Biomedical subjects

H Link

Publications and source records attributed to H Link.

At least 289 records · Page 16Linked to original sources

PubMed1994

Optic neuritis: findings on MRI, CSF examination and HLA class II typing in 60 patients and results of a short-term follow-up.

Optic neuritis (ON) is a common first manifestation of multiple sclerosis (MS), and examination of patients with ON provides opportunities to study the early clinical stages of MS. This prospective study compares results of brain magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) examinations and HLA-Dw2 phenotyping in 60 consecutive patients with ON. At a median of 17 days after the onset of ON, 69% had oligoclonal IgG bands, and at a median on 79 days after onset, 53% had multiple (> or = 3) white matter lesions on MRI. Subgroup analyses revealed that MRI abnormalities and oligoclonal IgG bands were equally common in patients examined early or late after the onset of ON. Strong correlations were found between the presence of MRI abnormalities and oligoclonal IgG bands. The HLA-Dw2 phenotype was significantly increased in ON patients compared with controls, but also significantly different from a group of MS patients from the same geographical area. A significant relation was found between Dw2 phenotype and oligoclonal IgG bands. During a mean follow-up time of about 2 years, the diagnosis in 17 of the patients changed to clinically definite MS. Initially, 16 of them had oligoclonal IgG bands and 12 had three or more MRI lesions. Both MRI and CSF studies are important diagnostic tools in the workup of ON patients.

Adolescent↗

PubMed1994

The B cell repertoire in experimental allergic neuritis involves multiple myelin proteins and GM1.

Experimental allergic neuritis (EAN) is a T cell mediated disease associated with inflammation and demyelination of peripheral nerves. EAN is an experimental model of Guillain-Barré syndrome. The peripheral nerve myelin components P2 and P0 represent major neuritogens, but the diversity and quantity of B cell responses in EAN are unknown. Lewis rats were immunized with bovine peripheral nerve myelin (BPM), and levels of B cells secreting IgM and IgG antibodies to BPM, P2 and P0, the glycolipid GM1 and five peptides of myelin-associated glycoprotein (MAG) were determined. Already on day 7 post-immunization (p.i.), i.e. before the onset of clinical EAN, lymph nodes contained elevated levels of cells secreting IgM antibodies of all specificities examined. Maximum numbers of IgG antibodies secreting cells were generally reached at the height of clinical disease. The numbers of cells secreting IgG antibodies to BPM, P2, P0, GM1 and MAG peptides were also elevated before disease onset, but they were mostly higher than those of IgM antibodies and they reached their maximum only after recovery. The results imply that EAN is associated with strong B cell responses to all myelin antigens under study without restriction to any immunodominant myelin component or MAG peptides.

Amino Acid Sequence↗

PubMed1994

gamma delta+ T cells are increased in patients with Parkinson's disease.

The etiology of Parkinson's disease is mainly unknown. Immune abnormalities have been reported, including the occurrence of autoantibodies against neuronal structures and abnormal T cell functions. gamma delta+ T cells represent a recently recognized T cell subpopulation which is considered to play a role in immune responses in infections and autoimmunity. We examined by three-colour flow cytometry the proportions of gamma delta+ T cells in blood and cerebrospinal fluid (CSF) from patients with Parkinson's disease. Increased proportions of gamma delta+ T cells were found in CSF in Parkinson's disease compared to other neurological diseases (OND) and tension headache. In peripheral blood, patients with Parkinson's disease had higher numbers of gamma delta+ T cells compared to OND patients. No differences between gamma delta+ T cells in CSF compared to blood were demonstrable in the individual patient groups. CD25 was not expressed on gamma delta+ T cells in blood of the majority of cases, but 50% of patients with Parkinson's disease and 30% with OND and tension headache had CD25+ gamma delta+ T cells in CSF arguing for a preferential activation of gamma delta+ T cells in the CSF compartment. Whether the elevated gamma delta+ T cell population in Parkinson's disease reflects previously unrecognized inflammation or may occur also in non-inflammatory disorders remains to be elucidated.

Aged↗

PubMed1994

beta-Bungarotoxin binding protein is immunogenic but lacks myasthenogenicity in rats.

