Immature, but Not Mature, Dendritic Cells Are More Often Present in Aggressive Periodontitis Than Chronic Periodontitis: An Immunohistochemical Study

Differential expression of FSTL1 and its correlation with the pathological process of periodontitis

AIMS

This study aimed to elucidate the alterations in Follistatin-like protein 1 (FSTL1) and its association with the pathological process of periodontitis.

METHODS

This study included 48 patients with periodontitis and 42 healthy controls. The expression level of FSTL1 in the gingiva was determined by RT-qPCR, validated using the dataset GSE16134, and subsequently examined by western blotting. Bioinformatics analysis revealed a single-cell distribution of FSTL1, characteristic of angiogenesis and immune cell infiltration. The expression and distribution of FSTL1, vascular endothelial marker protein CD31 and myeloperoxidase (MPO), the indicator of neutrophil activity, were determined by immunohistochemistry (IHC). A series of correlation analyses was performed to determine the associations between FSTL1 and clinical parameters, including probing depth (PD) and clinical attachment loss (CAL), and their potential role in angiogenesis (CD31) and neutrophil infiltration (MPO).

RESULTS

FSTL1 was significantly upregulated in the gingiva of patients with periodontitis compared to their healthy counterparts. In addition, FSTL1 was positively correlated with the clinical parameters PD (r = .5971, p = .0005) and CAL (r = .6078, p = .0004). Bioinformatic analysis and IHC indicated that high FSTL1 expression was significantly correlated with angiogenesis and neutrophil infiltration in periodontitis. Moreover, receiver operating characteristic (ROC) analysis demonstrated that FSTL1 could serve as an independent indicator for evaluating the severity of periodontitis (area under the curve [AUC] = 0.9011, p < .0001).

CONCLUSION

This study demonstrated FSTL1 upregulation in periodontitis and its potential contribution to the disease via angiogenesis and neutrophil infiltration.

Comparison of immunoexpression of dendritic cells, mast cells and blood vessels in periodontal disease between adults and elderly

OBJECTIVE

The aim of this study was to compare, in adults and elderly individuals, the immunoexpression of immature and mature dendritic cells (DCs), mast cells, and blood vessels in healthy and diseased gingival tissues.

MATERIALS AND METHODS

The expressions of immunohistochemical markers, including CD1a (immature dendritic cells), CD83 (mature dendritic cells), tryptase (mast cells) and CD34 (blood vessels), were analyzed in gingival biopsies from elderly (n = 27) and adult (n = 127) patients presenting health, gingivitis and periodontitis. Positive cells for each specimen and marker were counted.

RESULTS

There were no differences in the immunostaining of DCs, mast cells and the amount of blood vessels among gingival biopsies with health, gingivitis and periodontitis in adult and elderly subjects (p > 0.05). Immature DCs were more frequent in tissues with gingivitis and periodontitis in elderly patients, when compared to adults (p < 0.05). Furthermore, degranulated mast cell counts were higher, whereas the number of microvessels was lower in gingivitis in the elderly, when compared to adults (p < 0.05).

CONCLUSIONS

Diseased periodontal sites in the elderly present an overall significant overexpression of immature DCs and degranulated mast cells, in relation to those of adults. Furthermore, gingivitis in elderly is associated with decreased microvessel growth. These immunoinflammatory differences between elderly and adults may have implications in periodontal tissue breakdown in the late adulthood. Further studies should be performed to elucidate this hypothesis.

CLINICAL RELEVANCE

Understading the relationship between aging and changes in immune cells during periodontal inflammation may lead to therapeutic targets for the future management of periodontal diseases.

Salivary levels of NLRP3 protein are significantly raised in chronic periodontitis: A systematic review and meta-analysis of clinical studies

Background

To date, there is no confirmatory diagnostic test that can identify the type of periodontal disease and the disease progress. With the advent of "molecular biomarkers," this systematic review and meta-analysis were designed with the sole purpose of identifying a novel biomarker, namely, nucleotide leucine rich repeat pyrin protein-3 (NLRP3) inflammasome which has already been extensively researched for chronic inflammatory and autoimmune diseases.

Types of Studies Reviewed

Only case observational studies that evaluated the presence of human NLRP3 inflammasome in the saliva of patients with chronic periodontitis with no overlying systemic disease and compared the same to healthy patients to obtain quantitative data that can be statistically analyzed were included. The confirmatory test used in all the studies was the enzyme-linked immunosorbent assay.

