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H Link

Publications and source records attributed to H Link.

At least 181 records · Page 10Linked to original sources

Experimental autoimmune myasthenia gravis induction in B cell-deficient mice.

Experimental autoimmune myasthenia gravis (EAMG) is an animal model for human myasthenia gravis (MG). Autoantibody-induced functional loss of nicotinic acetylcholine receptor (AChR) at the postsynaptic membrane is an important pathogenic feature of both MG and EAMG. To evaluate the extent at which the humoral immune response against AChR operates in the pathogenesis of EAMG, we immunized B cell knockout (muMT) and wild-type C57BL/6 mice with AChR and complete Freund's adjuvant. The ability of AChR-primed lymph node cells to proliferate and secrete IFN-gamma in response to AChR and its dominant peptide alpha146-162 were intact in muMT mice as in wild-type mice. Similar amounts of mRNA for IFN-gamma, IL-4 and IL-10 in AChR-reactive lymph node cells were detected in muMT and wild-type mice. However, muMT mice had no detectable anti-AChR antibodies and remained completely free from clinical EAMG. We conclude that B cells are critically required for the genesis of clinical EAMG, but not for AChR-specific T cell priming.

Animals↗

Prevention of experimental autoimmune neuritis by nasal administration of P2 protein peptide 57-81.

Experimental autoimmune neuritis (EAN) is a CD4+ T cell-mediated inflammatory demyelinating disease of the peripheral nervous system (PNS) that serves as a model for Guillain-Barre syndrome (GBS) in humans. Both EAN and GBS are associated with upregulated T and B cells responses to PNS myelin proteins including P2 protein, and by changes of the Th1/Th2 cell balance in favor of Th1. Here we report that EAN can be prevented by the dominant neuritogenic peptide 57-81 of the PNS P2 protein when given nasally before immunization of Lewis rats with bovine PNS myelin (BPM) + Freund's complete adjuvant (FCA). P2 peptide-tolerized rats were also resistant to EAN relapse after challenge with BPM. Tolerance to EAN in rats receiving high dose (60 microg/day/rat) P2 peptide nasally was associated with specific T and B cell anergy. This was characterized by the failure of T cells to proliferate in response to PNS myelin antigens, while responsiveness to phytohemagglutinin was retained. Numbers of BPM- and P2 peptide-reactive interferon-gamma mRNA expressing lymph node cells were reduced, while levels of P2 peptide-reactive interleukin 4 and transforming growth factor-beta mRNA-expressing cells were markedly upregulated on day 18 post immunization in the rats receiving high dose P2 peptide nasally. Tolerance to EAN was also associated with lower CD4+ cell infiltration, low-grade inflammation, or the absence of histological evidence of EAN, as well as with low IL-2 receptor and MHC class II molecule expression within the PNS. This is the first study showing that mucosal tolerance is applicable to EAN and, as an extension, could be considered in GBS.

Administration, Intranasal↗

Linomide (roquinimex) affects the balance between pro- and anti-inflammatory cytokines in vitro in multiple sclerosis.

OBJECTIVES: Multiple sclerosis (MS) is characterized by high levels of circulating mononuclear cells (MNC) that respond to myelin proteins like myelin basic protein (MBP) in vitro by expressing mRNA of both pro-inflammatory cytokines, e.g. interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and lymphotoxin (LT) that may make MS worse, and anti-inflammatory cytokines like IL-4, IL-10 and transforming growth factor-beta (TGF-beta) that may act beneficially. Substances that down-regulate cytokines such as TNF-alpha or promote IL-10 or TGF-beta can be anticipated to affect MS beneficially. MATERIAL AND METHODS: In situ hybridization to detect and enumerate IFN-gamma, TNF-alpha, LT, IL-4, IL-10 and TGF-beta mRNA expressing blood MNC after stimulation with myelin basic protein (MBP), control antigens and without antigen in presence and absence of Linomide (roquinimex, LS-2616) was employed. In parallel, ELISPOT assay to detect MBP- and PHA-reactive IFN-gamma secreting blood MNC+/-Linomide was used. RESULTS: Here we report that Linomide, a synthetic immunomodulator, at concentrations effective in vivo reduces the number of MBP-reactive TNF-alpha and increases MBP-reactive IL-10 and TGF-beta mRNA expressing MNC from MS patients' blood when analysed in vitro. Compared to dexamethasone, Linomide up-regulated levels of blood MNC expressing mRNA of TGF-beta after culture in presence of MBP. CONCLUSIONS: Changes of cytokine balance towards a production of anti-inflammatory cytokines could be a desirable effect to be evaluated in future drug studies of Linomide-like substances. At present, Linomide is not evaluable in MS clinical trials due to side-effects.

