Signs Of Immune Activation Research Articles

IMMU-48. SOLUBLE CIRCULATING IMMUNE CHECKPOINT MOLECULES IN MALIGNANT BRAIN TUMORS

Abstract Immune checkpoint therapy has been shown to be effective in several types of cancer, and tumor-directed immune activation is also a promising strategy in glioblastoma (GBM) patients. Our goal was to discover alterations in the circulating immunome of GBM patients and other cerebral tumor entities to identify soluble immune biomarkers and novel therapeutic targets. We analyzed 30 markers in plasma of 208 patients and healthy donors, using bead-based multiplex assays and flow cytometry. In a smaller cohort we further applied a high-sensitivity discovery biomarker platform with 368 markers. We included patients with 1) primary GBM (n=68), 2) recurrent GBM (n=25), 3) cerebral metastases (NSCLC, n=61; breast cancer, n=19), 4) meningioma (n=15) as well as 5) healthy donors (HD, n=20). We detected a distinct immune signature in the peripheral blood of patients with GBM, which was defined by an increased prevalence of soluble immune checkpoint markers (sCD27, sPD-L2, sGal-9), whereas soluble chemokines (CX3CL, CXCL12) were underrepresented. This signature was similar in primary and recurrent GBM, but differed markedly from other cerebral tumor entities as well as from HD. Primary GBM, but not their recurrent counterparts, additionally exhibited increased levels of neurotrophic factors (BDNF, b-NGF) and signs of immune activation with significantly increased levels of IL-18. The biomarker discovery platform further identified 76 proteins that were specifically regulated in GBM compared to HD, offering the potential to serve as biomarkers for disease activity. GBM patients with higher levels of BDNF displayed a significantly shorter survival than patients with lower levels (9.33 vs. 21.90 months; p=0.0001). Likewise patients with high concentrations of VEGF survived significantly shorter than those with low concentrations (12.97 vs. 21.90 months, p=0,0166). Taken together, we were able to delineate a specific immune profile of soluble markers in GBM patients compared to other cerebral tumor entities and to healthy individuals.

In Schizophrenia, Chronic Fatigue Syndrome- and Fibromyalgia-Like Symptoms are Driven by Breakdown of the Paracellular Pathway with Increased Zonulin and Immune Activation-Associated Neurotoxicity.

A meaningful part of schizophrenia patients suffer from physiosomatic symptoms (formerly named psychosomatic), which are reminiscent of chronic fatigue syndrome and fibromyalgia (FF) and are associated with signs of immune activation and increased levels of tryptophan catabolites (TRYCATs). The study aims to examine whether FF symptoms in schizophrenia are associated with the breakdown of the paracellular pathway, zonulin, lowered natural IgM responses to oxidative specific epitopes (OSEs); and whether FF symptoms belong to the behavioral-cognitive-physical-psychosocial- (BCPS)-worsening index consisting of indices of a general cognitive decline (G-CoDe), symptomatome of schizophrenia, and quality of life (QoL)-phenomenome. FF symptoms were assessed using the Fibromyalgia and Chronic Fatigue Rating scale in 80 schizophrenia patients and 40 healthy controls and serum cytokines/chemokines, IgA levels to TRYCATs, IgM to OSEs, zonulin and transcellular/paracellular (TRANS/PARA) molecules were assayed using ELISA methods. A large part (42.3%) of the variance in the total FF score was explained by the regression on the PARA/TRANS ratio, pro-inflammatory cytokines, IgM to zonulin, IgA to TRYCATs (all positively), and IgM to OSEs (inversely). There were highly significant correlations between the total FF score and G-CoDe, symtopmatome, QoL phenomenome, and BCPS-worsening score. FF symptoms belong to a common core shared by G-CoDe, symtopmatome, and QoL phenomenome. The physio-somatic symptoms of schizophrenia are driven by various pathways, including increased zonulin, breakdown of the paracellular tight-junctions pathway, immune activation with induction of the TRYCAT pathway, and consequent neurotoxicity. It is concluded that FF symptoms are part of the phenome of schizophrenia and BCPS-worsening as well.

Delayed Activation of T Cells at the Site of Infection Facilitates the Establishment of Trypanosoma cruzi in Both Naive and Immune Hosts.

