Interleukin 22 (IL-22) expression is associated with increased joint destruction and disease progression in rheumatoid arthritis (RA). Although IL-22 is considered a pro-inflammatory cytokine, its mechanism of action in RA remains incompletely understood. Here, we used the collagen-induced arthritis model in IL-22 deficient (IL-22(-/-) ) mice to study the role of IL-22 in RA. In spite of normal disease incidence, disease severity is significantly diminished in IL-22(-/-) mice. Moreover, pathogenicity of Th17 cells and development and function of B cells are unaffected. In contrast, splenic plasma cells, as well as serum autoantibody titers, are reduced in the absence of IL-22. At the peak of disease, germinal centers (GCs) are severely reduced in the spleens of IL-22(-/-) mice, correlating with a decline in GC B-cell numbers. Within the GC, we identified IL-22R1 expressing follicular dendritic cell-like stromal cells. Human lymphoid stromal cells respond to IL-22 ex vivo by inducing transcription of CXCL12 and CXCL13. We therefore postulate IL-22 as an important enhancer of the GC reaction, maintaining chemokine levels for the persistence of GC reactions, essential for the production of autoantibody-secreting plasma cells. Blocking IL-22 might therefore prevent immune-complex deposition and destruction of joints in RA patients.

Beyond the production of autoantibodies, B-cells are thought to play a role in systemic sclerosis (SSc) by secreting proinflammatory/profibrotic cytokines. B-cells are a heterogeneous population with different subsets distinguished by their phenotypes and cytokine production. Data about B-cell subsets, cytokine production and intracellular pathways leading to this production are scarce in SSc. The aim of our study was to describe B-cell homeostasis, activation, proliferation, cytokine production in B-cells and serum and B-cell intracellular signaling pathways in SSc. We hypothezided that B-cell homeostasis and cytokine production were altered in SSc and could be explained by serum cytokine as well as by intracellular signaling pathway abnormalities. Forty SSc patients and 20 healthy controls (HC) were prospectively included. B-cell subsets were determined by flow cytometry using CD19, CD21, CD24, CD38, CD27, IgM and IgD. CD25, CD80, CD95, HLA-DR were used to assess B-cell activation. Intracellular production of IL-10 and IL-6 were assessed by flow cytometry after TLR9 and CD40 stimulation. IL-6, IL-10, Ki67, Bcl2 mRNA were quantified in B-cells. Cytokine production was also assessed in sera and supernatants of B-cell culture, using a multiplex approach. Signaling pathways were studied through phosphorylation of mTOR, ERK, STAT3, STAT5 using a flow cytometry approach. We found that SSc patients exhibited an altered peripheral blood B-cell subset distribution, with decreased memory B-cells but increased proportion of naive and CD21LoCD38Lo B-cell subsets. We observed an increased expression of activation markers (CD80, CD95, HLA-DR) on some B-cell subsets, mainly the memory B-cells. Secretion of IL-6, BAFF and CXCL13 were increased in SSc sera. There was no correlation between the peripheral blood B-cell subsets and the serum concentrations of these cytokines. After stimulation, we observed a lower proportion of IL-10 and IL-6 producing B-cells in SSc. Finally, we observed a significant decrease of mTOR phosphorylation in SSc patient B-cells. In conclusion, we observed an altered B-cell homeostasis in SSc patients compared to HC. Memory B-cells were both decreased and activated in patients. IL-10 producing B-cells were decreased in SSc. This decrease was associated with an alteration of mTOR phosphorylation in B-cells. Conversely, there was no correlation between serum cytokine profile and B-cell homeostasis alterations.

The aim of this study was to compare serum and cerebrospinal fluid (CSF) cytokine/chemokine levels between anti-NMDAR and anti-LGI1 encephalitis patients. Samples from fourteen anti-NMDAR encephalitis patients, ten anti-LGI1 encephalitis patients, and ten controls were analyzed for the following cytokines/chemokines: IL-1b, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-17A, IL-23, GM-CSF, IFN-gamma, TNF-alpha, and CXCL13. Compared with controls, CSF IL-17A, IL-6 and CXCL13 were elevated in anti-NMDAR encephalitis patients (post-hoc p-values 0.002, 0.011, and 0.011, respectively) but not in anti-LGI1 encephalitis patients. In the serum, only IL-2 was increased in anti-NMDAR encephalitis. Intrathecal IL-17/IL-6 activation is a characteristic of anti-NMDAR encephalitis.

