Flow cytometric evaluation of phagocytosis by peripheral blood polymorphonuclear leucocytes in human periodontal diseases

Neutrophil priming: Implications in periodontal disease

Periodontal disease is a well-regulated response to bacterial infection directed by the inflammatory cells of the host immune system. The host response to injury or insult is implicated to be a vital feature of the majority of periodontal diseases. The excessive activation of neutrophils plays a role in the pathogenesis in diseases such as acute respiratory distress syndrome, rheumatoid arthritis, and periodontitis by contributing to inflammatory tissue injury. In the recent times, there has been a shift of paradigm from a hypo- to hyper-responsive/primed model of neutrophil dysfunction in periodontal etiopathogenesis. The aim of this review is to outline the mechanisms and effects of neutrophil priming, and thereafter, discuss the current controversy that exists regarding the role of primed neutrophils in periodontal etiopathogenesis.

The gingival crevicular fluid levels of interleukin-11 and interleukin-17 in patients with aggressive periodontitis

BACKGROUND

The balance (ratio) of anti-inflammatory and proinflammatory cytokines is thought to play an important role in the pathogenesis of chronic periodontitis. Moreover, the imbalance of anti-inflammatory/proinflammatory cytokines may modulate disease progression in aggressive periodontitis (AgP). This study aims to investigate the levels of interleukin (IL)-11 and IL-17 and their ratio in gingival crevicular fluid (GCF) in patients with AgP.

METHODS

This study included 20 patients with generalized AgP (GAgP) and 18 healthy controls (HC). For each patient, the values of clinical parameters, such as gingival index, plaque index, probing depth, and clinical attachment level, were recorded. Levels of IL-11 and IL-17 in GCF samples were evaluated using enzyme-linked immunosorbent assay. The values of clinical parameters, cytokine levels, and the ratios of cytokines were evaluated.

RESULTS

The values of all the clinical parameters were significantly higher in the GAgP group than in the HC group (P < 0.001). The total amount and concentration of IL-11 and the concentration of the IL-17 and IL-11/IL-17 ratio were significantly lower in the GAgP group than in the HC group (P < 0.001). The total amount of IL-17 was not significantly different between the groups (P = 0.317).

CONCLUSIONS

The IL-11/IL-17 ratio was decreased in the GAgP group because of the decreased IL-11 levels. The IL-11/IL-17 axis and the link between IL-17 and neutrophil function disorders in AgP should be investigated to clarify the role of the IL-11/IL-17 axis and its balance and imbalance in the pathogenesis of AgP.

Relationship of neutrophil phagocytosis and oxidative burst with the subgingival microbiota of generalized aggressive periodontitis

INTRODUCTION

Polymorphonuclear neutrophil (PMN) dysfunctions have been associated with severe forms of periodontitis. This study evaluated the correlation between PMN phagocytosis and oxidative burst with the subgingival microbiota of patients with generalized aggressive periodontitis (GAgP).

METHODS

Heparinized peripheral blood samples were obtained from 18 GAgP patients and 11 periodontally healthy (PH) subjects, and PMNs were isolated on a Ficoll-Hypaque gradient. For phagocytosis analysis, PMNs were incubated with fluorescein-labeled Staphylococcus aureus. The oxidative burst was evaluated by incubation of PMNs with dihydroethidium and activation by S. aureus. The assays were examined using flow cytometry. Subgingival biofilm samples were obtained from periodontal sites with and without periodontitis and 24 species were detected by checkerboard.

RESULTS

A significantly lower phagocytosis rate was observed for patients with GAgP compared with PH subjects over time (P < 0.05). No differences between groups were found for superoxide production. GAgP patients presented significantly higher prevalence and levels of Porphyromonas gingivalis, Tannerella forsythia, and Aggregatibacter actinomycetemcomitans serotype b than controls (P < 0.05). Significant negative correlations between T. forsythia and P. gingivalis and PMN functions were observed.

CONCLUSIONS

GAgP subjects presented diminished phagocytic activity of peripheral PMNs and high prevalence and levels of classical periodontal pathogens.

Prevalence of Human Herpesviruses in Patients with Aggressive Periodontitis

BACKGROUND

Recent studies have demonstrated that various human viruses, especially cytomegalovirus (HCMV) and Epstein-Barr virus type-1 (EBV-1), seem to play a part in the pathogenesis of human periodontitis. The aim of this investigation was to evaluate the subgingival presence of HCMV and EBV in patients with aggressive periodontitis (AgP) and healthy subjects and to examine the effect of treatment on the incidence of these viruses 3 months following surgery.

