Relevance of Fc gamma RIIIa-158V-F polymorphism to recurrence of adult periodontitis in Japanese patients

Non-targeted characterization of attributes affecting antibody-FcγRIIIa V158 (CD16a) binding via online affinity chromatography-mass spectrometry

Antibodies facilitate targeted cell killing by engaging with immune cells such as natural killer cells through weak binding interactions with Fcγ receptors on the cell surface. Here, we evaluate the binding affinity of the receptor FcγRIIIa V158 (CD16a) for several therapeutic antibody classes, isoforms, and Fc-fusion proteins using an immobilized receptor affinity liquid chromatography (LC) approach coupled with online mass spectrometry (MS) detection. Aglycosylated FcγRIIIa was used in the affinity chromatography and compared with published affinities using glycosylated receptors. Affinity LC-MS differentiated the IgG1 antibodies primarily according to their Fc glycosylation patterns, with highly galactosylated species having greater affinity for the immobilized receptors and thus eluting later from the column (M5< G0F < G0 afucosylated ≅ G1F < G2F). Sialylated species bound weaker to their asialylated counterparts as reported previously. High mannose glycoforms bound weaker than G0F, contrary to previously published studies using glycosylated receptors. Also, increased receptor binding affinity associated with afucosylated antibodies was not observed with the aglycosylated FcγRIIIa. This apparent difference from previous findings highlighted the importance of the glycans on the receptors for mediating stronger binding interactions. Characterization of temperature-stressed samples by LC-MS peptide mapping revealed over 200 chemical and post-translational modifications, but only the Fc glycans, deamidation of EU N325, and an unknown modification to either proline or cysteine residues of the hinge region were found to have a statistically significant impact on binding.

Abbreviations: Antibody-dependent cell-mediated cytotoxicity (ADCC), chimeric antigen receptor (CAR), Chinese hamster ovary (CHO), dithiothreitol (DTT), electrospray ionization (ESI), hydrogen-deuterium exchange (HDX), filter aided-sample preparation (FASP), Fcγ receptor (FcγR), fragment crystallizable (Fc), high-pressure liquid chromatography (HPLC), immunoglobulin G (IgG), liquid chromatography (LC), monoclonal antibody (mAb), mass spectrometry (MS), natural killer (NK), N-glycolylneuraminic acid (NGNA), N-acetylneuraminic acid (NANA), principal component analysis (PCA), surface plasmon resonance (SPR), trifluoroacetic acid (TFA), and extracted mass chromatogram (XMC).

Extending traditional antibody therapies: Novel discoveries in immunotherapy and clinical applications

Immunotherapy has been well regarded as one of the safer and antigen-specific anti-cancer treatments compared to first-generation chemotherapy. Since Coley's discovery, researchers focused on engineering novel antibody-based therapies. Including artificial and modified antibodies, such as antibody fragments, antibody-drug conjugates, and synthetic mimetics, the variety of immunotherapy has been rapidly expanding in the last few decades. Genetic and chemical modifications to monoclonal antibody have been brought into academia, in vivo trials, and clinical applications. Here, we have looked around antibodies overall. First, we elucidate the antibody structure and its cytotoxicity mechanisms. Second, types of therapeutic antibodies are presented. Additionally, there is a summarized list of US Food and Drug Administration (FDA)-approved therapeutic antibodies and recent clinical trials. This review provides a comprehensive overview of both the general function of therapeutic antibodies and a few main variations in development, including recent advent with the proposed mechanism of actions, and we introduce types of therapeutic antibodies, clinical trials, and approved commercial immunotherapeutic drugs.