Results

The broad-based search led to a total of three articles that fulfilled the inclusion criteria so that a meta-analysis of the results could be carried out. Data reveal that NLRP3 levels are raised in chronic periodontitis cases (P = 0.05; relative risk = 1.05 [0.00-2.09]). The risk of bias assessment was carried out according to the Joanna Briggs Institute Critical Appraisal Checklist where ten-point criteria were outlined indicating a low risk of bias for three studies.

Clinical Implications

NLPR3 inflammasome could be tested as a reliable biomarker in saliva to identify the type and progress of the periodontal disease.

Revealing leukocyte populations in human peri-implantitis and periodontitis using flow cytometry

OBJECTIVE

To identify, quantify, and characterize leukocyte populations in PI and periodontitis using flow cytometry.

METHODS

Fresh biopsies from human PI and periodontitis lesions were processed to a single-cell suspension. The immune cell types were identified using flow cytometry.

RESULTS

Twenty-one biopsies were obtained and analyzed corresponding to fourteen PI and seven periodontitis samples. Participants' average age was 63.95 ± 14.77 years without a significant difference between PI and periodontitis patients, the female/male ratio was 8/12, and mean PD was 8.5 ± 2.17. High similarity was found between periodontitis and PI in the main immune cell types. Out of the leukocytes, the PMN proportion was 40% in PI and 33% in periodontitis. T-cells 22% in PI and 18% in periodontitis. Similar proportions of B-cells 10% and macrophages 6% were found in PI and periodontitis. Dendritic and NK cells were found in low proportions (~ 1%) in PI and periodontitis. T-cell sub-analysis showed that CD4-positive were more prevalent than CD8-positive in both diseases (CD4/CD8 ratio of 1.2).

CONCLUSION

With the use of flow cytometry analysis, the leukocyte populations in human peri-implantitis and periodontitis were classified. In PI and periodontitis, we identified similar proportions of specific (CD4/CD8) and innate (dendritic and NK) immune cells. These results corroborate previous histological studies.

CLINICAL RELEVANCE

Flow cytometry analysis can be used to identify and quantify immune cells in PI and periodontitis, including sub-classification of T cells (CD4/8) as well as detection of cells that require multiple markers for identification (such as dendritic cells).

Clinical and Pathological Implications of Increases in Tonsillar CD19+CD5+ B Cells, CD208+ Dendritic Cells, and IgA1-positive Cells of Immunoglobulin A Nephropathy

OBJECTIVE

Several studies indicated that tonsillectomy can improve the prognosis of patients with immunoglobulin A nephropathy (IgAN). However, the relationship between tonsillar immunity and IgAN is still unclear.

METHODS

A total of 14 IgAN patients were recruited in the current study from May 2015 to April 2016 in Tongji Hospital. B cells, dendritic cells (DCs), and IgA1 positive cells in human tonsils were detected using immunofluorescence and immunohistochemistry. Correlations between these cells and clinicopathologic features were evaluated.

RESULTS

CD19+CD5+ B cells were predominantly located in germinal centers and mantle zones of lymphoid follicles, the CD208+ DCs were distributed in the interfollicular and subepithelial area, and IgA1-positive cells were predominantly detected in mantle zones of lymphoid follicles and subepithelial tissues. The numbers of CD19+CD5+ B cells, CD208+ DCs, and IgA1-positive cells in tonsillar tissues from IgAN patients were significantly higher than those in the normal controls (P<0.01, respectively). CD19+CD5+ B cells, CD208+ DCs, and IgA1-positive cells in tonsillar tissues were significantly associated with 24-h proteinuria levels and tubular atrophy/interstitial fibrosis of IgAN.

CONCLUSION

CD19+CD5+ B cells, CD208+ DCs, and IgA1-positive cells in tonsillar tissues might be involved in the pathogenesis of IgAN.

The Th17/Treg cell balance: crosstalk among the immune system, bone and microbes in periodontitis

Periodontopathic bacteria constantly stimulate the host, which causes an immune response, leading to host-induced periodontal tissue damage. The complex interaction and imbalance between Th17 and Treg cells may be critical in the pathogenesis of periodontitis. Furthermore, the RANKL/RANK/OPG system plays a significant role in periodontitis bone metabolism, and its relationship with the Th17/Treg cell imbalance may be a bridge between periodontal bone metabolism and the immune system. This article reviews the literature related to the Th17/Treg cell imbalance mediated by pathogenic periodontal microbes, and its mechanism involving RANKL/RANK/OPG in periodontitis bone metabolism, in an effort to provide new ideas for the study of the immunopathological mechanism of periodontitis.

