Renal effects of treatment with a TLR4 inhibitor in conscious septic sheep

Introduction

Acute kidney injury (AKI) is a common and feared complication of sepsis. The pathogenesis of sepsis-induced AKI is largely unknown, and therapeutic interventions are mainly supportive. In the present study, we tested the hypothesis that pharmacological inhibition of Toll-like receptor 4 (TLR4) would improve renal function and reduce renal damage in experimental sepsis, even after AKI had already developed.

Methods

Sheep were surgically instrumented and subjected to a 36-hour intravenous infusion of live Escherichia coli. After 12 hours, they were randomized to treatment with a selective TLR4 inhibitor (TAK-242) or vehicle.

Results

The E. coli caused normotensive sepsis characterized by fever, increased cardiac index, hyperlactemia, oliguria, and decreased creatinine clearance. TAK-242 significantly improved creatinine clearance and urine output. The increase in N-acetyl-beta-D-glucosaminidas, a marker of tubular damage, was attenuated. Furthermore, TAK-242 reduced the renal neutrophil accumulation and glomerular endothelial swelling caused by sepsis. These effects were independent of changes in renal artery blood flow and renal microvascular perfusion in both cortex and medulla. TAK-242 had no effect per se on the measured parameters.

Conclusions

These results show that treatment with a TLR4 inhibitor is able to reverse a manifest impairment in renal function caused by sepsis. In addition, the results provide evidence that the mechanism underlying the effect of TAK-242 on renal function does not involve improved macro-circulation or micro-circulation, enhanced renal oxygen delivery, or attenuation of tubular necrosis. TLR4-mediated inflammation resulting in glomerular endothelial swelling may be an important part of the pathogenesis underlying Gram-negative septic acute kidney injury.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0488-y) contains supplementary material, which is available to authorized users.

Identification of clinical Pasteurella isolates by MALDI-TOF -- a comparison with VITEK 2 and conventional microbiological methods

The aim of this study was to compare the performance of four methods that are widely used in the clinical microbiology laboratory for identification of Pasteurella species. The 4 methods evaluated were VITEK2, VITEK MS (BioMerieux), and Bruker Biotyper MS (Bruker) as well as traditional biochemical tests. Sequencing of the sodA gene was used as the reference method. Sixty-five isolates of Pasteurella spp. from 65 patients were analyzed. One Pasteurella multocida isolate from American Type Culture Collection (Manassas, VA, USA) was used as a reference. Traditional biochemical tests accurately identified 62/66 (94%) isolates. Both Bruker and Vitek matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) identified 59/66 (89%) strains, but VITEK2 could only identify 32/66 (48.5%) isolates correctly. The mean time to identification using biochemical tests was 20 hours; VITEK2 took 6 hours and MALDI-TOF approximately 10 minutes. In conclusion, MALDI-TOF is a quick method, which accurately identified most isolates of Pasteurella to the species level. Thus, MALDI-TOF constitutes a valuable diagnostic tool in the clinical laboratory.

Comparison of the two blood culture systems, Bactec 9240 and BacT/Alert 3D, in the detection of Candida spp. and bacteria with polymicrobial sepsis

The purpose of this investigation was to evaluate the performance of the Bactec 9240 and BacT/Alert 3D blood culture systems in the detection of Candida spp. and bacteria in simulated polymicrobial sepsis models. A total of 28 clinical isolates of Escherichia coli, Staphylococcus aureus, Candida albicans, and Candida glabrata were studied. Five polymicrobial models of C. albicans + S. aureus, C. albicans + E. coli, C. glabrata + S. aureus, C. glabrata + E. coli, and C. albicans + C. glabrata were prepared. Each combination was inoculated in five different blood culture vials. The two systems were compared for culture positivity and time to detection (TTD). Twenty-four mixed cultures with a yeast and a bacteria were tested. Bactec Mycosis vials could detect yeasts in all 24 cultures. The aerobic vials from both Bactec and BacT/Alert could detect both yeasts and bacteria in 22/24 (91.66 %) cultures. Bactec Plus Anaerobic/F and BacT/Alert FN vials could detect both microorganisms in 19/24 (79.16 %) and 4/24 (16.67 %) vials, respectively. Seven polymicrobial sepsis models with C. albicans + C. glabrata were also tested. Mycosis vials could detect both yeasts in 7/7 mixed cultures. The aerobic vials from Bactec and BacT/Alert could detect both yeasts in 3/7 and 2/7 mixed cultures, respectively. Bactec Plus Aerobic/F had a shorter TTD compared to BacT/Alert FA and Bactec Plus Anaerobic/F vials (p < 0.0001 and p < 0.01, respectively). The present study shows that the Bactec and BacT/Alert systems have different characteristics in the detection of yeasts and bacteria with polymicrobial sepsis.

CD4+CD25high T cells are enriched in the tumor and peripheral blood of prostate cancer patients

In this study, we investigated whether CD4+CD25high regulatory T cells (Treg) are increased in the tumor tissue and peripheral blood of early-stage prostate cancer patients undergoing prostatectomy. We show that the prevalence of CD4+CD25high T cells inside the prostate was significantly higher in the tumor compared with benign tissue from the same prostate. Furthermore, the frequency of CD4+CD25high T cells in peripheral blood was significantly higher in prostate cancer patients compared with normal donors. A proportion of the CD4+CD25high T cells was also shown to be glucocorticoid-induced TNF receptor, ICOS, and FOXP3 positive. Moreover, CD4+CD25+ T cells from blood and supernatants from cultured prostate tumor tissue samples exhibited immunosuppressive function in vitro. Furthermore, supernatants from cultured prostate tissue samples and prostate cancer ascites fluid induced migration of CD4+CD25+ T cells and were shown to contain the regulatory T cell chemokine CCL22 by ELISA. Our findings indicate that Tregs are an important cellular component of early-stage prostate tumors, and thus new therapeutic strategies aimed at inhibition or depletion of Tregs may improve prostate cancer immunotherapy.