Visceral leishmaniasis is associated with atrophy and histological disorganization of splenic compartments. In this paper, we compared organized and disorganized splenic lymphoid tissue from dogs naturally infected with Leishmania infantum assessing the size of the white pulp compartments, the distribution of T, B and S100+ dendritic cells, using immunohistochemistry and morphometry and the expression of CCR7 and the cytokines, CXCL13, lymphotoxin (LT)-α, LT-β, CCL19, CCL21, TNF-α, IL-10, IFN-γ and TGF-β, using by real time RT-PCR. The lymphoid follicles and marginal zones were smaller (3.2 and 1.9 times, respectively; Mann-Whitney, P<0.02) in animals with disorganized splenic tissue in comparison to those with organized splenic lymphoid tissue. In spleens with disorganized lymphoid tissue, the numbers of T cells and S100+ dendritic cells were decreased in the follicles, and the numbers of B cells were reduced in both the follicles and marginal zones. CXCL13 mRNA expression was lower in animals with disorganized lymphoid tissue (0.5±0.4) compared to those with organized lymphoid tissue (2.7±2.9, both relative to 18S expression, P = 0.01). These changes in the spleen were associated with higher frequency of severe disease (7/12) in the animals with disorganized than in animals with organized (2/13, Chi-square, P = 0.01) splenic lymphoid tissue. The data presented herein suggest that natural infection with Leishmania infantum is associated with the impairment of follicular dendritic cells, CXCL13 expression, B cell migration and germinal center formation and associates these changes with severe clinical forms of visceral leishmaniasis. Furthermore the fact that this work uses dogs naturally infected with Leishmania infantum emphasizes the relevance of the data presented herein for the knowledge on the canine and human visceral leishmaniasis.

BACKGROUND

Acute rejection is still one of the main complications which enhances the cost and the risk to renal graft failure. Chemokines, interacting with respective receptors, can recruit leukocytes into grafts and mediate allograft rejection. In this study, we aimed to analyze gene expression of chemokines including CCL5/RANTES, CXCL10/IP-10, CXCL13/BCA-1, and receptors of CCR5, CXCR3, CXCR5 in peripheral blood mononuclear cells (PBMCs) during acute renal allograft rejection

METHODS

Gene expression of all these chemokines and receptors in PBMCs were analyzed by real-time PCR from 14 stable recipients, 32 biopsy-proven acute rejection (AR), and 5 acute tubular necrosis (ATN).

RESULTS

Gene expression of CCL5, CXCL10, CXCL13, and CCR5 were up-regulated both in AR and ATN group compared to stable recipients (fold change>2, P<0.05). Serum creatinine recovered to baseline level after anti-rejection therapy was defined as AR-sensitive and creatinine maintained above 200 μmol/L as AR-resistant. Expression of CXCL10 and CXCL13 were 5.98-, 2.94-, and 20.5, 10.8-fold change in AR-resistant and AR-sensitive compared to stable recipients, respectively. The expression of CXCL10 and CXCL13 was a twofold change in AR-resistant compared to AR-sensitive recipients (P<0.05). Five out of ten AR-resistant recipients lost graft function in the follow-up.

CONCLUSIONS

CXCL10 and CXCL13 expression were highly up-regulated in PBMCs in acute renal allograft rejection, especially in poor response to anti-rejection therapy and detrimental prognosis.

The chemokine, C-X-C motif ligand 13 (CXCL13), is constitutively expressed in lymphoid organs and controls the recruitment and compartmentalization of lymphocytes and antigen presenting cells within these specialized structures. Recent data, however, also find induction of this molecule during central nervous system (CNS) inflammation under a variety of circumstances. While its role(s) in the pathogenesis of neoplastic, infectious and autoimmune disorders of the CNS remain incompletely understood, several lines of evidence suggest that CXCL13 could become a relevant therapeutic target in at least some of these diseases. This review focuses on how CXCL13 contributes to the pathogenesis of selected CNS disorders involving both experimental animals and humans, paying particular attention to the issue of whether (and if so, how) blockade of this ligand or its receptor might benefit the host. Current blocking strategies largely involve the use of monoclonal antibodies, but an improved understanding of downstream signaling pathways makes small molecule inhibition a future possibility.

BACKGROUND

Young breast cancer occupies a higher and higher proportion of breast cancer, especially in Asia, and is associated with a more unfavorable prognosis compared with the disease arising in older women. However, the poor prognosis of young breast cancer cannot be fully explained by the clinical and molecular factors.

METHODS

This study investigated 1125 Chinese breast cancer patients diagnosed from 2009 to 2013. A data mining of gene expression profiles was performed for the young and older breast cancer patients, identifying significantly differentially expressed genes. Quantitative RT-PCR, Western blotting and immunohistochemistry assay were carried out for the clinical sample validations.

