The Fcgamma receptor genotype as a risk factor for generalized early-onset periodontitis in Japanese patients

The Genetic Aspects of Periodontitis Pathogenesis and the Regenerative Properties of Stem Cells

Periodontitis (PD) is a prevalent and chronic inflammatory disease with a complex pathogenesis, and it is associated with the presence of specific pathogens, such as Porphyromonas gingivalis. Dysbiosis and dysregulated immune responses ultimately lead to chronic inflammation as well as tooth and alveolar bone loss. Multiple studies have demonstrated that genetic polymorphisms may increase the susceptibility to PD. Furthermore, gene expression is modulated by various epigenetic mechanisms, such as DNA methylation, histone modifications, or the activity of non-coding RNA. These processes can also be induced by PD-associated pathogens. In this review, we try to summarize the genetic processes that are implicated in the pathogenesis of PD. Furthermore, we discuss the use of these mechanisms in diagnosis and therapeutic purposes. Importantly, novel treatment methods that could promote tissue regeneration are greatly needed in PD. In this paper, we also demonstrate current evidence on the potential use of stem cells and extracellular vesicles to stimulate tissue regeneration and suppress inflammation. The understanding of the molecular mechanisms involved in the pathogenesis of PD, as well as the impact of PD-associated bacteria and stem cells in these processes, may enhance future research and ultimately improve long-term treatment outcomes.

Polymorphisms in Genes Involved in Inflammation and Periodontitis: A Narrative Review

Current evidence pinpoints that the variability in periodontitis traits in humans may be attributable to genetic factors. Different allelic variants can result in alterations in tissue structure, antibody responses and inflammatory mediators. Consequently, genetic variations may act as protective or risk factors for periodontal diseases. A number of features of the inflammatory and immune response that seem to play a role in the development of periodontitis have a clearly established genetic basis. Identifying genes that contribute to the pathogenesis of periodontitis may be utilized for risk assessment in both aggressive and chronic periodontitis. The aim of this narrative review is to summarize the role of polymorphisms in genes involved in inflammation and periodontitis, including cellular receptors, tissue compatibility antigens, antibodies and cytokines.

Polymerase chain reaction: A molecular diagnostic tool in periodontology

This review discusses the principles of polymerase chain reaction (PCR) and its application as a diagnostic tool in periodontology. The relevant MEDLINE and PubMed indexed journals were searched manually and electronically by typing PCR, applications of PCR, PCR in periodontics, polymorphism studies in periodontitis, and molecular techniques in periodontology. The searches were limited to articles in English language and the articles describing PCR process and its relation to periodontology were collected and used to prepare a concise review. PCR has now become a standard diagnostic and research tool in periodontology. Various studies reveal that its sensitivity and specificity allow it as a rapid, efficient method of detecting, identifying, and quantifying organism. Different immune and inflammatory markers can be identified at the mRNA expression level, and also the determination of genetic polymorphisms, thus providing the deeper insight into the mechanisms underlying the periodontal disease.

Associations between FCGR2A rs1801274, FCGR3A rs396991, FCGR3B NA1/NA2 polymorphisms and periodontitis: a meta-analysis

The aim of this study was to determine whether the Fcγ receptors (FCGRs) polymorphisms confer susceptibility to periodontitis in ethnically different populations. We did a literature search using PubMed and Embase, and conducted a meta-analysis on the associations between the FCGR2A H131R (rs1801274), FCGR3A F158V (rs396991), and FCGR3B NA1/NA2 polymorphisms and periodontitis using allele contrast, the recessive model, the dominant model, and the homozygote contrast. A total of 17 separate comparisons with 1,421 patients with periodontitis and 1,454 controls, involving six Caucasian, six East Asian, two African and one South Asian population were considered in the meta-analysis. Meta-analysis of the FCGR2A H131R polymorphism showed no association between periodontitis and the FCGR2A R allele (OR=0.987, 95% CI=0.881-1.107, p=0.827). Stratification by ethnicity revealed an association between the RR+RH genotype with periodontitis in Caucasian population (OR=0.624, 95% CI=0.479-0.813, p=4.7×10(-5)), but not in East Asian, and African populations. Meta-analysis of the FCGR3A F158V polymorphism revealed an association between the FCGR3A V allele and periodontitis is in Caucasians (OR=1.457, 95% CI=1.014-2.092, p=0.042), but not in East Asians and Africans. In addition, analysis using the dominant model and homozygote contrast showed the same pattern for the FCGR3A V allele. Meta-analysis of the FCGR3B NA1/NA2 polymorphism using the recessive model revealed a significant association between the NA2/NA2 genotype and periodontitis in aggressive periodontitis (OR=2.853, 95% CI=1.673-4.863, 1.1×10(-5)). This meta-analysis demonstrates that the FCGR2A, and FCGR3A polymorphisms may confer susceptibility to periodontitis in Caucasians, and that the FCGR3B polymorphism may be associated with susceptibility to aggressive periodontitis.

Genetic polymorphism studies in periodontitis and Fcγ receptors

Periodontitis is a complex chronic subgingival plaque-induced inflammatory disease influenced by multiple factors, including genetics, behavior and the environment. Many genetic association studies have been conducted in periodontology. One of the most extensively investigated gene families is the Fcγ receptor gene family, which plays a key role in regulating host immune responses to bacteria. Unlike other genetic polymorphisms reported in periodontology, most Fcγ receptor polymorphisms reported not only have established biological functions but are reported to associate with other autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. There are, however, few recent reviews summarizing the association of this gene family with periodontitis. This article critically reviews the current understanding of genetic polymorphism studies in periodontitis, then summarizes the research status of Fcγ receptor polymorphisms and periodontitis and also of other genes involved in the regulatory network of Fcγ receptors, with special reference to their anticipated biological roles. Moreover, some possible future research directions in the related area are discussed.

Is self interdental cleaning associated with dental plaque levels, dental calculus, gingivitis and periodontal disease?

BACKGROUND AND OBJECTIVE

To ascertain whether interdental cleaning behaviours of Australian adults were associated with lower levels of plaque, gingivitis and periodontal disease.

