Interleukin Gene Variability and Periodontal Bacteria in Patients with Generalized Aggressive Form of Periodontitis.

Host genetic predispositions to dysregulated immune response can influence the development of the aggressive form of periodontitis (AgP) through susceptibility to oral dysbiosis and subsequent host-microbe interaction. This case-control study aimed to perform a multilocus analysis of functional variants in selected interleukin (IL) genes in patients with the generalized form of AgP in a homogenous population. Twelve polymorphisms in IL-1 gene cluster, IL-6 and its receptor, IL-10, IL-17A, and IL-18 were determined in 91 AgP patients and 210 controls. Analysis of seven selected periodontal bacteria in subgingival sulci/pockets was performed with a commercial DNA-microarray kit in a subgroup of 76 individuals. The pilot in vitro study included stimulation of peripheral blood monocytes (PBMC) from 20 individuals with periodontal bacteria and measurement of IL-10 levels using the Luminex method. Only the unctional polymorphism IL­10-1087 A/G (rs1800896) and specific IL-10 haplotypes were associated with the development of the disease (P < 0.05, Pcorr > 0.05). Four bacterial species occurred more frequently in AgP than in controls (P < 0.01, Pcorr < 0.05). Elevated IL-10 levels were found in AgP patients, carriers of IL­10-1087GG genotype, and PBMCs stimulated by periodontal bacteria (P < 0.05, Pcorr > 0.05). We therefore conclude that a combination of genetic predisposition to the altered expression of IL-10 and the presence of specific periodontal bacteria may contribute to Th1/Th2 balance disruption and AgP development.

Aggressive periodontitis and NOD2 variants.

Aggressive periodontitis (AgP) occurs at an early age and causes rapid periodontal tissue destruction. Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) encodes a protein with two caspase recruitment domains and eleven leucine-rich repeats. This protein is expressed mainly in peripheral blood leukocytes and is involved in immune response. NOD2 variants have been associated with increased susceptibility to Crohn's disease, and recently, NOD2 was reported as a causative gene in AgP. The present study aimed to identify potential NOD2 variants in an AgP cohort (a total of 101 patiens: 37 patients with positive family histories and 64 sporadic patients). In the familial group, six patients from two families had a reported heterozygous missense variant (c.C931T, p.R311W). Four patients in the sporadic group had a heterozygous missense variant (c.C1411T, p.R471C), with no reported association to the disease. Overall, two NOD2 variants, were identified in 10% of our AgP cohort. These variants were different from the major variants reported in Crohn's disease. More cases need to be investigated to elucidate the role of NOD2 variants in AgP pathology.

Hidden noise in immunologic parameters might explain rapid progression in early-onset periodontitis.

To investigate in datasets of immunologic parameters from early-onset and late-onset periodontitis patients (EOP and LOP), the existence of hidden random fluctuations (anomalies or noise), which may be the source for increased frequencies and longer periods of exacerbation, resulting in rapid progression in EOP. Principal component analysis (PCA) was applied on a dataset of 28 immunologic parameters and serum IgG titers against periodontal pathogens derived from 68 EOP and 43 LOP patients. After excluding the PCA parameters that explain the majority of variance in the datasets, i.e. the overall aberrant immune function, the remaining parameters of the residual subspace were analyzed by computing their sample entropy to detect possible anomalies. The performance of entropy anomaly detection was tested by using unsupervised clustering based on a log-likelihood distance yielding parameters with anomalies. An aggregate local outlier factor score (LOF) was used for a supervised classification of EOP and LOP. Entropy values on data for neutrophil chemotaxis, CD4, CD8, CD20 counts and serum IgG titer against Aggregatibacter actinomycetemcomitans indicated the existence of possible anomalies. Unsupervised clustering confirmed that the above parameters are possible sources of anomalies. LOF presented 94% sensitivity and 83% specificity in identifying EOP (87% sensitivity and 83% specificity in 10-fold cross-validation). Any generalization of the result should be performed with caution due to a relatively high false positive rate (17%). Random fluctuations in immunologic parameters from a sample of EOP and LOP patients were detected, suggesting that their existence may cause more frequently periods of disease activity, where the aberrant immune response in EOP patients result in the phenotype "rapid progression".