CD4+CD25high T cells are enriched in the tumor and peripheral blood of prostate cancer patients

In this study, we investigated whether CD4+CD25high regulatory T cells (Treg) are increased in the tumor tissue and peripheral blood of early-stage prostate cancer patients undergoing prostatectomy. We show that the prevalence of CD4+CD25high T cells inside the prostate was significantly higher in the tumor compared with benign tissue from the same prostate. Furthermore, the frequency of CD4+CD25high T cells in peripheral blood was significantly higher in prostate cancer patients compared with normal donors. A proportion of the CD4+CD25high T cells was also shown to be glucocorticoid-induced TNF receptor, ICOS, and FOXP3 positive. Moreover, CD4+CD25+ T cells from blood and supernatants from cultured prostate tumor tissue samples exhibited immunosuppressive function in vitro. Furthermore, supernatants from cultured prostate tissue samples and prostate cancer ascites fluid induced migration of CD4+CD25+ T cells and were shown to contain the regulatory T cell chemokine CCL22 by ELISA. Our findings indicate that Tregs are an important cellular component of early-stage prostate tumors, and thus new therapeutic strategies aimed at inhibition or depletion of Tregs may improve prostate cancer immunotherapy.

Modulation of immune responses and suppression of experimental autoimmune myasthenia gravis by surgical denervation of the spleen

Critical interactions between the nervous system and the immune system during experimental autoimmune myasthenia gravis (EAMG) were examined in an animal model for human MG after immunization of adult female Lewis rats with Torpedo acetylcholine receptor (AChR) and complete Freund's adjuvant. Immunized rats depicted marked clinical severity of the disease. Using enzyme-linked immunospot (ELISPOT) assay and in situ hybridization techniques, immune responses in these animals were examined and showed elevated numbers of anti-AChR IgG secreting B cells and AChR reactive interferon (IFN)-gamma-secreting cells, enhanced mRNA expression of the proinflammatory cytokines IFN-gamma and tumour necrosis factor (TNF)-alpha as Th1 subset and the anti-inflammatory cytokines interleukin (IL)-4 and IL-10 as a Th2 subset, and transforming growth factor (TGF)-beta as a Th3 cytokine. Corticosterone and prostaglandin E(2) (PGE(2)) levels were measured by radioimmunoassay and illustrated increased production after immunization. Surgical denervation of the spleen reduced significantly the clinical severity of the disease, suppressed the numbers of IgG and IFN-gamma-secreting cells, down-regulated the mRNA expression for cytokines and reduced corticosterone and PGE(2) production. As controls, sham-operated rats were used and showed results as the EAMG non-denervated control rats. The data present herein, and for the first time, substantial effects of the nervous system on immune responses that may influence the outcome of EAMG. These effects were not dependent on cytokine inhibitory mediators such as prostaglandins or stress hormones. IL-10 and TGF-beta, the two potent immunosuppressive cytokines, were also suppressed, indicating a general suppression by splenic denervation. More investigations are initiated at our laboratories to understand the evident neural control over the immune system during challenges leading to the break of tolerance and development of autoimmunity, which may assist in innovative therapeutic approaches.

Presence and specificity of tumor associated lymphocytes from ascites fluid in prostate cancer

BACKGROUND

In the present study, we had the rare opportunity to study immunological responses of TAL from ascites fluid in a patient with hormone-refractory prostate cancer.

METHODS

We evaluated tumor antigen-specific T-cell responses, induced by either prostate specific antigen (PSA) pulsed dendritic cells (DCs) or PSA peptides, in TAL and peripheral blood lymphocytes.

RESULTS

DC stimulation with PSA protein induced recognition of naturally processed PSA epitopes by both blood and ascites T cells. In contrast, only ascites T cells recognized the PSA-3 peptide, after stimulation with PSA-pulsed DCs or peptides. Finally, although IFNgamma secreting T cells were detectable in both blood and ascites by ELISPOT, multiplex cytokine assay detected the presence of predominantly Th2 cytokines.

CONCLUSIONS

Although tumor antigen-specific TAL were detected in ascites fluid, these cells were producing immunosuppressive cytokines which may contribute to tumor escape from recognition and/or destruction by the immune system.

Immune Monitoring in a Phase 1 Trial of a PSA DNA Vaccine in Patients with Hormone-Refractory Prostate Cancer

Prostate cancer remains a leading cause of cancer illness and death among men in Europe. No curative treatment exists when the disease has spread beyond the prostate. Immunotherapy with DNA vaccines has emerged as a potential therapeutic approach for the induction of antitumor specific cytotoxic T lymphocytes. In this study six patients with hormone-refractory prostate cancer were monitored for their ability to mount PSA-specific cellular responses after receiving a pVAX/PSA DNA vaccine (patients 1-3, 100 microg; patients 7-9, 900 microg) with recombinant GM-CSF and IL-2 as adjuvants. IFNgamma ELISPOT showed that naturally processed PSA protein and PSA peptides are recognized by T cells in the blood of some prostate cancer patients after a PSA DNA vaccine. Analysis of other cytokines showed the production of IL-4 and IL-6 but importantly did not show an increase in the number of IL-10-producing cells after vaccination in any of the patients. The authors conclude that a pVAX/PSA DNA vaccine can induce PSA-specific cellular immune responses in patients with hormone-refractory prostate cancer, thus emphasizing the potential for PSA as a target molecule for the immunotherapy of prostate cancer.

