BackgroundA relationship between rheumatoid arthritis (RA) and periodontitis has been suggested from findings that individuals with RA are prone to have advanced periodontitis and vice versa. In search of possible common pathogenetic features of these two diseases, we investigated the presence of citrullinated proteins and expression of endogenous peptidylarginine deiminases (PAD2 and PAD4), in periodontal tissue of individuals with periodontitis and healthy controls, in relation to the periodontal pathogens Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), producing leukotoxin as virulence factor. These two oral bacteria have been suggested to be linked to anti-citrullinated protein antibodies in patients with RA.MethodsGingival tissue biopsies were obtained from 15 patients with periodontitis and 15 individuals without periodontal disease. Presence of CD3-positive lymphocytes, citrullinated proteins, PAD2, PAD4, P. gingivalis as well as A. actinomycetemcomitans and Mannheimia haemolytica produced leukotoxins were analysed by immunohistochemistry, followed by triple-blind semi-quantitative analysis. Mann–Whitney and Fisher’s exact tests were used to analyse differences between groups. PADI2 and PADI4 mRNA levels were assessed by RT-qPCR and analysed using Wilcoxon signed rank test.ResultsIncreased staining of citrullinated proteins was observed in gingival connective tissue from subjects with periodontitis (80%, 12/15) compared to healthy gingival tissue (27%, 4/15), whereas no differences were observed in gingival epithelium. There was also an increased staining of the citrullinating enzymes PAD2 and PAD4 in gingival connective tissue of patients with periodontitis whereas similar levels of PAD2 and PAD4 were observed in the gingival epithelium of the two groups. Similarly, the mRNA levels of PADI2 and PADI4 were also increased in the gingival tissue of patients with periodontitis compared to healthy controls. Furthermore, presence of P. gingivalis and leukotoxins was comparable in both epithelium and connective tissue, from the different investigated individuals with and without periodontitis, and there were no correlations between the presence of periodontal pathogens and the expression of citrullinated proteins or PAD enzymes.ConclusionChronic gingival inflammation is associated with increased local citrullination and PAD2 and PAD4 expression in periodontitis. The increased citrullination and PAD2 and PAD4 expression in periodontitis were, however, independent of the presence of periodontal pathogen P. gingivalis and A. actinomycetemcomitans leukotoxin.Electronic supplementary materialThe online version of this article (10.1186/s12967-018-1588-2) contains supplementary material, which is available to authorized users.

Periodontitis is a highly prevalent chronic inflammatory disease of the periodontium, leading ultimately to tooth loss. In order to characterize the gene expression of periodontitis-affected gingival tissue, we have here simultaneously quantified and localized gene expression in periodontal tissue using spatial transcriptomics, combining RNA sequencing with histological analysis. Our analyses revealed distinct clusters of gene expression, which were identified to correspond to epithelium, inflamed areas of connective tissue, and non-inflamed areas of connective tissue. Moreover, 92 genes were identified as significantly up-regulated in inflamed areas of the gingival connective tissue compared to non-inflamed tissue. Among these, immunoglobulin lambda-like polypeptide 5 (IGLL5), signal sequence receptor subunit 4 (SSR4), marginal zone B and B1 cell specific protein (MZB1), and X-box binding protein 1 (XBP1) were the four most highly up-regulated genes. These genes were also verified as significantly higher expressed in gingival tissue of patients with periodontitis compared to healthy controls, using reverse transcription quantitative polymerase chain reaction. Moreover, the protein expressions of up-regulated genes were verified in gingival biopsies by immunohistochemistry. In summary, in this study, we report distinct gene expression signatures within periodontitis-affected gingival tissue, as well as specific genes that are up-regulated in inflamed areas compared to non-inflamed areas of gingival tissue. The results obtained from this study may add novel information on the genes and cell types contributing to pathogenesis of the chronic inflammatory disease periodontitis.

