Introduction: Accumulating evidence has demonstrated that circular RNAs (circRNAs) play a key role in the tumorigenesis of various types of cancers, including clear cell renal cell carcinoma (ccRCC).

Materials and methods: Reverse transcription-quantitative polymerase chain reaction was used to detect the expression of circRNA homeodomain interacting protein kinase 3 (circHIPK3) and microRNAs (miRNAs), including miR-508-3p. The clinical measurement of circHIPK3 was evaluated by Kaplan-Meier survival analysis and receiver operating characteristic analysis. Cell Counting Kit-8 and Transwell chamber assays were performed to determine the changes in the proliferative and metastatic ability of A498 and 786-O cells. C-X-C motif chemokine ligand 13 (CXCL13) protein expression was detected by Western blot analysis. The targeted binding effect between miR-508-3p and circHIPK3 or CXCL13 was confirmed by constructed luciferase and RNA immunoprecipitation (RIP) assays, respectively. Fluorescence in situ hybridization (FISH) assay was used to measure the subcellular localization of circHIPK3 and miR-508-3p.

Results: It was found that circHIPK3 was markedly upregulated in ccRCC tissue and cell lines, and circHIPK3-upregulation was closely correlated with poor clinicopathological features in patients with ccRCC. It was found that both miR-508-3p and circHIPK3 were localized in the cytoplasm of ccRCC cells. The up- and downregulation of circHIPK3 positively regulated ccRCC cell proliferation and metastasis, and this regulatory effect was reversed by miR-508-3p. Through luciferase and RIP assays, it was confirmed that circHIPK3 could interacted with miR-508-3p. Furthermore, it was revealed that CXCL13, which was negatively correlated with miR-508-3p, was upregulated in ccRCC. It was also shown that CXCL13 was a downstream target of miR-508-3p. miR-508-3p suppressed ccRCC cell proliferation and metastasis by targeting CXCL13. Lastly, it was demonstrated that circHIPK3 promoted CXCL13 to facilitate ccRCC cell proliferation and metastasis by decoying miR-508-3p.

Conclusion: In brief, the results of the present study showed that circHIPK3 promoted ccRCC cell proliferation and metastasis by altering miR-5083p/CXCL13 signaling. The present findings might provide a novel target for the molecular treatment of ccRCC.

Keywords: CXCL13; ccRCC; circHIPK3; metastasis; miR-508-3p; proliferation.

Objective: Genome-wide association studies (GWAS) in rheumatoid arthritis (RA) have discovered over 100 RA loci, explaining patient-relevant RA pathogenesis but showing a large fraction of missing heritability. As a continuous effort, we conducted GWAS in a large Korean RA case-control population.

Methods: We newly generated genome-wide variant data in two independent Korean cohorts comprising 4068 RA cases and 36 487 controls, followed by a whole-genome imputation and a meta-analysis of the disease association results in the two cohorts. By integrating publicly available omics data with the GWAS results, a series of bioinformatic analyses were conducted to prioritise the RA-risk genes in RA loci and to dissect biological mechanisms underlying disease associations.

Results: We identified six new RA-risk loci (SLAMF6, CXCL13, SWAP70, NFKBIA, ZFP36L1 and LINC00158) with p_meta<5×10^-8 and consistent disease effect sizes in the two cohorts. A total of 122 genes were prioritised from the 6 novel and 13 replicated RA loci based on physical distance, regulatory variants and chromatin interaction. Bioinformatics analyses highlighted potentially RA-relevant tissues (including immune tissues, lung and small intestine) with tissue-specific expression of RA-associated genes and suggested the immune-related gene sets (such as CD40 pathway, IL-21-mediated pathway and citrullination) and the risk-allele sharing with other diseases.

Conclusion: This study identified six new RA-associated loci that contributed to better understanding of the genetic aetiology and biology in RA.

Keywords: arthritis, rheumatoid; autoimmune diseases; polymorphism, genetic.

Lyme neuroborreliosis (LNB) is one of the manifestations of Lyme disease. Although it is known that immune reaction of LNB patients is dominated by Th1 and Th2 responses and patients have elevated numbers of B cells in their cerebrospinal fluid (CSF), not all the cells involved in inflammation and cytokine secretion have been characterized. The current diagnostics of LNB is based on intrathecal production of antibodies. In recent years, the measurement of chemokine CXCL13 concentration from the CSF has been introduced as a new promising diagnostic tool for LNB to complement the antibody-based diagnostic methods. A few other cytokines have also been analyzed as possible diagnostic markers. However, multiplex analyses simultaneously evaluating the concentrations of a large number of different cytokines in the CSF of LNB patients have been lacking thus far. Extensive cytokine profiling CSF samples of LNB patients would also help in understanding the complex immunopathogenesis of LNB.