Myasthenia gravis is an autoimmune disease resulting from autoaggressive immunity to the nicotinic acetylcholine receptor (AChR) of the neuromuscular junction. Immunization with AChR leads to experimental autoimmune myasthenia gravis (EAMG). AChR binds to alpha-bungarotoxin, and this property is utilized to purify AChR. The utilization of beta-bungarotoxin (beta-BGT) allows the purification of a different protein of striated muscle. To examine the myasthenogenic activity of the beta-BGT binding protein, we immunized Lewis rats with the beta-BGT binding protein or AChR from Torpedo. While AChR-immunized rats developed typical signs of EAMG, beta-BGT binding protein immunized rats showed no definite clinical signs of muscular weakness during observation periods up to 14 weeks after immunization. High levels of anti-AChR IgG antibodies and low levels of antibodies against beta-BGT binding protein were present in the AChR-immunized rats, while high levels of IgG antibodies to the beta-BGT binding protein and low anti-AChR IgG antibody levels were found in the rats immunized with the beta-BGT binding protein. No relationship was observed between antibody levels and severity of EAMG. The anti-AChR and anti-beta-BGT binding protein IgG antibodies showed only low degrees of cross-reactivity. We conclude that the beta-BGT binding protein is immunogenic also in EAMG, while it is still an open question whether it also has myasthenogenic properties.

Animals↗

PubMed1994

Augmented interferon-gamma, interleukin-4 and transforming growth factor-beta mRNA expression in blood mononuclear cells in myasthenia gravis.

The abnormal T lymphocyte-dependent production of antibodies to the nicotinic acetylcholine receptor (AChR) in myasthenia gravis (MG) suggests a role for immunoregulatory cytokines. We examined the T helper type 1 (Th1) cell-associated interferon-gamma (IFN-gamma) that promotes cell-mediated immunity, the Th2 cell-related interleukin-4 (IL-4) that augments B cell immunity, and transforming growth factor-beta (TGF-beta) that downregulates immune responses but enhances isotype switching. Blood mononuclear cells (MNC) expressing cytokine mRNA were enumerated after in situ hybridization with labelled complementary DNA oligonucleotide probes for IFN-gamma, IL-4 and TGF-beta. MG patients had elevated numbers of cells expressing IFN-gamma and IL-4 compared to patients with non-inflammatory neurological diseases and healthy controls, implying that both Th1- and Th2-like cells are involved in MG. TGF-beta-positive cells were also elevated in MG. The levels of cytokine-positive MNC were similar in MG and in control patients with other inflammatory neurological diseases. There were no associations between numbers of cytokine-positive blood MNC and clinical variables of MG, but individual patients need to be studied over the course of MG to clarify a relation between the cytokines under study and clinical or laboratory variables of MG.

Adolescent↗

PubMed1994

Optic neuritis is associated with myelin basic protein and proteolipid protein reactive cells producing interferon-gamma, interleukin-4 and transforming growth factor-beta.

Studies on patients with monosymptomatic optic neuritis (ON) should give opportunities to identify features typical for early multiple sclerosis (MS). There are increased T and B cell responses to the myelin components myelin basic protein (MBP) and proteolipid protein (PLP) in both ON and MS, but there is little information on the types of cytokines produced by such cells. We describe the use of in situ hybridization with complementary DNA oligonucleotide probes to detect and enumerate mononuclear cells expressing mRNA for the cytokines interferon-gamma (IFN-gamma) which augments cell-mediated immunity; interleukin-4 (IL-4) which promotes the B cell response; and transforming growth factor beta (TGF-beta) that in many cases downregulates immune responses. Expression of these cytokines was studied in mononuclear cells from peripheral blood and cerebrospinal fluid (CSF) from patients with ON and MS after in vitro exposure to MBP and PLP, and in absence of antigen. There were elevated levels of cells that in response to MBP and PLP expressed IFN-gamma, IL-4 and TGF-beta mRNA in blood and further enriched in CSF in both ON and MS, compared to patients with other neurological diseases. The results suggest that IFN-gamma, IL-4 as well as TGF-beta are involved in both ON and MS, and that the cytokine profile in early MS as reflected by ON is not different from that in clinically definite MS.

Adult↗

PubMed1994

V delta 1 gene usage, interleukin-2 receptors and adhesion molecules on gamma delta+ T cells in inflammatory diseases of the nervous system.