A phase I trial of DNA vaccination with a plasmid expressing prostate-specific antigen in patients with hormone-refractory prostate cancer

Prostate-specific antigen (PSA) is a serine protease secreted at low levels by normal luminal epithelial cells of the prostate and in significantly higher levels by prostate cancer cells. Therefore, PSA is a potential target for various immunotherapeutical approaches against prostate cancer. DNA vaccination has been investigated as immunotherapy for infectious diseases in patients and for specific treatment of cancer in certain animal models. In animal studies, we have demonstrated that vaccination with plasmid vector pVAX/PSA results in PSA-specific cellular response and protection against tumour challenge. The purpose of the trial was to evaluate the safety, feasibility and biological efficacy of pVAX/PSA vaccine in the clinic. A phase I trial of pVAX/PSA, together with cytokine granulocyte/macrophage-colony stimulating factor (GM-CSF) (Molgramostim) and IL-2 (Aldesleukin) as vaccine adjuvants, was carried out in patients with hormone-refractory prostate cancer. To evaluate the biologically active dose, the vaccine was administered during five cycles in doses of 100, 300 and 900 μg, with three patients in each cohort. Eight patients were evaluable. A PSA-specific cellular immune response, measured by IFN-γ production against recombinant PSA protein, and a rise in anti-PSA IgG were detected in two of three patients after vaccination in the highest dose cohort. A decrease in the slope of PSA was observed in the two patients exhibiting IFN-γ production to PSA. No adverse effects (WHO grade >2) were observed in any dose cohort. We demonstrate that DNA vaccination with a PSA-coding plasmid vector, given with GM-CSF and IL-2 to patients with prostate cancer, is safe and in doses of 900 μg the vaccine can induce cellular and humoral immune responses against PSA protein.

Splenic denervation suppresses mRNA gene expression and protein production of IL-1beta and IL-6 by peritoneal macrophages in both Trypanosoma brucei brucei-infected and non-infected rats

OBJECTIVE

To test the hypothesis that the nervous system participates in modulating the immune response during experimental African trypanosomiasis caused by Trypanosoma brucei brucei.

METHODS AND RESULTS

Using in situ hybridization and immunochemistry, we studied the effects of splenic sympathectomy on mRNA gene expression and protein production of IL-1beta and IL-6 in splenic and peritoneal macrophages (PMPhi) of Sprague-Dawley rats infected with T. brucei brucei and non-infected rats. The enhancements of mRNA gene expression and production of IL-1beta and IL-6 by peritoneal macrophages were significantly suppressed by the splenic sympathectomy in both infected and non-infected rats.

CONCLUSIONS

Our data indicate a probably stimulatory role of the sympathetic nervous system during the host immune response in both normal and T. brucei brucei-infected rats.

Cytokines in multiple sclerosis: methodological aspects and pathogenic implications

Multiple sclerosis (MS) is one of the leading causes of disability among young adults of Caucasian origin. One hundred and fifty years after the first description of the disease, the cause of MS remains unknown. Ironically, the few hypotheses concerning MS pathogenesis that are valid today were first proposed over a hundred years ago. However, equipped with the advanced technology of molecular biology and imaging systems, we are at present progressively uncovering dues to understanding the pathogenesis of the disease. It is dearly evident that aberrant immune responses occur in MS, and it is likely that the spectrum of cytokines produced decisively influences disease outcome. The detrimental consequences of IFN-gamma and the beneficial effects of IFN-beta treatment in MS support this hypothesis. However, there are still major gaps in our knowledge of the involvement of cytokines in MS. Numerous studies have addressed the question of cytokine levels in MS, often with conflicting results; elevated, normal and decreased levels of almost all cytokines have been reported. This scenario most probably reflects methodological dilemmas as well as the complex biology of cytokines. Here we focus on possible reasons for the discrepancies of results reported on cytokines in MS and summarize findings obtained in particular by the application of enzyme-linked immunospot (ELISPOT) assays to cytokine studies in MS.

Monocyte-derived dendritic cells express and secrete matrix-degrading metalloproteinases and their inhibitors and are imbalanced in multiple sclerosis

Dendritic cells (DC) are antigen-presenting cells (APC) that most efficiently initiate and control immune responses. Migration processes of blood DC are crucial to exert their professional antigen-presenting functions. Matrix-degrading metalloproteinases (MMP) are proteolytic enzymes, which are considered to be key enzymes in extracellular matrix (ECM) turnover and mediators of cell migration. Tissue inhibitors of metalloproteinases (TIMP) are important regulators of MMP activity. Here we investigate whether blood monocyte-derived immature DC (iDC) and mature DC (mDC) express, produce and secrete functionally active MMP-1, -2, -3 and -9 and their inhibitors TIMP-1 and -2, and examine their involvement in multiple sclerosis (MS). On mRNA level, we observed high numbers of MMP-2 and TIMP-2 mRNA expressing iDC in MS. On protein level, high percentages of MMP-1, -2 and -9 expressing iDC by flow cytometry, and high MMP-1 secretion by Western blot together with high MMP-2 and -9 activities in iDC supernatants as studied with zymography were observed. Similarly, MS is associated with high percentages of MMP-2 and -3 and of TIMP-1 expressing mDC by flow cytometry together with high MMP-3 secretion and high MMP-9 activity in culture supernatants. Spontaneous migratory capacity of both iDC and mDC over ECM-coated filters was higher in MS compared to healthy controls (HC). In conclusion, blood monocyte-derived iDC and mDC express, produce and secrete several MMP and TIMP. Alterations in these molecules as observed in MS may be functionally important for DC functioning.