MATERIAL AND METHODS

Data were obtained from the National Survey of Adult Oral Health 2004-06. Outcome variables were three indicators of oral hygiene outcomes (the presence or not of dental plaque, dental calculus and gingivitis) and two of periodontal disease (the presence or not of at least one tooth with a periodontal pocket or clinical attachment loss of ≥ 4 mm). The independent variable was classified into the following three groups: regularly clean interproximally 'at least daily' (daily+); 'less than daily' (< daily); and 'do not regularly clean interproximally' (reference group). Poisson regression with robust variance estimation was used to calculate prevalence ratios (PRs) and 95% confidence intervals (95% CIs) relative to the reference group, adjusted for covariates.

RESULTS

Regular self interdental cleaning was associated with less dental plaque (< daily, PR = 0.89, 95% CI = 0.84, 0.95; and daily+, PR = 0.89, 95% CI = 0.82, 0.96), less dental calculus (< daily, PR = 0.88, 95% CI = 0.80, 0.97; and daily+, PR = 0.79, 95% CI = 0.70, 0.89) and lower levels of moderate/severe gingivitis (daily+, PR = 0.85, 95% CI = 0.77, 0.94). Periodontal pocketing was less likely for the < daily group (PR = 0.61, 95% CI = 0.46, 0.82), but was not associated with daily+ cleaning (PR = 0.99, 95% CI = 0.663, 1.49). There was not a significant association between interdental cleaning and clinical attachment loss (< daily, PR = 0.90, 95% CI = 0.77, 1.05; and daily+, PR = 1.17, 95% CI = 0.95, 1.44).

CONCLUSION

Regular interdental cleaning was associated with better oral hygiene outcomes, such as dental plaque and gingivitis, although there was no significant association between regular interdental cleaning and clinical attachment loss.

Association of the FcγRIIB-nt645+25A/G polymorphism with the expression level of the FcγRIIb receptor, the antibody response to Porphyromonas gingivalis and the severity of periodontitis

BACKGROUND AND OBJECTIVE

Human FcγRIIb is an immunoglobulin G (IgG) receptor that inhibits the activation of B lymphocytes through cross-linking with the B-cell receptor via immune complexes. This function acts as a negative regulator of antibody production. Our previous studies have demonstrated the gene polymorphisms in FcγRIIb to be associated with periodontitis. In this study, we presented a polymorphism--FcγRIIB-nt645+25A/G (rs2125685)--in intron 4 and analyzed its functional relevance to periodontitis. We examined whether the FcγRIIB-nt645+25A/G polymorphism is associated with periodontal parameters, the IgG response to the periodontopathic bacterium Porphyromonas gingivalis and/or the expression level of FcγRIIb on peripheral B lymphocytes.

MATERIAL AND METHODS

Thirty-two patients with chronic periodontitis were genotyped with nested PCR and by direct sequencing of genome DNA. The levels of serum IgG and of specific IgG subclasses for P. gingivalis sonicate and for the recombinant 40-kDa outer membrane protein (OMP) were determined. The expression levels of FcγRIIb on peripheral B lymphocytes from 19 healthy donors were measured by flow cytometry.

RESULTS

Patients with the FcγRIIB-nt645+25AA genotype showed significantly higher mean clinical attachment levels compared to patients with the FcγRIIB-nt645+25GG genotype (p = 0.003) and a significantly lower IgG response to P. gingivalis sonicate and to the 40-kDa OMP. The expression levels of FcγRIIb protein on the cell surface in peripheral B lymphocytes were higher in healthy donors with the FcγRIIB-nt645+25AA genotype than in those with the FcγRIIB-nt645+25GG genotype (p = 0.03).

CONCLUSION

The higher expression levels of FcγRIIb in subjects with the FcγRIIB-nt645+25AA genotype may induce a lower level of production of IgG against P. gingivalis and therefore more severe periodontitis.

Analysis of plasma calprotectin and polymorphisms of S100A8 in patients with aggressive periodontitis

BACKGROUND AND OBJECTIVE

Calprotectin is an important proinflammatory mediator in various inflammatory diseases and is composed of two subunits (S100A8 and S100A9). However, the level of calprotectin in plasma of patients with aggressive periodontitis and its relationship with gene polymorphisms of S100A8 are unclear.

MATERIAL AND METHODS

The plasma concentrations of calprotectin were measured, using an enzyme immunoassay, in 139 patients with aggressive periodontitis and in 88 periodontally healthy control subjects. These patients were genotyped for the rs3795391 and rs3806232 polymorphisms of S100A8.

RESULTS

The plasma concentration of calprotectin in patients with aggressive periodontitis was significantly higher than in controls (2.17 mg/L vs. 1.72 mg/L, respectively, p = 0.001). The percentage of the AA genotype of S100A8 rs3795391 was significantly higher in patients than in controls (82% vs. 69.3%, respectively, p = 0.027), while the frequency of the allele G was decreased among patients compared with controls (9.6% vs. 16.1%, respectively, p = 0.036), which was especially apparent in men (rs3795391 genotype, p = 0.005; rs3795391 allele, p = 0.015). The mean probing depth in patients carrying the AA genotype was significantly higher than that of patients carrying the GA + GG genotype of two polymorphisms of S100A8 (rs3795391, p = 0.035; rs3806232, p = 0.040), whereas the levels of calprotectin between different genotypes were not significantly different (rs3795391, p = 0.11; rs3806232, p = 0.15).

CONCLUSION

These findings indicate that aggressive periodontitis is associated with elevated levels of plasma calprotectin and that gene polymorphisms of S100A8 may influence the susceptibility and severity of aggressive periodontitis.

Contemporary concepts in the diagnosis of periodontal disease

Periodontitis is an inflammatory disease of bacterial origin that results in the progressive destruction of the tissues that support the teeth, specifically the gingiva, periodontal ligament, and alveolar bone. The diagnosis of periodontal disease currently relies almost exclusively on clinical parameters and traditional dental radiography. In this article, the authors review current diagnostic techniques and present new approaches and technologies that are being developed to improve assessment of this common condition.

