HLA-D types and serum IgG responses to Capnocytophaga in diabetes and periodontitis

Association between salivary microbiota and tacrolimus pharmacokinetic variability in kidney transplant

Kidney transplantation (KT) serves as a highly effective treatment for end-stage renal disease (ESRD). Nonetheless, the administration of tacrolimus, a commonly used immunosuppressant in KT, faces challenges due to the lack of dependable biomarkers for its efficacy and the considerable variability in tacrolimus pharmacokinetics (TacIPV). In this study, 183 saliva samples from 48 KT recipients under tacrolimus therapy, alongside 9 healthy control samples, were subjected to 16S rRNA sequencing. The analysis revealed significant differences in the composition of salivary microbiota among KT recipients, patients with ESRD, and healthy controls. Moreover, trough blood concentrations (C0) of tacrolimus were associated with alterations in microbiota composition. Notably, Capnocytophage consistently exhibited a negative correlation in both group-level and individual trends. Furthermore, distinct taxa were identified that effectively distinguished recipients with varying TacIPV, as demonstrated by a cross-validation random forest model (mean AUC = 0.7560), with Anaerolinea emerging as a prominent contributor to the classifier. These findings suggest that salivary microbiota is closely linked to tacrolimus C0 levels and could aid clinicians in differentiating KT recipients based on TacIPV.

Association of human leukocyte antigens Class I and Class II antigens with chronic periodontitis in East India

CONTEXT

Human leukocyte antigens (HLAs) have an important role in the determination of susceptibility and resistance to periodontal diseases in humans, which may vary from population to population.

AIMS

The aim of this study was to find out the association of HLA Classes I and II genes with chronic periodontitis in East Indian population.

MATERIALS AND METHODS

In a cross-sectional study design, a total of sixty participants of chronic periodontitis (CP) (mean age: 44.12 ± 5.85) and sixty subjects of periodontal disease-free controls (NP) Periodontitis free controls (mean age 41.85 ± 7.71) were analyzed for their various HLA combinations using serologic (microlymphocytotoxicity test) method. The results are further compared with the HLA profile of 100 samples of blood donors for which periodontal status was unknown. All the data were statistically analyzed by applying Chi-square test.

RESULTS

HLA-B7 (P = 0.003), DR7 (P = 0.001), DR53 (P = 0.001), and DQ3 (P = 0.001) were identified as susceptible phenotypes to CP, whereas HLA-A1 (P = 0.010), A3 (P = 0.001), and Cw4 (P = 0.001) phenotypes were identified to be associated with disease resistance.

CONCLUSION

The HLA-B7, DR7, DR53, and DQ3 alleles may represent as risk factors for CP in Eastern Population of India, whereas HLA-A1, A3, and Cw4 may indicate to protective factors for CP of the same.

A tale of two risks: smoking, diabetes and the subgingival microbiome

Although smoking and diabetes have been established as the only two risk factors for periodontitis, their individual and synergistic impacts on the periodontal microbiome are not well studied. The present investigation analyzed 2.7 million 16S sequences from 175 non-smoking normoglycemic individuals (controls), smokers, diabetics and diabetic smokers with periodontitis as well as periodontally healthy controls, smokers and diabetics to assess subgingival bacterial biodiversity and co-occurrence patterns. The microbial signatures of periodontally healthy smokers, but not diabetics, were highly aligned with the disease-associated microbiomes of their respective cohorts. Diabetics were dominated by species belonging to Fusobacterium, Parvimonas, Peptostreptococcus, Gemella, Streptococcus, Leptotrichia, Filifactor, Veillonella, TM7 and Terrahemophilus. These microbiomes exhibited significant clustering based on HbA1c levels (pre-diabetic (<6.5%), diabetic (6.5–9.9%), diabetics >10%). Smokers with periodontitis evidenced a robust core microbiome (species identified in at least 80% of individuals) dominated by anaerobes, with inter-individual differences attributable largely to the ‘rare biosphere’. Diabetics and diabetic smokers, on the other hand, were microbially heterogeneous and enriched for facultative species. In smokers, microbial co-occurrence networks were sparse and predominantly congeneric, while robust inter-generic networks were observed in diabetics and diabetic smokers. Smoking and hyperglycemia impact the subgingival microbiome in distinct ways, and when these perturbations intersect, their synergistic effect is greater than what would be expected from the sum of each effect separately. Thus, this study underscores the importance of early intervention strategies in maintaining health-compatible microbiomes in high-risk individuals, as well as the need to personalize these interventions based on the environmental perturbation.