Aggregatibacter actinomycetemcomitans (Aa) Under the Radar: Myths and Misunderstandings of Aa and Its Role in Aggressive Periodontitis.

Aggregatibacter actinomycetemcomitans (Aa) is a low-abundance Gram-negative oral pathobiont that is highly associated with a silent but aggressive orphan disease that results in periodontitis and tooth loss in adolescents of African heritage. For the most part Aa conducts its business by utilizing strategies allowing it to conceal itself below the radar of the host mucosal immune defense system. A great deal of misinformation has been conveyed with respect to Aa biology in health and disease. The purpose of this review is to present misconceptions about Aa and the strategies that it uses to colonize, survive, and evade the host. In the process Aa manages to undermine host mucosal defenses and contribute to disease initiation. This review will present clinical observational, molecular, and interventional studies that illustrate genetic, phenotypic, and biogeographical tactics that have been recently clarified and demonstrate how Aa survives and suppresses host mucosal defenses to take part in disease pathogenesis. At one point in time Aa was considered to be the causative agent of Localized Aggressive Periodontitis. Currently, it is most accurate to look at Aa as a community activist and necessary partner of a pathogenic consortium that suppresses the initial host response so as to encourage overgrowth of its partners. The data for Aa's activist role stems from molecular genetic studies complemented by experimental animal investigations that demonstrate how Aa establishes a habitat (housing), nutritional sustenance in that habitat (food), and biogeographical mobilization and/or relocation from its initial habitat (transportation). In this manner Aa can transfer to a protected but vulnerable domain (pocket or sulcus) where its community activism is most useful. Aa's "strategy" includes obtaining housing, food, and transportation at no cost to its partners challenging the economic theory that "there ain't no such thing as a free lunch." This "strategy" illustrates how co-evolution can promote Aa's survival, on one hand, and overgrowth of community members, on the other, which can result in local host dysbiosis and susceptibility to infection.

One-year follow-up of the immune profile in serum and selected sites of generalized and localized aggressive periodontitis.

BACKGROUND: The local and systemic immunological profiles of important inflammatory mediators in the localized (LAgP) and generalized (GAgP) forms of aggressive periodontitis are still unknown, as well as the effect of periodontal therapy on these parameters. The aim of this prospective study was to evaluate clinical and immune responses of patients with AgP undergoing nonsurgical treatment. MATERIAL AND METHODS: Eighteen patients with GAgP, 10 with LAgP and 10 healthy participants were included in this study. AgP participants were submitted to scaling and root planing plus systemic antibiotics (amoxicillin and metronidazole). At baseline and 1-year follow-up were measured clinical parameters, such as probing depth [PD] and clinical attachment loss [CAL], and the levels of 10 immunological mediators (GM-CSF, M-CSF, MCP-1, ICAM-1, CXCL8, IL-1ß, TNF-α, IL-17, IL-4, and IL-10) in the gingival crevicular fluid (GCF) of selected sites [AgP forms: PD ≥ 6 mm or the deepest, bleeding on probing (BoP) and bone loss measured by periapical radiography; healthy individuals: PD ≤ 3 mm, no BoP, no bone loss] and serum. RESULTS: After periodontal treatment both forms of AgP presented a significant reduction of PD and CAL, an increase of GM-CSF, ICAM-1, MCP-1, TNF-α, IL-17, IL-4, and IL-10 in the GCF, as well as of GM-CSF and IL-4 in the serum, and a reduction in the serum concentration of IL-1ß. Serum levels of M-CSF, ICAM-1, and MCP-1 remained significantly below those found in healthy individuals in both forms of AgP even after therapy. An increase in the systemic or local levels of MCP-1, ICAM-1 and the anti-inflammatory profile (IL-4, IL-10) was correlated with an improvement in clinical parameters of LAgP patients. Also, a local reduction of IL-1ß levels in both forms of AgP was correlated with an increase in the clinical attachment gain. CONCLUSION: Nonsurgical periodontal therapy was successful in improving clinical parameters and modulating the immune response in both forms of AgP. However, this therapeutic approach does not seem to affect the deficient level of important serum mediators involved in mechanisms of cell transmigration.

Comparative analysis of immune cell subsets in peripheral blood from patients with periodontal disease and healthy controls.

