Immunoglobulin isotypes in gingival crevicular fluid: possible protective role of IgA

Oral Mucosal Immunity and HIV/SIV Infection

Human Immunodeficiency Virus (HIV) transmission through genital and rectal mucosa has led to intensive study of mucosal immune responses to HIV and to the development of a vaccine administered locally. However, HIV transmission through the oral mucosa is a rare event. The oral mucosa represents a physical barrier and contains immunological elements to prevent the invasion of pathogenic organisms. This particular defense differs between micro-compartments represented by the salivary glands, oral mucosa, and palatine tonsils. Secretory immunity of the salivary glands, unique features of cellular structure in the oral mucosa and palatine tonsils, the high rate of oral blood flow, and innate factors in saliva may all contribute to the resistance to HIV/Simian Immunodeficiency Virus (SIV) oral mucosal infection. In the early stage of HIV infection, humoral and cellular immunity and innate immune functions in oral mucosa are maintained. However, these particular immune responses may all be impaired as a result of chronic HIV infection. A better understanding of oral mucosal immune mechanisms should lead to improved prevention of viral and bacterial infections, particularly in immunocompromised persons with Acquired Immune Deficiency Syndrome (AIDS), and to the development of a novel strategy for a mucosal AIDS vaccine, as well as vaccines to combat other oral diseases, such as dental caries and periodontal diseases.

What do 'omic technologies have to offer periodontal clinical practice in the future?

BACKGROUND AND OBJECTIVE

Periodontal diseases are the most common chronic inflammatory diseases of humans and a major cause of tooth loss. Inflammatory periodontitis is also a complex multifactorial disease involving many cell types, cell products and interactions. It is associated with a dysregulated inflammatory response, which fails to resolve, and which also fails to re-establish a beneficial periodontal microbiota. There is a rich history of biomarker research within the field of periodontology, but exemplary improvements in analytical platform technologies offer exciting opportunities for discovery. These include the 'omic technologies, such as genomics, transcriptomics, proteomics and metabolomics, which provide information on global scales that can match the complexity of the disease. This narrative review focuses on the recent advances made in in vivo human periodontal research by use of 'omic technologies.

MATERIAL AND METHODS

The Medline database was searched to identify articles currently available on 'omic technologies with regard to periodontal research.

RESULTS

One hundred and sixty-one articles focusing on biomarkers of and 'omic advances in periodontal research were analysed for their contributions to the understanding of periodontal diseases.

CONCLUSION

The data generated by the use of 'omic technologies have huge potential to inform paradigm shifts in our understanding of periodontal diseases, but data management, analysis and interpretation require a thoughtful and systematic bioinformatics approach, to ensure meaningful conclusions can be made.

Crevicular Porphyromonas gingivalis-specific immunoglobulin A levels in healthy and periodontitis-affected Thai cohorts

Abstract Aim:  Immunoglobulin A is a key humoral immune component involved in defense mechanisms against infections. Periodontitis, the chronic inflammatory disease causing periodontal destruction, adversely affects adults worldwide, including Thailand. As the development of periodontitis is partly mediated by immune components, levels of total and Porphyromonas gingivalis-specific immunoglobulin A in gingival crevicular fluid of Thai cohorts were studied.

METHODS

  Gingival crevicular fluid was collected from 24 patients with severe generalized chronic periodontitis and 22 healthy controls. The amount and concentration of total and Porphyromonas gingivalis-specific immunoglobulin A in each gingival crevicular fluid sample were determined by enzyme-linked immunosorbent assay.

RESULTS

  The control group contained the highest concentrations of both types of gingival crevicular fluid-immunoglobulin A, but the lowest levels of these antibodies were found in the deep sites of the periodontitis group. Moreover, the concentrations of gingival crevicular fluid-immunoglobulin A and the degree of periodontitis severity appeared to have an inverse relationship. There was no significant difference in the amounts of gingival crevicular fluid-immunoglobulin A in the control and periodontitis groups.

CONCLUSIONS

  This study supports the hypothesis that high concentrations of specific gingival crevicular fluid-immunoglobulin A antibodies directed against Porphyromonas gingivalis, a potent periodontic microorganism, could retard periodontitis development.