RESULTS

The investigation firstly displayed that young patients (≤45 years) accounted for 47.6 % (535/1125) of breast cancer, and clinically associated with some unfavorable factors related to poor prognosis, such as invasive pathological type, high tumor grade, lymph node positive, ER negative and triple-negative subtype. Subsequently, 553 significantly differentially expressed genes were identified by the data mining. Of them, a set of genes related to immune function were observed to be up-regulated in young patients with breast cancer. Impressively, the CXCL13 (C-X-C motif chemokine 13) expression level showed the most significant difference (FC = 2.64, P = 8.2 × 10(-4)). Furthermore, the validations with clinical samples and correlation analysis demonstrated that CXCL13 was indeed highly expressed in young breast cancer and closely associated with some prognostic factors including lymph node positive and ER negative.

CONCLUSIONS

This is the first to indicate the clinical relevance of CXCL13 to young breast cancer and represents a potential therapeutic target for young breast cancer.

BACKGROUND

C-X-C motif chemokine 10 (CXCL10) is produced in response to interferon-γ, and tumor necrosis factor-α (TNF-α) triggers the accumulation of activated lymphocytes. CXCL13 is constitutively expressed in secondary lymphoid tissues, and the expression is upregulated by TNF-α, via T cell stimulation. It appears that CXCL10 and CXCL13 could play a potential role in the pathogenesis of adult-onset Still's disease (AOSD), therefore, we investigated the associations between CXCL10 and CXCL13 levels and clinical manifestations in patients with active AOSD.

METHODS

Blood samples were collected from 39 active AOSD patients, 32 rheumatoid arthritis (RA) patients and 40 healthy controls (HC). Of the AOSD patients, follow-up samples were collected from 15 9.6 ± 9.2 months later. Serum levels of CXCL10 and CXCL13 were determined using enzyme-linked immunosorbent assay. CXCL10, CXCL13, and C-X-C chemokine receptor type 3 (CXCR3) expression levels in biopsy specimens obtained from 26 AOSD patients with skin rashes were investigated via immunohistochemistry.

RESULTS

The CXCL10 levels in AOSD patients (1,031.3 ± 2,019.6 pg/mL) were higher than in RA (146.3 ± 91.4 pg/mL, p = 0.008) and HC (104.4 ± 47.9 pg/mL, p = 0.006). Also, the CXCL13 levels of AOSD patients (158.8 ± 151.2 pg/mL) were higher than those of RA (54.4 ± 61.1 pg/mL, p < 0.001) and HC (23.5 ± 18.1 pg/mL, p < 0.001). Serum CXCL10 levels correlated with ferritin and systemic scores. Serum CXCL13 levels correlated with those of hemoglobin, C-reactive protein, ferritin, and albumin, and systemic scores. In follow-up AOSD patients, the levels of CXCL10 and CXCL13 fell significantly (153.7 ± 130.1 pg/mL, p = 0.002, and 89.1 ± 117.4 pg/mL, p = 0.001, respectively). On immunohistochemistry, the percentages of inflammatory cells expressing CXCL10 ranged from 1 to 85%, CXCL13 from 1 to 72%, and CXCR3 from 2 to 65%. The percentage of CXCL10-positive inflammatory cells was higher in skin biopsy samples exhibiting mucin deposition than in those that did not (p = 0.01). CXCL13 levels were correlated with those of CD4 and CD68.

CONCLUSIONS

Serum CXCL10 and CXCL13 levels may serve as clinical markers for assessment of disease activity in AOSD. CXCL10/CXCR3 and CXCL13 may contribute to the inflammatory response, especially skin manifestations thereof, in AOSD.

PKCε, an oncogenic member of the PKC family, is aberrantly overexpressed in epithelial cancers. To date, little is known about functional interactions of PKCε with other genetic alterations, as well as the effectors contributing to its tumorigenic and metastatic phenotype. Here, we demonstrate that PKCε cooperates with the loss of the tumor suppressor Pten for the development of prostate cancer in a mouse model. Mechanistic analysis revealed that PKCε overexpression and Pten loss individually and synergistically upregulate the production of the chemokine CXCL13, which involves the transcriptional activation of the CXCL13 gene via the non-canonical nuclear factor κB (NF-κB) pathway. Notably, targeted disruption of CXCL13 or its receptor, CXCR5, in prostate cancer cells impaired their migratory and tumorigenic properties. In addition to providing evidence for an autonomous vicious cycle driven by PKCε, our studies identified a compelling rationale for targeting the CXCL13-CXCR5 axis for prostate cancer treatment.