HLA Haplotypes and Genotypes Frequencies in Brazilian Chronic Periodontitis Patients

Human leukocyte antigens (HLA) have a pivotal role in immune response and may be involved in antigen recognition of periodontal pathogens. However, the associations of HLA with chronic periodontitis (CP) have not been previously studied in the Brazilian population. In an attempt to clarify the issue of genetic predisposition to CP, we examined the distribution of HLA alleles, genotypes, and haplotypes in patients from Southern Brazil. One hundred and eight CP patients and 151 healthy and unrelated controls with age-, gender-, and ethnicity-matched were HLA investigated by polymerase chain reaction with sequence specific oligonucleotides. To exclude smoking as a predisposing factor, statistical analyses were performed in the total sample and in nonsmoking individuals. The significant results showed a positive association of the A∗ 02/HLA-B∗ 40 haplotype with CP (total samples: 4.2% versus 0%, Pc = 0.03; nonsmokers: 4.3% versus 0%, Pc = 0.23) and a lower frequency of HLA-B∗ 15/HLA-DRB1∗ 11 haplotype in CP compared to controls (total samples: 0.0% versus 4.3%, Pc = 0.04; nonsmokers: 0 versus 5.1%, P = 1.0). In conclusion, the HLA-A∗ 02/B∗ 40 haplotype may contribute to the development of CP, while HLA-B∗ 15/DRB1∗ 11 haplotype might indicate resistance to disease among Brazilians.

Periodontitis, Porphyromonas, and the pathogenesis of rheumatoid arthritis

Epidemiological data indicate a link between rheumatoid arthritis (RA) and periodontal disease (PD). In vitro and in vivo studies have sought to dissect potential mechanisms by which PD may contribute to initiation and progression of RA. However, these are both multifactorial, chronic diseases, and their complex etiologies and pathogenesis themselves remain incompletely understood. Could there really be an etiological link or does this simply represent a statistical coincidence muddied by common risk factors? This review seeks to provide background on these two diseases in the context of recent discoveries suggesting that their pathogenesis may be related. In particular, the process of citrullination, a post-translational protein modification, has been highlighted as a process common to both diseases. The evidence for a relationship between the diseases is explored and its potential mechanisms discussed.

Autoimmunity to specific citrullinated proteins gives the first clues to the etiology of rheumatoid arthritis

Rheumatoid arthritis (RA) is now clearly a true autoimmune disease with accumulating evidence of pathogenic disease-specific autoimmunity to citrullinated proteins. Citrullination, also termed deimination, is a modification of arginine side chains catalyzed by peptidylarginine deiminase (PAD) enzymes. This post-translational modification has the potential to alter the structure, antigenicity, and function of proteins. In RA, antibodies to cyclic citrullinated peptides are now well established for clinical diagnosis, though we argue that the identification of specific citrullinated antigens, as whole proteins, is necessary for exploring pathogenic mechanisms. Four citrullinated antigens, fibrinogen, vimentin, collagen type II, and alpha-enolase, are now well established, with others awaiting further characterization. All four proteins are expressed in the joint, and there is evidence that antibodies to citrullinated fibrinogen and collagen type II mediate inflammation by the formation of immune complexes, both in humans and animal models. Antibodies to citrullinated proteins are associated with HLA 'shared epitope' alleles, and autoimmunity to at least one antigenic sequence, the CEP-1 peptide from citrullinated alpha-enolase (KIHAcitEIFDScitGNPTVE), shows a specific association with HLA-DRB1*0401, *0404, 620W PTPN22, and smoking. Periodontitis, in which Porphyromonas gingivalis is a major pathogenic bacterium, has been linked to RA in epidemiological studies and also shares similar gene/environment associations. This is also the only bacterium identified that expresses endogenous citrullinated proteins and its own bacterial PAD enzyme, though the precise molecular mechanisms of bacterial citrullination have yet to be explored. Thus, both smoking and Porphyromonas gingivalis are attractive etiological agents for further investigation into the gene/environment/autoimmunity triad of RA.