Fcgamma receptor polymorphisms and their association with periodontal disease: a meta-analysis

AIM

A systematic review and a meta-analysis were conducted in order to investigate the potential association of Fcgamma receptor (FcgammaR) polymorphisms with susceptibility to aggressive and chronic periodontal disease.

MATERIALS AND METHODS

A database search yielded a total of 17 studies involving 1685 cases and 1570 controls. Three polymorphisms were included in the meta-analysis: FcgammaRIIA H131R (rs1801274), FcgammaRIIIA F158V (rs396991) and FcgammaRIIIB NA1/NA2. Random-effect models were used in the analysis. Odds ratios (ORs) along with their 95% confidence intervals (CIs) were computed to compare the distribution of alleles and genotypes between cases and controls.

RESULTS AND CONCLUSIONS

The FcgammaRIIIB NA1/NA2 polymorphism was associated with both aggressive (per-allele OR 2.005, 95% CI: 1.044, 3.851) and chronic periodontitis (recessive contrast NA2NA2 versus NA1NA1+NA1NA2 OR 1.397, 95% CI: 1.039, 1.878). The analysis showed weak evidence for association between the FcgammaRIIA H131R polymorphism and aggressive periodontitis in Asians (R versus H allele OR 1.579, 95% CI: 1.025, 2.432). On the contrary, no relationship was identified between FcgammaRIIIA F158V and periodontal disease. Accumulating evidence from basic research makes the suggested association between FcgammaRIIIB NA1/NA2 polymorphism and periodontitis biologically plausible. Further research, however, is needed in order to assess possible gene-gene or gene-environment interactions (i.e. with smoking).

Gene polymorphisms in chronic periodontitis

We aimed to conduct a review of the literature for gene polymorphisms associated with chronic periodontitis (CP) susceptibility. A comprehensive search of the literature in English was performed using the keywords: periodontitis, periodontal disease, combined with the words genes, mutation, or polymorphism. Candidate gene polymorphism studies with a case-control design and reported genotype frequencies in CP patients were searched and reviewed. There is growing evidence that polymorphisms in the IL1, IL6, IL10, vitamin D receptor, and CD14 genes may be associated with CP in certain populations. However, carriage rates of the rare (R)-allele of any polymorphism varied considerably among studies and most of the studies appeared under-powered and did not correct for other risk factors. Larger cohorts, well-defined phenotypes, control for other risk factors, and analysis of multiple genes and polymorphisms within the same pathway are needed to get a more comprehensive insight into the contribution of gene polymorphisms in CP.

The association of Fcgamma receptor IIIb genetic polymorphism and susceptibility to periodontitis in Taiwanese individuals

AIM

The allelic polymorphism of FcgammaRIIIb, the neutrophil-specific receptor involved in the phagocytosis of immunoglobulin G-opsonized bacteria, has functionally distinct capacities that are important in host defence mediated by neutrophils. The aim of this study was to identify whether the polymorphism of FcgammaRIIIb is associated with periodontitis in Taiwanese individuals.

MATERIALS AND METHODS

This case-control study included of 93 aggressive periodontitis (AgP) patients, 372 chronic periodontitis (CP) patients and 158 healthy controls (HC). The FcgammaRIIIb genotypes were determined by PCR using allele-specific primers. The risk for periodontitis associated with genotypes was calculated as the odds ratio (OR).

RESULTS

A significant difference was observed in the distribution of the FcgammaRIIIb genotype between either AgP and HC, or AgP and CP, but not between CP and HC. The OR for carriage of the NA2 allele (NA1NA2+NA2NA2 versus NA1NA1) in AgP was 3.27 [95% confidence interval (CI)=1.57-7.51, p=0.0027] and 2.94 (95% CI=1.49-6.48, p=0.0037), as compared with HC and CP. After adjusting for possible confounding factors, the association was still significant.

CONCLUSIONS

The results of the present study suggest that subjects carrying at least one copy of the FcgammaRIIIb-NA2 allele might be associated with susceptibility to AgP. However, the clinical implications of the FcgammaRIIIb allelic polymorphism should be determined by further studies.

Low-affinity Fcgamma receptors, autoimmunity and infection

Low-affinity Fcgamma receptors (FcgammaRs) mediate the effects of immunoglobulin G (IgG) antibodies on leukocytes, including recruitment to inflammatory lesions, phagocytosis, antibody-dependent cellular cytotoxicity, release of inflammatory mediators and regulation of B cell activation. These functions are an important part of the mammalian response to infection, but if deployed inappropriately can cause autoimmune disease. Although most FcgammaRs are activatory, there is also an inhibitory FcgammaR that, when bound to IgG immune complexes, is able to downregulate the effects of both the activatory FcgammaRs and the B cell receptor. This review discusses the role of the low-affinity FcgammaRs in a balanced immune response and how perturbations in FcgammaR function result in susceptibility to infection or autoimmunity.

Association of interleukin-1 receptor antagonist +2018 gene polymorphism with Japanese chronic periodontitis patients using a novel genotyping method

Genetic variants at multiple loci have been shown to be associated with periodontitis risk. In this study, we have focused on nine functional gene polymorphisms encoding immunoregulation-related molecules such as cytokines (interleukin-1 (IL-1), transforming growth factor-beta1 (TGF-beta1)) and cell surface receptors (immunoglobulin G and A Fc receptors (Fc gamma R and Fc alpha R)). In total, 113 Japanese patients with chronic periodontitis (CP) and 108 race-matched healthy controls were genotyped with the modified serial invasive signal amplification reaction. There was a significant difference in the distribution of IL-1 receptor antagonist (RN) +2018 T/C allele between the patient and control groups, with enrichment of the +2018 C in controls (P = 0.021, odds ratio = 0.38). An increased frequency of the IL-1 haplotype comprising IL-1A +4845 G, IL-1B -31 C, and IL-1RN +2018 C was observed in controls (P = 0.004). Moreover, a multivariate logistic regression analysis revealed that subjects with IL-1RN +2018 C allele were less likely to have CP (P = 0.016, odds ratio = 0.29). These findings document the association of IL-1RN +2018 C with reduced susceptibility to CP in the Japanese.