Ovarian cancer is an insidious and aggressive disease of older women, typically undiscovered before peritoneal metastasis due to its asymptomatic nature and lack of early detection tools. Epidemiologic studies suggest that child-bearing (parity) is associated with decreased ovarian cancer risk, although the molecular mechanisms responsible for this phenomenon have not been delineated. Ovarian cancer preferentially metastasizes to the omental fat band (OFB), a secondary lymphoid organ that aids in filtration of the peritoneal serous fluid (PSF) and helps combat peritoneal infections. In the present study, we assessed how parity and age impact the immune compositional profile in the OFB of mice, both in the homeostatic state and as a consequence of peritoneal implantation of ovarian cancer. Using fluorescence-activated cell sorting analysis and quantitative real-time PCR, we found that parity was associated with a significant reduction in omental monocytic subsets and B1-B lymphocytes, correlating with reduced homeostatic expression levels of key chemoattractants and polarization factors (Ccl1, Ccl2, Arg1, and Cxcl13). Of note, parous animals exhibited significantly reduced tumor burden following intraperitoneal implantation compared with nulliparous animals. This was associated with a reduction in tumor-associated neutrophils and macrophages, as well as in the expression levels of their chemoattractants (Cxcl1 and Cxcl5) in the OFB and PSF. These findings define a preexisting "parity-associated microenvironmental niche" in the OFB that is refractory to metastatic tumor seeding and outgrowth. Future studies designed to manipulate this niche may provide a novel means to mitigate peritoneal dissemination of ovarian cancer.

Circulating cytokines, chemokines, and soluble cytokine receptors can serve as biomarkers of inflammation and immune dysregulation. Good reliability of multiplex platforms, which allow for simultaneous, comprehensive biomarker assessment, is critical for their utility in epidemiologic studies. We examined the reliability of the Meso-Scale Discovery (MSD) platform to simultaneously quantitate 15 cytokines and chemokines and the Luminex platform (R&D Systems) to quantitate 5 soluble receptors and 2 chemokines and cytokines and evaluated long-term within-person correlation of these biomarkers.

The detectability and reliability of these assay systems were assessed using the same external controls across plates and archived sera from 250 HIV- men in the Multicenter AIDS Cohort Study. Using up to four visits per person from 1984 to 2009, age-adjusted intraclass correlation coefficients (ICC) of biomarkers with >80% detectability (CCL11, CXCL8, CXCL10, CCL2, CCL4, CCL13, CCL17, CXCL13, IL-10, IL-12p70, IL-6, TNF-α, BAFF, sCD14, sCD27, sgp130, sIL-2Rα, and sTNF-R2) were obtained using linear mixed models.

Most biomarkers were detectable in 80% of control samples; IFN-γ, GM-CSF, and IL-2 were undetectable in >20% of samples. Among the HIV-uninfected men, most biomarkers showed fair to strong within-person correlation (ICC>0.40) up to 15years. The ICC for CXCL8 was good in the short term but decreased with increasing time between visits, becoming lower (ICC<0.40) after 8years.

These multiplexed assays showed acceptable reliability for use in epidemiologic research, despite some technical variability and limitations in cytokine quantitation. Most biomarkers displayed moderate-to-excellent intra-individual variability over the long term, suggesting their utility in prospective studies investigating etiologic associations with diverse chronic conditions.

We have shown that the live-attenuated HSV-1 VC2 vaccine strain with mutations in glycoprotein K (gK) and the membrane protein UL20 is unable to establish latency in vaccinated animals and produces a robust immune response capable of completely protecting mice against lethal vaginal HSV-1 or HSV-2 infections. To better understand the immune response generated by vaccination with VC2, we tested its ability to elicit immune responses in rhesus macaques. Vaccinated animals showed no signs of disease and developed increasing HSV-1 and HSV-2 reactive IgG1 after two booster vaccinations, while IgG subtypes IgG2 and IgG3 remained at low to undetectable levels. All vaccinated animals produced high levels of cross protective neutralizing antibodies. Flow cytometry analysis of cells isolated from draining lymph nodes showed that VC2 vaccination stimulated significant increases in plasmablast (CD27highCD38high) and mature memory (CD21-IgM-) B cells. T cell analysis on cells isolated from draining lymph node biopsies demonstrated a statistically significant increase in proliferating (Ki67+) follicular T helper cells and regulatory CXCR5+ CD8+ cytotoxic T cells. Analysis of plasma isolated two weeks post vaccination showed significant increases in circulating CXCL13 indicating increased germinal center activity. Cells isolated from vaginal biopsy samples collected over the course of the study exhibited vaccination-dependent increases in proliferating (Ki67+) CD4+ and CD8+ T cell populations. These results suggest that intramuscular vaccination with the live-attenuated HSV-1 VC2 vaccine strain can stimulate robust IgG1 antibody responses that persist for >250days post vaccination. In addition, vaccination lead to the maturation of B cells into plasmablast and mature memory B cells, the expansion of follicular T helper cells, and affects in the mucosal immune responses. These data suggest that the HSV VC2 vaccine induces potent immune responses that could help define correlates of protection towards developing an efficacious HSV-1/HSV-2 vaccine in humans.