Impact of smoking on dendritic cells in patients with oral squamous cell carcinoma

Smoking has been shown to alter innate and adaptive immune responses and is directly associated with the onset of oral squamous cell carcinoma (OSCC). The purpose of this study was to evaluate the effect of cigarette smoke exposure on dendritic cells (DCs) from OSCC patients. CD1a and CD83 antibodies were used to identify immature and mature DCs, respectively, by immunohistochemistry in OSCC samples of 24 smokers and 24 non-smokers. Density of DCs was calculated in intra and peritumoral areas. Clinical and microscopic findings were reviewed and analyzed for all patients. Smokers with OSCC had a lower density of intra and peritumoral DCs when compared to non-smokers. Tumors classified as moderately/poorly differentiated had lower peritumoral CD1a+ DCs than well-differentiated tumors (p < 0.001). Smoking contributed to a depletion of immature and mature DCs in the OSCC.

Dysbiosis From a Microbial and Host Perspective Relative to Oral Health and Disease

The significance of microbiology and immunology with regard to caries and periodontal disease gained substantial clinical or research consideration in the mid 1960's. This enhanced emphasis related to several simple but elegant experiments illustrating the relevance of bacteria to oral infections. Since that point, the understanding of oral diseases has become increasingly sophisticated and many of the original hypotheses related to disease causality have either been abandoned or amplified. The COVID pandemic has reminded us of the importance of history relative to infectious diseases and in the words of Churchill "those who fail to learn from history are condemned to repeat it." This review is designed to present an overview of broad general directions of research over the last 60 years in oral microbiology and immunology, reviewing significant contributions, indicating emerging foci of interest, and proposing future directions based on technical advances and new understandings. Our goal is to review this rich history (standard microbiology and immunology) and point to potential directions in the future (omics) that can lead to a better understanding of disease. Over the years, research scientists have moved from a position of downplaying the role of bacteria in oral disease to one implicating bacteria as true pathogens that cause disease. More recently it has been proposed that bacteria form the ecological first line of defense against "foreign" invaders and also serve to train the immune system as an acquired host defensive stimulus. While early immunological research was focused on immunological exposure as a modulator of disease, the "hygiene hypothesis," and now the "old friends hypothesis" suggest that the immune response could be trained by bacteria for long-term health. Advanced "omics" technologies are currently being used to address changes that occur in the host and the microbiome in oral disease. The "omics" methodologies have shaped the detection of quantifiable biomarkers to define human physiology and pathologies. In summary, this review will emphasize the role that commensals and pathobionts play in their interaction with the immune status of the host, with a prediction that current "omic" technologies will allow researchers to better understand disease in the future.

Etiology of aggressive periodontitis in individuals of African descent

Aggressive periodontitis (AgP) is a form of periodontitis that affects adolescents and has a significantly higher prevalence in individuals of African descent. AgP typically shows familial aggregation, suggesting a genetic predisposition. Young age, good health status, rapid attachment loss, and familial aggregation are the primary features of this disease. AgP has been closely linked to specific bacterial strains of Aggregatibacter actinomycetemcomitans. A. actinomycetemcomitans strains isolated from patients with AgP produce leukotoxin (LtxA), which specifically affects polymorphonuclear leukocytes in primates, especially humans. High-throughput 16S rRNA gene sequencing and bioinformatics analyses revealed differences in the subgingival microbiota between patients with AgP and those with chronic periodontitis (ChP). The genera Atopobium and Prevotella show increased prevalences in AgP than in ChP. According to AgP susceptibility, several single nucleotide polymorphisms have been detected in different genes in individuals of African descent. Interleukin (IL)-1α and IL-1β genetic polymorphisms may be associated with the severity of both ChP and AgP. An elevated serum level of IL-17 produced by Th17 cells may be a characteristic of AgP. Analyses of the relationships among bacteria, host defenses, genetic predisposition, and numerous other factors are required to understand the progression of this disease.