Adjuvants, Immunologic↗

The B-cell repertoire in myasthenia gravis includes all four acetylcholine receptor subunits.

By enumerating cells secreting IgG antibodies of particular specificities using an enzyme-linked immunospot (ELISPOT) assay, the B-cell responses to Torpedo acetylcholine receptor (AChR) and its alpha-, beta-, gamma- and delta-subunits in peripheral blood from patients with myasthenia gravis (MG), and controls with other neurological diseases (OND) as well as healthy subjects were determined. Compared to controls, the patients with MG had elevated numbers of B cells secreting antibodies against AChR and its alpha-, beta-, gamma- and delta-subunits in peripheral blood in parallel. The mean numbers of anti-AChR antibody secreting cells were about 17 per 10(5) blood MNC, and for the subunits 10 to 15 in MG patients, compared to between 0.8 and 1.9 per 10(5) blood MNC in OND patients, and 0.1 to 0.3 in healthy controls. Such B cells detected in controls probably represent naturally occurring B cells responded to AChR and its subunits. The finding that most (60%) MG patients had B cells predominantly recognizing the alpha-subunit may be an indirect argument for the existence of a main immunogenic region (MIR). In the remaining 40% of patients with MG the predominant B-cell responses were directed to beta-, gamma- or delta-subunit. The data suggest that all four AChR subunits may function as strong immunogens in MG, though the alpha-subunit may be the major immune target in a substantial proportion of MG patients.

Adult↗

Ischemic stroke is associated with a systemic increase of blood mononuclear cells expressing interleukin-8 mRNA.

BACKGROUND AND PURPOSE: Ischemic brain injury secondary to an arterial occlusion is characterized by acute local inflammation. Blood polymorphonuclear leukocytes (PMNL), primarily neutrophils, adhere to endothelial cells and rapidly invade the injured brain after the arterial occlusion. This neutrophilic invasion might correlate with the production of certain chemoattractants by blood mononuclear cells (MNC). We evaluated mRNA expression of the CXC chemokine interleukin (IL)-8, and the CC chemokines monocyte chemoattractant protein-1, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta in blood MNC from patients with ischemic stroke. METHODS: Peripheral blood was obtained at 8 AM on days 1 to 7 (mean, day 3) after onset of symptoms. In situ hybridization with radiolabeled synthetic oligonucleotide probes for the chemokines was adopted to measure chemokine mRNA expression in MNC. An enzyme-linked immunosorbent assay for IL-8 was used to measure IL-8 levels in plasma. RESULTS: Most patients with ischemic stroke had high numbers of IL-8 mRNA expressing blood MNC, regardless of the time interval between onset of clinical symptoms and examination. There was a marked difference between patients with ischemic stroke and healthy subjects (median, 6228 versus 885 positive cells per 10(5) MNC; P<.0001). IL-8 levels in plasma correlated positively to IL-8 mRNA expression in examined patients (n=7) with ischemic stroke (r=.78, P<.05). In contrast, mRNA expression for the CC chemokines showed no significant difference between patients with ischemic stroke and healthy control subjects. CONCLUSIONS: This study demonstrated a systemic increase of IL-8 mRNA expressing MNC and IL-8 levels in plasma from patients with ischemic stroke, suggesting that IL-8 could be involved in recruiting blood PMNL to the sites of cerebral ischemia.

Aged↗

The cytokine storm in multiple sclerosis.