The human dental follicle partially differentiates into the periodontal ligament (PDL), but their biological functions are different. The gene-expression profiles of the dental follicle and PDL were compared using the cDNA microarray technique. Microarray analysis identified 490 genes with a twofold or greater difference in expression, 365 and 125 of which were more abundant in the dental follicle and PDL, respectively. The most strongly expressed genes in the dental follicle were those related to bone development and remodeling (EGFL6, MMP8, FRZB, and NELL1), apoptosis and chemotaxis (Nox4, CXCL13, and CCL2), and tooth and embryo development (WNT2, PAX3, FGF7, AMBN, AMTN, and SLC4A4), while in the PDL it was the tumor-suppressor gene WIF1. Genes related to bone development and remodeling (STMN2, IBSP, BMP8A, BGLAP, ACP5, OPN, BMP3, and TM7SF4) and wound healing (IL1, IL8, MMP3, and MMP9) were also more strongly expressed in the PDL than in the dental follicle. In selected genes, a comparison among cDNA microarray, real-time reverse-transcription polymerase chain reaction, and immunohistochemical staining confirmed similar relative gene expressions. The gene-expression profiles presented here identify candidate genes that may enable differentiation between the dental follicle and PDL.

Quilty effect (QE) is a frequent, yet enigmatic feature of cardiac allograft, since it is apparently devoid of clinical significance, though its association with acute (A) rejection (R) is strongly suspected. It was observed in 126/379 biopsies from 22 patients during the first posttransplant year. Most grade (G)2R biopsies displayed a concomitant QE. The following features typical of QE were identified: (a) focal angiogenesis and lymphangiogenesis associated with bFGF, VEGF-C and VEGF-A expression, (b) marked infiltrate of CD4(+)T and CD20(+)B followed by CD8(+)T lymphocytes arranged around PNAd(+)HEV-like vessels. Most QE appear as distinct B-T-cell-specific areas with lymphoid follicles sometimes endowed with germinal center-like structures containing VCAM-1(+)CD21(+)FDC and CD68(+)macrophages, which frequently expressed CXCL13. These cells were also found in mantle-like zones, where small lymphocytes expressed CXCR5, otherwise in the whole area of not clustered lymphoid aggregates. CXCL13 was also expressed, in association with CD20(+)B lymphocyte recruitment, in G2R biopsies obtained from patients with recurrent AR. QE has features of a tertiary lymphoid tissue suggesting an attempt, by the heart allograft, to mount a local response to a persistent alloantigen stimulation resulting in aberrant CXCL13 production, as also occurs in recurrent AR. CXCL13-CXCR5 emerge as a common molecular pathway for QE and recurrent episodes of AR.

While myriad molecular formats for bispecific antibodies have been examined to date, the simplest structures are often based on the scFv. Issues with stability and manufacturability in scFv-based bispecific molecules, however, have been a significant hindrance to their development, particularly for high-concentration, stable formulations that allow subcutaneous delivery. Our aim was to generate a tetravalent bispecific molecule targeting two inflammatory mediators for synergistic immune modulation. We focused on an scFv-Fc-scFv format, with a flexible (A4T)3 linker coupling an additional scFv to the C-terminus of an scFv-Fc. While one of the lead scFvs isolated directly from a naïve library was well-behaved and sufficiently potent, the parental anti-CXCL13 scFv 3B4 required optimization for affinity, stability, and cynomolgus ortholog cross-reactivity. To achieve this, we eschewed framework-based stabilizing mutations in favor of complementarity-determining region (CDR) mutagenesis and re-selection for simultaneous improvements in both affinity and thermal stability. Phage-displayed 3B4 CDR-mutant libraries were used in an aggressive "hammer-hug" selection strategy that incorporated thermal challenge, functional, and biophysical screening. This approach identified leads with improved stability and>18-fold, and 4,100-fold higher affinity for both human and cynomolgus CXCL13, respectively. Improvements were exclusively mediated through only 4 mutations in VL-CDR3. Lead scFvs were reformatted into scFv-Fc-scFvs and their biophysical properties ranked. Our final candidate could be formulated in a standard biopharmaceutical platform buffer at 100 mg/ml with<2% high molecular weight species present after 7 weeks at 4 °C and viscosity<15 cP. This workflow has facilitated the identification of a truly manufacturable scFv-based bispecific therapeutic suitable for subcutaneous administration.