Microbiologic and immunologic characteristics of periodontal disease in Hispanic americans with type 2 diabetes

BACKGROUND

The microbiology of periodontitis in type 1 diabetes has been reported, but less is known about type 2 diabetes. Moreover, these data have not linked microbial colonization, host response, and clinical presentation in type 1 or type 2 diabetes. The objectives of this study were to relate periodontal status, periodontal microorganisms, and host-response characteristics in Hispanic Americans with type 2 diabetes.

METHODS

Plaque and serum samples were obtained from 63 Hispanic American subjects with and without type 2 diabetes. The microbiology of subgingival plaque samples was evaluated using DNA checkerboard hybridization, and serum antibody to a battery of oral microorganisms was determined using an enzyme-linked immunosorbent assay.

RESULTS

In general, similar pathogens were present in periodontitis sites from subjects with and without type 2 diabetes, although the periodontitis sites in diabetes showed a higher frequency of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), and Campylobacter spp. Serum antibody to Campylobacter rectus was elevated in type 2 diabetes, whereas antibody to P. gingivalis and C. rectus were elevated in subjects with periodontitis, irrespective of diabetes status. Stratification of the population based upon antibody to P. gingivalis or C. rectus suggested a linkage between elevated antibody to P. gingivalis, increased frequency of diabetes, and significantly worse periodontitis.

CONCLUSION

The increased severity of periodontal disease with type 2 diabetes may reflect an alteration of the pathogenic potential of periodontal bacteria and/or a modification of the characteristics of the host's inflammatory response that may contribute to a breakdown in the homeostasis of the periodontium.

Are there HLA combinations typical supporting for or making resistant against aggressive and/or chronic periodontitis?

OBJECTIVE AND BACKGROUND

Human leukocyte antigens (HLA)/alleles have been considered as risk factors for periodontal disease. However, data from HLA associations is not consistent. Diversity of HLA antigen combinations and en bloc inherited HLA alleles (haplotypes), as known in systemic diseases, can be variable factors in disease association. Therefore, the aim of this study was to investigate the incidence of HLA homozygosities, heterozygosities and estimated haplotypes in German Caucasian groups with generalized aggressive (N = 50) and chronic (N = 102) periodontitis in comparison to control probands without periodontitis (N = 102).

METHODS

HLA-A, -B, -Cw, -DRB1, -DRB3/4/5, -DQB1 typing was carried out using both serologic (microlymphocytotoxicity test) and genomic (PCR-SSP: PCR with sequence specific primers) techniques. Frequencies of all homozygosities, heterozygosities and haplotypes were determined in all patients and controls.

RESULTS

In both patient groups, associations to HLA homozygosities and heterozygosities were found. Most striking was the significantly lower frequency of HLA-DRBblank* homozygosity (non-DRB3*/DRB4*/DRB5*) in chronic periodontitis (p < 0.05), whereas HLA-DRB1*15 : DRB5*(DR51) : DQB1*06 showed a slightly higher homozygosity rate in all patients. As the combination HLA-A*02,A*03 was significantly decreased in aggressive periodontitis (p < 0.05), HLA-A*01,A*03 heterozygosity was significantly lowered in chronic periodontitis (p < 0.05). Among others, the known positive associations for HLA-A*68/69 (A28) and HLA-DRB1*04 were confirmed by the haplotypes HLA-A*68/69 : Cw*07 : B*18 in aggressive periodontitis (p < 0.05) and HLA-Cw*08 : B*14 : DRB1*04 in chronic periodontitis (p < 0.05).

CONCLUSION

The present study elucidates the variety of HLA associations and therefore the difficulty to assign single HLA markers to periodontal disease. Susceptibility/resistance of both aggressive and chronic periodontitis may rather be influenced by particular HLA marker combinations. Associated HLA haplotypes may be of further importance for unknown gene loci representing a part of the genetic background for periodontitis. The different associations in aggressive and chronic periodontitis indicate different susceptibility/resistance factors for both diseases.