Although parasite entry through breaks in the skin or mucosa is one of the main routes of natural transmission of Trypanosoma cruzi, little is known about the host cell types initially invaded nor the ability of those host cells to initiate immune responses at the site of infection. To gain insights into these early events, we studied the fate of fluorescently tagged T. cruzi delivered subcutaneously in mouse footpads or ears. We demonstrate that the majority of parasites introduced into the skin initially proliferate there until 8 to 10 days postinfection, when the parasite load decreases. This decline in parasite numbers is dependent on the presence of an intact T cell compartment and on the ability of hosts to produce gamma interferon (IFN-γ). Many of the parasite-containing cells at the initial infection site display a macrophage/monocyte phenotype but with low expression of activation markers, suggesting that these cells provide an early niche for T. cruzi proliferation, rather than being active in parasite control. It is only after the first round of T. cruzi replication and release from host cells that signs of immune activation and control of parasites become apparent. The delay in the activation and failure to rapidly control parasite replication are observed even when T. cruzi-primed T cells are present, such as in chronically infected mice. This failure of a primed immune system to recognize and react prior to extensive parasite expansion at the infection site likely poses a significant challenge for the development of vaccines aiming to prevent T. cruzi infection. IMPORTANCE Trypanosoma cruzi, the parasite causing Chagas disease, usually infects through the mucosa or breaks in the skin, but little is known about the parasite's fate at the site of entry or the early events involving immune control there. Here, we track the local proliferation and subsequent dissemination of fluorescently tagged T. cruzi and the initial immune response at the point of entry. We show that T. cruzi preferentially infects innate immune cells in the skin and that the stimulation of an adaptive T cell response does not occur until after the release of parasites from this first round of infected host cells. This first immunologically "silent" proliferation occurs even in the presence of a strong immune T cell memory generated by previous infection. This capacity of T. cruzi to establish infections while avoiding initial immune recognition has important implications for the potential to develop vaccines to prevent T. cruzi infection.

International validation of the Immunoscore-biopsy (ISB) to guide selection and monitoring of patients treated with watch-and-wait (WW) strategy for rectal cancer.

3517 Background: The WW strategy for patients with rectal cancer who achieved a clinical complete response (cCR) after neoadjuvant therapy (nT) allows to avoid major resection and the associated morbidity and mortality. Standardized criteria to select and monitor WW patients, including biomarkers predicting recurrence after nT, are lacking. The prognostic impact of the immune infiltrate in colorectal cancers is now demonstrated and has been implemented into clinics through the Immunoscore, the first standardized digital-pathology-based assay, recommended by academic institutions. We evidenced that an Immunoscore adapted to biopsies (ISB) performed at diagnosis, predicts the response to nT and the risk of recurrence after nT. Its clinical utility was suggested in a test cohort of WW patients (El Sissy et al., Clin Cancer Res 2020). The aim of this study was to confirm the ability of the ISB to predict clinical outcomes, improve patients’ eligibility for the WW strategy, and optimize a follow-up schedule. Methods: A total of 304 WW patients from 10 centers across 7 countries were included. Tumor biopsies before treatment were immunostained for CD3+ and CD8+ T-cells and converted to ISB using the pre-defined cut-off. The primary endpoint was time-to-recurrence (TTR). Secondary endpoint was disease-free-survival (DFS). As immune response originates in draining lymph nodes, signs of immune activation were carried out in lymph nodes of additional patients managed by radical surgery with complete pathological response (pCR; n = 12) or non-pCR (n = 12) by 3' RNA-Seq and immunofluorescence technologies. Results: High-ISB patients presented with the lowest risk of recurrence after WW. 5-year recurrence-free rates were 97% (92%-100%), 61% (49%-76%), and 56% (44%-73%) with ISB High, Intermediate, and Low, respectively (HR [Low-vs-High] = 14.3, 95% CI 1.8-100). In patients with cCR after nT (n = 209), High-ISB showed a significant association with prolonged TTR and DFS (Logrank P = 0.005 and P = 0.006, respectively). When ISB was evaluated as a continuous variable, the risk of recurrence was increasing along with decreasing ISB (Wald tests, all P < 0.005). In multivariate analyses, ISB was independent of age, sex, location, and cTNM stage and was the single parameter correlated with TTR (HR [ISB High-vs-Low] = 0.08, 95% CI 0.01-0.6; P = 0.015) and DFS (P = 0.013). Unlike for patients with cCR, no difference according to ISB was observed for those with incomplete response (n = 41) or treated with brachytherapy (n = 34). Finally, intranodal signs of T-cell and B-cell activation were only evidenced in patients with pCR. Conclusions: ISB provides a reliable biomarker to predict clinical outcomes, improve eligibility, and optimize patients’ follow-up. Intranodal T-cell and B-cell activation further supports the immune benefit of both organ and lymph node preservation.