This study investigates the expression of T cell receptor V delta 1 chain, interleukin-2 receptor alpha-chain (CD25) and adhesion molecules ICAM-1 (CD54), LFA-1 (CD11a/18) and CD44 on gamma delta+ T cells by three-color flow cytometry on cerebrospinal fluid (CSF) and blood cells in patients with multiple sclerosis (MS), other inflammatory neurological diseases (OIND) and other neurological diseases (OND). Of gamma delta + T cells in CSF and blood, 20-40% belonged to the 'epithelial' V delta 1 subtype. MS patients had the lowest levels in both CSF and blood, but the differences between the patient groups were not significant. The activation markers CD25 and CD54 were expressed by only a small proportion of gamma delta+ T cells and in a minority of patients. Although the occurrence of CD25+ and CD54+ gamma delta+ T cells was somewhat higher in CSF than in blood and in inflammatory diseases than in controls, the small numbers of CD25+ and CD54+ gamma delta+ T cells preclude establishing differences amongst compartments and patient groups. The adhesion molecules CD11a/18 and CD44 were constitutively expressed on all T cells. Therefore, we compared the relative antigen density per cell as measured by the relative fluorescence index (RFI) between CSF and blood, between the patient groups and between gamma delta+ and total T cells. The only difference encountered was a slightly higher expression of adhesion molecules on gamma delta+ compared to total T cells, with preference to MS patients. In conclusion, the V delta 1+ subtype of gamma delta+ T cells does not dominate in the CSF compartment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

HIV antigen-reactive T cells detected by antigen-induced interferon gamma secretion.

The T cell repertoire to human immunodeficiency virus (HIV) was studied in HIV-infected patients of different clinical stages by the detection and enumeration of cells that secreted interferon gamma (IFN-gamma) in short-term cultures of blood mononuclear cells after stimulation in vitro with the HIV recombinant antigens pB1, p121, p24-15, gp160bac, and the HIV V3 loop peptide. T cell reactivities to cytomegalovirus (CMV) and Mycobacterium tuberculosis-purified protein derivative (PPD) were examined in parallel. Among 29 patients with HIV infection, 48% had blood cells recognizing one or more of the five HIV antigens. The mean numbers of HIV antigen-reactive T cells varied between 1/approximately 6000 blood cells for pB1 and 1/approximately 20,000 cells for p24-15. None of the five HIV antigens studied was identified as an immunodominant T cell epitope in HIV infection. T cells from 20% of the patients responded to all five HIV antigens in parallel, but the antigen preferentially recognized varied from patient to patient. Those with more advanced disease had a tendency to lower numbers of HIV antigen-reactive T cells. Most HIV-infected patients had both CMV- and PPD-reactive T cells, but numbers were significantly lower in more advanced disease. It should be possible to adopt the present method to evaluate fine specificities of the T cell repertoire to other antigens and to study the involvement of other cytokines besides IFN-gamma, for example, the Th2 cell-related cytokine interleukin 4.

Adult↗

PubMed1994

Altered surface marker expression and function of G-CSF-induced neutrophils from test subjects and patients under chemotherapy.

We have previously reported an altered surface marker expression and chemotaxis of G-CSF-induced neutrophils from patients with severe congenital neutropenia. However, effects of G-CSF and influence of the underlying disease on neutrophils could not be discerned. In this study we have evaluated the effects of G-CSF on neutrophil phenotype and function in patients under chemotherapy and in healthy test subjects. We found a significantly enhanced expression of Fc gamma RI, CD14 and CD54 and a decrease in the level of Fc gamma RIII during G-CSF treatment. In addition, motility of G-CSF-induced neutrophils was significantly decreased. The effects were seen in patients under cytotoxic chemotherapy and in healthy test subjects. Surface marker alterations and neutrophil motility were affected by G-CSF administration in a dose-dependent manner. Kinetic studies on neutrophils from healthy test subjects demonstrated that all effects could be seen after a single administration of 300 micrograms G-CSF and began to appear within 4 h. Release of partially immature neutrophils from the bone marrow and indirect activation of these cells by G-CSF are discussed as possible reasons for the findings presented. They demonstrate that G-CSF has profound effects on neutrophil phenotype and function in vivo which might have clinical implications.

Antigens, Surface↗

PubMed1994

Cellular mRNA expression of interferon-gamma, IL-4 and transforming growth factor-beta (TGF-beta) by rat mononuclear cells stimulated with peripheral nerve myelin antigens in experimental allergic neuritis.

Experimental allergic neuritis (EAN) serves as a useful model for inflammation in the peripheral nervous system. To study the potential role of important immunoregulatory and effector cytokines in EAN, we examined the expression of mRNA for interferon-gamma (IFN-gamma), IL-4 and TGF-beta by in situ hybridization in lymph node and splenic cells cultured with bovine peripheral nerve myelin (BPM), P2 and P0 during the course of EAN in Lewis rats. Levels of IFN-gamma mRNA-expressing mononuclear cells (MNC) from lymph nodes and spleens roughly correlated with clinical status, consistent with a disease-promoting role for IFN-gamma. BPM, P0 and P2-reactive IFN-gamma mRNA-expressing T cells appeared in lymph nodes and spleen before onset of the disease, whereas a significant TGF-beta response to BPM, P2 and P0 was observed at lower levels than the IFN-gamma response and at onset of recovery, consistent with a disease down-regulating role of TGF-beta. IL-4 mRNA-expressing cells were found at levels similar to TGF-beta mRNA-expressing cells, and with the latest peak of the three cytokines examined. This result suggests that IL-4 may also suppress IFN-gamma expression at late recovery phase of EAN.

