Biomedical subjects

Hans Link

Publications and source records attributed to Hans Link.

30 records · Page 2Linked to original sources

PubMed2003

Secondary lymphoid organ chemokines are elevated in the cerebrospinal fluid during central nervous system inflammation.

Secondary lymphoid organ chemokines have been implicated in chronic inflammation. Their expression in the central nervous system (CNS) has not been studied. Here, levels of secondary lymphoid organ chemokines CCL19 (Exodus-3, MIP-3beta), CCL21 (Exodus-2, 6Ckine, SLC) and CXCL12 (SDF-1alpha) were analysed by ELISA in cerebrospinal fluid (CSF) and plasma from patients with multiple sclerosis (MS); acute optic neuritis (ON) with oligoclonal IgG in the CSF (i.e., first bout of MS); acute ON without oligoclonal IgG (non-MS-type ON); other inflammatory neurological diseases (OIND); and non-inflammatory neurological diseases (NIND). NIND CSF contained CCL19 and CXCL12, while CCL21 was not detected. Intrathecal production of CCL19 and CCL21 was elevated in MS, MS-type ON, and OIND, but not in non-MS-type ON. In MS, CSF levels of CCL19 weakly correlated with CSF cell counts. Intrathecal production of CXCL12 was elevated only in OIND. The role of elevated CCL19 and CCL21 in MS could be retention of mature dendritic cells (DC) in the CNS, recruitment of nai;ve T cells and activated B cells, as well as de novo formation of secondary lymphoid structures in MS plaques.

Adult↗

PubMed2003

Birth cohort effects in multiple sclerosis.

PURPOSE: To identify potential birth cohort effects in multiple sclerosis in Sweden and particularly in Stockholm county. METHODS: Data on multiple causes of death from multiple sclerosis during 1962 to 1995 in Sweden and 1968 to 1995 in Stockholm county were analyzed using age-period-cohort models and curvature. RESULTS: Mortality from multiple sclerosis was higher in Sweden than in Stockholm county, with stable time trends, slight period effects and marked age effects. Cohorts born before or after a central period, from 1910 through 1930, registered lower mortality. A periodic wave-form mortality pattern was identified, following a 5-to-6-year cycle for cohorts born before 1925 both in and outside Stockholm county, and changing to longer or irregular cycles for cohorts born after 1930. CONCLUSIONS: Although methodological constraints inducing the saw-tooth pattern cannot be excluded, these results are consistent with etiologic hypotheses claiming a role for environmental factors in multiple sclerosis.

Adult↗

PubMed2003

Dehydroepiandrosterone therapy ameliorates experimental autoimmune myasthenia gravis in Lewis rats.

To detect a possible effect of dehydroepiandrosterone (DHEA) in the pathogenesis of experimental autoimmune myasthenia gravis (EAMG), DHEA (0.5 mg/rat) was administrated intraperitoneally to Lewis rats every other day from day 4 postimmunization (p.i.) to day 35 p.i. with Torpedo acetylcholine receptor (AChR) and Freund's complete adjuvant. Rats treated with DHEA had a lower clinical score (mean clinic score, 2 versus 0.5 on day 37 p.i.) and a lower body weight loss (mean body weight, 169 versus 142 g on day 37 p.i.) compared with control EAMG rats. DHEA treatment decreased serum anti-AChR IgG and IgG2b antibody titers on days 7, 14, and 21 p.i. and inhibited the levels of anti-AChR IgG antibody secreting cells (60%), accompanied by decreased IL-4 (33%) and augmented TGF-beta1-positive cells (41%) among lymph node mononuclear cells. These results obtained from EAMG in Lewis rats further encourage us to study DHEA treatment in human MG.

Acetylcholinesterase↗

PubMed2003

Inflammation in the central nervous system: the role for dendritic cells.

