Covid-19 and oral diseases: Crosstalk, synergy or association?

The coronavirus disease 2019 (Covid-19) is a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that clinically affects multiple organs of the human body. Cells in the oral cavity express viral entry receptor angiotensin-converting enzyme 2 that allows viral replication and may cause tissue inflammation and destruction. Recent studies have reported that Covid-19 patients present oral manifestations with multiple clinical aspects. In this review, we aim to summarise main signs and symptoms of Covid-19 in the oral cavity, its possible association with oral diseases, and the plausible underlying mechanisms of hyperinflammation reflecting crosstalk between Covid-19 and oral diseases. Ulcers, blisters, necrotising gingivitis, opportunistic coinfections, salivary gland alterations, white and erythematous plaques and gustatory dysfunction were the most reported clinical oral manifestations in patients with Covid-19. In general, the lesions appear concomitant with the loss of smell and taste. Multiple reports show evidences of necrotic/ulcerative gingiva, oral blisters and hypergrowth of opportunistic oral pathogens. SARS-CoV-2 exhibits tropism for endothelial cells and Covid-19-mediated endotheliitis can not only promote inflammation in oral tissues but can also facilitate virus spread. In addition, elevated levels of proinflammatory mediators in patients with Covid-19 and oral infectious disease can impair tissue homeostasis and cause delayed disease resolution. This suggests potential crosstalk of immune-mediated pathways underlying pathogenesis. Interestingly, few reports suggest recurrent herpetic lesions and higher bacterial growth in Covid-19 subjects, indicating SARS-CoV-2 and oral virus/bacteria interaction. Larger cohort studies comparing SARS-CoV-2 negative and positive subjects will reveal oral manifestation of the virus on oral health and its role in exacerbating oral infection.

EBV-positive Mucocutaneous Ulcer With Small Lymphocytic Infiltration Mimicking Nonspecific Ulceration.

Epstein-Barr virus (EBV)-associated lymphoproliferative disorder may resemble nonspecific inflammation. We report 3 cases of immunosuppressed adult patients with small lymphocytic EBV ulcers in the skin and oral mucosa, characterized by a lack of atypical lymphocytic infiltration. All 3 cases were diagnosed in routine practice. For comparisons, cases of conventional Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) were reviewed which were extracted from our pathology archives (n=11). The present patients were 2 females and 1 male, aged above 70 years. The primary disease was rheumatoid arthritis (n=2) and dermatitis herpetiformis (n=1). The main source of immunosuppression was prednisolone (n=2) and methotrexate (n=1). The ulcers were located in the oral cavity, buttock, and/or external genitalia. Histology evaluation revealed nonspecific lymphocytic infiltration. Epstein-Barr virus-encoded small RNA (EBER)-positive cells were small and coexpressed CD20. The number of EBER-positive cells ranged from 52 to 132/HPF, which was within the range of that observed in the reviewed conventional EBVMCUs (range, 48 to 1328; median, 121). All 3 cases regressed spontaneously or by the reduction of immunosuppressants. Although the present cases lacked cytologic atypia, those clinical course and loads of EBER-positive cells (>50/HPF) suggested EBV involvement. Current cases of EBVMCU with small lymphocytic infiltration underscore the need for EBER in situ hybridization when an etiology of ulcer with predominant lymphocytes in an immunosuppressed patient is unclear.

A Novel RELA Truncating Mutation in a Familial Behçet's Disease-like Mucocutaneous Ulcerative Condition.

OBJECTIVE: Monogenic Behçet's disease (BD)-like conditions are increasingly recognized and to date have been found to predominantly involve loss-of-function variants in TNFAIP3. This study was undertaken to identify genetic and pathobiologic mechanisms associated with a BD-like mucocutaneous ulcerative syndrome and neuromyelitis optica (NMO) occurring in 3 generations of an Irish family (n = 5 cases and 5 familial controls). METHODS: Whole-exome sequencing was used to identify potential pathogenic variants in affected family members and determine segregation between affected and unaffected individuals. Relative v-rel reticuloendotheliosis viral oncogene homolog A (RELA) expression in peripheral blood mononuclear cells was compared by Western blotting. Human epithelial and RelA-/- mouse fibroblast experimental systems were used to determine the molecular impact of the RELA truncation in response to tumor necrosis factor (TNF). NF-κB signaling, transcriptional activation, apoptosis, and cytokine production were compared between wild-type and truncated RELA in experimental systems and patient samples. RESULTS: A heterozygous cytosine deletion at position c.1459 in RELA was detected in affected family members. This mutation resulted in a frameshift p.His487ThrfsTer7, producing a truncated protein disrupting 2 transactivation domains. The truncated RELA protein lacks a full transactivation domain. The RELA protein variants were expressed at equal levels in peripheral mononuclear cells. RelA-/- mouse embryonic fibroblasts (MEFs) expressing recombinant human RELAp.His487ThrfsTer7 were compared to those expressing wild-type RELA; however, there was no difference in RELA nuclear translocation. In RelA-/- MEFs, expression of RELAp.His487ThrfsTer7 resulted in a 1.98-fold higher ratio of cleaved caspase 3 to caspase 3 induced by TNF compared to wild-type RELA (P = 0.036). CONCLUSION: Our data indicate that RELA loss-of-function mutations cause BD-like autoinflammation and NMO via impaired NF-κB signaling and increased apoptosis.