Anti-CD137 monoclonal antibody enhances trastuzumab-induced, natural killer cell-mediated cytotoxicity against pancreatic cancer cell lines with low human epidermal growth factor-like receptor 2 expression

Because human epidermal growth factor-like receptor (HER) 2 is expressed on the surface of human pancreatic carcinoma cells to varying degrees, trastuzumab, an anti-HER2 monoclonal antibody (mAb), is expected to exert antibody-dependent, natural killer (NK) cell-mediated cytotoxicity (ADCC) against the cells. However, some reports found that the effect of trastuzumab against human pancreatic carcinoma cells was limited because most express only limited HER2. We examined whether anti-CD137 stimulating mAb could enhance trastuzumab-mediated ADCC against Panc-1, a human pancreatic cancer cell line with low HER2 expression, in vitro. Supplementation of anti-CD137 mAb could improve trastuzumab-mediated ADCC against Panc-1 which was insufficient without this stimulating antibody. The ADCC differed in individual cells, and this was related to the expression of CD137 on the surface of NK cells after trastuzumab stimulation in association with the Fcγ-RIIIA polymorphism. NK cells with Fcγ-RIIIA-VV/VF showed high levels of ADCC against Panc-1, but those with Fcγ-RIIIA-FF did not show optimal ADCC. In addition, trastuzumab-mediated ADCC against the human pancreatic cancer cell line Capan-1 with high HER2 expression was generally high and not affected by the Fcγ-RIIIA polymorphism. These results demonstrated that in Fcγ-RIIIA-VV/VF-carrying healthy individuals, trastuzumab plus αCD137 mAb could induce effective ADCC against HER2-low-expressing pancreatic cancer cell lines, and that such an approach may result in similar findings in patients with pancreatic cancer.

Frequency analysis of the g.7081T>G/A and g.10872T>G polymorphisms in the FCGR3A gene (CD16A) using nested PCR and their functional specific effects

Polymorphic variants p.66L>R/H (g.7081T>G/A; rs10127939) and p.176F>V (g.10872T>G; rs396991) in FCGR3A (CD16A) have been associated with defects in cytotoxic function of natural killer (NK) cells in humans. Genotyping of these variants in genomic DNA has been ambiguous because of high degree of homology between FCGR3A and FCGR3B. We designed a strategy to genotype these polymorphisms and to evaluate their effects on NK cells' cytotoxic activity. One hundred and fifteen individuals from different geographical regions of Colombia were included. Specific primers were designed to amplify FCGR3A exons 4 and 5 encompassing g.7081T>G/A and g.10872T>G by long-range and nested polymerase chain reaction and sequencing. The binding of different monoclonal antibodies to CD16A and NK antibody-dependent cellular cytotoxicity (ADCC) were evaluated. We demonstrate that amplifying and sequencing FCGR3A allows genotyping of g.7081T>G/A and g.10872T>G without interference from FCGR3B. Allele frequencies in our population were as follows: 7081T = 0.895, 7081G = 0.065, 7081 A = 0.039, 10872T = 0.673, and 10872G = 0.326. We also observed linkage disequilibrium between variants 7081T and 10872G. Interestingly, 176FF variant affected the reactivity of MEM154 monoclonal antibody against CD16A, but it did not affect ADCC. Our studies aimed to determine whether clinical association exists between these polymorphisms and NK cell function defects in patients with compatible phenotypes.

Association of Fc gamma-receptors IIa, IIIa, and IIIb genetic polymorphism with susceptibility to chronic periodontitis in South Indian population

BACKGROUND AND OBJECTIVE

Fc gamma receptors (FcγRs) are the members of the immunoglobulin superfamily and may play a role in the pathogenesis of periodontitis. Genetic variation in these receptors and its link with various forms of periodontitis is being studied in different populations. The aim of the present study is to determine whether specific FcγRIIa, FcγRIIIa, and FcγRIIIb alleles and/or genotypes are associated with risk for susceptibility to generalized chronic periodontitis (GCP) in South Indian population.

MATERIALS AND METHODS

The study population consisted of 120 South Indian subjects; 60 with GCP and 60 periodontally healthy. Deoxyribonucleic acid (DNA) was extracted from samples collected by scrapping buccal epithelium. FcγRIIa and FcγRIIIa genotyping were performed by polymerase chain reaction (PCR) amplification of DNA with allele-specific primers followed by allele-specific restriction digestion of the products. However, FcγRIIIb genotyping was done by allele-specific PCR.

RESULTS

No significant difference in the distribution of FcγRIIa H/R and FcγRIIIa NA1/NA2 genotypes or their respective alleles was observed in GCP patients and healthy subjects. For FcγRIIIa F/V genetic polymorphism, the homozygous V/V genotype and V allele were significantly overrepresented in GCP patients while F/F genotype and F allele in controls.