B-cell movement into lymphoid follicles depends on the expression of the chemokine receptor CXCR5 and the recently reported Epstein-Barr virus-induced receptor 2 (EBI2). In cooperation with CXCR5, EBI2 helps to position activated B cells in the follicle, although the mechanism is poorly understood. Using human HEK293T cells and fluorescence resonance energy transfer (FRET) techniques, we demonstrate that CXCR5 and EBI2 form homo- and heterodimers. EBI2 expression modulated CXCR5 homodimeric complexes, as indicated by the FRET(50) value (CXCR5 homodimer, 0.9851±0.0784; CXCR5 homodimer+EBI2, 1.7320±0.4905; P<0.05). HEK293T cells expressing CXCR5/EBI2 and primary activated murine B cells both down-modulated CXCR5-mediated responses, such as Ca(2+) flux, cell migration, and MAPK activation; this modulation did not occur when primary B cells were obtained from EBI2(-/-) mice. The mechanism involves a reduction in binding affinity of the ligand (CXCL13) for CXCR5 (K(D): 5.05×10(-8) M for CXCR5 alone vs. 1.49×10(-7) M for CXCR5/EBI2) and in the efficacy (E(max)) of G-protein activation in CXCR5/EBI2-coexpressing cells (42.33±4.3%; P<0.05). These findings identify CXCR5/EBI2 heterodimers as functional units that contribute to the plasticity of CXCL13-mediated B-cell responses.

Chemotaxis is essential for shaping immune responses and chemokine-receptor antagonists are now being evaluated as therapies for various inflammatory and autoimmune diseases. However, the dysregulation of chemotaxis in autoimmune disease may involve both promotion and inhibition of B-cell migration. This review focuses on the disparate mechanisms by which two inflammatory cytokines that have been associated with autoimmune disease, namely interferon-alpha (IFN-alpha) and interleukin-17 (IL-17), may regulate B-cell migratory responses. Chemotactic responses play a key role in orchestrating the cell-cell interactions in the germinal centers (GCs). This process involves active shuttling of the antigen-carrying B cells between the marginal zone and the GCs. We have shown that in autoimmune BXD2 mice, the migration of marginal zone precursor B cells is promoted by high levels of IFN-alpha produced by plasmacytoid dendritic cells in the marginal sinus that antagonize the activity of the S1P(1) chemokine receptor. In contrast, within the GCs, interleukin-17A (IL-17A) upregulates the expression of regulators of G protein signaling (RGS) in B cells to desensitize the G protein-coupled receptor (GPCR) signaling pathway of CXCL12 and CXCL13 chemokines. This promotes a prolonged stable interaction of B and T cells in the GC that induces high levels of activation-induced cytidine deaminase (AICDA) thereby enabling development of pathogenic autoantibody-producing B cells.

A distinct subset of T helper cells, named follicular T helper cells (T(FH), has been recently described. T(FH) cells are characterized by their homing capacities in the germinal centers of B-cell follicles where they interact with B cells, supporting B-cell survival and antibody responses. T(FH) cells can be identified by the expression of several markers including the chemokine CXCL13, the costimulatory molecules PD1 and inducible costimulator, and the transcription factor BCL6. They appear to be relevant markers for the diagnosis of angioimmunoblastic T-cell lymphoma (AITL) and have helped to recognize subsets of peripheral T-cell lymphoma, not otherwise specified, with nodal or cutaneous presentation expressing T(FH) antigens that might be related to AITL. In B-cell neoplasms, T(FH) cells are present within the microenvironment of nodular lymphocyte-predominant Hodgkin lymphoma and follicular lymphoma, where they likely support the growth of neoplastic germinal center-derived B cells. Interestingly, the amount of PD1+ cells in the neoplastic follicles might have a favorable impact on the outcome of follicular lymphoma patients. Altogether, the availability of antibodies directed to T(FH)-associated molecules has important diagnostic and prognostic implications in hematopathology. In addition, T(FH) cells could represent interesting targets in T(FH)-derived lymphomas such as AITL, or in some B-cell neoplasms where they act as part of the tumor microenvironment.