METHODS

A polymerase chain reaction (PCR) method determined the presence of HCMV and EBV-1. Subgingival plaque samples from 17 consecutive AgP patients and 16 healthy controls were collected. The following indices were measured: plaque index (PI), gingival index (GI), probing depths (PD), and clinical attachment loss (CAL). Clinical parameters were assessed pretherapy and at 3 months following surgical and antimicrobial therapy.

RESULTS

HCMV was detected in 64.7% of AgP patients but not detected in healthy subjects (P < 0.001) and EBV-1 in 70.6% of AgP patients and 6.3% of the healthy controls (P < 0.001). HCMV and EBV-1 coinfection was detected in 41.7% of AgP patients. A statistically significant decrease was found in all clinical parameters 3 months after treatment. There was a statistically significant decrease in HCMV and EBV-1 following therapy (P < 0.001; no HCMV; 1 patient with EBV-1).

CONCLUSIONS

These findings indicate that subgingival presence of EBV-1 HCMV is strongly associated with aggressive periodontitis, and coinfection with HCMV and EBV-1 appears to be particularly deleterious to periodontal health.

Granulocyte concentrates: how can we assess their quality?

The use of granulocyte transfusions to treat and prevent life-threatening infection in patients lacking neutrophil numbers or function may become increasingly important in aiding advances in the treatment of haematological malignancies. A critical factor in determining the outcome of granulocyte transfusion is the number of cells transfused, and collection of sufficiently high concentration of cells from donors remains challenging. A number of tests of granulocyte function can be performed in vitro to assess the quality of granulocyte concentrates, which may be useful in helping to optimize granulocyte collection, processing and storage methods. Studies that have examined neutrophil function in granulocyte concentrates to date have tended to focus on the assessment of viability, chemotaxis, phagocytosis and oxidative killing. How useful in vitro tests of neutrophil function are in predicting neutrophil function following granulocyte transfusion remains to be established in conjunction with well-designed clinical trials.

HLA-A, B, Cw, DRB1, DRB3/4/5, DQB1 in German patients suffering from rapidly progressive periodontitis (RPP) and adult periodontitis (AP)

BACKGROUND/AIM

There is growing indication that differences in host response determine susceptibility and resistance to periodontal disease. Particularly, the effect of histocompatibility antigens (HLA) on early onset periodontitis (EOP) has been studied. As most of the results are not conclusive and to date no report has been done on German patients, the aim of this study was to investigate the distribution of HLA alleles in a group of 50 German RPP patients and 102 German AP patients and to compare them to 102 control probands without periodontitis.

METHODS

Diagnosis was established according to standardised clinical criteria. HLA typing was performed using serologic and molecular biologic (PCR-SSP) techniques.

RESULTS

Compared to the controls, RPP patients had a significantly higher frequency of HLA-DRB1*13 and a significantly lower frequency of HLA-DRBblank*(non-DRB3/4/5). AP patients showed a significantly increased occurrence of HLA-B*14 and -Cw*08 as well as a significantly decreased frequency of HLA-A*03. In both patient groups HLA-A*11 and -A*29 had an increased frequency and HLA-A*31 and -A*30/31 were decreased. These differences were statistical significant in the whole patient group (RPP + AP).

CONCLUSIONS

Based on modern DNA techniques the present study shows an association of HLA to both RPP and AP. Certain HLA alleles seem to be associated with susceptibility or resistance to periodontitis in general. However, before this knowledge can be used for differential diagnosis or prognosis, further investigations are necessary.

Periodontal diseases in the child and adolescent

BACKGROUND

Periodontal diseases are among the most frequent diseases affecting children and adolescents. These include gingivitis, localized or generalized aggressive periodontitis (a.k.a., early onset periodontitis which includes generalized or localized prepubertal periodontitis and juvenile periodontitis) and periodontal diseases associated with systemic disorders. The best approach to managing periodontal diseases is prevention, followed by early detection and treatment.

METHODS

This paper reviews the current literature concerning the most common periodontal diseases affecting children: chronic gingivitis (or dental plaque-induced gingival diseases) and early onset periodontitis (or aggressive periodontitis), including prepubertal and juvenile periodontitis. In addition, systemic diseases that affect the periodontium and oral lesions commonly found in young children are addressed. The prevalence, diagnostic characteristics, microbiology, host-related factors, and therapeutic management of each of these disease entities are thoroughly discussed.

Heterogeneity of host immunological risk factors in patients with aggressive periodontitis

BACKGROUND

The pathogenesis of early-onset periodontitis (EOP) can be explained by various host risk factors. Previous studies have focused on a single (among many possible) immunological risk factor and the association among the factors has not been assessed. We comprehensively investigated the associations among multiple host immunological risk factors in EOP patients to further elucidate their role in the pathogenesis of EOP.