Targeting Endoglin Expressing Cells in the Tumor Microenvironment Does Not Inhibit Tumor Growth in a Pancreatic Cancer Mouse Model.

BackgroundPancreatic ductal adenocarcinoma (PDAC) is one of the most lethal forms of cancer and is known to have low immunogenicity and an immunosuppressive microenvironment. It is also characterized by high accumulation of dense stroma, composed of mostly cancer-associated fibroblasts (CAFs). Multiple subsets of CAFs are described, with one of them expressing the transforming growth factor (TGF)-β co-receptor endoglin. In previous work, we and others have shown that endoglin-expressing CAFs stimulate tumor progression and metastasis. Therefore, in this study, we set out to investigate the role of endoglin-expressing CAFs in pancreatic cancer progression.MethodsFirst, we investigated the expression of endoglin on CAFs in both human tissues as well as a mouse model for PDAC. Since CAF-specific endoglin expression was high, we targeted endoglin by using the endoglin neutralizing antibody TRC105 in the murine KPC model for PDAC.ResultsAlthough some signs of immune activation were observed, TRC105 did not affect tumor growth. Since 90% of the CD8+ T-cells expressed the immune checkpoint PD-1, we investigated the combination with a PD1 checkpoint inhibitor, which did not enhance therapeutic responses. Finally, genetic deletion of endoglin from collagen 1a1 expressing cells also did not affect the growth of the mouse KPC tumors.ConclusionOur results show that although endoglin is highly expressed on PDAC-CAFs and signaling is efficiently inhibited by TRC105, this does not result in decreased tumor growth in the KPC model for pancreatic cancer.

Evaluation of Immune Dysregulation in an Austrian Patient Cohort Suffering from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe multi-systemic disease characterized by debilitating fatigue that is not relieved by rest. The causes of the disease are still largely unexplained, and no causative treatment is currently available. Changes in the immune response are considered as fundamental in the development of ME/CFS. Thus, we aimed to evaluate the immunological profile of ME/CFS patients in a retrospective data analysis. As part of the routine workup for ME/CFS patients, a differential blood count, leukocyte subtyping, and quantification of immunoglobulins and IgG subclasses, as well as a complement analysis, was performed. Out of 262 ME/CFS patients, 64.9% had a reduction or deficiency in at least one of the listed immune parameters. In contrast, 26.3% showed signs of immune activation or inflammation. A total of 17.6% of the ME/CFS patients had an unclassified antibody deficiency, with IgG3 and IgG4 subclass deficiencies as the most common phenotypes. Reduced MBL (mannose-binding lectin) levels were found in 32% of ME/CFS patients, and MBL deficiency in 7%. In summary, the present results confirmed the relevance of immune dysfunction in ME/CFS patients underlining the involvement of a dysfunctional immune response in the disease. Thus, immune parameters are relevant disease biomarkers, which might lead to targeted therapeutic approaches in the future.

Tumor-Suppressing, Immunostimulating, and Hepatotoxic Effects of Immunostimulatory RNA in Combination with Dacarbazine in a Murine Melanoma Model

Melanoma is one of the most aggressive tumors and is accompanied by the induction of local and systemic inflammatory responses. Combinations of chemotherapeutic agents with immunotherapy are therefore commonly used for melanoma treatment. A B16 melanoma model was used to study the tumor suppressive, immunostimulating, and hepatotoxic effects of a combination of a small double-stranded immunostimulatory RNA (isRNA) with 3'-trinucleotide overhangs and the cytotoxic drug dacarbazine compared with respective monotherapies. The drugs efficiently suppressed the tumor growth and acted synergistically. Histological and immunohistochemical examinations of tumor nodes showed that the combination of isRNA and dacarbazine significantly decreased mitotic activity and more efficiently increased apoptosis in tumor tissue as compared with either monotherapy. Regardless of the treatment regimen, signs of immune activation were observed in the spleen, including an increase in the number and diameter of lymphoid follicles and the volume density of the white pulp. Destructive changes were detected in the livers of nontreated animals with B16 melanoma. Administration of isRNA in combination with dacarbazine did not cause any additional damage to liver parenchyma, while stimulating regenerative processes in hepatic tissue of tumor-bearing animals.