CSF samples were analyzed from 43 LNB patients, 19 controls, 18 tick-borne encephalitis patients, and 31 multiple sclerosis patients. In addition, CSF samples from 23 LNB patients obtained after the antibiotic treatment were examined. Altogether, the concentrations of 49 different cytokines were determined from all of the samples. The concentrations of 48 different cytokines were analyzed by magnetic bead suspension array using the Bio-Plex Pro Human Cytokine 21- and 27-plex panels, and the concentration of CXCL13 was analyzed by an ELISA based method.

Distinct cytokine profiles which were able to distinguish LNB patients from controls, tick-borne encephalitis patients, multiple sclerosis patients, and LNB patients treated with antibiotics were identified. LNB patients had elevated concentrations of all major T helper cell type cytokines (Th1, Th2, Th9, Th17, and Treg) in their CSF.

Despite the great differences in the CSF cytokine profiles of different patient groups, CXCL13 still remained as the best marker for LNB. However, IL-1ra might also be helpful as a marker for the antibiotic treatment response. Concerning the immunopathogenesis, this is the first report suggesting the involvement of Th9 cells in the immune response of LNB.

Background: Skin cutaneous melanoma (SKCM) is one of the most malignant and aggressive cancers, causing about 72% of deaths in skin carcinoma. Although extensive study has explored the mechanism of recurrence and metastasis, the tumorigenesis of cutaneous melanoma remains unclear. Exploring the tumorigenesis mechanism may help identify prognostic biomarkers that could serve to guide cancer therapy.

Method: Integrative bioinformatics analyses, including GEO database, TCGA database, DAVID, STRING, Metascape, GEPIA, cBioPortal, TRRUST, TIMER, TISIDB and DGIdb, were performed to unveil the hub genes participating in tumor progression and cancer-associated immunology of SKCM. Furthermore, immunohistochemistry (IHC) staining was performed to validate differential expression levels of hub genes between SKCM tissue and normal tissues from the First Affiliated Hospital of Soochow University cohort.

Results: A total of 308 differentially expressed genes (DEGs) and 12 hub genes were found significantly differentially expressed between SKCM and normal skin tissues. Functional annotation indicated that inflammatory response, immune response was closely associated with SKCM tumorigenesis. KEGG pathways in hub genes include IL-10 signaling and chemokine receptors bind chemokine signaling. Five chemokines members (CXCL9, CXCL10, CXCL13, CCL4, CCL5) were associated with better overall survival and pathological stages. IHC results suggested that significantly elevated CXCL9, CXCL10, CXCL13, CCL4 and CCL5 proteins expressed in the SKCM than in the normal tissues. Moreover, our findings suggested that IRF7, RELA, NFKB1, IRF3 and IRF1 are key transcription factors for CCL4, CCL5, CXCL10. In addition, the expressions of CXCL9, CXCL10, CXCL13, CCL4 and CCL5 were positively correlated with infiltration of six immune cells (B cell, CD8⁺T cells, CD4⁺T cells, macrophages, neutrophils, dendritic cells) and 28 types of TILs. Among them, high levels of B cells, CD8⁺T cells, neutrophils and dendritic cells were significantly related to longer SKCM survival time.

Conclusion: In summary, this study mainly identified five chemokine members (CXCL9, CXCL10, CXCL13, CCL4, CCL5) associated with SKCM tumorigenesis, progression, prognosis and immune infiltrations, which might help us evaluate several immune-related targets for cutaneous melanoma therapy.

Keywords: Biomarker; Chemokines; Cutaneous melanoma; Immune; Infiltration; Prognosis.

B lymphocytes are thought to play a relevant role in multiple sclerosis (MS) pathology. The in vivo analysis of intrathecally produced B cell-related cytokines may help to clarify the mechanisms of B cell recruitment and immunoglobulin production within the central nervous system (CNS) in MS.

Paired cerebrospinal fluid (CSF) and serum specimens from 40 clinically isolated syndrome suggestive of MS or early-onset relapsing-remitting MS patients (CIS/eRRMS) and 17 healthy controls (HC) were analyzed for the intrathecal synthesis of IgG (quantitative formulae and IgG oligoclonal bands, IgGOB), CXCL13, BAFF, and IL-21. 3D-FLAIR, 3D-DIR, and 3D-T1 MRI sequences were applied to evaluate white matter (WM) and gray matter (GM) lesions and global cortical thickness (gCTh).