METHODS

Sixty-eight EOP patients (50 generalized EOP, 18 localized EOP), 51 EOP-suspected patients (S-EOP), 43 adult periodontitis (AP) patients, and 36 periodontally healthy subjects (HS) participated in this cross-sectional study. We examined peripheral neutrophil functions, phenotypic and functional characterization of peripheral lymphocytes (lymphocyte subsets, T-cell proliferative activity), cytokine productivity (interleukin [IL]-1, IL-2, tumor necrosis factor [TNF]-alpha, interferon [IFN]-gamma, IL-4 and IL-6), serum immunoglobulin G (IgG) antibody titers against 12 periodontal bacteria, and HLA class II genotypes.

RESULTS

G-EOP, S-EOP, and AP patient groups showed significantly lower percentages of pan T cells and CD8-positive cells (P < 0.02) compared with the HS group. L-EOP patients showed depressed IL-4 and TNF-alpha productivity compared with the HS group (P < 0.02). The EOP group showed significantly elevated antibody levels against Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, and Fusobacterium nucleatum compared with the HS group (P < 0.05). The frequency with DQB1*0503 was significantly higher in the EOP patient group than the HS group (P = 0.045) due to the higher frequency in L-EOP patients than the HS group (P = 0.035). There were wide interindividual variations in each of the tests among patient and HS groups; however, EOP patients showed wider intradiagnostic group variations in certain host defensive cell functions than the other groups. There were some EOP patients who showed extremely low or high values in some tests; the EOP patients could be further divided into subgroups according to their host defensive and immunological profiles. However, there was heterogeneity in some of the other host immunological tests even in the subgroups.

CONCLUSIONS

The association of host immunological risk factors in EOP patients is widely varied and more complex than previously thought. These results indicate the difficulty of explaining the pathogenesis of EOP based on a single host risk factor and also emphasize the importance of critical assessment of not only EOP patient groups, but also individual patients.

A potential role of an intracellular signaling defect in neutrophil functional abnormalities and promotion of tissue damage in patients with localized juvenile periodontitis

Localized juvenile periodontitis is a destructive form of periodontal inflammatory disease which has its onset at puberty. The etiopathology of the disease is still unclear but neutrophils have been suggested to play a major role both in the production and development of the disorder. About 70% of the patients with localized juvenile periodontitis exhibit neutrophil functional abnormalities, such as decreased chemotaxis and phagocytosis. Interestingly, it has been frequently reported that the same hypoactive cells show an enhanced respiratory burst response and increased adhesion. Several possible mechanisms explaining neutrophil anomalies in localized juvenile periodontitis have been proposed. These include the presence of soluble serum factors capable of modulating neutrophil function, altered cell-surface receptor expression and/or function, and a change in the post-receptor signaling events. Recently, a growing evidence has accumulated showing that the diacylglycerol metabolism could be altered in neutrophils from patients with localized juvenile periodontitis. This change, which may be due to a defect in a major diacylglycerol metabolizing enzyme, diacylglycerol kinase, results in enhanced accumulation of diacylglycerol in activated cells. Because diacylglycerol is an endogenous activator of protein kinase C, the increased and prolonged generation of diacylglycerol could lead to abnormal pattern of protein kinase C-regulated neutrophil functions, explaining the parallel hypo- and hyperactivities.

Early-onset and adult periodontitis associated with abnormal cytokine production by activated T lymphocytes

There is growing evidence for an important role of the immune system in the pathogenesis of periodontitis. To further characterize the possible immunoregulatory dysfunction of peripheral blood mononuclear cells (PBMC) in periodontitis patients, we investigated functional aspects of PBMC from patients with early-onset periodontitis (EOP) and adult periodontitis (AP). Compared to controls, we observed decreased proliferative responses of PBMC from patients with EOP following stimulation with a mitogenic stimulus (phytohemagglutinin). To investigate whether this abnormality reflects a modulation in cytokine production, we measured the in vitro production of interleukin (IL)-3, IL-5, granulocyte macrophage colony-stimulating factor (GM-CSF), and interferon-gamma (IFN-gamma) by activated PBMC. PBMC in EOP patients expressed significantly decreased levels of IFN-gamma protein in response to mitogenic stimulation. Reduced IFN-gamma secretion was associated with decreased IFN-gamma and IL-2 mRNA expression in these cells, as well as decreased HLA-DR surface expression on monocytes. On the other hand, we observed significantly higher levels of IL-5 and GM-CSF in the same system using PBMC from AP patients. These were comparable to the levels observed for patients with allergic asthma. These data imply that EOP is associated with decreased Th1-like cytokine expression, and that the PBMC response from patients with AP is predominantly Th2/Th0 in nature.