IntroductionEpstein-Barr virus (EBV) is a ␥-herpes virus of the Lymphocryptovirus genus that has succeeded to colonize Ͼ 90% of the adult population. 1 As a general characteristic of these viruses, they can all infect and immortalize B-lymphocytes in vitro. The in vitro EBV-infected B cells proliferate and give rise to lymphoblastoid cell lines (LCLs). The pattern of latent EBV gene expression seen in LCLs is referred to as the type III latency, in which 9 virally encoded proteins are expressed (EBV nuclear antigen 1-6 [EBNA1-6], Latent Membrane Protein-1 [LMP-1], LMP-2A, and LMP-2B). 1 Similarly to the EBV gene expression seen in LCLs, type III latent B cells were found in healthy persons during the primary infection 2 and the virus carrier state. 3 These cells are highly immunogenic and are eliminated by the cellular immune response. 4 After the primary infection the virus establishes a life-long infection in the memory B-cell reservoir, from where it is thought to reactivate and produce new progeny that are shed in the saliva. 1,5 In immunodeficient states, in which the cellular immune responses are compromised, the EBV-infected type III B cells can give rise to lymphoproliferations/lymphomas, as seen in the posttransplantation lymphoproliferations 6,7 and some AIDS lymphomas. 8 Depending on the histologic origin, the activation state, and the differentiation stage of the virus-carrying cells, EBV can adopt other viral gene expression patterns as well. 9 This is evidenced by the type I EBV gene expression seen in Burkitt lymphomas (BLs), primary effusion lymphomas, 10 and diffuse large B-cell lymphomas, whereby EBNA-1 is the only viral protein expressed. However, EBNA-1 is coexpressed with LMP-1 and LMP-2 in the EBV-carrying classical HL (cHL 11 ; type II latency), nasal natural killer/T-cell lymphoma, 12,13 some nasopharyngeal carcinomas (NPCs), 14,15 and peripheral T-cell lymphomas. 16 The expression of LMP-1 in type III latency is driven by the EBNA-2 protein. 1 The molecular mechanism of LMP-1 expression in type II latent cells, thus in the absence of EBNA-2, is only partially known. EBV-positive cHL is unique among the type II malignancies because all the Hodgkin/Reed-Sternberg (HRS) cells express high levels of LMP-1, whereas LMP-1 expression is heterogeneous in other tumors. 15 Not just the mechanism of LMP-1 expression in the HRS cells is unknown, but it is still an open question whether LMP-1 is needed for the survival or proliferation of these malignant cells. Although the type II EBV latency is seen in a proportion of cHLs, the available HL-derived cell lines are EBV negative. Thus, there is no in vitro system in which this type of virus-cell interaction can be studied.We have previously reported that exposure of the in vitro EBV-converted HL-derived cell line KMH2-EBV to CD40 ligand (CD40L) and interleukin-4 (IL-4) led to EBNA-2-independent expression of LMP-1. 17 In the continuation of this work we identify now IL-4, IL-13, and CD40L as potent inducers of LMP-1 not only Submitted January 21, 2010...

Precursor-B cell receptor (pre-BCR) signaling represents a crucial checkpoint at the pre-B cell stage. Aberrant pre-BCR signaling is considered as a key factor for B-cell precursor acute lymphoblastic leukemia (BCP-ALL) development. BCP-ALL are believed to be arrested at the pre-BCR checkpoint independent of pre-BCR expression. However, the cellular stage at which BCP-ALL are arrested and whether this relates to expression of the pre-BCR components (IGHM, IGLL1 and VPREB1) is still unclear. Here, we show differential protein expression and copy number variation (CNV) patterns of the pre-BCR components in pediatric BCP-ALL. Moreover, analyzing six BCP-ALL data sets (n = 733), we demonstrate that TCF3-PBX1 ALL express high levels of IGHM, IGLL1 and VPREB1, and are arrested at the pre-B stage. By contrast, ETV6-RUNX1 ALL express low levels of IGHM or VPREB1, and are arrested at the pro-B stage. Irrespective of subtype, ALL with high levels of IGHM, IGLL1 and VPREB1 are arrested at the pre-B stage and correlate with good prognosis in high-risk pediatric BCP-ALL (n = 207). Our findings suggest that BCP-ALL are arrested at different cellular stages, which relates to the expression pattern of the pre-BCR components that could serve as prognostic markers for high-risk pediatric BCP-ALL patients.