Animals↗

PubMed1994

Increased levels of interferon-gamma (IFN-gamma), IL-4 and transforming growth factor-beta (TGF-beta) mRNA expressing blood mononuclear cells in human HIV infection.

Evidence has been presented for the involvement of IFN-gamma, IL-4 and TGF-beta in AIDS. Measured plasma levels may, however, poorly reflect in vivo production, since cytokines act auto- and paracrinally and have very short half life in plasma. In situ hybridization with complementary DNA oligonucleotide probes was used to enumerate blood mononuclear cells expressing cytokine messenger RNA (mRNA). HIV-infected patients had elevated blood levels of cells expressing each of the cytokines, with predominance for cells expressing TGF-beta mRNA. All AIDS patients included had elevated numbers of IL-4 mRNA-expressing cells, and levels of cells expressing this cytokine correlated inversely with counts of CD4+ cells in blood, reflecting the involvement of Th2-like cells in later stages of HIV infection. The described approach should be useful in further studies of cytokines in HIV infection and other diseases.

Adult↗

PubMed1994

Peptide specificity of anti-myelin basic protein antibodies in patients with acute optic neuritis and the HLA system.

Multiple sclerosis (MS) may be an autoimmune disease, partially caused by autoreactivity to myelin basic protein (MBP) and other central nervous system proteins. Acute optic neuritis (ON) is a frequent first symptom of MS. The role of the HLA system in anti-MBP antibody production in ON was investigated employing a restriction fragment length polymorphism system for genomic HLA-DQ and -DR typing and an immunospot assay for the detection of individual cells secreting antibodies to three different synthetic MBP peptides. Thirty-two out of 40 patients (80%) with ON had cells in cerebrospinal fluid secreting anti-MBP peptide antibodies while this occurred in 10/19 patients with other neurological diseases (53%; mainly in patients with inflammatory diseases in the central nervous system). This difference was statistically significant (P = 0.03). None of the three examined peptides were immunodominant in any patient group. It was found, however, that presence of HLA DR15, which is associated with MS, may be associated further with predominant production of antibodies to the MBP amino acids 63-88 in patients with ON (P = 0.002, corrected for multiple comparisons).

Adult↗

PubMed1994

Multiple sclerosis: occurrence of myelin basic protein peptide-reactive T cells in healthy family members.

Genetic factors influence the susceptibility to multiple sclerosis (MS). This disease is accompanied by augmented T cell responses to CNS myelin components such as myelin basic protein. To evaluate the familial occurrence of such T cell autoreactivity, we have studied 12 MS families including 37 healthy first-degree relatives for occurrence of numbers of interferon-gamma (IFN-gamma) secreting cells among blood mononuclear after culture in presence of myelin basic protein (MBP), eight synthetic MBP peptides and the control antigen acetylcholine receptor (AChR). There were no differences between MS patients and healthy family members regarding frequencies of autoreactive T cells recognizing MBP, the eight different MBP peptides or AChR. None of the MBP peptides predominated as T cell antigen among the MS patients or their unaffected family members. In some families the highest number of MBP peptide reactive T cells were found among unaffected family members. No correlation was observed between numbers of MBP or MBP peptide reactive T cells in various subjects and their HLA-DR-DQ phenotypes. In conclusion, this study has revealed the presence of MBP and MBP peptide reactive T cells of similar frequencies in MS patients and their healthy family members.

Adult↗

PubMed1994

Optic neuritis and multiple sclerosis: the T cell repertoires to myelin proteins and MBP peptides change with time.