93-OR: Expression of Genes Associated with Host Viral Responses in Insulitic Islets

Background: Type 1 diabetes (T1D) is an autoimmune condition long hypothesized to be enhanced or triggered by viral infections. Islet pathology in T1D is characterized by destruction and subsequent loss of insulin producing pancreatic beta cells. In this study we evaluated specific physiological pathways associated with the disorder’s pathogenesis by examining differential expression of host genes within islets, with special emphasis on identifying evidence suggestive of responses to a viral infection. Methods: Pancreatic tissue samples were obtained from nondiabetic donors, autoantibody positive donors, and donors with T1D through the Network for Pancreatic Organ donors with Diabetes (nPOD) program. Laser microdissection was used to isolate individual islets based on immunohistochemical documentation of presence or absence of insulin (INS+) and T-lymphocytes (CD3+). RNA was isolated and microarray used to assess transcriptomes. Results: Increased expression in insulitic islets was seen in a variety of genes including TLR pathway inhibitors: LAIR1 (p=2.77E-8), SIGLEC7 (p=8.33E-6), SIGLEC9 (p=1.59E-4), and C1q (p=6.11E-16); as well as genes downstream of the TLR pathway: CD163 (p=2.34E-11), CTSS (p=9.89E-7) and IFNγ (p=5.9E-8). We also observed variances in the frequency of viral response genes, including those known to be associated with T1D at a GWAS level: STAT1 (p=1.64E-7) and OAS3 (p=1.04E-8). Pathway analysis demonstrated increased representation of antigen processing and presentation genes (p=3.0E-14). Conclusions: In sum, these studies noted an increased expression of multiple host genes associated with anti-viral responses. The demonstration of specific protein involvement in host responses to infections are up-regulated in T1D islets, specifically in those with signs of immune activation and residual insulin positivity (INS+CD3+), supports the potential involvement of host viral response pathways in the development of T1D. Disclosure G. Nelson: None. N.I. Lenchik: None. M. Campbell-Thompson: None. M.A. Atkinson: None. I.C. Gerling: None. Funding National Institutes of Health (UC4DK104155)

Immune activation enhances epithelial nerve growth in provoked vestibulodynia

Provoked vestibulodynia manifests as allodynia of the vulvar vestibular mucosa. The exact mechanisms that result in altered pain sensation are unknown. Recently, we demonstrated the presence of secondary lymphoid tissue, which is the vestibule-associated lymphoid tissue in the vestibular mucosa, and showed that this tissue becomes activated in provoked vestibulodynia. The purpose of this study was to examine whether expression of intraepithelial nerve fibers and nerve growth factor are related to immune activation in provoked vestibulodynia. Vestibular mucosal specimens were obtained from 27 patients with severe provoked vestibulodynia that was treated by vestibulectomy and from 15 control subjects. We used antibodies against the protein gene product 9.5, the neuron specific neurofilament, and nerve growth factor for immunohistochemistry to detect intraepithelial nerve fibers and nerve growth factor expressing immune cells in the vestibular mucosa. For intraepithelial nerve fibers, we determined their linear density (fiber counts per millimeter of the outer epithelial surface, protein gene product 9.5) or presence (neuron specific neurofilament). Nerve growth factor was analyzed by counting the staining-positive immune cells. Antibodies against CD20 (B lymphocytes) and CD3 (T lymphocytes) were used to identify and locate mucosal areas with increased density of lymphocytes and the presence of germinal centers (ie, signs of immune activation). B-cell activation index was used to describe the overall intensity of B-cell infiltration. We found more protein gene product 9.5-positive intraepithelial fibers in vestibulodynia than in the control samples (6.3/mm [range, 0.0-15.8] vs 2.0/mm [range, 0.0-12.0]; P=.006). Neuron specific neurofilament -positive intraepithelial fibers were found in 17 of 27 vestibulodynia cases (63.0%) and in none of the control cases. Protein gene product 9.5-positive intraepithelial fibers were more common in samples with more pronounced immune activation. The density of these fibers was higher in samples with than without germinal centers (6.1/mm [range, 4.3-15.8] vs 3.0/mm [range, 0.0-13.4]; P=.020). A positive correlation between the fiber density and B-cell activation index score of the sample was found (Spearman's Rho, 0.400; P=.004; R2=0.128). No significant difference, however, was found in the density or presence of nerve fibers between samples with high and low T-cell densities. We identified areas of minor and major vestibular glands in 16 of the patient samples and in 1 control sample. Protein gene product 9.5-positive nerve fibers were found more often in glandular epithelium surrounded by B-cell infiltration than in glands without B cells (P=.013). Also, the presence of neuron specific neurofilament-positive fibers in glandular epithelium was associated with B-cell infiltrates (P=.053). Nerve growth factor-positive immune cells were more common in mucosal areas with than without B-cell infiltration and intraepithelial nerve fibers. Excessive epithelial nerve growth in provoked vestibulodynia is associated with increased B-cell infiltration and the presence of germinal centers. This supports the fundamental role of immune activation in provoked vestibulodynia.