Active and alpha-1 proteinase inhibitor complexed leukocyte elastase levels in crevicular fluid from patients with periodontal diseases

Human leukocyte elastase is present in large amounts in the crevicular fluid of patients with periodontal disease and was considered as a putative biological marker of the evolution of such diseases. The aim of this work was to measure spectrophotometrically amounts of active elastase (AE) and elastase complexed to alpha 1 proteinase inhibitor (E-alpha 1-PI) in gingival crevicular fluid obtained, from patients suffering from rapidly progressive periodontitis (RPP group) or adult periodontitis (AP group) with different probing depths (3 to 5 mm and > 6 mm). AE and E-alpha 1-PI concentrations were negligible in healthy individuals. AE, but not E-alpha 1-PI, concentration appears to vary significantly with the probing depth in patients suffering either from rapidly progressive or adult periodontitis. No correlations were found between levels of AE and E-alpha 1-PI in the different groups of patients. AE concentration seems to be a marker of periodontal diseases in relation with probing depth.

Effects of Porphyromonas gingivalis culture products on the morphology of peripheral blood polymorphonuclear leucocytes from periodontitis patients and healthy subjects

The effects of Porphyromonas gingivalis culture supernatant from strain W50, its avirulent variant (W50/BE1) and sterile BM culture medium on the morphological changes in polymorphonuclear leucocytes (PMN) from 10 patients with periodontitis (3 juvenile periodontitis, 7 rapidly progressive periodontitis) were compared with those from 10 healthy controls. Large non-polar cells ( > 160 microns2) were increased in patients to 182.8% (p = 0.0076) and 245.5% (p = 0.0002) of control values with W50 and W50/BE1 supernatant respectively. In contrast, numbers of small non-polar cells ( < 80 microns2) and polarised cells were decreased in the patient group. Patient/control ratios for small non-polar cells were 30.3% (p = 0.0007) and 33.6% (p = 0.0005) with W50 and W50/BE1, respectively, and 38.2% (p = 0.0147) for polarised cells exposed to W50 supernatant. The data indicate that PMN from patients with periodontitis differ significantly from those of healthy controls in the shape changes which occur after exposure to P. gingivalis culture supernatant.

An animal model for the assessment of gingival lesions

A model of gingival inflammation was performed in Sprague-Dawley rats weighing 180-200 g. Mechanical bamboo stick-induced injury was inflammatory when bacteria contaminated the sticks. Bacteria were first obtained from gingival fluid collected from a patient with adult periodontitis. Another strain from Institut Pasteur (IP 6444) induced similar inflammation. Inflammation was then quantified 10 days later by means of elastase assays performed in gingival extracts. In parallel, elastic structures were observed and elastic fibers were quantified by automated image analysis. This technique of "impaction" was able to induce a gingival inflammatory reaction characterized by a significant increase of gingival elastase content, infiltration of gingival tissues by elicited cells, and gingival elastic fiber breakdown. These parameters were correlated, and measurement of one of them might be useful for pharmacological studies applied to the treatment of periodontal lesions. An example of results obtained from animals treated by heparine was shown.

Increased oxidative product formation by peripheral blood polymorphonuclear leukocytes in human periodontal diseases

We examined the oxidative burst (hydrogen peroxide-dependent oxidative product formation) of polymorphonuclear leukocytes (PMNL) in the peripheral blood from the patients with various types of periodontal diseases including localized juvenile (LJP), generalized juvenile (GJP) and adult periodontitis (AP). Heparinized peripheral blood was obtained from 15 LJP, 13 GJP and 52 AP patients and from 30 healthy control subjects. The oxidative product (2',7'-dichlorofluorescein; DCF) formation of PMNL by stimulation with phorbol myristate acetate myristate acetate was evaluated by a rapid quantitative assay using flow cytometry. The results indicated that all patient groups contained variable populations with normal or increased DCF formation, while the control subjects exhibited DCF formation as a single population. No significant differences in average DCF formation were found among the three patient groups. Although individual patients gave various values, the average DCF formation of the three patient groups was much higher than that of the control group. Statistical analysis revealed a significant positive correlation between DCF formation and the clinical periodontal parameters on an individual basis. Furthermore, after initial periodontal treatment, DCF formation decreased to normal levels. These results suggest that the capacity of peripheral blood PMNL to mount oxidative burst reactions might reflect the inflammatory status of periodontal disease.