Compared to HC, CIS/eRRMS having IgGOB (IgGOB+, 26 patients) had higher intrathecal IgG indexes (p < 0.01), lower values of BAFF Index (11.9 ± 6.1 vs 17.5 ± 5.2, p < 0.01), and higher CSF CXCL13 levels (27.7 ± 33.5 vs 0.9 ± 1.5, p < 0.005). In these patients, BAFF Index but not CSF CXCL13 levels inversely correlated with the intrathecal IgG synthesis (r>> 0.5 and p < 0.05 for all correlations). CSF leukocyte counts were significantly higher in IgGOB+ compared to IgGOB- (p < 0.05) and HC (p < 0.01), and correlated to CSF CXCL13 concentrations (r 0.77, p < 0.001). The gCTh was significantly lower in patients with higher CSF CXCL13 levels (2.41 ± 0.1 vs 2.49 ± 0.1 mm, p < 0.05), while no difference in MRI parameters of WM and GM pathology was observed between IgGOB+ and IgGOB-.

The intrathecal IgG synthesis inversely correlated with BAFF Index and showed no correlation with CSF CXCL13. These findings seem to indicate that intrathecally synthesized IgG are produced by long-term PCs that have entered the CNS from the peripheral blood, rather than produced by PCs developed in the meningeal follicle-like structures (FLS). In this study, CXCL13 identifies a subgroup of MS patients characterized by higher leukocyte counts in the CSF and early evidence of cortical thinning, further suggesting a role for this chemokine as a possible marker of disease severity.

In order to extend our studies designed to elucidate the mechanism of action of intravenous methylprednisolone (ivMP) in symptomatic therapy of relapses in multiple sclerosis (MS) victims, we have evaluated the expression of chemokines: macrophage inflammatory protein 3alpha (MIP-3alpha) and B-lymphocyte chemoattractant (CXCL13) before and after treatment. The data from further exploration of the MP mechanism of action in MS relapses may be helpful in establishing the treatment design, that would be specific both for individuals, and for the disease phase. The mean levels of MIP-3alpha in sera of MS patients showed no statistically significant differences compared to control subjects. The comparison of MIP-3alpha level before and after therapy with ivMP gave the same result. The CXCL13 expression in serum was significantly higher in the group of MS patients than in healthy subjects. After therapy with ivMP the estimated level demonstrated an increase as related to the initial values found in MS patients. Such a response was seen also in the responder but not in nonresponder subgroup. The enhancement of CXCL13 expression after iv MP therapy in MS relapses may explain the lack of a long-term effect of MP therapy in MS. The observed difference in CXCL13 expression between responder and non-responder group of patients should be regarded as a step towards elucidation of the therapeutic effect of ivMP in MS relapses.

Recent studies have demonstrated that CXCL13 serum levels correlate significantly with systemic lupus erythematosus (SLE) disease activity. However, experimental studies show that CXCL13 production can also be induced by bacterial exposure as well as in response to inflammatory cytokines. This report asks whether CXCL13 serum levels are elevated in patients with evidence of bacterial infections and whether there is a correlation with the C-reactive protein (CRP) levels or the severity of illness in critically ill patients. CXCL13 levels were compared in 39 patients with active SLE (without concomitant infection), 40 non-SLE patients with sepsis, and 40 healthy controls by enzyme-linked immunosorbent assay (ELISA) methodology. We also tested storage conditions and freeze-thaw cycles for stability of CXCL13 in serum samples. Our studies demonstrated that the median CXCL13 serum levels were significantly elevated in patients with SLE [median 83 pg/ml (interquartile range 38-366)] or sepsis [359 pg/ml (151-459)] compared with healthy controls [32 pg/ml (27-41), p < 0.001]. The CXCL13 serum levels correlated with disease activity in SLE (CXCL13 vs. SLEDAI r = 0.65, p < 0.001), but were not associated with severity of illness score in critically ill patients (CXCL13 vs. SOFA r = -0.15, p = 0.35). However, CXCL13 serum levels were clearly associated with CRP levels in both sepsis (r = 0.45, p = 0.003) and SLE (r = 0.39, p = 0.02). In conclusion, CXCL13 is a stable serum marker for disease activity in SLE patients, but concomitant infections can also lead to increased CXCL13 levels.

BACKGROUND

Infiltrating T-helper cells, cytotoxic T-cells, B-cells and monocytes are thought to mediate the damage to myelin, oligodendrocytes and axons in multiple sclerosis (MS), which results in progressive disability.

OBJECTIVE

The objective of this paper is to explore gene expression profiles of leukocytes in the cerebrospinal fluid (CSF) compartment of MS patients during relapse.

METHODS

Global gene expression was analyzed by DNA microarray analysis of cells in CSF from MS patients and controls, and verifications were performed with real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

Fifty percent of the recently described risk genes for MS and 28% of non-risk genes were differently expressed in MS patients compared to controls (χ(2)-test, p=7.7 × 10(-5)). Genes involved in T- and NK-cell processes were up-regulated, and genes involved in processes targeting innate immunity or B-cells were down-regulated in MS. Increased expression of EDN1 and CXCL11 and decreased expression of HMOX1 was verified with real-time PCR and increased expression of CXCL13 was verified with ELISA in CSF.