Non-T(H)1 cytokines are augmented systematically early in Guillain-Barré syndrome

The T(H)1 vs non-T(H)1 cytokine balance in Guillain-Barré syndrome (GBS) is unknown. Using enzyme-linked immunospot (ELISPOT) assays, we observed elevated numbers of interleukin (IL)-6 and IL-10-secreting blood mononuclear cells (BMNC) during the acute phase in untreated patients, and low levels of tumor necrosis factor alpha-secreting BMNC in the recovery phase of GBS. Numbers of IL-12p70-secreting BMNC were not affected over the course of GBS. The non-T(H)1 cytokine profile observed early in GBS may explain the self-limited clinical course associated with GBS.

Enzyme-linked immunospot assays provide a sensitive tool for detection of cytokine secretion by monocytes

Blood monocytes as well as tissue-differentiated macrophages play a pivotal role in controlling immune reactions. Monocytes regulate the extent, nature, and duration of immune responses by secretion of cytokines. Interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), IL-10, and IL-12 are of particular interest, since IL-12 shifts the immune response towards a Th1 type, facilitating the production of, e.g., TNF-alpha and IL-6, while IL-10 counteracts Th1 responses and promotes the production of Th2-related cytokines such as IL-4. A tight regulation of these four cytokines keeps the balance and decides whether Th1 or Th2 will predominate in immune reactions. Enzyme-linked immunospot (ELISPOT) assays are among the most-sensitive and -specific methods available for cytokine research. They permit ex vivo identification of individual cells actively secreting cytokines. In the present study we prepared monocytes from healthy subjects' blood and adapted ELISPOT assays to define optimal conditions to detect and enumerate monocytes secreting IL-6, TNF-alpha, IL-10, and IL-12. The optimal time for monocyte incubation was 24 h, and optimal monocyte numbers (in cells per well) were 2,000 for IL-6, 1,000 for TNF-alpha, 50,000 for IL-10, and 100,000 for enumeration of IL-12 secreting monocytes. Among healthy subjects, 10% +/- 5% of the monocytes secreted IL-6, 12% +/- 12% secreted TNF-alpha, 0.1% +/- 0.1% secreted IL-10, and 0.2% +/- 0.3% secreted IL-12 (values are means +/- standard deviations). In conclusion, ELISPOT assays constitute a valuable tool to enumerate monocytes secreting IL-6, TNF-alpha, IL-10, and IL-12 and probably to enumerate monocytes secreting other cytokines and proteins.

Systemic immune response in whiplash injury and ankle sprain: elevated IL-6 and IL-10

Whiplash injury and whiplash-associated disorders (WAD) are significant problems of modern society. Numerous attempts have been made to characterize the nature of whiplash injury. Whether the immune system is involved during the disease process is not known. In a prospective study, using enzyme-linked immunospot (ELISPOT) assays, we examined numbers of blood mononuclear cells (MNC) secreting pro- (IFN-gamma, TNF-alpha, IL-6) and anti-inflammatory (IL-10) cytokines in patients with WAD and, for reference, patients with ankle sprain and multiple sclerosis and healthy subjects. An immune response reflected by elevated numbers of TNF-alpha- and IL-10-secreting blood MNC was observed in patients with WAD examined within 3 days compared to 14 days after the whiplash injury. The patients with WAD examined within 3 days after the injury had also higher numbers of IL-6 and IL-10 secreting blood MNC compared to healthy subjects. The alterations of cytokine profiles observed in WAD were also observed in patients with ankle sprain when examined within 3 days after trauma. In contrast, there were no differences for cytokine profiles between patients with WAD examined 14 days after the whiplash injury and healthy subjects. Relatively minor trauma like WAD and ankle sprain are associated with a systemic dysregulation in numbers of cells secreting pro- as well as anti-inflammatory cytokines.

Matrix metalloproteinase and cytokine profiles in monocytes over the course of stroke

Stroke is a common cause of death and disability in our society. Stroke is associated with changes in immune responses within the central nervous system as well as systemically. The cells contributing to such changes as well as the factors contributing to formation of the inflammatory infiltrate observed in stroke remain to be clarified. In this study, blood monocytes and corresponding mononuclear cells (MNC) were separated and examined in parallel within 4 days and 1-3 months after onset of ischemic stroke. Numbers of TNF-alpha-, IL-12-, IL-6-, and IL-10-secreting cells and of cells expressing mRNA for matrix metalloproteinase (MMP)-1, -2, -7, -9 and tissue inhibitor of MMP (TIMP)-1 were studied. The TNF-alpha-, IL-12-, and IL-6-secreting monocytes and MNC were elevated during the acute phase compared to healthy controls. Such differences were not observed when stroke patients were examined during convalescence. The IL-10-secreting monocytes did not change over the course of stroke. Levels of monocytes expressing MMP-1, MMP-7 and TIMP-1 mRNA were elevated in the acute phase of stroke patients compared to convalescence and healthy controls, as were levels of MMP-1, -2, -7, -9 and TIMP-1 mRNA expressing blood MNC. The MMP-2 and -9 activity as measured by zymography also was higher in MNC supernatants in the acute phase of stroke compared to convalescence. The high levels of proinflammatory cytokines and MMPs in blood monocytes and MNC further demonstrate the presence of systemic aberrations in the acute phase of stroke. Such changes may contribute to the influx of blood-borne cells into the ischemic lesions during the acute phase of stroke.