CONCLUSION

The present study demonstrates that FcγRIIIa V/V genotype, as well as V allele, could be a possible risk factor for chronic periodontitis in South Indian population.

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.

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.

FcgammaRIIIa-V/F 158 polymorphism in Turkish children with asthma bronchiale and allergic rhinitis

Fc receptors (FcR) play an important role in immune regulation. This might be linked to the variability in immune response, therefore relating to the pathogenesis of atopic diseases. The aim of the present study was to evaluate the FcgammaRIIIa gene polymorphism in Turkish children with asthma and allergic rhinitis. The study included 364 atopic children (184 bronchial asthma, 180 allergic rhinitis) and 234 healthy subjects as the control group, aged between 5 to 16 years. Patients were recruited from outpatient clinics of allergy and general pediatric care. Plasma IgE concentrations were measured by immunoassays and skin prick test was done in children with atopic diseases. The FcgammaRIIIa gene polymorphism was determined using the polymerase chain reaction method. Distribution of V158V genotype was significantly different among patient groups compared to controls (for asthmatic children OR: 5.33, 95% CI: 2.80-10.23, p < 0.001; for allergic rhinitis OR: 3.25, 95% CI: 1.75-6.07, p = 0.001). Distribution of 158 V allele was significantly different among asthmatic children (OR: 2.20, 95% CI: 1.65-2.92, p < 0.001) and allergic rhinitis patients (OR: 1.77, 95% CI: 1.32-2.35, p < 0.001) compared to healthy controls. Our study shows that the V158V genotype in FcgammaRIIIa gene polymorphism may be a genetic risk factor for the development of atopic diseases.

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.

Association of the OGG1 Ser326Cys polymorphism with tooth loss

Although tooth loss is a serious health problem for elderly people, little is known about the genetic basis for susceptibility to it. In the present study we aimed to find a single nucleotide polymorphism (SNP) associated with tooth loss. DNA samples from 119 outpatients (mean age=78.8 years) were genotyped on seven polymorphisms (tumor necrosis factor-alpha -1031T/C, interleukin-1beta -511C/T, interleukin-6 -634C/G, macrophage migration inhibitory factor -173G/C, interleukin-1 receptor antagonist variable number of tandem repeat in intron 2, matrix metalloproteinase-1 -16071G/2G, and oxoguanine glycosylase 1 (OGG1) Ser326Cys (1245C/G)), and the results were statistically evaluated. Of the seven polymorphisms tested, only OGG1 Ser326Cys was revealed to associate with tooth loss at a statistically significant level (P=0.0086). In addition, a multivariate logistic regression analysis in which age, gender, body mass index (BMI), and ischemic heart disease were included as independent variables indicated that Ser326Cys could be an independent factor affecting tooth loss (OR, 3.191; 95%CI, 1.174-8.672). The data suggest that the OGG1 Ser326Cys polymorphism may be associated with tooth loss.

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.

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.

Fcgamma receptor polymorphisms in relation to periodontitis

OBJECTIVES

Evidence suggests functional relevance for polymorphisms in FcgammaR in relation to inflammatory and infectious diseases. The present aim was to investigate genetic polymorphisms in three FcgammaR in relation to susceptibility and severity of periodontitis.

MATERIAL AND METHODS

The study population consisted of 68 periodontitis patients and 61 controls (Northern European Caucasian background, mean ages 44 and 42 years, respectively). Among the patients, 12 subjects were diagnosed with aggressive periodontitis (AgP) and 56 individuals were diagnosed with chronic periodontitis (CP). Radiographic bone levels were scored for all teeth in the patients. Subjects were typed for the following genes (alleles): FcgammaRIIa (R131 or H131), FcgammaRIIIa (V158 or F158) and FcgammaRIIIb (NA1 or NA2).