CONCLUSIONS

DNA microarray analysis is useful in identifying differently expressed genes in CSF leukocytes, which may be important in MS in vivo. Our findings suggest that many of the risk genes for MS are differently expressed in the disease-mediating leukocytes that penetrate the blood-brain barrier.

In multiple sclerosis (MS) lymphoid follicle-like aggregates have been reported in the meninges of patients. Here we investigated the functional relevance of B cell infiltration into the central nervous system (CNS) in MP4-induced experimental autoimmune encephalomyelitis (EAE), a B cell-dependent mouse model of MS. In chronic EAE, B cell aggregates were characterized by the presence of CXCL13(+) and germinal center CD10(+) B cells. Germline transcripts were expressed in the CNS and particularly related to TH17-associated isotypes. We also observed B cells with restricted VH gene usage that differed from clones found in the spleen. Finally, we detected CNS-restricted spreading of the antigen-specific B cell response towards a myelin and a neuronal autoantigen. These data imply the development of autonomous B cell-mediated autoimmunity in the CNS in EAE - a concept that might also apply to MS itself.

Primary cutaneous follicular helper T (TFH)-cell lymphoma has recently been proposed, and is characterized by proliferation of malignant T cells expressing TFH-cell markers, such as CXCL13, accompanied by numerous reactive B cells. We report here a patient whose skin histology showed massive infiltration of both T and B cells, with a proliferation of arborizing high endothelial venules and follicular dendritic cells. Infiltrating T cells were positive for CXCL13, programmed death (PD)-1, inducible T-cell co-stimulator, and BCL-6. Southern blot analyses using DNA from the skin revealed monoclonality of both T and B cells. The patient had marked resistance to treatments, and complete remission was achieved only after allogeneic stem cell transplantation. The present case showed overlapping features with angio-immunoblastic T-cell lymphoma (AITL), although systemic symptoms were not observed. Further study is needed to define the criteria of this provisional entity, representing the cutaneous counterpart of the nodal follicular peripheral T-cell lymphoma or AITL.

OBJECTIVE

Study the impact of CXCL13 neutralization on germinal center (GC) response in vivo, and build quantitative relationship between target coverage and pharmacological effects at the target tissue.

METHODS

An anti-CXCL13 neutralizing monoclonal antibody was dosed in vivo in a T-dependent mouse immunization (TDI) model. A quantitative site-of-action (SoA) model was developed to integrate antibody PK and total CXCL13 levels in serum and spleen towards estimating target coverage as a function of dose. To aid in the SoA model development, a radio-labeled study using [I(125)] CXCL13 was conducted in mice. Model estimated target coverage was linked to germinal center response using a sigmoidal inhibitory effect model.

RESULTS

In vivo studies demonstrated that CXCL13 inhibition led to an architectural change in B-cell follicles, dislocation of GCs and a significant reduction in the GC absolute numbers per square area (GC/mm(2)). The SoA modeling analysis indicated that ~79% coverage in spleen was required to achieve 50% suppression of GC/mm(2). The 3 mg/kg dose with 52% spleen coverage resulted in no PD suppression, whereas 30 mg/kg with 93% coverage achieved close to maximum PD suppression, highlighting the steepness of PD response.

CONCLUSIONS

This study showcases an application of SoA modeling towards a quantitative understanding of CXCL13 pharmacology.

Posttransplant lymphoproliferative disease (PTLD) is a severe complication of immunosuppressive treatment in organ-grafted children. Early diagnosis of PTLD is hampered by both unspecific clinical symptoms and lack of easy accessible markers. The homeostatic chemokine CXCL13, which plays a crucial role in B-cell homing and lymphoid organ development, is expressed in some lymphomatous diseases. This study aims to investigate whether serum CXCL13 (sCXCL13) levels correlate with occurrence and regression of PTLD in pediatric solid-organ graft recipients. Serum samples from PTLD patients (n = 21), patients with Epstein-Barr virus (EBV) reactivation (n = 18), and healthy age-matched controls (n = 19) were tested for CXCL13 using a commercially available ELISA kit. sCXCL13 levels were significantly higher in PTLD patients than in healthy children. PTLD patients had also higher sCXCL13 values than pediatric solid-organ recipients with EBV reactivation. An increase in sCXCL13 levels was observed from EBV reactivation to PTLD diagnosis in most cases. Elevated sCXCL13 levels were detected up to 2 years prior to PTLD diagnosis and correlated well with response to cytoreductive treatment in individual patients. sCXCL13, thus, may be a readily available surrogate marker for the diagnosis of PTLD and for monitoring of response to treatment in patients with initially elevated sCXCL13 levels.

OBJECTIVE

Knowledge of the role of chemokines in the inflammation during neuroborreliosis (NB) is limited. We evaluated the pre- and post-treatment concentration of CXCL8, CXCL10, CXCL11, CXCL12, and CXCL13 in serum (s) and cerebrospinal fluid (csf) in patients with NB.