Citation classics in periodontology: a controlled study

AIM

The aims of this study were to identify the most cited articles in Periodontology published from January 1990 to March 2005; and to analyse the differences between citation Classics and less cited articles.

MATERIAL AND METHODS

The search was carried out in four international periodontal journals: Journal of Periodontology, Journal of Clinical Periodontology, International Journal of Periodontics and Restorative Dentistry and Journal of Periodontal Research. The Classics, that are articles cited at least 100 times, were identified using the Science Citation Index database. From every issue of the journals that contained a Classic, another article was randomly selected and used as a Control.

RESULTS

Fifty-five Classics and 55 Controls were identified. Classic articles were longer, used more images, had more authors, and contained more self-references than Controls. Moreover Classics had on the average a bigger sample size, often dealt with etiopathogenesis and prognosis, but were rarely controlled or randomized studies.

CONCLUSIONS

Classic articles play an instructive role, but are often non-Controlled studies.

Heterogeneity of IgG glycosylation in adult periodontal disease

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

Relationship between periodontal disease status and combination of biochemical assays of gingival crevicular fluid

BACKGROUND

Currently, no biochemical assay involving gingival crevicular fluid is utilized routinely as a screening test for periodontal disease.

OBJECTIVE

The objective of the present study was to evaluate the potential of gingival crevicular fluid assay as a screening methodology.

METHODS

The subject population was comprised of 27 volunteers. Nine participants were classified as 'subject with periodontal destruction' (SPD) exhibiting at least one site with pocket depth and attachment loss>3.5 mm, whereas the remaining individuals were categorized as 'subject with minimal periodontal destruction' (SMD). Gingival crevicular fluid was collected from fixed sites via a standardized method. Biochemical assays of 12 substances (hemoglobin, albumin, transferrin, alpha(1)-antitrypsin, fibronectin, IgA, IgG, IgM, lactoferrin, myeloperoxidase and neutrophil elastase) were conducted at a commercial laboratory. Power transformation of total quantities in gingival crevicular fluid was performed for statistical analysis.

RESULTS

Relationships between total quantity of each substance and periodontal disease status were unclear. Logistic regression analysis yielded six predictive models, which consisted of substance pairs: neutrophil elastase/IgA, neutrophil elastase/hemoglobin, neutrophil elastase/alpha(1)-antitrypsin and neutrophil elastase/IgG, and IgA/albumin and IgA/transferrin (p<0.05). Regression lines for SPD and SMD on a scattergram of IgA and neutrophil elastase were nearly parallel within the range of amounts in gingival crevicular fluid. The predictive model derived from both substances afforded sensitivity and specificity of 88% and 94%, respectively.

CONCLUSIONS

These results indicated that the combination of IgA and neutrophil elastase in gingival crevicular fluid may be crucial for prediction of periodontal disease status. Furthermore, these data suggested that biochemical assays employing both substances in gingival crevicular fluid may provide a satisfactory screening test for periodontal disease.

A novel polymorphism of FcalphaRI (CD89) associated with aggressive periodontitis

Immunoglobulin A Fc receptor (FcalphaRI) has been implicated in the pathogenesis of periodontitis, because increased IgA responses and FcalphaRI-bearing neutrophils are observed in the disease lesions. Inter-individual differences in susceptibility to periodontitis may be attributable to genetic variability in FcalphaRI-mediated immunity. We here identified an FcalphaRI novel polymorphism (nt 324 A-to-G transition) in the membrane-distal extracellular domain encompassing the ligand-binding site, not resulting in an amino acid change. We compared the FcalphaRI genotype distributions among 46 Japanese aggressive periodontitis (AGP) patients, 80 race-matched healthy controls (HCs), and 59 Caucasian HCs. No ethnic differences were observed in the FcalphaRI genotype distributions between Japanese and Caucasian HC. Notably, we observed a difference in the genotype distribution between the AGP and HC groups. Carriage rate of the nt 324 A allele was higher in the AGP (65.2%) than that in the HC group (42.5%) (odds ratio 2.54). Polymorphonuclear neutrophils from peripheral blood and gingival crevicular fluid exhibited a decreased phagocytosis of periodontopathic bacteria (Porphyromonas gingivalis) in the nt 324 A/A patients as compared with the nt 324 G/G patients. These results document a genetic polymorphism at the FcalphaRI ligand-binding site to be associated with susceptibility to AGP.