Dendritic cells (DCs) are a subclass of antigen-presenting cells critical in the initiation and regulation of adaptive immunity against pathogens and tumors, as well as in the triggering of autoimmunity. Recent studies have provided important knowledge regarding distribution of DCs in the central nervous system (CNS) and their role in intrathecal immune responses. DCs are present in normal meninges, choroid plexus, and cerebrospinal fluid, but absent from the normal brain parenchyma. Inflammation is accompanied by recruitment and/or development of DCs in the affected brain tissue. DCs present in different compartments of the CNS are likely to play a role in the defence against CNS infections, and also may contribute to relapses/chronicity of CNS inflammation and to break-down of tolerance to CNS autoantigens. CNS DCs can therefore be viewed as a future therapeutic target in chronic inflammatory diseases such as multiple sclerosis.

Animals↗

PubMed2003

Dendritic cell vaccine design: strategies for eliciting peripheral tolerance as therapy of autoimmune diseases.

Dendritic cells (DC), as potent antigen-presenting cells (APC), constitute a complex system of cells that initiate and regulate immune responses that result in two opposite outcomes: immunity or tolerance. The fine regulation of these two distinct functions is not completely understood. After loading with antigen, DC exhibit the properties of both antigen and adjuvant, the functional components of vaccines. For a long time, attention has focused on the exceptional ability of DC as professional APC capable of eliciting T and B cell-mediated responses, and on their potential as immunotherapy in cancer. DC exhibit both heterogeneity and plasticity. On the one hand, distinct DC subsets exhibit distinct functions. On the other hand, DC functions can be altered by the cytokine environment or other factors. There is increasing evidence that DC could be used as a tool to induce peripheral tolerance. Because DC-based immunotherapy in autoimmune diseases depends on tolerogenic DC, discerning markers for tolerogenic DC is of great importance. Immature DC, plasmacytoid DC and interleukin-10-modified DC can mediate immune tolerance by inducing T-cell anergy or T-helper type 2 responses. Several possibilities exist for rational modulation of DC to achieve therapeutic tolerance against autoimmune diseases. The final goal is to create optimal prerequisites to use autologous DC that are prepared from the individual patient with autoimmune disease, to render such DC tolerogenic by exposure in vitro to factors that promote tolerogenicity, and to re-infuse these pretreated DC to the patient in order to treat the ongoing autoimmune disease and prevent its future exacerbation.

Autoimmune Diseases↗

PubMed2002

Anti-TNF-alpha antibodies suppress the development of experimental autoimmune myasthenia gravis.

To understand the role of TNF-alpha in the induction of experimental autoimmune myasthenia gravis (EAMG) and detect a possible effect of anti-TNF-alpha antibodies in the treatment of EAMG, anti-TNF-alpha antibodies were administrated intraperitoneally to Lewis rats twice per week for 5 weeks from the day of immunization with Torpedo AChR and complete Freund's adjuvant (CFA). Administration of anti-TNF-alpha antibodies resulted in lower incidence of EAMG, and in delayed onset and only mild muscle weakness compared with control EAMG rats. These mild clinical signs were accompanied by lower AChR-specific lymphocyte proliferation, down-regulated IFN-gamma and IL-10, and up-regulated TGF-beta. The lower levels of anti-AChR IgG, Ig2a and IgG2b and decreased anti-AChR IgG affinity were found in rats treated with anti-TNF-alpha antibodies. These results demonstrate that anti-TNF-alpha antibodies can suppress the induction and development of EAMG.

Animals↗

PubMed2002

Multiple sclerosis and optic neuritis: CCR5 and CXCR3 expressing T cells are augmented in blood and cerebrospinal fluid.

A role for chemokines as mediators of Th1 cell recruitment to the central nervous system (CNS) is probable in MS. Therefore we studied expression of Th1-related CCR5 and CXCR3 chemokine receptors in patients with MS and controls. Patients with untreated MS had elevated percentages of CCR5 and CXCR3 expressing T cells vs. healthy controls (HC) in blood, and vs. other non-inflammatory neurological diseases (OND) patients in CSF. Such elevation was not found in MS patients examined during ongoing treatment with IFN-beta. Patients with optic neuritis (ON), a common first manifestation of MS, had elevated percentages of CXCR3 expressing T cells in blood compared with HC, and of CCR5 expressing T cells in CSF compared with OND patients. High chemokine receptor expression may be one prerequisite for Th1 cells to migrate to the CNS. Inhibition of chemokine receptor expression may constitute a potentially important therapeutic effect of IFN-beta.