RESULTS

There was a statistically significant increase in pre-treatment s CXCL8, CXCL10, CXCL11, CXCL12, CXCL13 and csf CXCL8, CXCL11, CXCL12, CXCL13 in patients with early form of NB. CXCL8, CXCL11, CXCL12 and CXCL13 increase was the highest in csf. After treatment, a significant decrease in csf chemokine levels (except CXCL10) and s levels (except CXCL11) was observed.

CONCLUSIONS

CXCL8, CXCL10, CXCL11, CXCL12, CXCL13 are involved in the pathomechanism of NB but their role is different in s and csf. CXCL13 seems to be a good biomarker for NB. In early NB, it may facilitate the diagnosis and monitoring of therapy. However tick-borne encephalitis needs to be excluded as it also increases chemokine concentration. Decrease in all examined chemokines in s and csf after treatment suggests that chemokines may be useful in monitoring response to NB therapy.

Chlamydia trachomatis is the most common cause of acute salpingitis worldwide. The socioeconomic impact of sexually transmitted infections (STI) caused by C. trachomatis is considerable. The purpose of this study was to investigate secretion of a unique chemokine, CXCL13, during the inflammatory process in human fallopian tube tissue in response to infection with C. trachomatis. We employed two models for our experiments: archived fallopian tube paraffin sections from known cases of salpingitis of unknown etiology and human fallopian tube organ culture established from fresh fallopian tube biopsies subsequently infected in vitro with C. trachomatis serovar E. We used immunohistochemistry, microarray analysis and cytometric bead array to study these specimens. In both models, we found that the fallopian tissue infected with C. trachomatis expressed CXCL13 and other characteristics of tertiary lymphoid tissue. In addition, we found that CXCL13 was expressed in multiple cell types, including endothelial cells, demonstrating a mechanism for the lymphoid aggregation seen in fallopian tube tissue during salpingitis and infection with C. trachomatis.

BACKGROUND

Combined pegylated interferon-α and ribavirin therapy has sustained virological response (SVR) rates of 54% to 61%. Pretreatment predictors of SVR to interferon therapy have not been fully investigated yet. The current study assesses a group of chemokines that may predict treatment response in Egyptian patients with chronic HCV infection.

METHODS

CXCL5, CXCL9, CXCL11, CXCL12, CXCL 13, CXCL 16 chemokines and E-Cadherin were assayed in 57 chronic HCV patients' sera using quantitative ELISA plate method. All studied patients were scheduled for combined pegylated interferon alpha and ribavirin therapy (32 patients received pegylated interferon α 2b, and 25 patients received pegylated interferon α 2a). Quantitative hepatitis C virus RNA was done by real time RT-PCR and HCV genotyping by INNOLIPAII.

RESULTS

There was no significant difference (p>> 0.05) in baseline HCV RNA levels between responders and non-responders to interferon. A statistically significant difference in CXCL13 (p = 0.017) and E-Cadherin levels (P = 0.041) was reported between responders and nonresponders at week 12. Significant correlations were found between changes in the CXCL13 levels and CXCL9, CXCL16, E-cadherin levels as well as between changes in E-cadherin levels and both CXCL16 and ALT levels that were maintained during follow up. Also, significant changes have been found in the serum levels of CXCL5, CXCL13, and CXCL16 with time (before pegylated interferon α 2 a and α 2 b therapy, and at weeks 12 and 24) with no significant difference in relation to interferon type and response to treatment.

CONCLUSIONS

Serum levels of CXCL13 and E-Cadherin could be used as surrogate markers to predict response of combined PEG IFN-α/RBV therapy, especially at week 12. However, an extended study including larger number of patients is needed for validation of these findings.

UNASSIGNED

NCT01758939.

At least three phenotypically and morphologically distinguishable types of branched stromal cells are revealed in the human splenic white pulp by subtractive immunohistological double-staining. CD271 is expressed in fibroblastic reticulum cells of T-cell zones and in follicular dendritic cells of follicles. In addition, there is a third CD2711- and CD271+/) stromal cell population surrounding T-cell zones and follicles. At the surface of follicles the third population consists of individually variable partially overlapping shells of stromal cells exhibiting CD90 (Thy-1), MAdCAM-1, CD105 (endoglin), CD141 (thrombomodulin) and smooth muscle α-actin (SMA) with expression of CD90 characterizing the broadest shell and SMA the smallest. In addition, CXCL12, CXCL13 and CCL21 are also present in third-population stromal cells and/or along fibres. Not only CD27+ and switched B lymphocytes, but also scattered IgD++ B lymphocytes and variable numbers of CD4+ T lymphocytes often occur close to the third stromal cell population or one of its subpopulations at the surface of the follicles. In contrast to human lymph nodes, neither podoplanin nor RANKL (CD254) were detected in adult human splenic white pulp stromal cells. The superficial stromal cells of the human splenic white pulp belong to a widespread cell type, which is also found at the surface of red pulp arterioles surrounded by a mixed T-cell/B-cell population. Superficial white pulp stromal cells differ from fibroblastic reticulum cells and follicular dendritic cells not only in humans, but apparently also in mice and perhaps in rats. However, the phenotype of white pulp stromal cells is species-specific and more heterogeneous than described so far.