RESULTS

Hardy-Weinberg equilibrium criteria were fulfilled for the different genotypes at the three genes investigated. The frequency of the FcgammaRIIIa-V158 allele in the patient population (53%) was higher than in the control group (39%) (OR 1.73 [1.06-2.85], p=0.034). The V158 carriage rate in AgP was even higher (63%). The frequency of the FcgammaRIIa-H131 allele in the total periodontitis population was 58%; for AgP this was 79%, compared with 51% in the control population (OR 3.68 [1.29-10.5], p=0.013). Also, the frequency of the FcgammaRIIa-H/H131 genotype was significantly higher in AgP patients than in controls (OR 9.07 [1.29-63.56], p=0.026, adjusted for smoking status and other potential confounders). Moreover, patients with the FcgammaRIIa-H/H131 genotype had more severe radiographic bone loss than patients with the other FcgammaRIIa genotypes.

CONCLUSION

The current study of relative small sample size suggests that the FcgammaRIIa-H/H131 genotype may be a putative susceptibility and severity factor, and the FcgammaRIIIa-V158 allele a putative susceptibility factor for periodontitis in Northern European Caucasians. These results need further verification and the biological importance of these findings needs further investigation.

Rapid single-step FCGR3A genotyping based on SYBR Green I fluorescence in real-time multiplex allele-specific PCR

A polymorphism at position 559 in the cDNA of the FCGR3A gene encoding the FcgammaRIIIa generates two allotypes with either a valine (Val) or a phenylalanine (Phe) at amino acid position 158. This polymorphism is of major importance in immunopathology and in pharmacogenetics, especially monoclonal antibody treatments. In this study, we report a single-step and single-tube method for FCGR3A-158V/F genotyping by real-time multiplex allele-specific PCR and melting curve analysis in the presence of SYBR Green I fluorescent dye. Results obtained from 113 samples showed 100% accuracy compared to those obtained with a conventional PCR-based allele-specific restriction assay. Although this method requires expensive equipment, it is inexpensive in terms of consumables. It is also very rapid, reliable and suitable for large-scale analysis.

Risk of periodontitis in systemic lupus erythematosus is associated with Fcgamma receptor polymorphisms

BACKGROUND

Leukocyte Fc receptors for immunoglobulin G (FcgammaR) play a major role in the handling of immune complexes and pathogens in systemic lupus erythematosus (SLE) and periodontitis. Both diseases have been shown to be partly influenced by genetic components including FcgammaR genotype. The aim of this study was therefore to evaluate whether FcgammaR gene polymorphisms are associated with periodontitis risk in SLE patients.

METHODS

The study subjects consisted of 42 SLE patients with periodontitis (SLE/P), 18 SLE patients without periodontitis (SLE/H), 42 healthy subjects with periodontitis (H/P), and 42 healthy subjects without periodontitis (H/H), who were all unrelated Japanese non-smokers. Genomic DNA was isolated from peripheral blood, and FcgammaR genotypes for 3 biallelic polymorphisms (FcgammaRIIa-R131/H131, FcgammaRIIIa-158V/158F, FcgammaRIIIb-NA1/NA2) were determined by allele-specific polymerase chain reactions.

RESULTS

The SLE/P group was found to have more mild levels of periodontal destruction than the H/P group (P < 0.01). There was a significant difference in the distribution of FcgammaRIIa genotypes between SLE/P and H/H groups (P = 0.004). A significant overrepresentation of the FcgammaRIIa-R131 allele was found in the SLE/P group compared to the H/H group (SLE/P versus H/H: odds ratio [OR] 3.13, 95% confidence interval [CI] 1.46-6.77, P = 0.0013). Furthermore, the prevalence of periodontitis was found to be 70% in SLE patients. The FcgammaRIIa-R131 allele was also found to be overrepresented in the SLE/P group compared to the SLE/H group (SLE/P versus SLE/H: OR 3.40, 95% CI 1.18-10.25, P = 0.011).

CONCLUSION

These results show the FcgammaRIIa-R131 allele to be associated with periodontitis risk in SLE patients.