MS is associated with a cytokine storm characterized by the parallel upregulation of proinflammatory (IFN-gamma, TNF-alpha, and beta, and IL-12) and immune response-down-regulating (TGF-beta, IL-10) cytokines. Also IL-6 and the cytolytic molecule perforin are upregulated. Even when evaluated in individual MS patients over the disease course, no Th1/Th2 dichotomy is obvious but, instead, upregulation of Th1 + Th2 + Th3 cytokines simultaneously, probably reflecting the complex pathology of MS in lesion size, time and distribution in the individual patient. Few correlations have been observed between cytokines and clinical MS variables, though upregulation of TGF-beta seems to correlate with benign course and minor disability. Both pro- and antiinflammatory cytokines are also produced by microglia and astrocytes, constituting a CNS-cytokine network that interacts with the cytokine network of the immune system. This complexity is to be kept in mind when searching for cytokine abnormalities in MS.

Cytokines↗

Optic neuritis and cytokines: no relation to MRI abnormalities and oligoclonal bands.

Acute unilateral monosymptomatic optic neuritis (ON) is a common first manifestation of MS if associated with multiple MS-like lesions on brain MRI and oligoclonal IgG bands (OB) in the CSF, whereas ON patients lacking these laboratory abnormalities are considered to have a good prognosis regarding future MS development. Several cytokines involved in immune regulation are upregulated in blood and even more noticeable in CSF in MS. To study a possible relation between cytokine profiles and presence versus absence of MS-like brain MRI lesions and CSF OB, we used in situ hybridization to examine mRNA expression of the proinflammatory interleukin-12 (IL-12), interferon-gamma, and tumor necrosis factor-alpha and the immune response downregulating IL-10, transforming growth factor-beta, and IL-4 in blood and CSF mononuclear cells (MNC) from 59 patients with untreated ON. There were no differences in numbers of MNC in blood or CSF expressing any of the cytokines under study, upon subgrouping the ON patients regarding presence (n = 31) versus absence (n = 28) of MRI lesions, presence (n = 45) versus absence (n = 14) of OB, or duration after onset of ON (<1 month, n = 30, versus >1 month, n = 29). Similarly, no differences were observed for numbers of myelin basic protein-reactive blood MNC expressing any of these cytokines after subgrouping according to these variables. Our findings suggest that the cytokine profile, as examined in this study, is less useful to determine the risk of future development of clinically definite MS in ON patients or as indicator for therapeutic interventions in ON. An upregulation of both pro- and anti-inflammatory cytokines in ON patients seems to be more related to the CNS disease per se, whether limited to the optic nerve or not, than to the inflammatory process characteristic for MS.

Adolescent↗

Optic neuritis: prognosis for multiple sclerosis from MRI, CSF, and HLA findings.

We investigated the paraclinical profile of monosymptomatic optic neuritis (ON) and its prognosis for multiple sclerosis (MS). The correct identification of patients with very early MS carrying a high risk for conversion to clinically definite MS is important when new treatments are emerging that hopefully will prevent or at least delay future MS. We conducted a prospective single observer and population-based study of 147 consecutive patients (118 women, 80%) with acute monosymptomatic ON referred from a catchment area of 1.6 million inhabitants between January 1, 1990 and December 31, 1995. Of 116 patients examined with brain MRI, 64 (55%) had three or more high signal lesions, 11 (9%) had one to two high signal lesions, and 41 (35%) had a normal brain MRI. Among 143 patients examined, oligoclonal IgG (OB) bands in CSF only were demonstrated in 103 patients (72%). Of 146 patients analyzed, 68 (47%) carried the DR15,DQ6,Dw2 haplotype. During the study period, 53 patients (36%) developed clinically definite MS. The presence of three or more MS-like MRI lesions as well as the presence of OB were strongly associated with the development of MS (p < 0.001). Also, Dw2 phenotype was related to the development of MS (p = 0.046). MRI and CSF studies in patients with ON give clinically important information regarding the risk for future MS.

Adolescent↗

Increased incidence of Guillain-Barré syndrome postpartum.