Chemokines and their receptors in whiplash injury: elevated RANTES and CCR-5

The human sufferings and socioeconomic burden due to whip-lash-associated disorders (WAD) are obvious but the pathogenesis of WAD is obscure. The possible involvement of the immune system during the disease process in WAD is not known. Effector molecules including chemokines and their receptors could play a role in WAD. In a prospective study using flow cytometry, we examined percentages of blood mononuclear cells (MNC) expressing the chemokines RANTES, MCP-1, MIP-1alpha, MIP-1beta, and IL-8, the chemokine receptor CCR-5, the T cell activation marker CD25, and the T cell chemoattractant IL-16 in patients with WAD and, for reference, in healthy controls. Higher percentages of RANTES-expressing blood MNC and T cells were observed in patients with WAD examined within 3 days compared to 14 days after the whiplash injury and, likewise, compared with healthy controls. The patients with WAD examined within 3 days after the accident also had higher percentages of CCR-5-expressing blood MNC, T cells, and CD45RO+ T cells compared to healthy controls. In contrast, there were no differences for any of these variables between patients with WAD examined 14 days after injury and healthy controls. In conclusion, WAD is associated with a systemic but transient dysregulation in percentages of RANTES and CCR-5 expressing MNC and T cells.

Multiple sclerosis: elevated expression of matrix metalloproteinases in blood monocytes

Multiple sclerosis (MS) is an inflammatory, demyelinating disease of the central nervous system (CNS) characterized by blood-brain barrier (BBB) breakdown. Disruptions of BBB continuity result in an influx of activated T cells and monocytes, and could contribute to lesion formation in the CNS. Matrix metalloproteinases (MMP) are enzymes implicated in BBB disruption, and in degradation of extracellular matrix proteins and myelin components. An imbalance in levels of MMP and tissue inhibitors of MMP (TIMP) has been implicated in the pathogenesis of MS. Since monocytes form a major cell population in acute MS lesions and may facilitate their entrance into the CNS by secretion of MMP, knowledge on MMP expression by blood monocytes could be useful to improve our understanding of the pathogenesis of MS. In the present study, we examined the expression of MMP-1, -3, -7, -9, -14 and TIMP-1 mRNA by blood monocytes in patients with MS using in situ hybridization. Levels of MMP-1, -3, -7, -9 and of TIMP-1 mRNA expressing monocytes were elevated in MS compared to controls, while those of MMP-14 did not differ. We therefore conclude that MS is associated with elevated levels of MMP and TIMP expressing blood monocytes that may contribute to MS pathogenesis.

IL-12/IL-12R system in multiple sclerosis

IL-12/IL-12 receptor (IL-12R) system orchestrates the Th1 pathway of the immune system by maintaining one of the major bridges between innate and adaptive immune responses. Here, we studied both sides of this system in patients with multiple sclerosis (MS) and in controls. MS patients displayed elevated IL-12Rbeta1 and IL-12Rbeta2 expression on PHA-activated T cells compared to healthy subjects. Higher percentages of IL-12Rbeta1 and IL-12Rbeta2 positive T cells in cerebrospinal fluid (CSF) compared to blood were observed both in MS and other neurological diseases (OND). In contrast, numbers of IL-12 secreting blood mononuclear cells (MNC) were similar in MS and controls. The functional importance of high IL-12Rbeta2 in MS was underlined by the finding that IL-12 stimulated IFN-gamma production and proliferation of PHA-activated T cells correlated with levels of IL-12Rbeta2 expression. Our data indicates a dysregulation of the IL-12/IL-12R system in MS. It is suggested that even in the absence of increased IL-12 levels, the net effect of IL-12 might be augmented in MS by elevated expression of its receptor.

Monocytes in multiple sclerosis: phenotype and cytokine profile

Multiple sclerosis (MS) is an inflammatory demyelinating disease characterised by immune abnormalities in the central nervous system (CNS) as well as systemically. Activated, blood-borne monocytes are abundant in MS lesions, the properties of circulating monocytes are incompletely known. To delineate phenotype and levels of cytokine secreting monocytes in MS patients' blood, ELISPOT assays were used for detection and enumeration of monocytes secreting the cytokines IL-6, IL-12, TNF-alpha and IL-10. In parallel, the expression by monocytes of co-stimulatory molecules (CD40, CD80, CD86), major histocompatibility complex molecules (HLA-ABC, HLA-DR) and Fcgamma receptors (CD16, CD64) was examined by flow cytometry. Levels of blood monocytes secreting IL-6 and IL-12 were higher in patients with untreated MS and other neurological diseases (OND) compared to healthy controls, while levels of monocytes secreting TNF-alpha and IL-10 did not differ between groups. MS patients' blood monocytes also displayed elevated mean fluorescence intensity for the co-stimulatory molecule CD86, and MS patients with longer disease duration (>10 years) and higher disease severity (EDSS >3) had higher percentages of CD80 expressing monocytes compared to patients with short duration or lower severity. In conclusion, monocyte aberrations occur in MS and may change over the disease course.