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

BACKGROUND/AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Gender differences in HLA phenotype frequencies found in German patients with generalized aggressive periodontitis and chronic periodontitis

HLA antigens have been considered as risk factors for periodontitis. Differences in prevalence and in the extent of attachment loss between males and females have suggested that gender-dependent HLA deviations could play a role in individual predisposition to periodontitis. The aim of the present study was therefore to investigate the incidence of gender-dependent HLA associations in 50 patients with generalized aggressive periodontitis (AP) and 102 patients with chronic periodontitis (CP) in comparison to 102 probands without any attachment loss caused by periodontitis. HLA typing was carried out using a microlymphocytotoxic test and a polymerase chain reaction with sequence-specific primers (PCR-SSP). Female AP patients showed an increase in the frequency of HLA-A*68/69 and a decrease in the frequency of DRBblank* (non-DRB3/4/5*) and DQB1*05-positive probands. Only in female CP patients was HLA-DQB1*0303 absent, whereas HLA-DQB1*06 homozygosity increased significantly. With regard to the (AP + CP) periodontitis group as a whole, the increased frequency of HLA-DQB1*06 homozygosity in females was similar to the findings obtained in the AP group. Evidently, gender is a confounding variable, which should be considered in further studies of HLA and periodontitis.

Papillon-Lefèvre syndrome: analysis of HLA antigens

OBJECTIVES

Papillon-Lefèvre syndrome (PLS) is a rare disease associated with prepubertal periodontitis. Our previous studies demonstrated that three unrelated patients with PLS showed the similar antigen-specific immune responses to Actinobacillus actinomycetemcomitans. The initiation of antigen-specific immune responses was involved with human leukocyte antigens (HLA) on antigen-presenting cells. The aim of this study was to examine HLA haplotypes in the three patients with PLS.

SUBJECTS AND METHODS

The three PLS patients, their mothers and the father of one patient participated in this study. HLA class I and class II antigens were determined serologically and DNA typing for DRB1 and DQB1 was performed using the restriction fragment length polymorphism-polymerase chain reaction method.

RESULTS

The distribution of serologic HLA haplotypes, in two of three patients, was found to be quite similar. The DNA typing revealed that DRB1*0406, DRB1*08032, DQB1*0302, DQB1*06011 genotypes were shared in the two patients. The probability of sharing these four DNA types in unrelated individuals was nearly 1:40,000 in the Japanese population.

CONCLUSION

Our results suggest that HLA antigen may be included as a possible host factor in the pathogenesis of PLS and that a genetically controlled immune response may account for an increased susceptibility to periodontal infection.

HLA genetics for diagnosis of susceptibility to early-onset periodontitis

Human leukocyte antigens (HLA) are essential in the recognition of foreign antigens in humoral immune response, which is genetically predetermined. Susceptibility to certain diseases that involve the immune response has been studied in relation to distinct HLA types. Although some diseases have been found to correlate to specific HLA loci positively, it has been difficult to isolate HLA types that predispose patients to periodontal destruction. Here, we review the current knowledge and recent advances in HLA genetics and its biology, which determine susceptibility to early-onset periodontitis (EOP). The HLA-DRB1*1501-DQB1*0602 genotype has been found with increasing frequency in EOP patients. This HLA genotype expresses aspartic acid at position 57 and glycine at position 70 on the DQ beta chain, suggesting a capability to bind certain bacterial antigens. The T cell response against the outer membrane protein (Ag53) of Porphyromonas gingivalis was examined via this HLA genotype. Strong T cell response against Ag53 p141-161 was inhibited partially by anti-DR antibody, but not by anti-DQ antibody. Possible host and bacterial peptides capable of binding DRB1*1501 were elucidated when the peptide sequence was compared to gene and protein databases. These results suggest that patients who have the HLA-DRB1*1501-DQB1*0602 genotype may have an accelerated T cell response to certain periodontopathic bacteria such as P. gingivalis in hyperimmune reactions and thus increased susceptibility to EOP.

Growth and hydrolytic enzyme production of Capnocytophaga gingivalis on different protein substrates

Capnocytophaga gingivalis was grown with proteins (albumin, collagen, mucin and hemoglobin) as carbon and energy sources in chemostat culture. The mu max (0.34 h-1) and biomass yield (0.96 g.l-1) were as high with hemoglobin (3 g.l-1) as with glucose (3 g.l-1) (20). Albumin, collagen and mucin also supported an increased mu max, or yield or both, in comparison with basal (tryptone/thiamine) medium. In steady-state, trypsin-like protease specific activity increased 3- to 5-fold in the presence of albumin, collagen and hemoglobin: whereas the greatest increase (21-fold) in alpha-glucoside activity was in the presence of mucin. There were significant, but less substantial changes in other hydrolytic enzymes (aminopeptidase, acid and alkaline phosphatases). The bulk of the detected hydrolytic activity (> 66%) was associated with the cells. The data indicate that C. gingivalis regulates its production of hydrolytic enzymes in response to environmental conditions.