Periodontitis is a chronic inflammatory disease caused by the colonization of teeth by the bacterial plaque biofilm and the resultant host immune responses in adjacent periodontal tissues. Disease severity can vary dramatically between patients with periodontitis, with some subjects displaying inflammation without bony destruction (gingivitis), while others experience chronic progressive or rapidly aggressive gingival connective tissue damage and bone loss. To determine whether peripheral immune dysregulation is associated with periodontitis, we performed extensive analysis of immune cell subsets in peripheral blood from patients with chronic or aggressive periodontitis versus periodontally healthy control subjects. Peripheral blood mononuclear cells (PBMC) from patients with chronic periodontitis or aggressive periodontitis and from periodontally healthy controls were analysed by 8-10-colour flow cytometry for the frequencies of various lymphocyte subsets, including interleukin (IL)-17-, interferon (IFN)-γ-, tumour necrosis factor (TNF)-α- and IL-10-producing cells, and the frequencies and phenotype of monocytes. Cytokine levels in serum from the different groups were determined by Luminex assay. We found no significant differences in the frequencies of major immune cell populations [CD4+ T cells, CD8+ T cells, γδ T cells, CD4+ CD45RO+ CD25+ CD127low regulatory T cells (Tregs ), CD19+ B cells, CD14+ monocytes] or of cytokine-producing T cells, or in the phenotype of CD14+ monocytes in peripheral blood from these patient cohorts. Additionally, no significant differences were observed in serum levels of prototypical inflammatory cytokines. These results suggest that the local gingival inflammatory response is not reflected by obvious changes in major blood immune cell subset frequencies.

Aggregatibacter (Actinobacillus) actimycetemcomitans leukotoxin and human periodontitis - A historic review with emphasis on JP2.

Aggregatibacter (Actinobacillus) actimycetemcomitans (Aa) is a gram-negative bacterium that colonizes the human oral cavity and is causative agent for localized aggressive (juvenile) periodontitis (AgP). In the middle of 1990s, a specific JP2 clone of belonging to the cluster of serotype b strains of Aa with highly leukotoxicity (leukotoxin, LtxA) able to kill human immune cells was isolated. JP2 clone of Aa was strongly associated with in particularly in rapidly progressing forms of aggressive periodontitis. The JP2 clone of Aa is transmitted through close contacts. Therefore, AgP patients need intense monitoring of their periodontal status as the risk for developing severely progressing periodontitis lesions are relatively high. Furthermore, timely periodontal treatment, including periodontal surgery supplemented by the use of antibiotics, is warranted. More importantly, periodontal attachment loss should be prevented by early detection of the JP2 clone of Aa by microbial diagnosis testing and/or preventive means.

Dental implants in a patient with suspected leucocyte adhesion deficiency.

Aggressive periodontitis and premature tooth loss in leucocyte adhesion deficiency (LAD) have adverse functional and psychological consequences on affected individuals. Dental implant rehabilitation might become necessary to overcome the functional and psychological adverse effects of LAD periodontitis, especially in patients with milder forms who are expected to have a relatively normal life expectancy. Outcome of dental implants in patients with LAD has not been previously reported; we describe the dental rehabilitation of a 24-year-old man with clinical features of LAD using endosseous dental implants.

Cytokine profile in gingival crevicular fluid and plasma of patients with aggressive periodontitis.

OBJECTIVE: This study aimed to determine the content of cytokines in gingival crevicular fluid (GCF) as well as in plasma of Sudanese patients with aggressive periodontitis (AgP) and healthy controls (HC). MATERIALS AND METHODS: Nineteen AgP patients and 19 HC were included. The mean probing pocket depth and clinical attachment level of the GCF sampled sites in patients were both ≥5 mm. The GCF and plasma levels of 27 cytokines were determined using 27-multiplex fluorescent bead-based immunoassays. Ratios were calculated among cytokines of the T-helper cell subsets Th1 and Th2. Descriptive statistics, the Mann-Whitney U-test and Spearman's rho rank correlation coefficient analysis were used. RESULTS: Interferon-γ was the only cytokine found in significantly lower levels in GCF of patients compared with HC. Levels of interleukin (IL)-10, IL-13, IL-1Ra, monocyte chemoattractant protein-1 (MCP-1), regulated on activation normal T-cell expressed and secreted (RANTES), granulocyte-colony-stimulating factor (G-CSF), and granulocyte-macrophage-CSF (GM-CSF) were significantly lower in plasma of AgP compared with HC. The ratios of Th1:Th2 in GCF and Treg:Th17 in plasma were significantly lower in AgP. CONCLUSIONS: The lower levels of cytokines detected systemically in plasma of AgP patients may have an impact on the immune response. The lower ratio of Th1:Th2 cytokines in GCF samples of AgP patients suggests a role for Th2 at the local site of disease.