Phenotypes and cytokine profiles of enriched blood dendritic cells in healthy individuals

Dendritic cells (DC) are highly specialized for initiating adaptive immune responses and are capable of producing a wide variety of cytokines. However, cytokine profiles of the DC naturally present in human blood have received relatively little attention. The objective of this study was to investigate expression of surface markers and cytokines by blood DC not subjected to prolonged culture and/or polyclonal activation, to identify surface phenotypes of cytokine-expressing DC and to evaluate sex and age differences in cytokine profiles of DC. For this purpose, DC were enriched from blood of healthy donors by the use of the adherence method, and expression of surface molecules and intracellular IFN-g, IL-10, IL-12 and IL-15 was studied by flow cytometry. Enriched blood DC expressed higher levels of IFN-g, IL-12 and IL-15, compared to whole mononuclear cells (MNC) incubated for the same time. Expression of IFN-g and IL-12 was confined to the mature CD83+CD11c+ DC subset. Enriched DC from females' blood displayed higher levels of CD80, IL-10 and IL-15. Taken together, enriched blood DC spontaneously express larger amounts of IFN-g, IL-12 and IL-15 than MNC. Sex differences in expression of CD80, IL-10 and IL-15 may have a modulatory influence on immune responses in males and females.

IL-12 elispot assays to detect and enumerate IL-12 secreting cells

The cytokine IL-12 promotes Th(1)type immune responses and plays a key role in immune regulation. The complex nature of IL-12 hampered its detection without use of stimulants that might give less relevant information. To detect circulating IL-12 p40, we developed enzyme-linked immunospot (ELISPOT) assays that allow enumeration of IL-12 p40 secreting cells without prior in vitro stimulation of the cells. In parallel, intracellular staining of IL-12 p40 by flow cytometry was performed to compare the two methods. IL-12 p40 secreting cells were detected in healthy subjects at a mean number of 103+/-155 per 10(5)blood mononuclear cells (MNC). Numbers of IL-12 p40 secreting blood MNC correlated with IL-12 p40 positive blood MNC detected by flow cytometry. Bacterial endotoxins and the inflammatory cytokines TNF-alpha and IFN-gamma control IL-12 production by antigen presenting cells. Utilizing IL-12 p40 ELISPOT assays, we could confirm occurrence of elevated numbers of IL-12 p40 secreting blood MNC after stimulation with TNF-alpha, IFN-gamma, LPS, LPS+TNF-alpha or LPS+IFN-gamma, compared to cultures without stimulant. Due to its central role in inflammation and autoimmunity, IL-12 is an attractive target for immunotherapy. IL-12 p40 ELISPOT assays represent a sensitive, specific and reliable tool for investigating the role of IL-12 in both health and disease.

Multiple sclerosis: pro- and anti-inflammatory cytokines and metalloproteinases are affected differentially by treatment with IFN-beta

Interferon-beta (IFN-beta) has a beneficial influence on the course of multiple sclerosis (MS) and has become standard treatment of this disease, though its mechanisms of action are incompletely understood. This study examines the effect of IFN-beta treatment on the cytokines IL-6, TNF-alpha, IFN-gamma and IL-10; the metalloproteinases MMP-3, -7 and -9 and the tissue inhibitor of metalloproteinase-1 (TIMP-1). IFN-beta treatment resulted in decreased numbers of mononuclear cells (MNC) secreting IL-6 and TNF-alpha and expressing mRNA of MMP-3 and MMP-9 compared to pretreatment levels. On the contrary, numbers of IL-10 secreting MNC and TIMP-1 mRNA expressing were augmented during IFN-beta therapy. Whether the down-regulatory effects on pro-inflammatory and upregulatory effects on anti-inflammatory molecules are a direct result of IFN-beta on the immune system or secondary to clinical stabilization of MS pathology induced by IFN-beta remains to be evaluated.

Multiple sclerosis is associated with an imbalance between tumour necrosis factor-alpha (TNF-alpha)- and IL-10-secreting blood cells that is corrected by interferon-beta (IFN-beta) treatment

The up-regulated B cell responses detectable in cerebrospinal fluid (CSF) and the augmented myelin antigen-specific T cell responses observed in the CSF as well as systematically in patients with multiple sclerosis (MS) suggest the involvement of cytokines in disease development and perpetuation. Here we report on the parallel involvement of TNF-alpha, IL-6, IFN-gamma and IL-10 in MS and controls, using enzyme-linked immunospot (ELISPOT) assays to detect and enumerate cytokine-secreting mononuclear cells (MNC) prepared from blood and, for IL-6 and IL-10, from CSF without in vitro stimulation. MS is associated with elevated levels of TNF-alpha-secreting blood MNC when compared with levels in groups of control patients with myasthenia gravis (MG) and other neurological diseases (OND) or healthy subjects. This elevation was confined to patients with untreated MS and not present in those examined during ongoing treatment with IFN-beta. Untreated patients with MS had lower numbers of IL-10-secreting blood MNC compared with the three control groups. In patients undergoing treatment with IFN-beta, numbers of IL-10-secreting cells were in the same range as in controls. Normalization of TNF-alpha from elevated, and of IL-10 from decreased levels could be one reason for the beneficial effects of IFN-beta in MS, although it remains to be shown whether these changes reflect phenomena primarily involved in MS pathogenesis or secondary changes. In CSF, levels of IL-10-secreting cells were higher than in blood in both MS and OND, with no difference between these groups. Systemic aberrations of IL-6 and IFN-gamma and of IL-6 in CSF in MS versus controls were only minor, irrespective of treatment with IFN-beta.