Association of Fc gamma receptor IIIB polymorphism with renal-allogrft in Chinese

BACKGROUND

Several studies have identified FcgammaRIIIb (Fcgr3b) polymorphisms that determine susceptibility to autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. The objective of the study was to clarify whether FcgammaRIIIb allele polymorphism influence susceptibility to end stage renal disease (ESRD) patients with renal transplantation.

METHODS

DNA fragments were amplified by PCR-SSP using genomic DNA from 172 unrelated, healthy blood donors and 171 renal recipients in our Kidney Disease Centre. We performed direct sequencing using 20 PCR products of renal recipients carrying different FcgammaRIIIb forms according to the allele-specific PCR.

RESULTS

FcgammaRIIIb NA1/NA2 genotype frequency showed significant difference between renal recipients and healthy controls (chi(2)=19.3, P<0.005). In addition, the allele frequency also showed significant difference between the two groups. Lower frequency of genotype FcgammaRIIIb NA1/NA1 was observed in renal recipients than in healthy controls (chi(2)=5.06, P=0.024). In comparison with nonrejectors, rejectors displayed no significant defference of FcgammaRIIIb NA1/NA2 genotype frequency, as well as allele frequency.

CONCLUSION

FcgammaRIIIb NA1/NA2 heterozygote genotype frequency was increased in ESRD patients in Chinese. The present findings showed that FcgammaRIIIb genotype related to the disease susceptibility, although FcgammaRIIIb polymorphisms did not affect the acute rejection.

A nonfucosylated anti-HER2 antibody augments antibody-dependent cellular cytotoxicity in breast cancer patients

PURPOSE

Removal of fucose residues from the oligosaccharides of human antibody is a powerful approach to enhance antibody-dependent cellular cytotoxicity (ADCC), a potential important antitumor mechanism of therapeutic antibodies. To provide clinically relevant evidence of this mechanism, we investigated ADCC of a fucose-negative version of trastuzumab [anti-human epidermal growth factor receptor 2 (HER2) humanized antibody] using peripheral blood mononuclear cells (PBMC) from breast cancer patients as effector cells.

EXPERIMENTAL DESIGN

Thirty volunteers, including 20 breast cancer patients and 10 normal healthy control donors, were recruited randomly, and aliquots of peripheral blood were collected. ADCC of commercial trastuzumab (fucosylated) and its fucose-negative version were measured using PBMCs drawn from the volunteers as effector cells and two breast cancer cell lines with different HER2 expression levels as target cells. Relationships between cytotoxicity and characteristics of the patients, such as content of natural killer cells in PBMCs, type of therapy, FCGR3A genotypes, etc. were also analyzed.

RESULTS

ADCC was significantly enhanced with the fucose-negative antibody compared with the fucose-positive antibody using PBMCs from either normal donors or breast cancer patients. Enhancement of ADCC was observed irrespective of the various clinical backgrounds of the patients, even in the chemotherapy cohort that presented with a reduced number of natural killer cells and weaker ADCC.

CONCLUSIONS

This preliminary study suggests that the use of fucose-negative antibodies may improve the therapeutic effects of anti-HER2 therapy for patients independent of clinical backgrounds.

The combined genotypes of stimulatory and inhibitory Fc gamma receptors associated with systemic lupus erythematosus and periodontitis in Japanese adults

BACKGROUND

The pathobiology of systemic lupus erythematosus (SLE) is similar to that of periodontitis in that the immunoglobulin G Fc receptor (FcgammaR) and proinflammatory cytokines play an important role. Genetic variations of FcgammaR and interleukin (IL)-1 are associated with susceptibility to both diseases. Therefore, we evaluated whether the combination of FcgammaR or IL-1 polymorphic genes represents a common risk factor for SLE and periodontitis.

METHODS

The study population consisted of Japanese adults with SLE and periodontitis (SLE+P group; n = 46), SLE only (SLE group; n = 25), periodontitis only (P group; n = 58), and healthy individuals with no systemic or oral disease (H group; n = 44). Clinical periodontal condition was evaluated by measurement of probing depth, clinical attachment level, and alveolar bone loss. Genomic DNA was isolated from peripheral blood and analyzed for determination of FcgammaR genotypes (FcgammaRIIA, FcgammaRIIB, FcgammaRIIIA, and FcgammaRIIIB) and IL-1 genotypes (IL-1A +4845 and IL-1B +3954) by allele-specific polymerase chain reactions or DNA sequencing.

RESULTS

A significant overrepresentation of the R131 allele of stimulatory FcgammaRIIA and the 232T allele of inhibitory FcgammaRIIB was found in the SLE+P group compared to the H group (P = 0.01 and P = 0.0009, respectively). The combination of FcgammaRIIA-R131 and FcgammaRIIB-232T alleles yielded a strong association with SLE and periodontitis (SLE+P group versus P group: P = 0.01, odds ratio: 3.3; SLE+P group versus H group: P = 0.0009, odds ratio: 11.2). Furthermore, SLE patients with the combined FcgammaR risk alleles exhibited more severe periodontal tissue destruction compared to other SLE patients. The frequencies of IL-1 polymorphic alleles were too low to assess the association with SLE or periodontitis.

CONCLUSION

The combination of stimulatory FcgammaRIIA and inhibitory FcgammaRIIB genotypes may increase susceptibility to SLE and periodontitis in the Japanese population.

NADPH oxidase (CYBA) and FcgammaR polymorphisms as risk factors for aggressive periodontitis: a case-control association study

INTRODUCTION

Neutrophils (PMN) in aggressive periodontitis (AgP) patients have been reported to be hyperactive especially with regards to superoxide production. Polymorphisms in genes influencing PMN function have been proposed as candidate risk factors for AgP. The aim of this study was to test the association of specific gene polymorphisms affecting PMN functions with AgP.

MATERIALS AND METHODS

Two hundred and twenty-four patients with confirmed diagnosis of AgP and 231 subjects with healthy periodontium took part in the study. A blood sample was collected from subjects and genotypes for p22phox (CYBA) NADPH oxidase, FP, Fcalpha and Fcgamma receptors were analysed in a blind fashion.