FcgammaR polymorphisms: Implications for function, disease susceptibility and immunotherapy

Leukocyte Fcgamma receptors (FcgammaR) confer potent cellular effector functions to the specificity of IgG. FcgammaR-induced leukocyte functions, including antibody-dependent cellular cytotoxicity, phagocytosis, superoxide generation, degranulation, cytokine production and regulation of antibody production, are essential for host defense and immune regulation. The efficacy of IgG-induced FcgammaR function displays inter-individual heterogeneity due to genetic polymorphisms of three FcgammaR subclasses, FcgammaRIIa (CD32a), FcgammaRIIIa (CD16a), and FcgammaRIIIb (CD16b). FcgammaR polymorphisms have been associated with infectious and autoimmune disease, or with disease severity. FcgammaR polymorphisms may furthermore serve as markers for therapeutic efficacy and side-effects of treatment with monoclonal antibodies. In this review, FcgammaR function and the relevance of FcgammaR polymorphisms as prognostic markers for inflammatory disease and antibody-based immunotherapy are discussed.

Fcgamma receptor IIa and IIIa polymorphisms in childhood immune thrombocytopenic purpura

Fcgamma receptor-mediated destruction of autoantibody-sensitized platelets is central to the immune pathophysiology of childhood immune thrombocytopenic purpura (ITP). Allelic variants exist among the random population for some Fcgamma receptors. The variants represent single nucleotide polymorphisms, leading to functional differences in the ability to bind immunoglobulin (Ig)G or IgG subclasses. The genotypic frequencies for two Fcgamma receptor single nucleotide polymorphisms, FcgammaRIIa-131 arginine (R) versus histidine (H) and FcgammaRIIIa-158 valine (V) versus phenylalanine (F) were examined in 98 children diagnosed with childhood ITP. The genotype frequencies were compared with those of 130 healthy control subjects. Chi-square analysis was used to determine whether the allelic frequencies of the high-affinity receptor variants were associated with childhood ITP. Both the FcgammaRIIa-131H and the FcgammaRIIIa-158V were significantly over-represented in children with ITP versus the control subjects (P-values 0.03). The same statistical difference was noted with the combined FcgammaRIIa-131H and FcgammaRIIIa-158V allelic gene frequencies. There was no statistical difference between children who later developed chronic ITP compared with children with acute ITP, suggesting that additional factors are responsible for the development of the chronic form of the disease. These observations underscore the importance of Fcgamma receptor-mediated cell clearance in childhood ITP.

Association of interleukin-1 receptor antagonist gene polymorphisms with early onset periodontitis in Japanese

BACKGROUND/AIMS

Early onset periodontitis (EOP), newly 'aggressive periodontitis', is considered to have genetic basis, which have not been clearly defined. The interleukin-1 (IL-1) gene cluster polymorphism as one of genetic factors may influence the expression of several chronic inflammatory diseases. The aim of this study is to investigate the frequency of single nucleotide polymorphisms (SNPs) in the genes encoding IL-1alpha, IL-1beta and a variable number of tandem repeat (VNTR) polymorphisms in the IL-1 receptor antagonist gene (IL-1RN) in 47 generalized EOP (G-EOP) patients and 97 periodontally healthy controls.

MATERIAL AND METHODS

All subjects were of Japanese descent and systemically healthy. They were identified according to established clinical criteria. SNPs in the IL-1alpha (+ 4845) and IL-1beta (- 511, + 3954) genes were analyzed by amplifying the polymorphic region using polymerase chain reaction (PCR), followed by restriction-enzyme digestion and agarose gel electrophoresis. IL-1RN (VNTR) polymorphisms were then detected by PCR amplification and fragment size analysis.

RESULTS

There was no significant difference in the IL-alpha (+ 4845) and IL-1beta (- 511, + 3954) genotypes and allele frequencies between G-EOP patients and healthy controls. However, the frequency of IL-1RN (VNTR) polymorphic alleles was found to be significantly increased in G-EOP patients (chi2 test, P = 0.007; odds ratio = 3.40). Additionally, the carriage rate of IL-1RN (VNTR) polymorphisms was significantly higher in G-EOP patients than in healthy controls (chi2 test, P = 0.005; odds ratio = 3.81).

CONCLUSION

These findings suggest that IL-1RN (VNTR) polymorphisms are associated with G-EOP in Japanese.