Signs of immune activation and local inflammation are present in the bronchial tissue of patients with untreated early rheumatoid arthritis

ObjectivesEvents in the lungs might contribute to generation of anticitrullinated protein antibodies (ACPA) in rheumatoid arthritis (RA). We investigated if signs of immune activation are present in bronchial biopsies and...

A55: Changes in peripheral blood lymphocyte subpopulations implicated in regulatory and cytotoxic immune reactions mirror the process of immunoediting in cervical pre-invasive cancer

Background The ability to promote an immunosuppressive microenvironment has been recognized as one of the “next generation” cancer hallmarks, being most apparent in case of HPV-induced carcinogenesis, since it is a prerequisite to the virus persistence and proliferation of keratinocytes expressing HPV-antigens. With respect to HPV-associated cervical cancer, it is commonly known that initial pre-cancerous intraepithelial lesions frequently undergo reverse development due to effective recognition and eradication by the immunocompetent cells. Both innate (e.g. NK) and adaptive (helper and cytotoxic O-cells) arms of immunity have been implicated in the regression of neoplastic cells, with NK T-cells considering as a connecting link between two branches. Progression of intraepithelial neoplasia leads to the establishment of pre-invasive cancer, which can be regarded as the result of a completed immunoediting of the tumor locus, because further, with 100% probability, it turns into invasive metastatic form. We assumed that the signs of immune activation, on the one hand, and the signs of immunosuppression, on the other hand, despite the locality of pre-invasive cervical cancer, can be found in the circulation and can be relevant to the development of tolerogenic microenvironment. The aim of the present work was to investigate the number of functionally different subpopulations of T- and NK-lymphocytes in the blood of patients with pre-invasive cervical cancer. Material and methods Blood samples were taken from 35 HPV(+) patients diagnosed with cancer in situ. The control group consisted of 30 healthy HPV(−) women with no pathology of the cervix. Lymphocytes were immunophenotyped by MACSQuant flow cytometer. The percentage of the following populations were measured: CD3+CD95+/high, CD3+CD4+, CD3+CD4+CD95+/high, CD3+CD8+, CD3+CD8+CD95+/high, CD4+CD25+, CD4+CD25high, CD4+CD25+CD127dim/neg, CD4+CD25+FoxP3+ (CD4 Tregs), CD8+CD25+, CD8+CD25+CD127dim/neg, CD8+CD25+FoxP3+ (CD8 Tregs), CD3−CD16+, CD3−CD56+, CD3−(CD16±)CD56bright, CD3−CD16+CD56+, CD3−CD16low/negCD56+, CD3−CD16+CD56- (NK subpopulations), CD3+CD56+, CD3+CD16+CD56+ (NK T-lymphocytes). Results Increase in the number of CD4 Tregs that are known to exert immunosuppressive effect was found in cancer patients’ group, namely the increased quantity of cells with CD4+CD25+ (especially, CD4+CD25high fraction), CD4+CD25+CD127dim/neg, or CD4+CD25+FoxP3+ phenotypes was shown. At the same time, the portion of CD4+FoxP3+ lymphocytes didn’t differ between the studied groups. A rare population of CD8+ Tregs (CD8+CD25+CD127dim/negFoxP3+) also exhibited a tendency to accumulate in the blood of cancer patients compared with the control. Analysis of the major subpopulation of NK cells performing cytotoxic reactions didn’t reveal significant difference between the examined groups. Similar result was obtained in relation to the other functional groups of NK cells, specifically CD3−CD16±CD56bright (cytokine-producing NKs with low cytotoxicity), CD3−CD16dim/−CD56+ (NKs with potential anti-tumor activity), and CD3−CD16+CD56 – (NKs associated with viral infection or NK-precursors). However, an increase of NK T-lymphocyte amounts was established, arguing both activation of anti-tumor response and its inhibition, in view of functional polymorphism of this population. Similarly, the increased number of CD3+CD95+/high cells and CD3+CD4+CD95+/high T-helpers may have dual significance, taking into account that the mid-early T-cell activation marker CD95/Fas presents the key death-receptor (earlier we have revealed the elevated activity of caspases involved in the Fas-mediated signaling in circulating lymphocytes of cervical cancer patients). The total numbers of CD3+CD4+ T-helpers and CD3+CD8+ T-killers were generally comparable between the groups analyzed, with T-killers displaying slightly decreased percentage in the patient group. Conclusion The processes supporting establishment of immunosuppressive microenvironment extend beyond the local level during the earliest steps of cervical cancer progression. The observed changes may reflect the shift of equilibrium between immune activation and suppression, which is the essence of immunoediting. Further phenotypic analysis of cell subpopulations reported here is required for understanding the functional meaning of these changes. The study was supported by the grants NK-1404-32098, 11.G34.31.0052, the Program of strategic development of PetrSU for 2012-2016, and the State task for R&D.