RESULTS

The C242T p22phox NADPH oxidase T allele was significantly associated with AgP in a multiple logistic regression model adjusting for confounders, and this was observed for all subjects [p = 0.002, odds ratio (OR) = 1.87, 95% confidence interval (CI) = 1.27-2.83] and Caucasians (p = 0.009, OR=2.07, 95% CI = 1.20-3.59). Concomitant presence of C242T p22phox NADPH oxidase T allele and FcgammaRIIIb NA1 homozygosity was associated with the generalized AgP phenotype in Caucasians (p = 0.001, OR = 30.35, 95% CI = 3.81-241.97).

CONCLUSIONS

C242T p22phox NADPH oxidase and FcgammaR polymorphisms may predispose to AgP through a modulation of neutrophil superoxide production.

CSF1 gene associated with aggressive periodontitis in the Japanese population

Aggressive periodontitis (AgP) is characterized by the early onset of the rapid and progressive destruction of the alveolar bone. We investigated the correlation of single nucleotide polymorphisms (SNPs) in candidate genes with AgP in the Japanese population in order to determine the genetic risk factors for this complex disease. Among 11 genes related to bone formation and resorption, 43 known SNPs were tested in 98 case and 88 control samples for association with AgP by using SNP genotyping techniques. Among these, three polymorphisms located in the colony stimulating factor 1 (CSF1) gene showed a positive association with AgP. This is the first case of an association between a CSF1 polymorphism and a human disease.

Fcgamma receptor polymorphisms and periodontal status: a prospective follow-up study

AIMS

The aims of this study were to assess: (i) the distribution of Fcgamma receptor polymorphisms among patients with chronic periodontitis ("cases") and control subjects with no/minimal loss of periodontal tissue support in a Caucasian population; (ii) whether these polymorphisms can serve as severity markers for periodontitis; and (iii) whether they have any bearing on the response to periodontal therapy.

METHODS

The study sample consisted of 132 cases and 73 controls of comparable age and gender. Full-mouth periodontal status was assessed. Subgingival plaque (PL) samples and blood samples were obtained and analysed with respect to 19 bacterial species and homologous serum immunoglobulin G titres. Polymorphisms in the Fcgamma receptor IIa (131R/H) and IIIb (NA1/NA2) were assessed by polymerase chain reaction. Patients underwent periodontal therapy and were followed up at 4 and 30 months.

RESULTS

Neither polymorphism showed a skewed distribution among cases and controls. At baseline, periodontitis patients with Fcgamma RIIa-H/H131 genotype had more PL and deeper pockets than patients in other genotype groups (p < 0.05). Both bacterial levels and antibody titres were unrelated to genotype. The longitudinal analysis failed to detect an association between genotype and response to periodontal therapy.

CONCLUSIONS

The present data failed to demonstrate a clinically relevant relationship between the Fcgamma receptor IIa (131R/H) or IIIb (NA1/NA2) polymorphism and periodontal status.

Distribution of FcγRIIa and FcγRIIIb Genotypes in Patients With Generalized Aggressive Periodontitis

BACKGROUND

Polymorphisms in FcgammaR have been associated with different forms of periodontitis. This study determined the frequency of FcgammaRIIa and FcgammaRIIIb alleles/genotypes in patients with generalized aggressive periodontitis (GAgP).

METHODS

Thirty-one GAgP and 49 periodontally healthy Brazilian subjects participated in the study. Full-mouth periodontal examinations were carried out, and mouthwash samples were collected for human DNA isolation. FcgammaR genotyping was performed by polymerase chain reaction and hybridization with allele-specific oligonucleotide probes. Significant differences between groups were sought by Mann-Whitney, chi2, and Fisher exact tests and configural frequency analysis.

RESULTS

FcgammaRIIa-H131 (53.8%) and FcgammaRIIIb-NA1 (75%) were the most prevalent alleles in this sample population. A significant overrepresentation of FcgammaRIIIb-NA2 was observed in the GAgP group, whereas FcgammaRIIIb-NA1 was detected more often in healthy individuals (odds ratio, 32.5; 95% confidence interval [CI], 10.6 to 99.8; P<0.001). No significant differences in the distribution of the FcgammaRIIa genotypes were observed between the groups. The prevalence of FcgammaRIIIb-NA2/NA2 was higher in GAgP patients, whereas FcgammaRIIIb-NA1/NA1 was predominant in the healthy group (chi2=45.1; P<0.001). The combination of the genotypes FcgammaRIIIb-NA2/NA2 plus FcgammaRIIa-H/H131 was observed more frequently in GAgP subjects than expected from marginal frequencies (chi2=12.5; P<0.001).

CONCLUSIONS

The data suggest that the FcgammaRIIIb-NA2 allele and/or FcgammaRIIIb-NA2/NA2 genotype and the composite genotype FcgammaRIIIb-NA2/NA2 plus FcgammaRIIa-H/H131 may be associated with GAgP, whereas FcgammaRIIIb-NA1 and/or FcgammaRIIIb-NA1/NA1 may be related to periodontal health in this sample of the Brazilian population.

Genetic analysis of HLA, NA and HPA typing in type 2 diabetes and ASO

We examined the genetic status of human leucocyte antigens (HLA), human platelet alloantigens (HPA) and neutrophil-specific antigens (NA) in patients with type 2 diabetes mellitus and diabetic arteriosclerosis obliterans (ASO). To our knowledge, the present study is the first report showing the relationship among three genetic factors in type 2 diabetes mellitus and ASO patients. HLA typing was performed by the polymerase chain reaction (PCR)-restriction fragment length polymorphism method. HPA-typing and NA-typing were by a PCR-sequence-specific primer method. The incidence of HLA-DRB1*1501 was found to be significant in type 2 diabetes and non-diabetic, particularly ASO-positive patients, compared to control subjects. There were no differences in NA1/NA2 between the control and diabetic or non-diabetic ASO groups. However, the frequency of NA2/NA2 in ASO-positive diabetes and non-diabetic ASO patients was significantly higher than controls. The a/b genotype of HPA-5a/5b was significantly lower in type 2 diabetes and non-diabetic ASO-positive patients than in controls. These findings suggest that genetic studies of HLA, NA and HPA could be useful to understand the pathogenesis of type 2 diabetes and ASO.