Angioimmunoblastic T-cell lymphoma is an aggressive peripheral T-cell lymphoma whose natural history is not fully understood. Up to 17% of cases can present histologically with hyperplastic germinal centres (pattern I). The accurate recognition of Angioimmunoblastic T-cell lymphoma with pattern I remains a challenge and therefore the aim of this study is to phenotypically and morphologically characterize this variant with the use of the follicular helper T-cell (T(FH)) markers PD1, CXCL-13 and ICOS. Out of the 88 Angioimmunoblastic T-cell lymphoma cases reviewed, 10 showed hyperplastic follicles. Molecular probe methods for the detection of T-cell and B-cell clonality, as well as in-situ hybridization probes for EBV RNA expression, were carried out to leave no question as to the establishment of the diagnosis in each case. Of the 10 cases, all (100%) showed strong positive PD1 staining in perifollicular areas and in neoplastic cells surrounding small veins. CXCL13 and ICOS showed a similar staining pattern. By contrast, CD10 was found to only weakly label the neoplastic T cells, with only 5-10% of the target cell population staining for this marker. EBV was found in 9/10 cases. Clinically, 8/9 cases presented with stage IIIB/IVB and in 2/10 cases consecutive biopsies showed 'progression' from pattern I to classical Angioimmunoblastic T-cell lymphoma. In conclusion we have shown that the T(FH) cells markers PD1, CXCL13 and ICOS are useful adjuncts in the diagnosis of Angioimmunoblastic T-cell lymphoma with hyperplastic germinal centres. PD1 also highlighted the presence of neoplastic cells in the outer zone of lymphoid follicles, suggesting that Angioimmunoblastic T-cell lymphoma (pattern I) may originate from T(FH) cells in this region, in accordance with previous immunological studies. As the majority of cases in our series presented clinically with advanced stage disease, progression from pattern I to classical Angioimmunoblastic T-cell lymphoma may represent histological evolution rather than clinical progression.

To explore the mechanisms of MDSC trafficking and accumulation during tumor progression. In this study, we report significant CD40 upregulation in tumor-infiltrating MDSC when compared with splenic MDSC. Microarray analyses comparing CD40(high) and CD40l(ow) MDSC revealed 1872 differentially expressed genes, including CD83, CXCR5, BTLA, CXCL9, TLR1, FLT3, NOD2 and CXCL10. In vivo experiments comparing wild-type (WT) and CD40 knockout (KO) mice demonstrated that CD40 critically regulates CXCR5 expression. Consistently, the transwell analysis confirmed the essential role of CXCR5-CXCL13 crosstalk in the migration of CD40+ MDSC toward gastric cancer. Furthermore, more MDSC accumulated in the gastric cancers of WT mice when compared with KO mice, and the WT tumors mostly contained CD40+ cells. Functionally, tumors grew faster in WT than KO mice. In conclusion, we demonstrate that CD40 expression upregulates the chemokine receptor CXCR5 and promotes MDSC migration toward and accumulation within cancer. Therefore, this study provides preliminary evidence that CD40 may stimulate tumor growth by enabling immune evasion via MDSC recruitment and inhibition of T cell expansion.

BACKGROUND

Prostate cancer (PCa) cell lines and tissues differentially express CXCR5, which positively correlate with PCa progression, and mediate PCa cell migration and invasion following interaction with CXCL13. However, the differential expression of G protein α, β, and γ subunits by PCa cell lines and the precise combination of these proteins with CXCR5 has not been elucidated.

METHODS

We examined differences in G protein expression of normal prostate (RWPE-1) and PCa cell lines (LNCaP, C4-2B, and PC3) by western blot analysis. Further, we immunoprecipitated CXCR5 with different G protein subunits, and CXCR4, following CXCL13 stimulation. To investigate constitutive coupling of CXCR5 with CXCR4 and PAR-1 we performed invasion assay in PCa cells transfected with Gαq/i2 or Gα13 siRNA, following CXCL13 treatment. We also investigated Rac and RhoA activity by G-LISA activation assay in PCa cells following CXCL13/thrombin stimulation.

RESULTS

Of the 22 G proteins studied, Gαi1-3, Gβ1-4, Gγ5, Gγ7, and Gγ10 were expressed by both normal and PCa cell lines. Gαs was moderately expressed in C4-2B and PC3 cell lines, Gαq/11 was only present in RWPE-1 and LNCaP cell lines, while Gα12 and Gα13 were expressed in C4-2B and PC3 cell lines. Gγ9 was expressed only in PCa cell lines. Gα16, Gβ5, Gγ1-4, and Gγ13 were not detected in any of the cell lines studied. Surprisingly, CXCR4 co-immunoprecipitated with CXCR5 in PCa cell lines irrespective of CXCL13 treatment. We also identified specific G protein isoforms coupled to CXCR5 in its resting and active states. Gαq/11/Gβ3/Gγ9 in LNCaP and Gαi2/Gβ3/Gγ9 in C4-2B and PC3 cell lines, were coupled to CXCR5 and disassociated following CXCL13 stimulation. Interestingly, Gα13 co-immunoprecipitated with CXCR5 in CXCL13-treated, but not in untreated PCa cell lines. Inhibition of Gαq/i2 significantly decreased the ability of cells to invade, whereas silencing Gα13 did not affect CXCL13-dependent cell invasion. Finally, CXCL13 treatment significantly increased Rac activity in Gαq/i2 dependent manner, but not RhoA activity, in PCa cell lines.