Epigenetic regulation of inflammation in localized aggressive periodontitis.

BACKGROUND: We have previously demonstrated a Toll-like receptor (TLR)-mediated hyper-responsive phenotype in our cohort of localized aggressive periodontitis (LAP) individuals. However, mechanisms related to this phenotype are still not clear in the literature. The objective of this cross-sectional study is to examine the role of epigenetic regulation, specifically DNA methylation status of genes in the TLR pathway in this cohort. Peripheral blood was collected from 20 LAP patients and 20 healthy unrelated controls. Whole blood was stimulated with 1 µl (100 ng/µl) of purified Escherichia coli lipopolysaccharide (LPS) for 24 h and cyto/chemokines in the supernatants analyzed by Luminex multiplex assays. Genomic DNA extracted from buffy coats prepared from a second tube of whole blood was used for DNA methylation analysis by pyrosequencing of seven TLR signaling genes (FADD, MAP3K7, MYD88, IL6R, PPARA, IRAK1BP1, RIPK2). RESULTS: Significant differences in the methylation status were observed at specific CpG positions in LAP patients compared to healthy controls and interestingly also between severe and moderate LAP. Specifically, subjects with moderate LAP presented hypermethylation of both the upregulating (MAP3K7, MYD88, IL6R, and RIPK2) and downregulating (FADD, IRAK, and PPARA) genes, while severe LAP presented hypomethylation of these genes. Further analysis on CpG sites with significant differences in methylation status correlates with an increased pro-inflammatory cytokine profile for LAP patients. CONCLUSIONS: Our findings suggest that epigenetic modifications of genes in the TLR pathway may orchestrate the thresholds for balancing induction and prevention of tissue destruction during the course of disease, and thus differ significantly at different stages of the disease, where moderate LAP shows hypermethylation and severe LAP shows hypomethylation of several genes. TRIAL REGISTRATION: https://clinicaltrials.gov, NCT01330719.

Salivary and Serum Markers Related to Innate Immunity in Generalized Aggressive Periodontitis.

BACKGROUND: Host inflammatory and immune responses play an important role in aggressive periodontitis (AgP). Thus, this study aims to evaluate levels of the innate immunity-related markers calprotectin, colony-stimulating factor (CSF)-1, macrophage migration inhibitory factor (MIF), monokine induced by interferon-γ (MIG), and matrix metalloproteinase (MMP)-8 in serum and saliva from patients with generalized AgP and those with gingivitis or a healthy periodontium. METHODS: This study enrolled 40 individuals (17 males and 23 females; mean age 33.30 ± 9.31 years), 15 with generalized AgP, 15 with gingivitis, and 10 who were periodontally healthy. Full-mouth periodontal examinations were performed, and serum and saliva were collected. Levels of calprotectin, CSF-1, MIF, MIG, and MMP-8 were measured using enzyme-linked immunosorbent assays. RESULTS: In serum, mean levels of calprotectin were 2.06-fold higher in patients with AgP than in healthy patients (P = 0.01). Serum levels of MMP-8 were significantly elevated in patients with AgP compared with both healthy patients and those with gingivitis, by 2.60-fold and 2.77-fold, respectively (P = 0.03 and P = 0.009, respectively). In saliva, levels of MMP-8 were 5.66-fold higher in patients with AgP than in healthy patients (P = 0.02). CSF-1, MIF, and MIG levels in both serum and saliva did not differ significantly among the groups. CONCLUSIONS: Serum levels of calprotectin and MMP-8 are elevated in patients with AgP. MMP-8 levels are also increased in saliva from patients with AgP. These results support involvement of innate immune response in the pathogenesis of AgP.