Association of Clinical Phenotypes in Haploinsufficiency A20 (HA20) With Disrupted Domains of A20.

Background: Haploinsufficiency A20 (HA20) is a newly described monogenic disease characterized by a wide spectrum of manifestations and caused by heterozygous mutations in TNFAIP3 which encodes A20 protein. TNFAIP3 mutation leads to disruption of the A20 ovarian tumor (OTU) domain and/or the zinc finger (ZnF) domain. This study aims at exploring the association between the various manifestations of HA20 and different domains disruption of A20. Methods: We reviewed the HA20 cases in previous literature and summarized the clinical features, TNFAIP3 mutation loci and the disrupted domains caused by different sites and patterns of mutations. Patients were classified into three groups according to the A20 domains disruption. Results: A total of 89 patients from 39 families with a genetic diagnosis of HA20 were included. Overall, the age at onset of HA20 was early (median:5.92, IQR:1-10). Patients in the ZnF group showed the earliest onset (median:2.5, IQR:0.6-5), followed by patients in the OTU+ZnF group (median:6, IQR:1-10) and patients in the OTU group (median:10, IQR:8-14). The main manifestations of HA20 patients were recurrent oral ulcers (70%), recurrent fever (42%), gastrointestinal ulcers (40%), skin lesion (38%), genital ulcers (36%), and musculoskeletal disorders (34%). The percentage of patients with musculoskeletal disorders was significantly different among the three groups (p = 0.005). Patients in the OTU+ZnF group and ZnF group were more likely to develop musculoskeletal disorders than patients in the OTU group (p = 0.002 and p = 0.035, respectively). Besides, forty-three percent of HA20 patients were initially diagnosed as Behcet's disease (BD). Compared to the ZnF group, the OTU+ZnF group and OTU group had a higher percentage of patients initially diagnosed as BD (p = 0.006 and p < 0.001, respectively). Conclusion: HA20 is characterized by early-onset and the most common symptoms of HA20 are recurrent oral ulcers, fever and gastrointestinal ulcers. The onset of HA20 in patients with the ZnF domain disruption is earlier than patients with the OTU domain disruption. Compared to the OTU domain, the ZnF domain may be more closely related to musculoskeletal disorders.

Clinicopathological analysis of 34 Japanese patients with EBV-positive mucocutaneous ulcer.

Epstein-Barr virus (EBV)-positive mucocutaneous ulcer (EBVMCU) is a unifocal mucosal or cutaneous ulcer that is histologically characterized by proliferating EBV-positive atypical B cells. While EBVMCU demonstrates a histology similar to that of EBV-positive diffuse large B-cell lymphoma (DLBCL), their clinical behavior differs. Thus, characterizing distinguishing features of EBVMCU and EBV-positive DLBCL is critical. To identify unique characteristics between EBVMCU and lymphoma, we analyzed the clinicopathological and genetic features of 34 Japanese patients with EBVMCU and compared them to those of 24 EBV-positive DLBCL patients and 25 EBV-negative DLBCL patients. All patients with EBVMCU had localized ulcerative lesions, and 31 patients (91%) were using immunosuppressants, such as methotrexate (MTX) or hydroxycarbamide. All patients that were followed up with exhibited good prognosis following immunosuppressant reduction or chemotherapy. In addition, 17 EBV-positive DLBCL patients, and 15 EBV-negative DLBCL patients, received chemotherapy (P < 0.001, P < 0.001, respectively). Our data showed that EBVMCU did not increase indicators associated with lymphoma prognosis, such as soluble interleukin 2 receptor (sIL-2R) and lactate dehydrogenase (LDH) compared to those in the EBV-positive DLBCL or EBV-negative DLBCL groups (sIL-2R, P < 0.001, P = 0.025; LDH, P = 0.018, P = 0.038, respectively). However, histologically, EBVMCU exhibited EBV-positive, variable-sized, atypical B-cell proliferation. Thus, EBVMCU was histologically classified as: (1) polymorphous; (2) large cell-rich; (3) classic Hodgkin lymphoma-like; and (4) mucosa-associated lymphoid tissue lymphoma-like. Moreover, genetic analysis showed that immunoglobin heavy chain (IGH) gene rearrangement did not differ significantly between EBVMCU and EBV-positive DLBCL (44% vs. 32%; P = 0.377), or between EBVMCU and EBV-negative DLBCL (44% vs. 58%; P = 0.280). Therefore, it is difficult to distinguish EBVMCU from EBV-positive DLBCL using only pathological and genetic findings, suggesting that clinical information is important in accurately distinguishing between EBVMCU and EBV-positive DLBCL.