The objective of this study was to investigate the effect of human adipose tissue-derived mesenchymal stem cells (AdMSCs) on atopic dermatitis (AD) in the BALB/c mouse model. The AdMSCs attenuated clinical symptoms associated with AD, decreased numbers of degranulated mast cells (MCs), IgE level, amount of histamine released, and prostaglandin E2 level. Atopic dermatitis increased the expression levels of cytokines/chemokines, such as interleukin-5 (IL-5), macrophage inflammatory protein-1ß (MIP-1ß), MIP-2, chemokine (C-C motif) ligand 5 (CCL5), and IL-17, in BALB/c mouse. The AdMSCs showed decreased expression levels of these cytokines in the mouse model of AD. In vivo downregulation of MIP-2 attenuated the clinical symptoms associated with AD. Atopic dermatitis increased the expression levels of hallmarks of allergic inflammation, induced interactions of Fc𝜀RIβ with histone deacetylase 3 (HDAC3) and Lyn, increased ß-hexosaminidase activity, increased serum IgE level, and increased the amount of histamine released in an MIP-2-dependent manner. Downregulation of MIP-2 increased the levels of several miRNAs, including miR-122a-5p. Mouse miR-122a-5p mimic inhibited AD, while suppressor of cytokine signaling 1 (SOCS1), a predicted downstream target of miR-122a-5p, was required for AD. The downregulation of SOCS1 decreased the expression levels of MIP-2 and chemokine (C-X-C motif) ligand 13 (CXCL13) in the mouse model of AD. The downregulation of CXCL13 attenuated AD and allergic inflammation such as passive cutaneous anaphylaxis. The role of T cell transcription factors in AD was also investigated. Atopic dermatitis increased the expression levels of T-bet and GATA-3 [transcription factors of T-helper 1 (Th1) and T-helper 2 (Th2) cells, respectively] but decreased the expression of Foxp3, a transcription factor of regulatory T (Treg) cells, in an SOCS1-dependent manner. In addition to this, miR-122a-5p mimic also prevented AD from regulating the expression of T-bet, GATA-3, and Foxp3. Atopic dermatitis increased the expression of cluster of differentiation 163 (CD163), a marker of M2 macrophages, but decreased the expression of inducible nitric oxide synthase (iNOS), a marker of M1 macrophages. Additionally, SOCS1 and miR-122a-5p mimic regulated the expression of CD163 and iNOS in the mouse model of AD. Experiments employing conditioned medium showed interactions between MCs and macrophages in AD. The conditioned medium of AdMSCs, but not the conditioned medium of human dermal fibroblasts, negatively inhibited the features of allergic inflammation. In summary, we investigated the anti-atopic effects of AdMSCs, identified targets of AdMSCs, and determined the underlying mechanism for the anti-atopic effects of AdMSCs.

Mutations affecting the non-canonical pathway of NF-κB were recently identified to underlie a form of common variable immunodeficiency strongly associated with autoimmunity. Although intrinsic B-cell abnormalities explain most of the humoral defects of this disease, detailed data on the impact of NFKB2 on follicular helper (Tfh) and regulatory (Tregs) T cells are scarce. Here, we show that Tfh, CXCR5⁺, and CXCR5^- Treg cell subsets were significantly reduced in patients heterozygous for a truncating mutation of NFKB2. Plasma CXCL13 levels were reduced, underlining an important role for NFKB2 in regulating the germinal center (GC) response. Proinflammatory IFNγ, IL-17 and IL-10 cytokine production by CD4 T cells was lower in the mutated patients, but the production of IL-4 and IL-21 was not altered. Taken together, our findings show that NFKB2 influences the quality and efficiency of human GC reaction, by affecting not only the B cells but also GC-relevant T cell subsets.