Human Fc receptors: critical targets in the treatment of autoimmune diseases and transplant rejections

The receptors for the Fc region of immunoglobulins (FcR) are members of the immunoglobulin superfamily. They are expressed on various hematopoietic cells and constitute a link between humoral and cell-mediated immunity. The activation and downmodulation of immune responses are controlled by signals from activating and inhibitory FcR, expressed on the surface of immune cells. The signaling regions, defined as immunoreceptor-tyrosine-based activation motif and immunoreceptor-tyrosine-based inhibitory motif, are contained within the cytoplasmic domain of FcR or of the adaptor proteins associated with FcR. Activating and inhibitory FcR are usually coexpressed on the surface of the same cell and coengaged by the same ligand, functioning in concert to keep a balanced immune response. Impairment of the functional balance between activating and inhibitory FcR leads either to hyperactivity to foreign and self antigens or to unresponsiveness as seen in many autoimmune diseases and infections. Pathologic conditions in which immunoglobulin-FcR interactions play a major role, as well as the outcome of treatment with intravenous immunoglobulin and monoclonal antibodies, may be influenced by targeting FcR.

Effect of genetic variability on the inflammatory response to periodontal infection

AIM

To review the association between genetic variability and the inflammatory response induced by periodontal infection.

MATERIAL AND METHODS

A search of MEDLINE-PubMed was performed from January 2000 up to and including March 2005. The search included all types of publications, published in English without other limitations. The following search terms were used: "cytokine polymorphism", "gene polymorphism", "periodontitis", "gingivitis", "inflammation" and "host-response". The papers resulting from the above search were used as an additional source for relevant articles.

RESULTS

Genetic variability was examined for the correlation to clinical indicators of inflammation such as bleeding on probing (BOP), gingival inflammation, cytokine in gingival crevicular fluid (GCF) and cytokine production by inflammatory cells. According to the current literature, most of the studies found no association between genetic variability and BOP, gingival inflammation or cytokine concentrations in the GCF. These studies were hampered by inappropriate study designs and the use of inflammatory parameters as secondary rather than primary outcome variables. The data suggest that the production of inflammatory mediators by inflammatory cells may be affected by different genetic traits but further studies are needed in order to establish this association.

CONCLUSIONS

To date, there is no clear correlation between any of the gene polymorphisms and clinical indicators of inflammation. The powering of studies to reveal associations between single or multiple nucleotide polymorphisms and inflammatory parameters will need to involve a much larger number of subjects than were used in the past. The available data (including the interleukin-1 composite genotype) do not currently support the utility of such tests in the diagnosis and prognostic assessments of periodontal diseases.

Identification of genetic risk factors for periodontitis and possible mechanisms of action

AIM

To review the literature for genetic risk factors associated with periodontitis.

METHODS

Computerized search of the literature in English using key words: Periodontitis; Genes; Mutation; Polymorphism; Risk.

RESULTS AND CONCLUSIONS

Mutations in the cathepsin C gene (CTSC) have been identified as causal for the Papillon-Lefèvre syndrome (PLS), which includes prepubertal periodontitis (PP). Some CTSC mutations are causal for PP without PLS. No relationship has been demonstrated between CTSC mutations and other forms of periodontitis. Genetic polymorphisms in a candidate gene approach have been explored as risk factors for periodontitis. There is limited evidence that some polymorphisms in the genes encoding interleukins (IL)-1, Fc gamma receptors (Fc gammaR), IL-10 and the vitamin D receptor, may be associated with periodontitis in certain ethnic groups. However relatively large variations in carriage rates of the Rare (R)-alleles among studies on any polymorphism were observed. The available studies appear under-powered and do not adequately take into account other pertinent risk factors for periodontitis. Future studies should include larger cohorts, should clearly define phenotypes and should adequately control for other risk factors. In addition to the candidate gene approach, alternative strategies need to be considered to elucidate the gene variations, which confer risk for periodontitis.

Analytical epidemiology of periodontitis

AIMS

To review the literature related to the analytical epidemiology of periodontitis generated over the past decade. This review does not deal with descriptive epidemiologic studies of the prevalence, extent and severity of periodontitis with respect to global geography, but focuses exclusively on analytical epidemiology issues, including the challenges posed by the use of different case definitions across studies, current theories and models of disease progression, and risk factors associated with the onset and progression of periodontitis.

METHODS

Relevant publications in the English language were identified after Medline and PubMed database searches.

FINDINGS AND CONCLUSIONS

There is a conspicuous lack of uniformity in the definition of periodontitis used in epidemiologic studies, and findings from different research groups are not readily interpretable. There is a lack of studies that specifically address the distinction between factors responsible for the onset of periodontitis versus those affecting its progression. Colonization by specific bacteria at high levels, smoking, and poorly controlled diabetes have been established as risk factors for periodontitis, while a number of putative factors, including specific gene polymorphisms, have been identified in association studies. There is a clear need for longitudinal prospective studies that address hypotheses emerging from the cross-sectional data and include established risk factors as covariates along with new exposures of interest. Intervention studies, fulfilling the "targeting" step of the risk assessment process, are particularly warranted. Obvious candidates in this context are studies of the efficacy of elimination of specific bacterial species and of smoking cessation interventions as an alternative to the traditional broad anti-plaque approach in the prevention and control of periodontitis. Ideally, such studies should have a randomized-controlled trial design.

Severity of Guillain-Barré syndrome is associated with Fc gamma Receptor III polymorphisms

Macrophages and ganglioside-specific IgG are involved in the pathogenesis of Guillain-Barre syndrome (GBS). Leukocyte IgG receptors (Fc gammaR) confer potent cellular effector functions to the specificity of IgG. The efficacy of IgG-mediated cellular inflammatory responses is determined by functional polymorphisms of three Fc gammaR subclasses (Fc gammaRIIa: H131/R131; Fc gammaRIIIa: V158/F158; Fc gammaRIIIb: NA1/NA2). Fc gammaR genotype distributions were determined in a Dutch, and British cohort of GBS patients and controls. In addition, a meta-analysis incorporating all previously published data, encompassing a total of 345 GBS patients and 714 healthy controls, was performed. Results suggest that Fc gammaRIII genotypes may represent mild disease-modifying factors in GBS.