Genetic susceptibility to chronic periodontal disease

Evidence suggests that there is a significant genetic component to susceptibility and resistance to chronic periodontal disease. Data from both clinical studies and studies using animal models are reviewed here. Also outlined are the genomic methods that are now available for identifying susceptibility and resistance loci.

Analysis of vitamin D and Fcgamma receptor polymorphisms in Japanese patients with generalized early-onset periodontitis

Early-onset periodontitis (EOP) is considered to have a genetic basis which has not been clearly defined. Genetic polymorphisms of the vitamin D receptor (VDR-B-b) and the immunoglobulin-Fc-gamma receptor IIIb (FcgammaRIIIb-NA1-NA2) are associated with bone metabolism and infectious diseases, respectively. The purpose of this study was to investigate the associations of EOP with VDR and FcgammaRIIIb polymorphisms. Subjects were comprised of those with generalized EOP (G-EOP, n = 42), adult periodontitis (AP, n = 52), and healthy control (HC, n = 55). VDR and FcgammaRIIIb genotypes were determined by allele-specific polymerase chain-reactions. Our results indicated that frequencies of the VDR-B non-carrier and the FcgammaRIIIb-NA2 carrier were lower in the G-EOP compared with the AP and HC groups. Furthermore, we found a strong association between G-EOP and the VDR-Fc-gammaRIIIb composite genotype (G-EOP vs. AP - OR = 5.09, p = 0.009; G-EOP vs. HC - OR = 5.93, p = 0.004). In conclusion, no correlation was found between the VDR genotype and G-EOP. However, the VDR and Fc-gammaRIIIb genotype combination may be associated with susceptibility to G-EOP.

Candidate genes as potential links between periodontal and cardiovascular diseases

Recent epidemiological associations between periodontal disease and cardiovascular disease have led to a search for biological mechanisms that explain the associations. Genetic factors that influence biological processes involved in both diseases represent one of the potential mechanisms that may link periodontitis and cardiovascular disease. At present, several candidate genes have been investigated in one of the diseases but not the other. Although there are limited data to support a specific candidate gene as the explanation for observed associations between the 2 diseases, a few candidates look promising. One candidate that influences inflammation, interleukin-1 gene polymorphisms, has been associated with periodontal disease and cardiovascular disease. This review will consider biological mechanisms and genes that may be reasonable candidates for an etiological mechanism that influences the clinical characteristics of both periodontal disease and cardiovascular disease.

Analysis of single nucleotide polymorphisms in the 5'-flanking region of tumor necrosis factor-alpha gene in Japanese patients with early-onset periodontitis

BACKGROUND

Early-onset periodontitis (EOP) is considered to have a genetic basis, which has not been clearly defined. The tumor necrosis factor-alpha (TNF-alpha) gene polymorphism as one of the genetic factors may influence the expression of several chronic inflammatory diseases. The aim of the present study was to evaluate whether the polymorphisms in the 5'-flanking region of the TNF-alpha gene are associated with Japanese EOP patients.

METHODS

Forty-six Japanese, generalized EOP (G-EOP) patients and 104 Japanese healthy subjects were identified according to established clinical criteria. Twenty healthy subjects were analyzed by nucleotide sequence to screen polymorphisms of the 5'-flanking region of the TNF-alpha gene. Then, all subjects were analyzed by polymerase chain reaction and sequence-specific oligonucleotide probe (SSOP) methods.

RESULTS

We determined 5 single nucleotide polymorphisms at positions -1031 (T/C), -863 (C/A), -857 (C/T), -308 (G/A), and -238 (G/A) in the 5'-flanking region of the TNF-alpha gene. There were no significant differences in the genotype and allele frequency when we compared G-EOP patients to healthy subjects. Because the frequency of polymorphic alleles at positions -308 and -238 was very low in this study population, we demonstrated the existence of 4 detected haplotypes and 6 detected genotypes concerning 3 single nucleotide polymorphisms (-1031, -863, and -857). The frequency of the H1/H3 (TCC/TCT)-detected genotype tended to decrease in G-EOP patients compared to healthy subjects, but was not statistically significant.

CONCLUSION

These findings suggest there is no significant association between polymorphisms in the 5'-flanking region of the TNF-alpha gene and susceptibility to G-EOP in Japanese patients.