Abatacept treatment impairs the cell migration and wound healing of oral ulcers in rats: Role of interleukin (IL)-1ß, -6 and -10 and CD8/CD30 cells: Influence of abatacept treatment on oral wound healing: Experimental model on rats.

The present study aimed to evaluate the healing process of ulcers in the jugal mucosa of Wistar rats treated with abatacept. The rats were randomly assigned to four groups: saline-treated control (0.3 mL/kg) abatacept-treated groups at dosages of 3.2, 8.0 and 20.0 mg/kg/week. After two weeks of subcutaneous (SC) administration, ulcers were introduced into the left jugal mucosa with an 8-mm diameter punch. SC administration was continued until euthanasia (after 1, 3, 7, 14 and 21 days of ulceration), and ulcers were clinically measured and animals weighed. Histological slides were evaluated (healing scores and polymorphonuclear, mononuclear, vessel, and fibroblast/myofibroblast counts). We also performed collagenesis analysis (Picrosirius Red) and immunohistochemistry (induced nitric oxide synthase (iNOS), interleukin (IL)-1beta (1ß), -6, -10, plus the analysis of CD8 and CD30). The experiment was repeated to perform a vascular permeability assay. ANOVA 1-way or 2-way/Bonferroni and Kruskal-Wallis/Dunn tests were used for statistical analysis (GraphPad Prism 5.0®, p < 0.05). Abatacept treatment reduced the ulcer diameter and the numbers of polymorphonuclear and mononuclear cells; reduced the CD8+/CD30+ ratio and vascular permeability; and increased collagenesis and IL-10 expression at the beginning of the protocol. At the highest dose, there was a delay in repair and vascular proliferation; a reduction in the number of fibroblasts/myofibroblasts; and prolongation of iNOS, IL- and IL- expression. We conclude that abatacept accelerates the healing of oral ulcers by reducing the migration of inflammatory cells, but overdose of abatacept leads to delayed repair and prolongation of proinflammatory cytokine expression.

Oral Lesions in Autoimmune Bullous Diseases: An Overview of Clinical Characteristics and Diagnostic Algorithm.

Autoimmune bullous diseases are a group of chronic inflammatory disorders caused by autoantibodies targeted against structural proteins of the desmosomal and hemidesmosomal plaques in the skin and mucosa, leading to intra-epithelial or subepithelial blistering. The oral mucosa is frequently affected in these diseases, in particular, in mucous membrane pemphigoid, pemphigus vulgaris, and paraneoplastic pemphigus. The clinical symptoms are heterogeneous and may present with erythema, blisters, erosions, and ulcers localized anywhere on the oral mucosa, and lead to severe complaints for the patients including pain, dysphagia, and foetor. Therefore, a quick and proper diagnosis with adequate treatment is needed. Clinical presentations of autoimmune bullous diseases often overlap and diagnosis cannot be made based on clinical features alone. Immunodiagnostic tests are of great importance in differentiating between the different diseases. Direct immunofluorescence microscopy shows depositions of autoantibodies along the epithelial basement membrane zone in mucous membrane pemphigoid subtypes, or depositions on the epithelial cell surface in pemphigus variants. Additional immunoserological tests are useful to discriminate between the different subtypes of pemphigoid, and are essential to differentiate between pemphigus and paraneoplastic pemphigus. This review gives an overview of the clinical characteristics of oral lesions and the diagnostic procedures in autoimmune blistering diseases, and provides a diagnostic algorithm for daily practice.

Genome wide analysis for mouth ulcers identifies associations at immune regulatory loci.