Elevated CD40 ligand expressing blood T-cell levels in multiple sclerosis are reversed by interferon-beta treatment

Myelin protein reactive CD4+ T cells are considered to be involved in the proposed immunopathogenesis of multiple sclerosis (MS). One particularly important molecule for T-cell activation is the CD40L (gp39) that is expressed on the surface of T cells. This study focuses on the CD40 and the CD40L expression on mononuclear cells prepared from blood from patients with MS, other neurological diseases (OND) and healthy subjects. Immunostaining followed by a three channel flow cytometry was adopted. Patients with MS had higher levels of CD3+CD40L+, CD4+CD40L+ and CD8+CD40L+ T cells compared to patients with OND and healthy subjects. Cross-sectional comparisons revealed that the elevation of CD40L+ T cell subtypes was confined to the patients with untreated MS and not observed in the patients with MS treated with interferon-beta (IFN-beta). Follow up studies showed that levels of CD3+CD40L+ and CD4+CD40L+ T cells decreased in individual patients after the initiation of the IFN-beta treatment. The enhanced expression of CD40L on CD3+, CD4+ and CD8+ T cells in patients with MS may implicate a role for this molecule in disease immunopathogenesis.

Increased levels of circulating acetylcholine receptor (AChR)-reactive IL-10-secreting cells are characteristic for myasthenia gravis (MG)

Antibodies to the nicotinic AChR are pivotal in the immunopathogenesis of MG. Cytokines produced by T-helper cells are important regulators of humoral immune responses. IL-10 is considered an anti-inflammatory cytokine, but it promotes B cell activation and worsens experimental autoimmune MG in Lewis rats, an experimental model of MG. To study IL-10 and, as a control, interferon-gamma (IFN-gamma) in MG, we used an enzyme-linked immunospot (ELISPOT) assay, thereby assessing numbers of blood mononuclear cells (MNC) secreting IL-10 and IFN-gamma spontaneously and after stimulation with AChR. Low numbers of IL-10-secreting cells were regularly found in peripheral blood from patients with MG as well as in controls with other neurological diseases and healthy subjects. However, only MG patients had elevated blood levels of AChR-reactive IL-10- and IFN-gamma-secreting cells. The MG patients showed no responses to the control autoantigen myelin basic protein, underlining the specificity of the IL-10 and IFN-gamma responses. Immunosuppressive treatment reduced numbers of AChR-reactive IFN-gamma-secreting cells but increased the numbers of IL-10-secreting cells. The numbers of IL-10-secreting cells tended to be higher in patients with generalized versus ocular MG, further suggesting that the augmented IL-10 responses may be important in the pathogenesis and perpetuation of MG.

Multiple sclerosis is associated with high levels of circulating dendritic cells secreting pro-inflammatory cytokines

Recent evidence emphasises a pivotal role for dendritic cells (DC) in the control of immunity by priming and tolerising T cells. DC capture and process antigens, express co-stimulatory molecules, migrate to lymphoid organs and secrete cytokines to initiate immune responses. In multiple sclerosis (MS), autoreactive T cells are proposed to play a pathogenic role by secreting pro-inflammatory cytokines, but studies on DC are lacking. To evaluate the involvement of DC in patients with MS, a modified procedure was used to prepare DC from blood of patients with MS and healthy subjects. DC were found to be potent stimulators of T cells in allogeneic and, to a lesser extent, in autologous mixed leukocyte reaction (MLR). Enzyme-linked immunospot (ELISPOT) assays were adopted to determine levels of IFN-gamma, TNF-alpha, IL-6 and IL-10 secreting DC vs. mononuclear cells (MNC). Proportionally more DC than MNC secreted IFN-gamma and IL-10 in both MS and healthy subjects. Patients with MS had higher levels of IFN-gamma, TNF-alpha and IL-6 secreting DC than healthy subjects. The differences for IFN-gamma and TNF-alpha secreting cells were confined to the subgroup of untreated MS patients and not observed in the subgroup examined during ongoing treatment with IFN-beta. Circulating DC secreting pro-inflammatory cytokines may represent another focus for the study of both immuno-pathogenesis and therapeutic interventions in MS.

Metalloproteinases and their tissue inhibitors in multiple sclerosis

Matrix metalloproteinases (MMPs) comprise a family of proteolytic enzymes. MMPs are capable of disrupting the blood-brain barrier (BBB), mediating the destruction of extracellular matrix and myelin components. MMPs are also involved in the processing of a variety of cell surface molecules, including the proinflammatory cytokine TNF-alpha. Each of these mechanisms are thought to be important in the pathogenesis of multiple sclerosis (MS). We investigated mRNA expression of MMP-3, MMP-9 and two tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in parallel in blood mononuclear cells (MNC) from patients with MS and controls, using in situ hybridization. Numbers of MMP-9 mRNA-expressing cells in blood were higher in patients with MS compared to other neurological diseases (OND), other inflammatory neurological diseases (OIND) and healthy subjects (P<0.0001 for all comparisons). Patients with MS had also higher levels of MMP-3 and TIMP-1 mRNA expressing blood MNC compared to patients with OND and healthy subjects. A positive correlation was observed for MMP-9 and TIMP-1 mRNA expression in MS. These results demonstrate that MMPs and TIMPs are upregulated in MS and may contribute to the pathogenesis of the disease.