Age-associated B cells (ABCs) represent a distinct cell population expressing low levels of CD21 (CD21 ). The Ig repertoire expressed by ABCs in aged mice is diverse and exhibits signs of somatic hypermutation (SHM). A CD21 B-cell population is expanded in autoimmune diseases, e.g. systemic lupus erythematosus, as well as in lupus-prone NZB/W mice and in mice lacking a pre-B cell receptor (SLC ). However, the nature of the CD21 B cells (hereafter ABCs) in autoimmunity is not well understood. Here we show that in young SLC mice, the vast majority of the ABCs express memory B-cell (MBC) markers in contrast to wild-type controls. A similar population is present in lupus-prone MRL mice before and at disease onset. In SLC mice, a majority of the ABCs are IgM , their V genes have undergone SHM, show clonal diversification and clonal restriction at the H-CDR3 level. ABC hybridomas, established from SLC mice, secrete typical lupus autoantibodies, e.g. anti-Smith antigen, and some of those that bind to DNA comprise a H-CDR3 that is identical to previously described IgM anti-DNA antibodies from lupus-prone mice. Together, these results reveal that ABCs in autoimmune mice are comprised of autoreactive MBCs expressing highly restricted H-CDR3 repertoires.

The Rho GTPase Cdc42 coordinates regulation of the actin and the microtubule cytoskeleton by binding and activating the Wiskott–Aldrich syndrome protein. We sought to define the role of intrinsic expression of Cdc42 by mature B cells in their activation and function. Mice with inducible deletion of Cdc42 in mature B cells formed smaller germinal centers and had a reduced Ab response, mostly of low affinity to T cell–dependent Ag, compared with wild-type (WT) controls. Spreading formation of long protrusions that contain F-actin, microtubules, and Cdc42-interacting protein 4, and assumption of a dendritic cell morphology in response to anti-CD40 plus IL-4 were impaired in Cdc42-deficient B cells compared with WT B cells. Cdc42-deficient B cells had an intact migratory response to chemokine in vitro, but their homing to the B cell follicles in the spleen in vivo was significantly impaired. Cdc42-deficient B cells induced a skewed cytokine response in CD4+ T cells, compared with WT B cells. Our results demonstrate a critical role for Cdc42 in the motility of mature B cells, their cognate interaction with T cells, and their differentiation into Ab-producing cells.

Melatonin is a hormone that has immunomodulatory activity and is believed to influence the production of antibodies in mammals. The aim of the present study was to investigate the effect of suppressed melatonin synthesis on the antibody production. BALB/c mice were immunized with T-cell-dependent (TD) and T-cell-independent (TI) antigens and kept under (i) normal lighting, (ii) constant exposure to light, (iii) exposed to light and treated daily with melatonin. It was revealed that melatonin modulated TD and TI antibody production. Suppressed melatonin synthesis increased the amount of IgM, IgG1, IgG2b and IgG3 antibodies after immunization with TI antigen. The level of TD antibodies IgM, IgG2a, IgG2b and IgG3 also increased, however, the antigen-specific antibodies of IgG1 isotype significantly decreased in mice exposed to light. Daily melatonin treatment brought the antibody level back to normal. The antibody concentration in the sera of mice kept at normal lighting was significantly higher when the immunizations were performed in the evening. The action of melatonin on B cells via MT2 receptor was shown in vitro and in vivo.

We investigated the effect of probiotic supplements on oral wound healing, swelling, pain and discomfort after surgical removal of mandibular third molars. A second aim was to evaluate if the intervention could influence the concentrations of oxytocin in saliva. Sixty-four consecutive volunteers (18-34 years) were enrolled to a double-blind randomised placebo-controlled trial with two parallel arms. Following surgery, the patients were asked to take three lozenges per day containing two strains of Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) or placebo for two weeks. The clinical healing and extra-oral swelling were scored two weeks post-operatively. Samples of wound exudate were cultivated for the presence of Staphylococcus aureus and β-haemolytic streptococci. Salivary oxytocin concentrations were analysed from pre- and post-surgery samples using ELISA technique. Compliance and the subjective perception of swelling, pain and discomfort were reported daily through visual analogue scales in a logbook. All patients except three completed the protocol and the postoperative course was uneventful in most cases. Minor extra-oral swellings were noted in five patients, but none required antibiotic treatment. At the 2-week follow-up, there were no significant differences in clinical wound healing index, extra-oral swelling, bacterial growth or salivary oxytocin levels between the groups. The self-reported data unveiled, however, a significantly reduced sense of swelling, in particular during the second week after surgery in the probiotic test group (P<0.05). Likewise, significantly fewer nights with disturbed sleep and fewer days with sick-leave from work were reported among the participants in the test group (P<0.05). No differences were found in the post-operative use of analgesics. In conclusion, we found no significant influence of probiotic supplements on objective wound healing after surgical extraction of impacted mandibular third molars. However, since the patients’ perceived significant post-operative ameliorations, further studies are needed to explore the patient’s value of the intervention.