The Fc gamma receptor genotype as a severity factor for chronic periodontitis in Japanese patients

BACKGROUND

Functional polymorphisms of immunoglobulin G (IgG) Fc receptors (Fc gamma R) have been shown to be associated with generalized aggressive periodontitis (GAgP) or recurrence of chronic periodontitis (CP) in Japanese patients. The purpose of this study was to evaluate whether Fc gamma R polymorphisms are also associated with severity of CP.

METHODS

Fifty Japanese non-smoking patients with severe CP and 39 Japanese non-smoking patients with moderate CP were identified according to established clinical criteria, including measurements of probing depth (PD), clinical attachment level (CAL), and alveolar bone loss (BL). Fc gamma R genotypes for 3 bi-allelic polymorphisms (Fc gamma RIIa-R/H131, Fc gamma RIIIa-158V/F, Fc gamma RIIIb-NA1/NA2) were determined in these CP patients and 64 race-matched, non-smoking healthy controls by means of allele-specific polymerase chain reactions.

RESULTS

There was a significant over-representation of Fc gamma RIIIa-158V allele in severe CP patients compared to moderate CP patients (odds ratio 2.03, 95% confidence interval [CI] 1.03-4.01, chi 2 = 4.86, P = 0.028). In addition, we found a strong association between CP severity and Fc gamma R composite genotype comprising Fc gamma RIIIa-158V plus Fc gamma RIIIb-NA2 (severe CP versus moderate CP: odds ratio 4.69, 95% CI 1.52-15.10, chi 2 = 9.35, P = 0.002; severe CP versus healthy controls: odds ratio 4.10, 95% CI 1.62-10.59, chi 2 = 11.13, P = 0.0009). Moreover, CP patients positive for the composite genotype exhibited more severe signs of periodontitis than composite genotype-negative individuals (positive versus negative; mean PD: 3.8 mm versus 3.2 mm, P = 0.005; mean CAL: 4.5 mm versus 3.7 mm, P = 0.005; mean % BL: 37.6% versus 29.9%, P = 0.008).

CONCLUSION

Our results document the Fc gamma RIIIa-158V allele and possibly Fc gamma RIIIb-NA2 to be associated with severity of CP in Japanese patients.

Fcgamma receptors in autoimmune diseases

Fcgamma-receptors (Fcgamma-R) recognise the Fc portion of IgG and thus form a link between humoral and cellular immunity. These receptors are expressed by a variety of immune cells, and they function in the binding of immune complexes or IgG-opsonised particles, such as microbial pathogens. The are three major types of Fcgamma-R, namely Fcgamma-RI (CD64), Fcgamma-RII (CD32) and Fcgamma-RIII (CD16), and these differ in their ability to bind IgG and complexes. There are many isoforms of these receptors and a number of recently identified polymorphisms in their structure. This review describes the structure and function of these Fcgamma-Rs, and highlights how gene deficiencies and polymorphisms may contribute to the pathology of human diseases.

Polymorphisms of Fc gamma-receptors RIIa, RIIIa, and RIIIb in patients with adult periodontal diseases

Polymorphisms influencing the binding affinity between the Fcgamma receptors and IgG of different subclasses are thought to be of importance in the individual susceptibility to infections with Gram-negative bacteria contributing to periodontal disease. One hundred and fifty-four Caucasian subjects were clinically and radiographically examined for their periodontal status and genotyped for their allelic pattern of FcgammaRIIa, FcgammaRIIIa, and FcgammaIIIb polymorphism. In assessing periodontitis according to mean probing depth and attachment loss, no differences were found in allele frequencies or combined allotypes between the subjects with mild or moderate and those with severe signs of periodontitis. However, the extent and severity of bone loss were significantly associated with the genotype of the receptor FcgammaRIIIa. An increased risk of severe bone destruction was observed in individuals carrying the FcgammaRIIIa-VV genotype (OR = 5.3; 95% CI 1.4-26.2). FcgammaRIIIb is in linkage disequilibrium with FcgammaRIIIa. Hence it is also related to periodontal disease. There is no indication of an association between the polymorphism of FcgammaRIIa and periodontitis. The results are evidence that the FcgammaRIIIa genotype coding for the high affinity receptor imposes an additional risk of bone loss as does the FcgammaRIIIb genotype coding for the low affinity receptor.