CONCLUSIONS

These findings offer insight into molecular mechanisms of PCa progression and can help to design some therapeutic strategies involving CXCR5 and/or CXCL13 blockade and specific G protein inhibition to abrogate PCa metastasis.

The present study reveals an immunological characterization of circulating and tumor-infiltrating T follicular helper cells (Tfh), namely CXCR5+CD45RA-CD4+ T cells, and their related cytokines in hepatitis B virus-related hepatocellular carcinoma (HCC) patients. In HCC patients, circulating Tfh cells showed a CCR7+ and/or ICOS+ phenotype with increased Th2-like cells and decreased Th1-like and Th17-like subsets. Although the bulk frequency of circulating Tfh cells was not altered in HCC patients, the frequency of infiltrated CXCR5+CD45RA-CD4+ CD3+cells was higher in tumor than in para-tumor tissues, and Th1-like cells were the predominant phenotype. Circulating Tfh cells in HCC patients were defective in the production of IL-21 in vitro, which was in accordance with lower IL-21 levels in tumor tissues than in para-tumor tissues. Serum CXCL13 was increased in HCC patients and associated with recurrence-free survival after hepatectomy. This was confirmed in an additional HCC cohort of 111 patients with up to 5 years follow-up. Immunohistochemical staining indicated that the percentage of CXCR5+ or CXCL13+ cells was higher in poorly differentiated than in well-differentiated tumors. In conclusion, patients with HBV-related HCC showed altered phenotypes and impaired function of Tfh cells or subpopulations. CXCL13 could be a potential biomarker for predicting recurrence in HCC patients after hepatectomy.

Gut-associated lymphoid tissue (GALT) development requires interaction with the intestinal microbiota. Because murine secondary lymphoid tissue development is driven by positive feedback interactions between B cells and stromal cells, we used in situ hybridization to determine whether intestinal commensals influence such interactions during rabbit appendix development. The features of positive feedback interactions we examined (CXCL13 mRNA expression, B cell accumulation and FDC differentiation) increased during early follicle development, but stalled in the absence of intestinal commensals. These features were reinitiated by commensals that stimulated follicle development and intrafollicular B cell proliferation. Our results suggest that rabbit appendix follicles develop in two phases: an initial phase of B cell recruitment to nascent follicles, possibly through positive feedback interactions, and a subsequent phase of intrafollicular B cell proliferation stimulated by intestinal commensals. In addition, we found that intestinal commensals stimulate appendix CCL21 mRNA expression and T cell area formation.

OBJECTIVE

To compare the cyto- and chemokine profiles in the aqueous humor of PEXS eyes in the absence or presence of secondary glaucoma with or without luxation of the intraocular lens (IOL).

METHODS

Samples of aqueous humor were collected intraoperatively from 20 healthy controls and from 73 eyes with PEX-syndrome, which was manifested in the absence of any other local or systemic desease. The latter group was sub-devided into eyes with an early form of PEX-syndrome in the absence of complications (PEX, n = 33), those with a late form of PEX-syndrome and glaucoma (PEXG, n = 30), and those with a late form of PEX-syndrome with luxation of the IOL that required surgery (PEXL, n = 10). The samples were analyzed in parallel after storage at -80°C. The levels of 40 cytokines were simultaneously quantified using the Bio-Plex® multiplex beads system. The inter-group data were statistically compared using the Kruskal-Wallis test (p ≤ 0.01).

RESULTS

PEX and PEXG were comparable in their cytokine profiles for all 40 cytokines, whereas the cytokine profile in PEXL-eyes revealed higher levels of all but 5 cytokines (CXCL13, CCL27, IL-2, CCL3, CCL20; p ≤ 0.01). This latter finding is indicative of a non-specific inflammatory reaction in the context of IOL-luxation. The concentrations of 6 cytokines lay below the detection limit in all groups.

CONCLUSIONS

The local up-regulation of 85% of the detectable cytokines in the aqueous humor of PEXL-eyes may be linked either with a progression of the disease or a breakdown of the antero-posterior barrier in the context of IOL-luxation.