Aggressive periodontitis: The unsolved mystery.

Aggressive periodontal disease is an oral health mystery. Our current understanding of this disease is that specific bacteria invade the oral cavity and the host reacts with an inflammatory response leading to mass destruction of the alveolar bone. Aggressive periodontal disease is typically observed in a population under the age of 30 and occurs so rapidly that it is difficult to treat. Unfortunately, the consequence of this disease frequently involves tooth extractions. As a result, the aftermath is chewing disability and damage to self-esteem due to an altered self-image. Furthermore, patients are encumbered by frequent dental appointments which have an economic impact in regards to both personal financial strain and absent days in the workplace. Aggressive periodontal disease has a tremendous effect on patients' overall quality of life and needs to be investigated more extensively in order to develop methods for earlier definitive diagnosis and effective treatments. One of the mysteries of aggressive periodontal disease is the relatively nominal amount of plaque present on the tooth surface in relation to the large amount of bone loss. There seems to be a hidden factor that lies between the response by the patient's immune system and the bacterial threat that is present. A better mechanistic understanding of this disease is essential to provide meaningful care and better outcomes for patients.

The role of platelets in inflammatory immune responses in generalized aggressive periodontitis.

AIM: To investigate the relationship between inflammatory markers and platelet size in generalized aggressive periodontitis (GAgP). MATERIAL AND METHODS: Periodontal, inflammatory and platelet indices were compared between 59 GAgP patients and 59 healthy subjects. Gingival biopsies from five patients and five healthy subjects were examined by immunohistochemistry and electron microscopy. Changes in patient periodontal and platelet indices were re-evaluated at 3 months after periodontal therapy. RESULTS: Platelet size was decreased significantly in GAgP patients compared to healthy subjects (p ≤ 0.003). Weak negative correlations between platelet size and periodontal parameters were found in GAgP patients (p ≤ 0.025). Platelet aggregates and adhesion to the endothelium or leucocytes were found in venules and connective tissues of gingival biopsies from GAgP patients. Mean platelet volume (MPV) and platelet large cell ratio increased after periodontal therapy in GAgP patients (p ≤ 0.038). The increase in MPV was related to the decrease in bleeding index in GAgP patients after periodontal therapy (p < 0.001; r = 0.357). CONCLUSION: Platelet size was reduced in GAgP patients compared to healthy controls, possibly due to the consumption of large platelets at sites of periodontal inflammation. Platelets may be involved in host responses to periodontal infection in GAgP.

Gingival crevicular fluid and serum hCAP18/LL-37 levels in generalized aggressive periodontitis.

OBJECTIVES: hCAP18/LL-37 is an endogenous antibiotic having a role in innate immunity. The aim of the present study was to evaluate serum and gingival crevicular fluid (GCF) hCAP18/LL-37 levels in patients with generalized aggressive periodontitis (G-AgP). MATERIALS AND METHODS: Twenty-six G-AgP patients, 24 gingivitis patients, and 25 healthy subjects were included in this study. Periodontal parameters including probing depth, clinical attachment level, plaque index, and papilla bleeding index were recorded. GCF and serum hCAP18/LL-37 levels were analyzed by enzyme-linked immunosorbent assay. RESULTS: GCF hCAP18/LL-37 level was significantly higher in G-AgP compared to others (p = 0.038, p < 0.001). Gingivitis patients had significantly higher GCF hCAP18/LL-37 levels than controls (p < 0.001). No significant differences were observed in serum hCAP18/LL-37 levels among the study groups (p = 0.524). While there were positive correlations between GCF hCAP18/LL-37 levels and periodontal parameters of sampling sites (p < 0.005), no significant correlation was observed between serum hCAP18/LL-37 levels and whole-mouth periodontal parameters (p > 0.05). CONCLUSION: Increased levels of GCF hCAP18/LL-37 in G-AgP might show that it is abundantly expressed in the presence of periodontal tissue destruction. Serum hCAP18/LL-37 levels do not seem to be related with the presence of G-AgP. CLINICAL RELEVANCE: hCAP18/LL-37 antimicrobial peptide might be associated with periodontal tissue destruction in the presence of aggressive periodontitis.