Mouth ulcers are the most common ulcerative condition and encompass several clinical diagnoses, including recurrent aphthous stomatitis (RAS). Despite previous evidence for heritability, it is not clear which specific genetic loci are implicated in RAS. In this genome-wide association study (n = 461,106) heritability is estimated at 8.2% (95% CI: 6.4%, 9.9%). This study finds 97 variants which alter the odds of developing non-specific mouth ulcers and replicate these in an independent cohort (n = 355,744) (lead variant after meta-analysis: rs76830965, near IL12A, OR 0.72 (95% CI: 0.71, 0.73); P = 4.4e-483). Additional effect estimates from three independent cohorts with more specific phenotyping and specific study characteristics support many of these findings. In silico functional analyses provide evidence for a role of T cell regulation in the aetiology of mouth ulcers. These results provide novel insight into the pathogenesis of a common, important condition.

Regulatory T Cells and Their Association with Serum Markers and Symptoms in Systemic Lupus Erythematosus and Rheumatoid Arthritis.

PURPOSE: Impairment in number and functions of regulatory T cells (Treg) has been found to be associated with many autoimmune diseases including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This study was conducted to identify and compare Treg by flow cytometry using two different staining approaches. METHODS: Treg were identified by using CD4+CD25+high and CD4+CD25+CD127dim staining approaches in SLE and RA patients and healthy controls. Association of both identified Treg levels with various serum markers and clinical presentation was also examined. RESULTS: Blood CD4+CD25+CD127dim cells levels were 11.4+3.57 %, 9.76+2.37 % and 6.95+1.16 %; while CD4+CD25+high cells were 1.46+1.09 %, 0.95+0.59 % and 1.87+1.14 % in SLE patients, RA patients and healthy controls respectively. Number of CD4+CD25+CD127dim cells was higher than CD4+CD25+high cells in blood samples of all three study groups. Levels of CD4+CD25+CD127dim cells were significantly higher in SLE and RA patients, compared to healthy controls, but this difference was not observed for CD4+CD25+high Treg. CD4+CD25+high levels showed significant correlation with serum C4, IFN-γ and IL-10 levels in healthy subjects and with C4 levels and fever in SLE patients. CD4+CD25+CD127dim levels showed significant association with alopecia and oral ulcers in SLE patients only, but no correlation with measured serum markers. CONCLUSION: Results suggest that both staining approaches detect Treg differently and also that Treg play different role in pathogenesis of SLE and RA.

[Study on the changes of iron metabolism in patients with recurrent oral ulcer and its relationship with cellular immune function].

PURPOSE: To study the relationship between abnormal iron metabolism and cellular immune dysfunction and recurrent oral ulcer. METHODS: A cross-sectional analysis of serum iron, ferritin and cellular immune function in 100 patients with recurrent oral ulcer and 100 healthy cases as control were performed. Logistic regression analysis was conducted to evaluate the relationship between serum ferritin and cellular immunity and recurrent oral ulcer using SPSS 19.0 software package. RESULTS: Serum iron, ferritin, CD3+, CD4+ and CD4+/CD8+ concentration significantly decreased in Rou group compared with the control group (P<0.01). Multiple logistic regression analysis showed serum iron, ferritin and CD3+, CD4+ decrease were the independent risk factors for the onset of ROU, whereas CD4+/CD8+ were the protective factors in the pathogenesis of ROU(P<0.05). CONCLUSIONS: Iron deficiency and cellular immune function is closely related to the pathogenesis of ROU.

Serum levels of IgG antibodies against alpha-enolase are increased in patients with Behçet's disease and are associated with the severity of oral ulcer, erythrocyte sedimentation rates, and C-reactive protein.

OBJECTIVES: Behçet's disease (BD) is a chronic inflammatory disease of unknown etiology, characterised by recurrent oral and genital ulcers, skin lesions, uveitis, and arthritis. It is regarded as vasculitis and anti-endothelial cell antibodies (AECA) are found in patients with BD. One of the endothelial cell antibodies was reported to recognise alpha-enolase. This study aimed to investigate expression of alpha-enolase in the surface of peripheral blood cells and serum anti-alpha-enolase antibody (AEA), and their association with clinical manifestations or disease activity of BD. METHODS: Cell surface alpha-enolase expression was examined from several cell types of peripheral blood, including lymphocytes, monocytes, and neutrophils using flow cytometry in patients with BD and healthy controls (HCs). IgG AEA levels were measured by enzyme-linked immunosorbent assay (ELISA) in sera from 110 patients with BD, and age/sex matched 110 HCs. Association of alpha-enolase or AEA with clinical manifestation was analysed. RESULTS: The frequency of surface alpha-enolase-expressing cells was increased in BD in lymphocytes and monocytes. Serum AEA levels were in- creased in BD patients (median [IQR], 0.360 [0.268-0.482], p < 0.0001), particularly with mucocutaneous involvement (0.367 [0.273-0.490], p < 0.0001) compared to HCs (0.274 [0.231-0.357]). The levels of AEA were correlated with the number of oral ulcer, ESR, and CRP. There was no association between serum levels of AEA and other clinical manifestations. CONCLUSIONS: Serum AEA was increased in BD patients and correlated with oral ulcer, ESR and CRP.