Advances in periodontal disease markers

A computer-assisted medline search was conducted to find the relevant articles concerning the periodontal disease markers in gingival crevicular fluid (GCF) and saliva published during the 10-year period from 1993 to July 2003. This review suggests that certain diagnostic uses of saliva and GCF show promise. Although both fluids have been used to evaluate the risk for an individual to develop periodontal disease and to monitor of the host response to periodontal therapy, GCF has the chance of being closely approximated to the periodontal tissues where periodontal disease begins. The enzymes contributed to extracellular matrix (ECM) molecules and non-ECM molecules degradation and markers for polymorphonuclear leukocytes (PMN) activity and influx into the gingival tissue seem to provide valuable information regarding the periodontal disease diagnosis and prognosis. There is also an increasing evidence implicating reactive oxygen species and nitric oxide pathway in the pathogenesis of periodontal diseases. Although promising results have been achieved with the assays evaluating the markers in assessment of periodontal disease status, up to now, none of these tests are used routinely. Further, one commercially available genetic test has been reported to have the potential to be used to predict the periodontal disease, but there are controversial reports on this genetic susceptibility test.

Isotypic antibody response to plaque anaerobes in periodontal disease

BACKGROUND

It has been suggested that locally produced immunoglobulin (Ig)A could be more protective than IgG and that there could be a relationship between crevicular fluid-specific IgA levels and the onset of periodontal disease. This study was designed to investigate this hypothesis regarding specific immune responses towards 4 plaque anaerobes in gingival crevicular fluid and saliva from patients with periodontopathies and controls.

METHODS

Gingival crevicular fluid (GCF) and whole saliva were collected from 35 adults with periodontitis and 24 periodontally healthy adults (controls). Antigens were extracted from Actinomyces actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum and used to set up specific enzyme-linked immunosorbent assay (ELISA) tests to assess IgA and IgG levels to these microorganisms in the fluids collected.

RESULTS

The crevicular fluid of periodontitis patients contained significantly higher levels of IgG to the 4 microorganisms tested than that of controls (P < 10(-6) for all comparisons). IgA levels to the 4 bacteria were statistically significantly much higher in control crevicular fluid (P < 10(-7) for all comparisons). Controls also had statistically significantly higher levels of specific salivary IgA than patients (P < 0.02 for all comparisons).

CONCLUSIONS

These data support the potentially protective role of specific IgA directed to oral microorganisms involved in the onset and development of periodontal disease.

Effective in vitro clearance of Porphyromonas gingivalis by Fc alpha receptor I (CD89) on gingival crevicular neutrophils

Porphyromonas gingivalis has been implicated as a causative pathogen in periodontitis. Immunotherapeutic approaches have recently been suggested to aid in the clearance of P. gingivalis from disease sites. Because antibody-Fc receptor (FcR) interactions play a role in the effector functions of polymorphonuclear neutrophils (PMN), we evaluated which FcR on PMN from gingival crevicular fluid (GCF) serves as an optimal target molecule for FcR-directed immunotherapy. GCF PMN and peripheral blood (PB) PMN from adult periodontitis patients were analyzed for their immunoglobulin G (IgG) and IgA FcR (Fc gamma R and Fc alpha R, respectively) expression and function by studying IgG- and IgA-mediated elimination of P. gingivalis. GCF PMN exhibited higher Fc alpha RI and Fc gamma RI levels and lower Fc gamma RIIa and Fc gamma RIIIb levels than PB PMN. Functional studies revealed that GCF PMN exhibited less of a capacity to phagocytose and kill IgG1-opsonized P. gingivalis than PB PMN. IgA1-mediated phagocytosis and killing capacity was, however, comparable between GCF PMN and PB PMN. In summary, these in vitro results document that Fc alpha RI represents a candidate target for FcR-directed immunotherapy for the clearance of P. gingivalis.