Inflammatory pathways in patients with heart failure and preserved ejection fraction

Immune activation is well established in patients with chronic heart failure and reduced ejection fraction (HF and reduced EF) and is associated with an impaired prognosis. Patients with heart failure and preserved ejection fraction (HF and preserved EF) have an impaired prognosis as well. It is not known whether they have signs of immune activation. Methods We studied patients with HF and preserved EF ( n = 17, NYHA II [ n = 7]/III [ n = 10]) and patients with HF and reduced EF ( n = 17 NYHA II [ n = 1]/III [ n = 16]) and 20 controls. Echocardiography demonstrated preserved ejection fraction (LVEF 59 ± 9%), but LV hypertrophy in patients with preserved EF as compared with patients with reduced EF (LVEF 23 ± 5%). We evaluated levels of TNFα, its receptors (sTNFR-1 and 2), IL-6, IL-10 and NT-proBNP. Results TNFα, was highest in HF with reduced EF (2.87 ± 0.65 vs 1.67 ± 0.58 pg/mL, p < 0.001) compared to preserved EF and similar between HF with preserved EF and controls. However, sTNFR1 (1618 ± 384 vs 1017 ± 302 pg/mL, p < 0.001) and sTNFR2 levels (3554 ± 916 vs 2041 ± 586 pg/mL, p < 0.001) in HF with preserved EF were significantly higher compared with controls. The same was true for IL-6, IL-10 and NT-proBNP. The highest cytokine and NT-proBNP levels were present in HF with reduced EF. There was a negative correlation between TNFα, and LVEF ( r = − 0.700; p < 0.0001) and positive correlations between sTNFR1 and 2 with NT-proBNP. Conclusion Patients with HF and preserved EF already show signs of systemic-immune activation which may contribute to the impaired prognosis and the progression to HF with reduced EF.

Inflammatory bowel disease (IBD) versus irritable bowel syndrome (IBS): are there any overlaps? Exploring their interrelationships

think about their interrelationhips, especially in terms of their pathogenesis. For example, it is recognized that infl ammation plays an important role in at least a subset of patients with IBS. A proportion of IBS patients without enteritis have signs of immune activation in the gut. Therefore IBS could have certain organic disorders in the enteric nervous system or the immune system. The clinical course of IBD, on the other hand, often can be affected by emotional factors. IBS-like symptoms are frequently reported in patients before the diagnosis of IBD, and sometimes IBD patients have been misdiagnosed with IBS for some period of time. We invited experts in IBS and IBD from the United Kingdom, the United States, and Japan to present their opinions on this topic from the viewpoint of their research fi eld, based on their latest fi ndings. Their excellent lectures and the productive discussions that followed greatly impressed all participants. We believe that this symposium will be benefi cial to all of us for conducting further study in this fascinating area of research, IBS and IBD.