FcγRIIIb Genotypes and Smoking in Periodontal Disease Progression Among Community-Dwelling Older Adults in Japan

BACKGROUND

FcgammaRIIIb genotypes and smoking are risk factors for periodontal disease. However, the interaction of FcgammaRIIIb- NA1-NA2 polymorphism with smoking remains unclear. The purpose of this study was to determine if FcgammaRIIIb-NA1-NA2 polymorphism and smoking are associated with periodontal disease progression among elderly people.

METHODS

Among 70-year-old subjects, 164 with neither diabetes mellitus nor blood sugar > or =140 mg/dl, who had more than 20 teeth and who could participate in both the baseline and the follow-up examinations were included in the study. The NA1 group comprised subjects with FcgammaRIIIb-NA1NA1 genotype (N = 53), while the NA2 group included subjects with FcgammaRIIIb-NA1NA2 or NA2NA2 genotype (N = 111). We examined the progression of periodontitis by measuring attachment loss during 3 years.

RESULTS

The frequency of subjects who showed > or =4 mm additional attachment loss at one or more sites was 55.6% for smokers and 37.2% for non-smokers. The odds ratio (OR) was 2.13 (confidence interval [CI]: 0.92 to 4.76). We found a better association between periodontal progression and smoking in the NA2 group. The OR for smokers was 3.03 (CI:1.12 to 8.33, P = 0.028). Additionally, the mean number of sites with > or =4 mm additional attachment loss per person between smokers and non-smokers in the NA2 group or between smokers and non-smokers in the NA1 group was 2.90 3.42 and 0.74 1.53 or 0.57 0.79 and 0.68 1.03, respectively (P <0.001; analysis of variance [ANOVA]).

CONCLUSION

Our results may suggest an association between smoking and periodontal disease progression in elderly people with FcgammaRIIIb-NA2 polymorphism.

Enhancement of the antibody-dependent cellular cytotoxicity of low-fucose IgG1 Is independent of FcgammaRIIIa functional polymorphism

PURPOSE

The most common polymorphic variant of Fcgamma receptor type IIIa (FcgammaRIIIa), FcgammaRIIIa-158F, has been associated with inferior clinical responses to anti-CD20 chimeric IgG1 rituximab compared with FcgammaRIIIa-158V. As we previously found that removal of fucose residues from the oligosaccharides of human IgG1 results in enhanced antibody-dependent cellular cytotoxicity, we compared the effects of the FcgammaRIIIa gene (FCGR3A) polymorphism on normal and low-fucose versions of rituximab on antibody-dependent cellular cytotoxicity.

EXPERIMENTAL DESIGN

The polymorphism at position 158 of FcgammaRIIIa was determined for the peripheral blood mononuclear cells (PBMCs) of 20 healthy donors. The PBMCs were then used as effector cells to compare the antibody-dependent cellular cytotoxicity of rituximab and a low-fucose version, KM3065. The contributions of the different cell types within the PBMC to antibody-dependent cellular cytotoxicity were examined.

RESULTS

We found KM3065-mediated antibody-dependent cellular cytotoxicity was increased 10 to 100-fold compared with rituximab for each of the 20 donors. In contrast to rituximab, KM3065 antibody-dependent cellular cytotoxicity enhancement was similar for both FCGR3A alleles and thus independent of genotype. In addition, antibody-dependent cellular cytotoxicity of both KM3065 and rituximab requires natural killer cells but not monocytes nor polymorphonuclear cells. The antibody-dependent cellular cytotoxicity (ADCC) of each of the 20 donors correlated with the natural killer cell numbers present in the PBMCs. Importantly, using KM3065, the ADCC mediated by effector cells bearing the lower affinity variant FcgammaRIIIa-158F was significantly increased compared with rituximab-mediated ADCC using effector cells bearing the higher affinity FcgammaRIIIa-158V receptors.

CONCLUSIONS

The use of low-fucose antibodies might improve the therapeutic effects of anti-CD20 therapy for all patients independent of FcgammaRIIIa phenotype beyond that currently seen with even the most responsive patients.

FcgammaRIIB gene polymorphisms in Japanese periodontitis patients

Human type II low-affinity receptor for immunoglobulin G (FcgammaRII) constitutes a clustered gene family consisting of FcgammaRIIA, IIB and IIC genes. FcgammaRIIB is unique in its ability to transmit inhibitory signals in B cells via immunoreceptor tyrosine-based inhibitory motif (ITIM). B-cell activation and subsequent elevated production of IgG are the immunopathological features of inflammatory disease such as periodontitis. To determine whether an association with periodontitis susceptibility exists, genetic polymorphisms of FcgammaRIIB were examined in Japanese patients with aggressive periodontitis (AGP) and chronic periodontitis (CP), and in the race-matched healthy controls (HCs). A significant difference was observed in the distribution of FcgammaRIIB-232I/T allele (exon 5) between the AGP and HC groups, with enrichment of the 232T in the AGP group (P=0.006). In addition, the FcgammaRIIB-nt 646-184A/G allele (intron 4) distribution was significantly different between the CP and HC groups, with enrichment of the nt 646-184A in the CP group (P=0.011). These results document the association of FcgammaRIIB gene polymorphisms with susceptibility to periodontitis in the Japanese.

Association of tumor necrosis factor receptor type 2 +587 gene polymorphism with severe chronic periodontitis

BACKGROUND

Genetic polymorphisms for cytokines and their receptors have been proposed as potential markers for periodontal disease. Tumor necrosis factor receptor 2 (TNFR2) is one of the cell surface receptors for TNF-alpha. Recent studies have suggested that TNFR2 gene polymorphism is involved in autoimmune and other diseases.

OBJECTIVES

The aim of the present study is to evaluate whether TNFR2(+587T/G) gene polymorphism is associated with chronic periodontitis (CP).