Gingival crevicular fluid inflammatory mediators and bacteriology of gingivitis in nonhuman primates related to susceptibility to periodontitis

The hypothesis to be tested was that the microbiota and resulting local host inflammatory response characteristics in oral conditions of high levels of chronic gingival inflammation increases susceptibility to progressing periodontitis. This study used cynomolgus monkeys, Macaca fascicularis (nonhuman primates), with high and low levels of long-standing gingival inflammation to define the profiles of gingival crevicular fluid mediators, cytokines and immunoglobulins; describe the subgingival microbiota; and evaluate their susceptibility to ligature-induced periodontitis. Sixteen nonhuman primates were stratified into two groups (HI, LO) based upon Bleeding Index as a measure of the natural level of inflammation (HI = 1.26 +/- 0.45; LO = 0.22 +/- 0.16). The host mediator levels, subgingival microbiota, and clinical characteristics of the LO and HI groups were compared after 30 days of oral hygiene, during a 30 day experimental gingivitis (7, 14, and 30 days), and during periodontitis (30, 60, and 90 days). The results demonstrated that nonhuman primates with high levels of long-standing gingival inflammation when compared to those nonhuman primates with low inflammation show: 1) different inflammatory mediator profiles in gingival crevicular fluid (particularly for immunoglobulin A (IgA) and IgG levels), 2) a different quantitative and qualitative subgingival microbiota; and 3) a similar progression of periodontitis. Thus, while variations in host inflammatory responses to local factors exist in the nonhuman primates, an extensive subgingival challenge (such as ligation) may negate these individual differences.

Changes in gingival crevicular fluid levels of immunoglobulin A following therapy: association with attachment loss

BACKGROUND

In previous studies, we demonstrated that increased levels of immunoglobulin A (IgA) in gingival crevicular fluid (GCF) may be "protective", while increased levels of the polymorphonuclear lysosomal enzyme, beta-glucuronidase, in GCF were associated with increased risk of disease activity. In this study, we examined the effect of scaling and root planing (SRP) on the levels of beta-glucuronidase, IgG, and IgA in GCF over a 24-week period and compared these to clinical attachment loss (CAL).

METHODS

Twenty-nine patients with periodontal disease were examined for attachment level, probing depth, plaque, and bleeding on probing at 6 sites per tooth. GCF was collected from the mesial aspect of all teeth excluding third molars and analyzed for beta-glucuronidase, IgG, and IgA. After baseline data were collected, each patient received SRP, and GCF was collected again at 2, 4, 6, 8, 12, and 24 weeks post-SRP while clinical data were obtained at 4, 8, 12, and 24 weeks. In addition, we analyzed whether the magnitude of the IgA response to SRP would affect the rate of periodontal disease progression by examining GCF IgA levels at 2 time intervals: 2 to 4 weeks post-SRP and 6 to 12 weeks post-SRP.

RESULTS

Seventeen patients (58.6%) exhibited at least 1 site losing > or =2.5 mm of CAL during the 24-week study. Beta-glucuronidase in GCF was significantly decreased at 2 weeks following SRP and then demonstrated a gradual increase throughout the study period. Levels of IgA in GCF significantly increased following SRP, reaching a peak at 6 weeks and then gradually decreasing throughout the study. Furthermore, we found an inverse relationship between GCF IgA levels at 6 to 12 weeks post-SRP and the occurrence of CAL.

CONCLUSIONS

These results support the hypothesis that maintenance of high levels of IgA in GCF may be "protective" against periodontal attachment loss. Furthermore, levels of beta-glucuronidase appear to be a more sensitive indicator of gingival inflammation than clinical measures.