Immunohistochemical characterization of immune cell infiltration in paediatric and adult Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia commonly affecting children with frequent somatic mutations in MAPK pathway genes including BRAF^V600E and MAP2K1. Some studies suggest that LCH cells can recruit and modulate inflammatory cells, which could provide reciprocal survival signals. To characterize the immune profile of infiltrating inflammatory cells, and to clarify their participation in LCH pathogenesis, a detailed immunohistochemical analysis was performed. Fifteen (10 children, 5 adults) LCH cases were assessed through macrophage (CD68 and CD163), mature dendritic cell (mDC; CD83 and CD208), regulatory T cell (Treg; CD4, CD25 and FOXP3) and cytotoxic lymphocyte (CL; CD56, CD57, perforin and granzyme B) immunomarkers. Moreover, lymphocytic and LCH markers were also analysed. All cases were S100, CD1a, CD207 and CD4-positive. Bcl-2 and cyclin D1 expression was observed in 13 of 15 cases. In the immune microenvironment, M2-polarized macrophages and Tregs were the predominant cell populations, followed by significantly (P < .005) smaller levels of mDCs and CLs. Additionally, the number of CD3 + cells was significantly higher than that of CD20 + cells. In the CD3 + cell population, there were a significantly higher number of CD4 + cells than CD8 + cells. While there were no differences when comparing the paediatric and adult populations, FOXP3 + cells were significantly higher in patients with multisystem involvement and treated with chemotherapy, than single-site cases and those without chemotherapy. Our results suggest that M2-polarized macrophages and Treg infiltration can promote LCH development and survival, probably through pro-tumoral, immunosuppressive and/or cytokine-mediated mechanisms. This work highlights the need for further exploration of immune-targeted therapy for LCH.

FOXP3+ and CD25+ cells are reduced in patients with stage IV, grade C periodontitis: A comparative clinical study

BACKGROUND AND OBJECTIVE

Some studies suggest that regulatory T cells (Tregs) have suppressive effects on inflammatory osteolysis. The aim of this study was to evaluate Treg immunomarkers in periodontitis-affected tissues from patients with periodontitis and clinically healthy gingiva (control).

MATERIAL AND METHODS

The presence and distribution of positive cells for CD4, CD25 and FOXP3 (Treg immunomarkers) in periodontitis-affected tissues (epithelium and lamina propria) of 30 patients (ten per group) with a diagnosis of stage IV, grade C periodontitis (IV-C), stage III, grade B periodontitis (III-B) and the control were evaluated. A two-way ANOVA followed by Fisher's LSD test was used to demonstrate differences between the groups and immunomarkers; Student's t test was used to demonstrate differences between the epithelium and the lamina propria.

RESULTS

Both IV-C and III-B periodontitis presented a significantly high proportion of immune-stained cells for all immunomarkers when compared to the control group. Notably, CD25+ and FOXP3+ cells were detected in a significantly higher number in III-B than IV-C periodontitis (P < .05).

CONCLUSION

Our results suggest the participation of Tregs on the osteoimmunological mechanisms in IV-C and III-B periodontitis patients, notably contributing to strategies for alveolar bone regeneration in clinical treatment decisions.

Salivary Levels of NLRP3 Inflammasome-Related Proteins as Potential Biomarkers of Periodontal Clinical Status

BACKGROUND

Emerging evidence suggests that activation of inflammasomes plays a central mechanism in pathogenesis of periodontitis. This study aims to compare salivary levels of nod-like receptor family pyrin domain containing protein (NLRP) 3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), cysteine aspartase (caspase)-1, and interleukin (IL)-1β from individuals with aggressive (AgP) or chronic periodontitis (CP) and healthy controls (HC), as well as elucidate its association with periodontal clinical status.

METHODS

Saliva samples from individuals with CP (n = 75), AgP (n = 20), and HC (n = 69) were collected. Periodontal status was assessed by measurement of probing depth, clinical attachment level, and extent and severity of disease. Salivary levels of analytes were analyzed by enzyme-linked immunosorbent assay. Association between biomarkers with CP or AgP was analyzed using multivariate binary logistic regression models.

RESULTS

Significantly higher levels of NLRP3, ASC, and IL-1β were detected in periodontitis groups in comparison to the periodontally HC group. However, no significant differences were observed for caspase-1 levels between clinical groups, and only NLRP3 salivary concentration was significantly higher in AgP compared with CP patients. Also, positive significant correlations among NLRP3, ASC, and IL-1β salivary concentrations and clinical parameters were observed. Logistic regression analyses revealed a strong/independent association of NLRP3, ASC, and IL-1β salivary levels with CP and AgP.

CONCLUSION

Although the concentration of caspase-1 in saliva samples makes its determination useless for detection of periodontal disease and/or its severity, salivary levels of NLRP3, ASC, and IL-1β may act as strong/independent indicators of amount and extent of periodontal breakdown in both CP and AgP and could potentially be used for prevention and therapy of this group of diseases.