Platelet activation and platelet-leukocyte interaction in generalized aggressive periodontitis.

Generalized aggressive periodontitis (GAgP) is an inflammatory disease of host response to bacterial challenge. To explore the role of platelets in host-microbial interactions in patients with periodontitis, 124 patients with GAgP and 57 healthy subjects were enrolled. Reliable indicators of subclinical platelet functional status, platelet count (PLT), platelet large cell ratio (PLCR), and mean platelet volume (MPV), were significantly lower in the GAgP group than in the control group and were negatively correlated with clinical periodontal parameters. The levels of important cytosolic protein in neutrophils, calprotectin (S100A8/A9) in plasma, and gingival crevicular fluid (GCF) were significantly higher in patients with GAgP compared with healthy subjects. Moreover, the GCF calprotectin level was negatively correlated with PLCR and MPV values. To explore the possible mechanisms of changes in platelet indices in periodontitis, flow cytometry analysis was performed, and patients with GAgP were found to have a higher status of platelet activation compared with healthy controls. Porphyromonas gingivalis (P. gingivalis) and recombinant human S100A8/A9 (rhS100A8/A9) induced platelet activation and facilitated platelet-leukocyte aggregate formation in whole blood of healthy subjects. In response to P. gingivalis and rhS100A8/A9, platelets from patients with GAgP increased activation and increased formation of platelet-leukocyte aggregates compared with those from healthy subjects. Platelet aggregates and platelets attached to leukocytes were found on gingival tissues from patients with GAgP, suggesting that decreased platelet size and count in the circulation might be related to consumption of large, activated platelets at inflamed gingiva. Platelets may have a previously unrecognized role in host response to periodontal infection.

Gingival Inflammation and Aggressive Periodontitis in a Child with a Specific Antibody Deficiency.

Exuberant gingival inflammation accompanied by periodontitis is a rare finding in a very young child and may indicate a defect in the host response. Affected children should be referred to appropriate specialists to establish a definitive diagnosis. A 5-year-old girl presented with persistent gingival inflammation and periodontal destruction. Immunological investigations identified specific polysaccharide antibody deficiency which, when treated, resulted in a significant improvement in the gingival condition. This case illustrates the need for integrated management by a wide range of dental and medical specialists. Antibody deficiency is rare but, if not identified and treated effectively, can be associated with chronic ill health and decreased life expectancy. CPD/Clinical Relevance: This article describes a rare case of gingival inflammation accompanied by periodontitis in a very young child secondary to an underlying host antibody deficiency and details the investigation, management and clinical outcomes.

Is there a common pathogenesis in aggressive periodontitis & ankylosing spondylitis in HLA-B27 patient?

HLA-B27 is having strong association to ankylosing spondylitis (AS) and other inflammatory diseases collectively known as seronegative spondyloarthropathy. In literature, although the evidence for association between AS and periodontitis as well as AS and HLA-B27 are there but the association of aggressive periodontitis in HLA-B27 positive patient with AS are not there. We hypothesize that there may be a common pathogenesis in aggressive periodontitis and ankylosing spondylitis in HLA-B27 patient. A 27-years-old female presented with the features of generalized aggressive periodontitis and difficulty in walking. On complete medical examination, ankylosing spondylitis was diagnosed with further positive HLA-B27 phenotype and negative rheumatic factor. This report may open up a new link to explore in the pathogenesis of aggressive periodontitis.

Inflammatory Response Influences Treatment of Localized Aggressive Periodontitis.

We previously reported a systemic hyperinflammatory response to bacterial lipopolysaccharide (LPS) in children with localized aggressive periodontitis (LAP). Additionally, different levels of this response were observed within the LAP group. It is unknown whether this hyperinflammatory response influences the clinical response to periodontal treatment in these children. Therefore, the goal of this study was to evaluate the influence of LPS responsiveness present prior to treatment on the clinical response to treatment within the LAP cohort. Prior to treatment, peripheral blood was collected from 60 African American participants aged 5 to 21 y, free of systemic diseases, and diagnosed with LAP. Blood was stimulated with ultrapure LPS from Escherichia coli, and Luminex assays were performed to quantify 14 cytokine/chemokine levels. Principal component and cluster analyses were used to find patterns of cytokine/chemokine expression among participants and subdivide them into clusters. Three distinct clusters emerged among LAP participants: a high responder group (high level of response for INFg, IL6, and IL12p40), a mixed responder group (low for some and high for other cytokines/chemokines), and a low responder group (low overall cytokine/chemokine response). Periodontal clinical parameters were compared among these groups prior to and 3, 6, and 12 mo following treatment with mechanical debridement and systemic antibiotics. High responders presented the lowest reductions in clinical parameters after treatment, whereas the low responders presented the highest reductions. In our LAP participants, distinct patterns of LPS response were significantly predictive of changes in clinical parameters after treatment. Future studies are needed to evaluate the underlying mechanisms predicting the heterogeneity of LAP activity, severity, and response to treatment (ClinicalTrials.gov NCT01330719).

