth that may ultimately result in tooth loss. The human leukocyte antigen (HLA) complex plays an important role in immune responsiveness and may be involved in antigen recognition of periodontal pathogens. A recent report of a Japanese population found an association between an atypical BamHI site in the HLA-DQB1 gene and a severe form of early-onset periodontitis (EOP). The aim of the present study was to test for the existence of the site in a European Caucasian EOP population using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. No statistically significant differences were found between the patients and controls with regard to the presence of the BamHI site. It was concluded that this lack of association could reflect racial genetic variation in HLA allelic frequencies.

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.

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.

Immunoglobulin allotypes and immunoglobulin G subclass responses to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in early-onset periodontitis

The present study was performed to estimate the observed frequencies of the immunoglobulin heavy-chain (Gm) and light-chain (Km) allotypes among patients with early-onset periodontitis (EOP) and their effect on the IgG2 subclass responses against Actinobacillus actinomycetemcomitans Y4 and Porphyromonas gingivalis 381, respectively. Sixty-nine EOP patients, including 11 with localized juvenile periodontitis (LJP), 19 who had LJP, 15 with LJP-rapidly progressing periodontitis (RPP), and 24 with RPP, were examined for the Gm and Km allotypes by a hemagglutination inhibition test. Levels of immunoglobulin G2 (IgG2) antibodies against the two organisms were determined by enzyme-linked immunosorbent assay. Fifty race- and age-matched, periodontally healthy subjects were also included as a control group. The observed frequencies of the Gm haplotype afnb and Km(1) were significantly higher in the RPP and LJP groups, respectively. The G2m(n)+ group of those with RPP and the Km(1)+ group of those with LJP had significantly higher levels of IgG2 antibodies to A. actinomycetemcomitans and P. gingivalis, respectively. The results indicate that linkage disequilibrium of the G2m(n) locus in RPP patients or the Km(1) locus in LJP patients may be associated with high IgG2 antibody responses to the respective bacteria. It was reasoned that the IgG2 antibody responses are associated with the immunoglobulin allotypes. The function of IgG2 antibodies in their reaction to different bacterial antigens may be interpreted as either protective or nonprotective in the two different types of EOP (i.e., LJP and RPP).