A new cell enzyme-linked immunosorbent assay demonstrates gamma interferon suppression by beta interferon in multiple sclerosis

Multiple sclerosis (MS) is a demyelinating disorder of the central nervous system of unknown etiology. Immune mechanisms involving the proinflammatory cytokine gamma interferon (IFN-gamma) are believed to play an important role in the pathogenesis of MS. IFN-beta-1b has been introduced as a treatment for MS and was found to reduce the number and severity of clinical exacerbations. To examine the influence of IFN-beta-1b on myelin basic protein (MBP)-specific and phytohemagglutinin-induced IFN-gamma production, we developed a cell-released capturing enzyme-linked immunosorbent assay (CRC-ELISA), which rapidly measures spontaneous and antigen- or mitogen-induced cellular IFN-gamma production. CRC-ELISA documented a significant MBP-specific T-cell response in the blood of untreated MS patients, as assessed by IFN-gamma production. This response was suppressed in MS patients treated with IFN-beta-1b. The present work confirms in vivo the in vitro suppressive effects of IFN-beta-1b on IFN-gamma production in MS. Moreover, it provides a powerful new technique for detection of cytokines.

Multiple sclerosis: levels of interleukin-10-secreting blood mononuclear cells are low in untreated patients but augmented during interferon-beta-1b treatment

The cytokine interleukin (IL)-10 has immune response down-regulatory properties, which include suppression of the synthesis of pro-inflammatory cytokines such as interferon (IFN)-gamma and of major histocompatibility complex (MHC) class II expression on monocytes. To further elucidate the involvement of IL-10 in multiple sclerosis (MS), an enzyme-linked immunospot assay was adopted to enumerate IL-10-secreting mononuclear cells (MNC) in peripheral blood. IFN-gamma secreting MNC were detected in parallel. Levels of IL-10-secreting cells were lower in patients with MS compared with other neurological diseases (OND) and healthy subjects. This difference was seen only in patients with untreated MS, and not in those undergoing treatment with IFN-beta-1b. No differences were observed when subgrouping the patients with MS regarding clinical phase (exacerbation, remission, secondary progression), duration of MS or disability status. Levels of IFN-gamma-secreting blood MNC did not differ in patients with MS, irrespective of treatment with IFN-beta-1b, compared with OND and healthy subjects. Patients with MS, but not the two groups of controls, had elevated numbers of IL-10- and IFN-gamma-secreting cells upon stimulation with MBP compared with culture in the absence of antigen. The data suggest that IL-10 is decreased in MS and that treatment resulting in its up-regulation beneficially influence the disease.

Interleukin-17 mRNA expression in blood and CSF mononuclear cells is augmented in multiple sclerosis

Myelin-directed autoimmunity is considered to play a key role in the pathogenesis of multiple sclerosis (MS). Increased production of both pro- and anti-inflammatory cytokines is a common finding in MS. Interleukin-17 (IL-17) is a recently described cytokine produced in humans almost exclusively by activated memory T cells, which can induce the production of proinflammatory cytokines and chemokines from parenchymal cells and macrophages. In situ hybridisation with synthetic oligonucleotide probes was adopted to detect and enumerate IL-17 mRNA expressing mononuclear cells (MNC) in blood and cerebrospinal fluid (CSF) from patients with MS and control individuals. Numbers of IL-17 mRNA expressing blood MNC were higher in patients with MS and acute aseptic meningoencephalitis (AM) compared to healthy individuals. Higher numbers of IL-17 mRNA expressing blood MNC were detected in MS patients examined during clinical exacerbation compared to remission. Patients with MS had higher numbers of IL-17 mRNA expressing MNC in CSF compared to blood. This increase in numbers of IL-17 mRNA expressing MNC in CSF was not observed in patients with AM. Our results thus demonstrate increased numbers of IL-17 mRNA expressing MNC in MS with higher numbers in CSF than blood, and with the highest numbers in blood during clinical exacerbations.

No evidence for elevated numbers of mononuclear cells expressing MCP-1 and RANTES mRNA in blood and CSF in multiple sclerosis

The perivascular accumulation of mononuclear cells (MNC) in brain white matter is critical in the development of active lesions in multiple sclerosis (MS). Chemokines contribute to leukocyte recruitment by increasing the adhesiveness of integrins expressed on leukocytes and by promoting migration through endothelium and extracellular matrix. By using an in situ hybridization technique, it was possible to enumerate blood and CSF MNC expressing mRNA for the two CC chemokines monocyte chemoattractant protein-1 (MCP-1) and RANTES (regulated upon activation, normal T cells, expressed and secreted) in MS patients and controls. No differences in numbers of blood MNC expressing MCP-1 or RANTES could be found in MS patients compared to healthy individuals or patients with acute aseptic meningoencephalitis (AM). High numbers of CSF MNC expressing MCP-1 and RANTES were found in some MS patients, but also in patients with AM. This shows that elevated numbers of MCP-1 and RANTES mRNA expressing CSF MNC are not specific for the inflammatory process in MS. We conclude that there is no evidence for a systemic dysregulation of the CC chemokines MCP-1 and RANTES in MS.