Increased frequency of FcgammaRIIIb-NA1 allele in periodontitis-resistant subjects in an elderly Japanese population

Many elderly people show minimum periodontal tissue destruction, which might be partly due to genetic advantages in host immune response against periodontopathic bacteria. The human IgG Fc receptor IIIb on neutrophils bears a NA1-NA2 polymorphism. The FcgammaRIIIb-NA1 displays a more efficient interaction with IgG1- and IgG3-opsonized bacteria, compared with the FcgammaRIIIb-NA2. We investigated a 70-year-old Japanese population (n = 599) to determine whether the FcgammaRIIIb polymorphism was associated with resistance to periodontitis. Among subjects with > or = 20 teeth present, periodontitis-resistant (n = 46) and periodontitis-susceptible groups (n = 73) were selected based on the percentage of sites with > or = 4 mm probing attachment loss in the entire dentition. The FcgammaRIIIb-NA1 allotype was overrepresented in the periodontitis-resistant group, compared with the periodontitis-susceptible group (chi2 = 4.89, p = 0.03, odds ratio = 1.87, 95% CI, 1.07 to 3.28). This suggests that FcgammaRIIIb-NA1 may be associated with resistance to periodontitis.

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

BACKGROUND

Genetic polymorphisms of immunoglobulin G (IgG) Fc receptors (FcgammaR) were recently shown to be associated with recurrence rates of adult periodontitis (AP). The purpose of this study was to evaluate whether FcgammaR polymorphisms are also associated with generalized early-onset periodontitis (G-EOP) in Japanese patients.

METHODS

Thirty-eight Japanese patients with G-EOP and 83 Japanese patients with AP were identified according to established clinical criteria, including measurements of probing depth, clinical attachment level, and alveolar bone level. FcgammaR genotypes for 3 bi-allelic polymorphisms were determined in these G-EOP and AP patients and 104 race-matched healthy controls by means of allele-specific polymerase chain reactions.

RESULTS

There was a significant difference in the distribution of FcgammaRIIIb genotypes between G-EOP patients and healthy controls (P = 0.02). Additionally, a significant over-representation of FcgammaRIIIb-NA2 allele was observed in G-EOP patients as compared to AP patients and controls (P= 0.02, P= 0.009, respectively). Moreover, we found a strong association between G-EOP and the composite genotype comprising FcgammaRIIIb-NA2 and FcgammaRIIIa-158F (G-EOP versus controls: odds ratio 2.4, 95% CI 1.0-6.0, chi2 = 4.13, P= 0.04).

CONCLUSIONS

This study indicates that the FcgammaRIIIb-NA2 allele and possibly FcgammaRIIIa-158F could be associated with susceptibility to G-EOP in Japanese patients.

A novel PCR-based method for direct Fc gamma receptor IIIa (CD16) allotyping

Leukocyte IgG receptors (Fc gamma R) are important immune-response modulating molecules. Fc gamma RIIIa is expressed on macrophages, NK-cells and gamma delta-T cells and exhibits a genetically determined, functional polymorphism at nucleotide 559. This allelic difference predicts either a phenylalanine (F158) or valine (V158) at amino acid 158 in the membrane-proximal extracellular domain, and has been shown to be associated with autoimmune and infectious diseases. Published methods to determine Fc gamma RIIIa genotypes are cumbersome. Therefore, we developed a novel, rapid and reliable PCR-based method to determine Fc gamma RIIIa genotypes. Comparison of genotyping results with direct Fc gamma RIIIa sequencing of 60 blood donors showed 100% accuracy of this new method. Since genotype frequencies of Fc gamma R polymorphisms depend strongly on race and ethnicity, we compared Fc gamma RIIIa genotype frequencies of 176 Caucasian Dutch and 104 Japanese blood donors. Interestingly, these frequencies were not significantly different (P>0.1), in contrast to the Fc gamma RIIa and Fc gamma RIIIb genotype frequencies (P<0.001).