Regulatory Cells, Th1/Th2 Unbalance, and Antibody-Induced Chronic Rejection in Operational Tolerance Induced by Donor-Specific Blood Transfusion

We developed a rodent model in which donor-specific blood transfusion (DSBT) promotes hyporesponsiveness and graft acceptance. In this model, signs of immune activation are present early posttransplant, with preserved proliferative responses against the donor and a dense cellular infiltrate in tolerant grafts. Intriguingly, an early accumulation of IFN-gamma is seen in grafts destined to become tolerized, supporting recent evidence that Th1 cytokines play a role in tolerance induction. Specific regulatory cells capable of propagating tolerance into naive recipients are operating. These mechanisms of immune activation and the generation of regulatory cells are influenced by immunosuppression (steroids and calcineurin inhibitors). In this model, in a second phase, a Th2 immune deviation occurs and is associated with the development of chronic rejection (vascular obliteration, endothelial IgG deposition, and complement binding). It remains unclear whether chronic rejection in this model is caused by Th2 type regulatory cells or whether chronic rejection is the consequence of an insufficient number of regulatory cells. In the clinic, the current strategy of profoundly inhibiting immune activation (in particular Th1 cytokines/responses) by using high dose calcineurin inhibitors and steroids may prove antagonistic with the development of tolerance, particularly when immunomodulatory strategies (such as DSBT) are applied. Development of chronic rejection in a regulation-based tolerance model suggests that deletion-based tolerogenic strategies may offer a more robust protection against chronic rejection.

High numbers of circulating activated T cells and raised levels of serum IL-2 receptor in bipolar disorder

Background Previously, we found an increased prevalence of thyroid autoantibodies in patients with bipolar disorder. In the present study, we investigated other signs of immune activation in bipolar patients, in particular an activation of the T cell system. Methods Fluorescence activated cell scanning (FACS) analysis was performed on lymphocytes of 64 outpatients with DSM-IV bipolar disorder using the T cell marker CD3 in combination with the activation markers MHC-class II, CD25, CD69 or CD71. In 34 patients, these assays were repeated after an interval of 2 years. In addition, T cell activation was determined by measuring serum soluble IL-2 receptor (sIL-2R) in 172 bipolar outpatients. Outcomes were compared with a healthy control group. Results Significantly higher numbers of circulating activated T cells and raised sIL-2R levels were found in euthymic, manic, and depressed bipolar patients when compared with healthy controls. In general, these abnormalities were stable over time. Manic patients showed significantly higher levels of sIL-2R in comparison with depressed patients. Conclusions The T cell system was found to be activated in both symptomatic and euthymic patients with bipolar disorder. The pathophysiological significance of these findings remains to be explored.

Immune markers in fibromyalgia: comparison with major depressed patients and normal volunteers

Background: There is a high degree of comorbidity between fibromyalgia and major depression. The latter is characterized by signs of immune activation, whereas the immune status in fibromyalgia is not yet elucidated. The aims of the present study were to examine (i) neopterin and biopterin excretion in 24-h urine of patients with fibromyalgia compared with normal volunteers and patients with major depression; and (ii) the effects of subchronic treatment with sertraline (11 weeks) on the urinary excretion of neopterin and biopterin. Methods: Measurements of neopterin, biopterin, pseudouridine, creatinine and uric acid in 24-h urine were performed by means of HPLC in 14 fibromyalgia and ten major depressed patients and 17 normal volunteers. Results: There were no significant differences in urine excretion of the above five analytes between patients with fibromyalgia and normal volunteers. Patients with major depression showed significantly higher urinary neopterin excretion than normal volunteers and fibromyalgia patients. Patients with fibromyalgia and major depression had a significantly increased neopterin/creatinine ratio. Fibromyalgia patients had significantly lower urinary excretion of creatinine than patients with major depression. In fibromyalgia patients, there were no significant effects of sertraline treatment on any of the urine analytes. Conclusions: The findings suggest that fibromyalgia, in contrast to major depression, may not be accompanied by activation of cell-mediated immunity. Limitation: Other immune markers should be measured in fibromyalgia before drawing definite conclusions. Clinical relevance: Increased urinary excretion of neopterin can be used as a marker for major depression, but not fibromyalgia.