A CXCL13-like chemokine cDNA was isolated from large yellow croaker (Pseudosciaena crocea) by expressed sequence tag (EST) analysis (LycCXCL13). The full-length cDNA of LycCXCL13 is 796 nucleotides (nt) encoding a protein of 97 amino acids (aa), with a putative molecular weight of 10.7 kDa. The deduced LycCXCL13 contains a 24-aa signal peptide and a 73-aa mature polypeptide, which possesses the typical arrangement of four cysteines as found in other known CXC chemokines (C(25), C(27), C(52) and C(68)). It shares 35, 36 and 39% aa sequence identities to green puffer CXCL13-like, Atlantic salmon CXCL13 and Japanese flounder CXCL13 chemokines, and 24-29% identities to CXCL13 chemokines in mammals, respectively. Phylogenetic analysis showed that LycCXCL13 is more closely related to the CXCL13 subgroup than to any other CXC chemokine subgroups. LycCXCL13 gene was constitutively expressed in all tissues examined, except for intestine. Upon induction with poly(I:C) or inactivated trivalent bacterial vaccine, LycCXCL13 gene expression was significantly up-regulated in spleen, head kidney, heart and gills at 24 h post-injection. Real-time PCR results showed that LycCXCL13 gene expression reached peak level in spleen and head kidney at 12 h after induction by poly(I:C), while its expression increased to the highest level in head kidney at 24 h or in spleen at 48 h by bacterial vaccine. Recombinant LycCXCL13 protein produced in E. coli BL21 exhibited obvious chemotaxis to the peripheral blood leucocytes (PBLs) from large yellow croaker. These results suggest that LycCXCL13 may be involved in inflammatory responses as well as homeostatic processes in large yellow croaker.

OBJECTIVE

Retrospective analyses were undertaken to assess the hypothesis that environmental variables influenced immunophysiological status of lacrimal glands from untreated female rabbits that had been housed out-of-doors until they were acquired for use as controls for experimental studies.

METHODS

Rabbits were euthanized within 5 days of arrival at University Vivaria. Glands were divided for histology and RNA extraction. Transcript abundances were determined with real time RT-PCR. Sections were stained for CD18 and rabbit thymic lymphocyte antigen. Environmental variables assessed were mean daily high temperature, low humidity, high temperature/low humidity ratio, and days with above average temperature/humidity ratio ("adverse days") during the prior 30 days.

RESULTS

Spearman's analyses revealed numerous significant correlations. Numbers of T cells and abundances of mRNAs for CD8; CCL2, and CCL4; IL-1α and IL-1β; the T(H)1 cytokine, IL-2; and the T(H)2- and B cell cytokines, IL-4, IL-6, IL-10, APRIL, and BAFF, all increased with adverse days, while IFN-γ mRNA abundance decreased. Glands from the group exposed to the most adverse days remained free of immunopathological lesions. Glands from the group exposed to the highest temperatures fell above the regression curves for IL-4, APRIL, and BAFF calculated for the other groups and had significantly higher abundances of mRNAs for prolactin, IL-18, CCL21, CCL28, CXCL8, and CXCL13. One of six glands from this group contained small immune cell aggregates; the others appeared normal. The only gland that presented with frank histopathology was from a group that had experienced benign conditions.

CONCLUSIONS

Increasing adverse days correlated with increasing abundances of transcripts, including mRNAs for IL-2, IL-10, and CD8, outside the T(H)1/T(H)2 paradigm. The findings raise intriguing questions as to whether and how such changes might be associated with homeostatic phenomena.

We report three cases of follicular dendritic cell sarcoma (FDCS) showing a hitherto undescribed histological pattern consisting of nodular tumor growth associated with small B lymphocytes. FDCS tumor cells consistently showed large epithelioid features and were intermingled with small lymphocytes in the nodules in two cases, whereas they formed cohesive aggregates surrounded by lymphocyte mantle in the other. These features were easily confused with lymphomatous proliferations and, in particular, subtypes of Hodgkin lymphoma, high-grade follicular lymphoma, and germinotropic large B-cell lymphomas. The diagnosis was established by the use of a broad panel of antibodies that showed a variable expression of the FDC markers CD21, CD23, CD35, clusterin, podoplanin, claudin 4, epidermal growth factor receptor, and CXCL13. The associated B lymphocytes revealed a mantle zone B phenotype, with expression of CD20 and PAX5, together with TCL1 and IgD. Of notice, in all cases, morphological features suggesting hyaline-vascular Castleman disease were recognized in the interfollicular areas, containing scattered epithelioid cells similar to those found in the nodules, thus providing a useful clue for FDCS diagnosis. Of the 3 cases, 1 presented multiple recurrences unresponsive to chemotherapy and radiotherapy and finally died of disease 14 years after diagnosis. This study further emphasizes the extreme variability of morphological presentation of FDCS and expands the spectrum of lesions showing a nodular growth pattern occurring in human lymph nodes.

OBJECTIVE

To better understand the role of chemokines during human B-cell development in bone marrow.

METHODS

Differentiation stage-specific B cells (pro-B, pre-B, immature, and mature) were analyzed for chemokine receptor expression and for migration to corresponding ligands. We also hypothesized that inflammatory conditions may cause the upregulation of certain chemokine receptors on early B cells, rendering them sensitive to extramedullary chemotactic cues. To test this hypothesis, we used human pre-B 697 cells to investigate whether various inflammatory agents could modify chemokine receptor expression and function.