METHODS

One hundred and ninety-six unrelated subjects (age 40-65 years) with different levels of CP were identified according to established criteria, including measurements of probing pocket depth (PPD), clinical attachment level (CAL), and alveolar bone loss (BL). All subjects were of Japanese descent and non-smokers. Single nucleotide polymorphism at position +587(T/G) in the TNFR2 gene was detected by a polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) method.

RESULTS

The frequency and the positivity of the +587G allele were significantly higher in severe CP patients than in controls (p=0.0097; odds ratio=2.61, p=0.0075; odds ratio=3.06). In addition, mean values of PPD, CAL, and BL were significantly higher in the +587G allele positive than in the negative subjects (p=0.035, 0.022, and 0.018, respectively).

CONCLUSIONS

These findings suggest that the TNFR2(+587G) polymorphic allele could be associated with severe CP in Japanese.

Association of Fcgamma receptor IIa genotype with chronic periodontitis in Caucasians

BACKGROUND

Functional polymorphisms of immunoglobulin G (IgG) Fc receptors IIIa and IIIb (FcgammaRIIIa and FcgammaRIIIb) have been shown as risk factors for periodontitis. The aim of this study is to examine whether FcgammaRIIa polymorphism is associated with a disease risk as well.

METHODS

Baseline periodontal and general health examinations were carried out on 1,221 Caucasian adults. From these, 422 subjects with moderate to severe, or little or no periodontal disease were assigned to two groups according to their mean clinical attachment loss (CAL). Subjects with mean CAL > or = 2.94 mm were diagnosed with chronic periodontitis (n = 213, 62 never-smokers and 151 smokers). Subjects with mean CAL < or = 1.77 mm were considered as having little or no periodontal disease and designated as controls (n = 209, 125 never-smokers and 84 smokers). The FcgammaRIIa genotype for three bi-allelic polymorphisms (FcgammaRIIa-R/ R131, R/H131, and H/H131) was determined by means of allele-specific polymerase chain reactions.

RESULTS

The distribution of FcgammaRIIa genotype between the patient and control groups was significantly different, with enrichment of the high ligand-binding genotype FcgammaRIIa-H/H131 in the patients (patients versus controls: 36.6% versus 25.4%; P = 0.04). Multivariate logistic regression model demonstrated that subject age and gender, smoking, and the FcgammaRIIa genotype were significantly associated with severity of chronic periodontitis. For smokers, a significant over-representation of FcgammaRIIa-H/H131 in the patient group compared to the control group (patients versus controls: 35.1% versus 19.0%; P = 0.03). Additionally, smokers with FcgammaRIIa-H/H131 exhibited significantly greater mean CAL (mean +/- SE: 3.44 +/- 0.16 mm) than those with FcgammaRIIa-R/H131 (2.91 +/- 0.14 mm) and R/R131 (2.82 +/- 0.16 mm) (P = 0.04). There was no association between FcgammaRIIa genotype and the disease susceptibility or severity in subjects who had never smoked.

CONCLUSIONS

Our results suggest that the FcgammaRIIa-H/H131 genotype may be associated with chronic periodontitis risk (and disease severity) in Caucasian smokers. Further studies with families and studies of mechanisms are necessary to help establish the extent to which this is a genetic determinant of periodontal diseases.

Interleukin-4 gene polymorphisms in Japanese and Caucasian patients with aggressive periodontitis

OBJECTIVES

Recently, interleukin (IL) 4 gene polymorphisms have been analyzed in association with periodontitis. Genetic differences between Caucasian and Japanese patients with periodontitis have previously been detected. The aim of the present study was to analyze IL-4 genotypes in Caucasian and Japanese patients with aggressive periodontitis (AgP).

MATERIAL AND METHODS

One hundred and twenty-four subjects were included in the study, 31 Japanese and 30 Caucasian patients with generalized AgP, plus 30 Japanese and 33 Caucasian healthy controls. IL-4 polymorphisms were determined by polymerase chain reaction. A logistic regression was used to investigate the possible association of the genotypes with the disease in both populations. Odds ratio (OR) estimates were analyzed for allele frequencies.

RESULTS

No significant association of IL-4 polymorphisms with the risk of AgP was determined in either population. However, the allele frequencies showed different results between populations. The carriage of the polymorphism in intron 2 was higher in Caucasian patients compared with controls (OR: 2.0, 95% confidence interval: [1.0;4.2]. Furthermore, the frequency of the IL-4 promoter/intron 2 composite genotype (PP+/IP+) in patients and controls, respectively, was found to be approximately 25% and 60% higher in the Japanese population than in the Caucasian population.

CONCLUSION

There was no evidence of an association of IL-4 genotypes and AgP in either population, although the frequencies of the IL-4 genotypes in the Japanese and the Caucasians were different.

Gm (23) allotypes and Fcgamma receptor genotypes as risk factors for various forms of periodontitis

OBJECTIVES

Given the diversity of the distribution of the Gm (23) allotypes and FcgammaR genotypes in different ethnic groups, it was our purpose to examine their clinical significance in periodontitis in Taiwan.

MATERIAL & METHODS

Genomic DNA of 50 patients with chronic periodontitis (CP), 30 patients with generalized aggressive periodontitis (G-AP) and 74 healthy controls were harvested. The Gm (23) allotypes were determined by radial immunodiffusion test, and the FcgammaR IIa (CD32) and IlIb (CD16) genotypes were determined by polymerase chain reaction-based allele-specific oligonucleotide hybridization.

RESULTS

The overall carrier rate of the Gm (23+) allotype was higher than 85%, and the Gm (23-) allotype was statistically over-represented in patients with CP compared to the controls. There were no differences in the distributions of the three genotypes of FcgammaR IIa and IIIb among the three tested groups. The frequency of the R131 allele of the FcgammaR IIa polymorphisms was higher in G-AP than in CP when R/H allelic frequencies (p = 0.01) were examined by the chi2 test.

CONCLUSION

The Gm (23-) allotype might be a potential risk factor for CP. Although the R131 allele of FcgammaR IIa occurred more frequently in G-AP than in CP, its clinical significance could not be justified in this study.