An association between increased serum-soluble interleukin-2 receptors and a disturbance in muscle force in schizophrenic patients

1. 1. Serum-soluble interleukin-2 receptors (SIL-2Rs), a sign of immune activation, are increased in approximately 30% of schizophrenic subjects. 2. 2. In a recent publication the authors found that SIL-2Rs were particularly elevated in schizophrenic subjects with tardive dyskinesia (TD). 3. 3. This paper investigates the relationship between muscle force instability and SIL-2Rs in 32 schizophenic patients, 10 of whom were neuroleptic-naive. 4. 4. The authors hypothesized that there would be a positive correlation between increased levels of SIL-2Rs and muscle force instability. 5. 5. Serum SIL-2Rs and muscle force instability were positively correlated (r = 0.54, p < .001) in the schizophrenic patients, and this correlation held even for the subset of neurolepticnaive patients (r = .73, df 8, p = .016). 6. 6. These findings suggest that there is an important correlation between immune activation and muscle force instability in schizophrenic patients.

Selected models of HIV-induced neurological disease.

The encephalopathy associated with HIV infection consists of a constellation of histopathological abnormalities including gliosis, multinucleated giant cell encephalitis, vacuolar myelopathy and white matter pallor, each of which may be evident singly or in combination in different individuals (Kure et al. 1990; Budka 1986). In infants, the lesions are more severe and include degeneration and mineralization in the basal ganglia, necrotizing encephalitis in cortical and subcortical structures and acquired microcephaly (Sharer et al. 1986), reflecting the massive loss of brain substance that occurs during infection in the brain. These changes are accompanied by production of β2-microglobulin, neopterin and quinolinic acid which are markers of immune activation, especially of macrophages (Brew et al. 1990, 1992; Heyes et al. 1991). Histological changes in such brains are marked by nodular accumulations of microglial cells, activation of perivascular macrophages and microglia, many of which express MHC II antigens, and activation and proliferation of astrocytes. Paradoxically, these signs of immune activation in the brain occur on a background of severe immunosuppression in the affected persons (Navia et al. 1986; Price 1994).

L'infiltrat salivaire labial dans le syndrome de Sjögren n'est pas un critère diagnostique mais le reflet de l'activation immunitaire systémique

Among 60 patients with Sjogren's syndrome (SS) according to the European criteria, we report the results and correlates of minor salivary gland biopsies (MSGB). The results show that inflammatory foci in MSGB are present in only 36 % of cases. They are correlated with clinical and biological signs of immune activation.

Effects of cytokines from activated immune cells on vascular cell growth and HIV-1 gene expression. Implications for AIDS-Kaposi's sarcoma pathogenesis.

Kaposi's sarcoma (KS) arises more frequently in homosexual and bisexual men than in other groups of HIV-1 infected individuals. Clinico-epidemiologic data indicate that homosexuals often are infected with multiple microbial agents and/or subjected to other antigenic stimuli, preceding or accompanying HIV-1 infection. Signs of immune activation, in fact, frequently have been detected in these individuals, and the onset of KS can precede any sign of immunodeficiency. These data have suggested that products from activated immune cells may affect the development of AIDS-KS. Here we report that conditioned media from activated or dysregulated T cells contain a variety of cytokines that promote the growth of spindle cells derived from KS lesions of AIDS patients (AIDS-KS cells) and induce normal vascular cells, potential cell progenitors of the AIDS-KS cells, to acquire features of the KS cell phenotype ("spindle" cell morphology and growth responsiveness to the mitogenic effect of extracellular HIV-1 Tat protein). The same conditioned media or cytokines promote HIV-1 gene expression and rescue defective HIV-1 proviruses, interrupting HIV-1 latency and increasing Tat production. The cellular and viral effects of cytokines are increased in an additive or synergistic manner by picomolar concentrations of extracellular Tat. These data suggest that cytokines produced by activated immune cells cooperate with HIV-1 infection in AIDS-KS pathogenesis.