RESULTS

Chemotaxis to CXCL12 was observed for all B cell subsets. However, chemotactic responses to CCL19, CCL21, CXCL13, and CCL20 were limited to late-stage, IgM+ bone marrow B cells (immature B and mature B). Chemotactic responses to corresponding ligands correlated with the pattern of chemokine receptor expression. The expression of CCR7, however, was low on early (pro-B and pre-B) B cells and did not induce chemotaxis. Interestingly, both CCL19 and CCL21 could trigger ERK1/2 phosphorylation in early B cells. Exposure of pre-B 697 cells to TNF-alpha upregulated CCR7 and CXCR5 expression, whereas it had no effect on CCR6 surface expression. Correspondingly, TNF-alpha-stimulated pre-B cells chemotaxed towards CCL19 and CXCL13, in contrast to non-TNF-alpha-stimulated controls.

CONCLUSIONS

We postulate that CXCR5, CCR7, and CCR6 participate in bone marrow trafficking and/or bone marrow egress of late-stage B cells under steady-state conditions, whereas inflammation-induced expression of CCR7 and CXCR5 may facilitate early B-cell emigration out of the bone marrow and their positioning in secondary lymphoid organs.

Helicobacter (H.) suis can colonize the stomach of pigs as well as humans, causing chronic gastritis and other gastric pathological changes including gastric ulceration and mucosa-associated lymphoid tissue (MALT) lymphoma. Recently, a virulence factor of H. suis, γ-glutamyl transpeptidase (GGT), has been demonstrated to play an important role in the induction of human gastric epithelial cell death and modulation of lymphocyte proliferation depending on glutamine and glutathione catabolism. In the present study, the relevance of GGT in the pathogenesis of H. suis infection was studied in mouse and Mongolian gerbil models. In addition, the relative importance of H. suis GGT was compared with that of the H. pylori GGT. A significant and different contribution of the GGT of H. suis and H. pylori was seen in terms of bacterial colonization, inflammation and the evoked immune response. In contrast to H. pyloriΔggt strains, H. suisΔggt strains were capable of colonizing the stomach at levels comparable to WT strains, although they induced significantly less overall gastric inflammation in mice. This was characterized by lower numbers of T and B cells, and a lower level of epithelial cell proliferation. In general, compared to WT strain infection, ggt mutant strains of H. suis triggered lower levels of Th1 and Th17 signature cytokine expression. A pronounced upregulation of B-lymphocyte chemoattractant CXCL13 was observed, both in animals infected with WT and ggt mutant strains of H. suis. Interestingly, H. suis GGT was shown to affect the glutamine metabolism of gastric epithelium through downregulation of the glutamine transporter ASCT2.

B-1 cells constitute a unique subpopulation of lymphocytes residing mainly in body cavities like the peritoneal cavity (PerC) but are also found in spleen and bone marrow (BM). As innate-like B cells, they mediate first line immune defense through low-affinity natural IgM (nIgM) antibodies. PerC B-1 cells can egress to the spleen and differentiate into nIgM antibody-secreting plasma cells that recognize conserved exogenous and endogenous cellular structures. Homing to and homeostasis within the PerC are regulated by the chemokine CXCL13 released by PerC macrophages and stroma cells. However, the exact mechanisms underlying the regulation of CXCL13 and B-1 homeostasis are not fully explored. B-1 cells play important roles in the inflammatory response to infection, autoimmunity, ischemia/reperfusion injury, obesity, and atherosclerosis. Remarkably, this list of inflammatory entities has a strong overlap with diseases that are regulated by complement suggesting a link between B-1 cells and the complement system. Interestingly, up to now, no data exist regarding the role of complement in B-1 cell biology. Here, we demonstrate for the first time that C5a regulates B-1 cell steady-state dynamics within the peritoneum, the spleen, and the BM. We found decreased B-1a cell numbers in the peritoneum and the spleen of C5aR1-/- mice associated with increased B1-a and B1-b numbers in the spleen and high serum titers of nIgM antibodies directed against phosphorylcholine and several pneumococcal polysaccharides. Similarly, peritoneal B-1a cells were decreased in the peritoneum and splenic B-1a and B-1b cells were increased in C5aR2-/- mice. The decrease in peritoneal B-1 cell numbers was associated with decreased peritoneal CXCL13 levels in C5aR1-/- and C5aR2-/- mice. In search for mechanisms, we found that combined TLR2 and IL-10 receptor activation in PerC macrophages induced strong CXCL13 production, which was significantly reduced in cells from C5aR1- and C5aR2-deficient mice and after combined C5aR-targeting. Such stimulation also induced marked local C5 production by PerC macrophages and C5a generation. Importantly, peritoneal in vivo administration of C5a increased CXCL13 production. Taken together, our findings suggest that local non-canonical C5 activation in PerC macrophages fuels CXCL13 production as a novel mechanism to control B-1 cell homeostasis.