Natural Killer Cell Subsets and Their Functional Activity in Behçet's Disease.

BACKGROUND: Behçet's disease (BD) is a rare, chronic autoinflammatory disorder of unknown origin. Natural killer (NK) cells are one of the major immunoregulatory cell groups of the innate immune system, but their role in BD pathogenesis is not well documented. OBJECTIVES: We aimed to investigate the role of NK cell subsets and their cytokine secretion and cytotoxic activity in patients with BD. PATIENTS AND METHODS: The study group consisted of BD patients who had only mucocutaneous involvement, and they were compared with healthy subjects. BD patients were divided into two groups according to their frequencies of oral ulcerations. NK cell cytotoxicity was determined using CD107a expression and a CFSE-based cytotoxicity test. Expression of NK cell receptors and surface markers and the intracellular IL-5, IL-10, IL-17, and IFN-γ levels in CD16+ NK cells were assessed by flow cytometry. RESULTS: Although the cytokine secretion pattern was different, no difference was obtained in cytotoxic activity, expression of activatory receptors, or degranulation of NK cells. CONCLUSION: Increases in NK1/NK2 ratio and CD16+IFN-γ+ NK1 cells might support the idea of a biased IFN-γ dominant immune response in the mucocutaneous involvement of BD pathogenesis. Although the cytokine secretion pattern was different, no difference was obtained in cytotoxic activity, expression of activatory receptors, or degranulation of NK cells.

Chronic granulomatous disease as a risk factor for cutaneous lupus in childhood.

Chronic granulomatous disease (CGD) is a primaryimmunodeficiency disorder that affects the phagocyticcells of the innate immune system. It is characterizedby recurrent or persistent infections with granulomaformation. Lupus-like lesions have been reported incarriers of CGD and less frequently, in patients withCGD. Immunological study in these patients areusually negative. We describe the case of an 8-yearoldboy with CGD who developed chronic and acutecutaneous lupus erythematous with angular cheilitis,oral ulcers, Raynaud phenomenon, and positiveserologies for antinuclear, anticentromere, and anti-Saccharomyces cerevisiae antibodies.

Clinical and immunological characteristics in 552 systemic lupus erythematosus patients in a southern province of China.

AIM: The purpose of this study was to gain a better understanding of systemic lupus erythematosus (SLE) in Hakka populations. METHODS: We studied the demographic, clinical and laboratory characteristics in a cohort of 552 SLE patients diagnosed at the Rheumatology Department in MeiZhou People's Hospital from January 2008 to December 2012. There were 495 women and 57 men (8.7 : 1) with a mean age of 35.3 years (range 12-78 years). The mean age at disease onset and the mean disease duration were 31.8 ± 14.4 years and 3.3 ± 2.8 years, respectively. RESULTS: The most common clinical manifestations were arthritis (61.6%), followed by malar rash (52.7%), photosensitivity (22.8%), mouth ulcers (17.0%) and discoid lupus (14.7%). The prevalence was 46.7% for nephritis (by biopsy), 18.3% for pleuritis, 15.6% for pericarditis and 4.9% for neuropsychiatric manifestations. The most common hematological manifestations were anemia (63.8%), followed by leucopenia (29.0%) and thrombocytopenia (14.9%). Antinuclear antibodies were detected in 99.8% of patients, followed by anti-double-stranded DNA (81.3%), anti-SSA (Sjögren's syndrome antigen A)/Ro (58.7%), anti-ribonucleoprotein (36.8%), anti-Sm (35.7%), and anti-SSB/La (15.0%). Anti-cardiolipin immunoglobulin G (IgG) and IgM were detected in 18.3% and 14.1% of patients, respectively. Active disease and infections were the two major causes of death. CONCLUSION: The clinical and immunological characteristics of the SLE patients in our study place our population in the middle of the spectrum between other Asian and Caucasian populations.