We studied the relation between pregnancy and Guillain-Barré syndrome in the Swedish female population ages 15-49 years during the period 1978-1993. Person-based information from the national Hospital In-patient Registry on patients discharged with a diagnosis of Guillain-Barré syndrome was linked to data on pregnancy and delivery from the Swedish Medical Birth Registry. We validated coded Guillain-Barré syndrome diagnoses and the time periods of clinical onset for patients hospitalized with Guillain-Barré syndrome during pregnancy or during the first 90-day postpartum period. We compared the incidence of Guillain-Barré syndrome in women in different exposure categories related to pregnancy with that in women neither pregnant nor in the 90-day postpartum period. Poisson regression analysis yielded age-adjusted rate ratios of 0.89 [95% confidence interval (CI) = 0.52-1.53] for pregnant women, 1.37 (95% CI = 0.64-2.91) for women during the first 90 days, and 2.93 (95% CI = 1.20-7.11) during the first 30 days after delivery. Our results indicate that the risk of Guillain-Barré syndrome increases after delivery, particularly during the first 2 weeks postpartum.

Adolescent↗

Altered tumor growth factor beta mRNA expression is associated with thymectomy-related clinical remission in myasthenia gravis.

Clinical remission in myasthenia gravis after thymectomy and immune suppressive treatment may be reflected by changes of immunoregulatory cytokines. Mononuclear cells from paired blood samples from fifteen patients with myasthenia gravis before and after thymectomy and immunosuppressive therapy were examined by in situ hybridization for acetylcholine receptor-induced mRNA expression of the T helper type 1 proinflammatory cytokines interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha) and TNF-beta, the T helper type 2 cytokines interleukin 4 (IL-4) and IL-10 and the immune response downregulating cytokine tumor growth factor beta (TGF-beta). A significant change was observed for TGF-beta, with increased expression after treatment and induction of clinical remission. Augmentation of TGF-beta may play a role in the induction of remission in myasthenia gravis.

Adolescent↗

A phase I/II study of sequential, dose-escalated, high dose ifosfamide plus doxorubicin with peripheral blood stem cell support for the treatment of patients with advanced soft tissue sarcomas.

BACKGROUND: This Phase I/II study investigates increasingly high doses of ifosfamide combined with full dose doxorubicin chemotherapy supported with peripheral blood stem cells (PBSC) and granulocyte-colony stimulating factor (G-CSF) in patients with metastatic soft tissue sarcoma (STS). METHODS: Patients with histologically proven metastatic or advanced adult STS without prior treatment received doxorubicin, 75 mg/m2, on Day 1 followed by 4-day continuous infusion of ifosfamide at 5 consecutive dose levels starting with 8 g/m2 and escalating to 16 g/m2 in increments of 2 g/m2. Three patients per dose level and a maximum of 5 treatment cycles per level at 3-week intervals were planned. Each cycle was followed by G-CSF and retransfusion of PBSC. PBSC separation was performed prior to chemotherapy by steady state mobilization with G-CSF. RESULTS: Eighteen patients (median age, 45 years, range, 25-57 years) were included, with 4, 3, 4, 4, and 3 patients assigned to Levels 1-5, respectively. Metastatic sites included the lungs in 12 patients (67%), lymph nodes in 8 patients (44%), and the liver in 5 patients (28%). Nine patients (50%) achieved objective responses with 4 complete responses (22%) and 5 partial responses (28%). Lung metastases and a histology of synovial sarcoma or malignant fibrous histiocytoma were favorable features for response to therapy. The median survival for all patients was 13+ months (range, 3-19+ months). Hematotoxicity was manageable and treatment could be administered at a median interval of 24 days. One case of World Health Organization Grade 3 neurotoxicity occurred. Nephrotoxicity was dose-limiting, with 1 patient in Level 4 (WHO Grade 2) and 2 patients in Level 5 (WHO Grade 3). CONCLUSIONS: Multiple cycles of dose-intensive therapy with doxorubicin and high dose ifosfamide can be administered safely with PBSC support. Nephrotoxicity is dose-limiting for ifosfamide at total doses of 16 g/m2. Multiple cycles of high dose chemotherapy at short treatment intervals using ifosfamide at a dose of 14 g/m2 should be investigated further in a neoadjuvant setting in patients with STS.

Adult↗

[Transplantation of hematopoietic stem cells. II: Indications for transplantation of hematopoietic stem cells after myeloablative therapy].