Epidemiology and diagnosis of HIV-associated periodontal diseases

A review of periodontal disease as a manifestation of HIV infection suggests a shift in emphasis over the past 5 years. Initially the focus was on newly described forms of periodontal disease (i.e., HIV-associated gingivitis or linear gingival erythema (LGE); HIV-associated periodontitis or necrotizing ulcerative periodontitis (NUP). While the clinical definition of LGE varies from study to study, an association between LGE and Candida infection has been described. Furthermore, the prevalence of NUP is quite low and this disorder is associated with severe immunosuppression. In contrast, the focus today is on the accelerated rate of chronic adult periodontitis occurring in seropositive patients. While the organisms that characterize adult periodontitis in seronegative individuals are present in subgingival plaque from seropositive individuals, reports suggest that atypical pathogens are also present (i.e., Mycoplasma salivarium, Enterobacter cloacae). Recent studies from our laboratory have identified a novel strain of Clostridium isolated from the subgingival plaque of injecting drug users that has pathologic potential. This organism, however, was found in both seropositive and seronegative individuals in this cohort, suggesting an association with lifestyle rather than serostatus. In addition, data has been published examining the local host response in periodontitis in seropositive individuals. Distinctly elevated levels of IgG in gingival crevicular fluid (GCF) have been observed in seropositive patients. Furthermore, data from our laboratory examining inflammatory mediators in GCF (polymorphonuclear leukocyte lysosomal enzyme beta-glucuronidase and the pro-inflammatory cytokine interleukin-1 beta) suggests an altered response in patients with HIV infection. The alteration manifests as the absence of the expected strong correlation between polymorphonuclear leukocyte activity in the gingival crevice and clinical measures of existing periodontal disease, as well as elevated levels of interleukin-1 beta in sites with deeper probing depths. Therefore, it can be concluded that the progression of periodontal disease in the presence of HIV infection is dependent upon the immunologic competency of the host as well as the local inflammatory response to typical and atypical subgingival microorganisms.

Inflammatory and immune mediators in crevicular fluid from HIV-infected injecting drug users

Gingival crevicular fluid (GCF) levels of the polymorphonuclear leukocyte (PMN) lysosomal enzyme beta-glucuronidase (beta G), the pro-inflammatory cytokine interleukin 1 beta (IL-1 beta), and immunoglobulins (IgA, IgG, and IgM) were examined in 16 HIV seropositive (HIV+) and 10 HIV seronegative (HIV-) injecting drug users (IDU). Each subject received a periodontal examination including assessment of probing depth, attachment level, bleeding on probing, and plaque and calculus accumulation. GCF was collected from the mesial surfaces of premolar and molar teeth using filter paper strips. Although HIV+ subjects had a significantly lower number of peripheral blood CD4+ T cells/mm3 compared to HIV- subjects, there were no significant differences in mean probing depth, percentage of sites exhibiting bleeding on probing, or plaque and calculus accumulation between HIV- and HIV+ subjects. When the GCF components were analyzed, we found no significant differences between HIV- and HIV+ subjects in GCF levels of beta G, IL-1 beta, IgA or IgM, but GCF levels of IgG were significantly increased in HIV+ subjects. When sites were categorized by probing depth, no differences in the levels of beta G, IgA, IgG, and IgM existed between sites with probing depth < or = 3 mm compared to sites with probing depth > or = 4 mm in both HIV- and HIV+ IDU. However, levels of IL-1 beta in GCF were increased in the deeper sites (> or = 4 mm) in HIV+ IDU when compared to sites with PD < or = 3 mm. Analyzing GCF constituents in relation to the CD4 cell number, no differences were found between subjects with < or = 400 or > 400 CD4 cells/mm3 with respect to the levels of IL-1 beta, IgG, and IgM. However, the level beta G was significantly decreased in the HIV+ IDU with < or = 400 CD4 cells when compared to those with > 400 CD4 cells/mm3, while levels of IgA were significantly higher in HIV+ subjects with < or = 400 CD4 cells/mm3. Our results suggest that levels of IgG, and in immunodeficient subjects IgA were increased in GCF of HIV+ IDU while decreased levels of beta G were found in immunodeficient HIV+ IDU. These findings may be local manifestations of systemic alterations and suggest that analysis of GCF may provide insight into the immune and inflammatory responses of HIV-infected individuals to periodontal microorganisms.

Crevicular fluid and serum IgG subclasses and corresponding mRNA expressing plasma cells in periodontitis lesions

Recent reports suggest that specific serum IgG subclasses are a feature of several forms of periodontitis. GCF antibodies are both serum-derived and locally produced by the abundant plasma cells of the diseased periodontal tissue. Previous work has shown that crevicular fluid (GCF) levels of IgG may be reduced in active and deep periodontal pockets when compared to other sites in chronic periodontitis patients (7). These findings, and more recent findings for IgA levels in GCF (5), suggest that GCF immunoglobulins may indicate "high risk" sites for periodontitis. In these studies, the relative distribution of IgG isotypes was not investigated, nor was the relative contribution of local and serum antibodies to the GCF immunoglobulin profile. Therefore, more precise investigation of the tissue distribution of local gingival IgG subclass producing plasma cells and their protein levels in the GCF from the same sites and in serum, was undertaken.