Adult↗

PubMed2002

Recruitment of dendritic cells to the cerebrospinal fluid in bacterial neuroinfections.

Dendritic cells (DC) accumulate in the CNS during inflammation and may contribute to local immune responses. Two DC subsets present in human cerebrospinal fluid (CSF) are probably recruited from myeloid (CD11c(+)CD123(dim)) and plasmacytoid (CD11c(-)CD123(high)) blood DC. In bacterial meningitis and especially in Lyme meningoencephalitis, numbers of myeloid and plasmacytoid DC in CSF were increased, compared to non-inflammatory neurological diseases, and correlated with chemotactic activity of CSF for immature monocyte-derived DC (moDC). Multiple DC chemoattractants, including macrophage inflammatory protein (MIP)-1beta, monocyte chemotactic protein (MCP)-1, MCP-3, RANTES and stromal cell-derived factor (SDF)-1alpha were elevated in CSF in these two neuroinfections. Chemotaxis of immature moDC induced by these CSFs could be partially inhibited by mAbs against CXCR4, the receptor for SDF-1alpha, and CD88, the receptor for C5a. SDF-1alpha present in CSF also chemoattracted mature moDC, which in vivo could correspond to a diminished migration of antigen-bearing DC from the CSF to secondary lymphoid organs. Regulation of DC trafficking to and from the CSF may represent a mechanism of controlling the CNS inflammation.

Adolescent↗

PubMed2002

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.

Adult↗

PubMed2002

Dendritic cells and immune responses in the central nervous system.

Explore the source record for details and available documents.

Central Nervous System↗

PubMed2002

Dendritic cells are present in ischemic brain after permanent middle cerebral artery occlusion in the rat.

BACKGROUND AND PURPOSE: Cerebral ischemia is associated with inflammation involving accumulation of polymorphonuclear neutrophils. T cells have been suggested to contribute to the secondary progression of ischemic brain injury. Dendritic cells (DC) are potent regulators of immunity by activating and tolerizing T cells. DC have previously been detected in rat meninges and choroid plexus. Hypothesizing that DC are involved in inflammation associated with cerebral ischemia, we investigated DC in the brain of Sprague-Dawley rats after permanent middle cerebral artery occlusion (pMCAO) versus sham operation. METHODS: All experimental rats (n=24) had the right MCA permanently occluded by inserting a nylon monofilament through the right external carotid artery. Immunohistochemistry was used to detect DC (OX62(+)), microglia/macrophages (OX42(+)) that developed into DC, and activated DC expressing major histocompatibility complex class II (OX6(+)) in the brain hemispheres at 1 hour to 6 days after pMCAO or sham operation. RESULTS: Levels of DC were elevated at 1 hour in the ischemic versus sham hemispheres (P<0.001) and ischemic versus nonischemic hemispheres (P<0.001). Activated DC expressing major histocompatibility complex class II (OX62(+)OX6(+)) were still elevated at 6 days after pMCAO in the ischemic versus nonischemic hemispheres (P<0.01). The area of brain lesion correlated with numbers of OX62(+) DC per 100-mm2 brain tissue section (r=0.79; P<0.0001). CONCLUSIONS: Increased levels of DC in the brain after pMCAO and correlation between DC numbers and brain lesion area indicate a role for DC in cerebral ischemia. This observation could constitute a basis for further studies on the role of DC in inflammation related to cerebral ischemia.

Animals↗

PubMedDate not supplied

Tolerogenic dendritic cells: the ins and outs of outcome.

Recent studies point to an important role for dendritic cells (DCs) in the induction of peripheral tolerance, revealing that the maturation and/or activation state of DCs might be a control point for the induction of peripheral tolerance. Recent progress in our understanding of the mechanisms mediating immune tolerance indicates them to be far more complex than hitherto anticipated. Factors deciding the outcome of vaccination with autologous DCs to prevent and treat diseases with an autoimmune background include maturation state of DCs, their administration route, long-term effects, antigen loading, and in vivo microenvironment. DC vaccination, although promising, is far from standardized. In this review, we discuss the ins and outs of DC-mediated immune tolerance and the need for careful experimental design to unequivocally prove the efficacy and reach the goal of optimized use of DCs in autoimmune diseases.

Antigen Presentation↗