The destruction of hematopoiesis and lymphopoiesis by total body irradiation or high dose chemotherapy for the treatment of malignancy can be reversed by the transplantation of allogeneic or autologous hematopoietic stem cells. In primary disorders of bone marrow or immune system, allogeneic stem cells replace deficient cells. Acute leukemias can be cured, with in 50 to 80% disease free survival after 5 to 8 years. The allogeneic graft versus leukemia effect by immunoreactive cells reduces the relapse rate in myeloid and lymphoid malignancies. 40 to 70% of patients with chronic myeloid leukemia remain disease free after more than 5 years. Patients with malignant lymphoma have a 40 to 70% chance of cure with autologous transplantation, which is not increased by allogeneic cells, because of a higher incidence of severe complications. An increasing number of patients without option for cure is treated with the aim of prolonging remission or retarding disease progression, such as in chronic myeloid leukemia, multiple myeloma and certain solid tumors. New studies suggest in breast cancer with axillary lymph node metastases, that adjuvant high dose chemotherapy with autologous stem cell support will significantly improve disease free survival from 30 to over 60% after 3 to 5 years. In congenital metabolic and storage diseases deficient enzymes are substituted by the allogeneic cells. Clinical trials explore the use of stem cell transplantation after myeloablative therapy in autoimmune disorders as well as in gene therapy with transfected hematopoietic stem cells.

Combined Modality Therapy↗

[Transplantation of hematopoietic stem cells. I: Definitions, principle indications, complications].

The transplantation of hematopoietic and lymphopoetic stem and progenitor cells has become a standard procedure for the treatment of many malignant diseases. Autologous stem cells are derived from the patient himself, allogeneic cells from an HLA-identical or HLA-compatible family or unrelated donor. Hematopoietic stem cells can be obtained from bone marrow, blood and fetal cord blood. After 3 to 5 days treatment, the granulocyte-colony stimulating factor (G-CSF) mobilizes stem- and progenitor cells from the marrow into the blood. This method is now standard in autologous transplantation and is increasingly preferred in allogeneic transplantation. The time to hematopoietic recovery is shorter with blood stem cells than with bone marrow cells. With myeloablative high dose therapy followed by stem cell transplantation, long term disease free survival is possible in many cases and great proportions of patients can be cured (see part II). Improvements of supportive care have reduced toxicity of treatment substantially, however severe complications still occur at oropharynx, gastrointestinal tract, liver, lung, skin, kidney, urinary tract and nervous system. After allogeneic transplantation immunocompetent donor cells can react with the recipients tissue. In HLA-identical donor and recipients differences in the minor histocompatibility antigens account for this graft-versus-host-reaction (GvH), which is mainly mediated by transplanted T-cells. The GvH-reaction can affect skin, liver, gut and other organs and cause clinically relevant GvH-disease (GvHD). The GvHD is more severe in HLA-mismatched or unrelated transplantations. Immunodeficiency and organ dysfunction due to GvHD may predispose infections and impair the outcome of transplantation. Unrelated cord blood stem cells may have a minor risk of inducing acute GvHD, as stem and T-cells are immature. After allogeneic stem cell transplantation, the relapse rate of leukemia or lymphoma is significantly reduced by immunoreactive cells:graft-versus-tumor (GvT) or graft-versus-leukemia effect (GvL).

Graft vs Host Disease↗

[Therapy of infections in patients with acute leukemia].

BACKGROUND: Infections are the major cause for treatment failure in acute leukemias. They mostly present as fever of unknown origin (FUO), a smaller but prognostically unfavorable group are pneumonias. The effective management of infectious complications requires a symptom and response adapted interventional strategy. THERAPEUTICAL APPROACH: In case of FUO standard therapy consists of the two drug combination of aminoglycoside plus acylaminopenicillin or third generation cephalosporine. In case of non-response carbapenems and a glycopeptide should be applied and a systemic antifungal treatment must be initiated. In pneumonia amphotericin B should be added to antibiotics already initially. Potent single agents with a broad spectrum of activity as well as new antifungal drugs provide attractive perspectives for future evaluations. CONCLUSIONS: By a consequent step-wise oscalating interventional treatment strategy infections in patients with acute leukemias can be successfully treated.

Acute Disease↗

Transforming growth factor-beta1 induces apoptosis of rat microglia without relation to bcl-2 oncoprotein expression.