Aggregatibacter actinomycetemcomitans, a potent immunoregulator of the periodontal host defense system and alveolar bone homeostasis.

Aggregatibacter actinomycetemcomitans is a perio-pathogenic bacteria that has long been associated with localized aggressive periodontitis. The mechanisms of its pathogenicity have been studied in humans and preclinical experimental models. Although different serotypes of A. actinomycetemcomitans have differential virulence factor expression, A. actinomycetemcomitans cytolethal distending toxin (CDT), leukotoxin, and lipopolysaccharide (LPS) have been most extensively studied in the context of modulating the host immune response. Following colonization and attachment in the oral cavity, A. actinomycetemcomitans employs CDT, leukotoxin, and LPS to evade host innate defense mechanisms and drive a pathophysiologic inflammatory response. This supra-physiologic immune response state perturbs normal periodontal tissue remodeling/turnover and ultimately has catabolic effects on periodontal tissue homeostasis. In this review, we have divided the host response into two systems: non-hematopoietic and hematopoietic. Non-hematopoietic barriers include epithelium and fibroblasts that initiate the innate immune host response. The hematopoietic system contains lymphoid and myeloid-derived cell lineages that are responsible for expanding the immune response and driving the pathophysiologic inflammatory state in the local periodontal microenvironment. Effector systems and signaling transduction pathways activated and utilized in response to A. actinomycetemcomitans will be discussed to further delineate immune cell mechanisms during A. actinomycetemcomitans infection. Finally, we will discuss the osteo-immunomodulatory effects induced by A. actinomycetemcomitans and dissect the catabolic disruption of balanced osteoclast-osteoblast-mediated bone remodeling, which subsequently leads to net alveolar bone loss.

Amoxicillin/metronidazole associated with nonsurgical therapy did not promote additional benefits in immunologic parameters in generalized aggressive periodontitis: A randomized controlled clinical trial.

OBJECTIVE: This randomized, blinded, placebo-controlled clinical trial compared the levels of interferon γ (IFN-γ), prostaglandin E2 (PGE2), and interleukin 6 (IL-6) in the gingival crevicular fluid (GCF) from generalized aggressive periodontitis (GAgP) patients treated with nonsurgical therapy associated or not with amoxicillin/metronidazole adjunctive. METHOD AND MATERIALS: Thirty-nine GAgP patients were followed during 6 months. The patients were randomly allocated to one of the groups: experimental (scaling and root planing plus 375 mg amoxicillin and 250 mg metronidazole for 7 days) and control (scaling and root planing + placebo). Probing pocket depth (PPD), relative clinical attachment level (rCAL), gingival margin position (GMP), and IL-6, IFN-γ, and PGE2 levels in GCF were evaluated at baseline, and at 3 and 6 months after treatment. RESULTS: Both therapies promoted PPD reductions, rCAL gains, and recession in GMP at the end of the study, with the experimental group presenting an additional PPD reduction in fullmouth analysis and deep pockets at the 3- and 6-month follow-ups (P < .05). During the period of the study, only the experimental group promoted a reduction in PGE2 levels in deep pockets at 3 and 6 months, while IFN-γ and IL-6 levels remained unchanged. However, the differences in the immunologic parameters were not statistically significant among the groups. CONCLUSION: It can be concluded that amoxicillin/ metronidazole associated with nonsurgical therapy promotes an additional PPD reduction in the treatment of GAgP; however, this therapy did not promote additional benefits in the evaluated immunologic parameters.