Transforming growth factor-beta (TGF-beta) plays a role as an immunosuppressive cytokine within the central nervous system (CNS). The CNS cells targeted by action of TGF-beta1 have not been defined. In this study, we tested the effect of TGF-beta1 on microglia, astrocytes and oligodendrocytes from newborn rats. TGF-beta1 selectively induced apoptosis of microglia, and not of astrocytes or oligodendrocytes. To study the apoptotic mechanism, bcl-2 oncoprotein expression in microglia, astrocytes and oligodendrocytes was measured. Bcl-2 was mainly expressed in microglia, indicating that microglial bcl-2 does not prevent TGF-beta1-mediated microglial apoptosis. The relative protein expression of bcl-2 in microglia was not related to frequency of microglial apoptosis. Thus, TGF-beta1-induced microglial apoptosis was regulated by a bcl-2-independent mechanism. Expression of cytokine (IL-1beta, IL-6, IL-12, IFN-gamma and TNF-alpha) mRNA on microglia was not influenced by treatment with TGF-beta1.

Animals↗

Three T-cell epitopes within the C-terminal 265 amino acids of the matrix protein pp65 of human cytomegalovirus recognized by human lymphocytes.

Although a T-cell response in human cytomegalovirus (HCMV)-immune individuals exists against the most abundantly expressed protein pp65 of the virus matrix, less is known about the determinants that evoke this response. The aim of the study was to identify regions within HCMV pp65 (ppUL83) that contain sequences for the cellular immune response by the use of three recombinant overlapping beta-galactosidase pp65 fusion proteins (C74, C35, and C47), covering the C-terminal 265 amino acids of the entire pp65 sequence. Two T-cell epitope determinants were recognized by human lymphocytes of healthy, HCMV-seropositive, human leukocyte antigen (HLA)-typed individuals. One T-cell determinant (amino acids [aa] 303-388) was localized in the mid-region of the entire pp65 sequence and a second T-cell determinant (aa 477-561) within the C-terminal region. By fine mapping with synthetic hexadecamer peptides three T-cell epitopes were identified within these two regions: P10-I (aa 361-376) in the mid-region, P3-II (aa 485-499), and P6-II (aa 509-524) in the C-terminal region. Inhibition studies with monoclonal antibodies to HLA class I or class II revealed a class II restricted response to peptides P10-I or P6-II, respectively. P10-I responders shared the HLA-DR11 allele and P6-II responders the -DR3 allele. Therefore, these T-cell epitopes of HCMV pp65 might be presented in association with particular HLA class II alleles.

Alleles↗

Cytokines and the pathogenesis of myasthenia gravis.

Myasthenia gravis (MG) and its animal model experimental autoimmune myasthenia gravis (EAMG) are caused by autoantibodies against nicotinic acetylcholine receptor (AChR) in skeletal muscle. The production of anti-AChR antibodies is mediated by cytokines produced by CD4+ and CD8+ T helper (Th) cells. Emerging investigations of the roles of cytokines in MG and EAMG have revealed that the Th2 cell related cytokine interleukin 4 (IL-4), an efficient growth promoter for B-cell proliferation and differentiation, is important for anti-AChR antibody production. IL-6 and IL-10 have similar effects. The Th1 cytokine IFN-gamma is important in inducing B-cell maturation and in helping anti-AChR antibody production and, thereby, for induction of clinical signs and symptoms. Results from studies of time kinetics of cytokines imply that IFN-gamma is more agile at the onset of EAMG, probably being one of the initiating factors in the induction of the disease, and IL-4 may be mainly responsible for disease progression and persistance. Even though other Th1 cytokines like IL-2, tumor necrosis factor alpha (TNF-alpha), and TNF-beta as well as the cytolytic compound perforin do not directly play a role in T-cell-mediated help for anti-AChR antibody production, they are actually involved in the development of both EAMG and MG, probably by acting in concert with other cytokines within the cytokine network. In contrast, transforming growth factor beta (TGF-beta) exerts immunosuppressive effects which include the down-regulation of both Th1 and Th2 cytokines in MG as well as EAMG. Suppressive effects are also exerted by interferon alpha (IFN-alpha). Based on elucidation of the role of cytokines in EAMG and MG, treatments that up-modulate TGF-beta or IFN-alpha and/or suppress cytokines that help B-cell proliferation could be useful to improve the clinical outcome.

Animals↗