Autoreactive T cells recognizing myelin basic protein (MBP), proteolipid protein (PLP) and MBP peptides have been described in multiple sclerosis (MS) and optic neuritis (ON), but their role in disease pathogenesis, if any, is unknown. A consistency of the T cell repertoire over the course of MS and ON should facilitate the development of specific immunotherapies. We have examined the T cell responses to autoantigens in two consecutive blood specimens taken from patients with ON and MS, and in two consecutive CSF specimens obtained from ON patients. As read-out numbers of T cells responding to antigen stimulation by the secretion of interferon-gamma were estimated. Pronounced differences in occurrence and numbers of T cells recognizing MBP, MBP peptides with the amino acid sequences 63-88, 110-128 and 148-165, and PLP were noticed in individual ON and MS patients over the course of disease. The MBP peptide among those three included, that was predominantly recognized by T cells in the individual patient, also varied over the course. The quantitative and qualitative changes of the myelin antigen-specific T cell response in MS and in ON, the latter to a certain extent reflecting the situation in early MS, do not favor the future useful development of specific immunotherapies in these diseases.

Adult↗

PubMed1994

Th1-like cell responses to peripheral nerve myelin components over the course of experimental allergic neuritis in Lewis rats.

Experimental allergic neuritis (EAN) is a T cell-mediated animal model of Guillain-Barré syndrome characterized by inflammation and demyelination of peripheral nerves. EAN can be induced by immunization of rats with bovine peripheral nerve myelin (BPM) or the myelin proteins P2 or P0, but the extent of T cell responses over the course of EAN is incompletely defined. We studied the T cell responses to these proteins and the glycolipid GM1 by enumerating T helper type 1 (Th1)-like cells secreting interferon-gamma (IFN-gamma) after short-term culture of mononuclear cells (MNC) in presence of antigen. Already 7 days post immunization (p.i.) with BPM and before onset of clinical EAN, lymph nodes contained elevated levels of P2 responsive T cells. At the height of EAN on day 14 p.i. and during recovery, T cell levels responding to BPM, P0 and GM1 were also elevated. The same temporal profiles and specificities were registered for antigen reactive spleen MNC. The results implicate that Th1-like cells with multiple specificities including the glycolipid GM1 occur at increased levels in lymphoid organs in EAN rats, and that IFN-gamma may be an important effector molecule in the induction of nerve damage.

Animals↗

PubMed1994

Parkinson's disease and immunological abnormalities: increase of HLA-DR expression on monocytes in cerebrospinal fluid and of CD45RO+ T cells in peripheral blood.

The etiology of Parkinson's disease is mainly unknown. Immune abnormalities have been described, but the cause of such abnormalities has not been resolved. We examined by two-colour flow cytometry HLA-DR antigen expression on monocytes from cerebrospinal fluid (CSF) and blood and, moreover, lymphocyte subpopulations (CD4+ CD45RO+, CD4+ CD45RA+, CD8+ CD11b+high) in peripheral blood from patients with Parkinson's disease compared with age-matched patients with other neurological diseases (OND) and tension headache. We found higher HLA-DR expression on CSF monocytes compared with blood monocytes. This difference was restricted to Parkinson's disease patients. T helper cell analysis revealed a decreased percentage of CD45RA+ "naive" and an increased percentage of CD45RO+ "memory" T cell subset from CD4+ T cells in peripheral blood of patients with Parkinson's disease compared with patients with tension headache. The proportions of CD8+ CD11b+high "suppressor" T cells remained unchanged, among the three patient groups compared. A selective loss of CD4+ CD45RA+ cells, previously observed in diseases like multiple sclerosis and Down's syndrome as compared with healthy controls suggests a common immunological abnormality in neurological disorders.

Adult↗

PubMed1994

Evaluation of the Urotest AB antibacterial substance detection test.

The Urotest AB was used to detect antimicrobial substances in urine samples. Of 1022 urine specimens evaluated, Urotest AB detected inhibitors in 38.9%. Of 159 urine specimens from patients thought to be taking an antibiotic, inhibitors were detected in 80.5%. This test may help to explain culture negative urine samples from symptomatic patients, and could help elucidate treatment failures and the epidemiology of antibiotic resistance.

Anti-Bacterial Agents↗

PubMed1994

Autoimmune T cell repertoire in optic neuritis and multiple sclerosis: T cells recognising multiple myelin proteins are accumulated in cerebrospinal fluid.

Monosymptomatic unilateral optic neuritis is a common first manifestation of multiple sclerosis. Abnormal T cell responses to myelin components including myelin basic protein (MBP), proteolipid protein (PLP), and myelin-associated glycoprotein (MAG) have been implicated in the pathogenesis of multiple sclerosis. Antigen-reactive T helper type 1 (Th1)-like cells that responded by interferon gamma (IFN-gamma) secretion on antigen stimulation in vitro were counted. Untreated patients with optic neuritis and multiple sclerosis had similarly raised levels of T cells recognising MBP, PLP, and MAG in peripheral blood. Such T cells were strongly enriched in CSF. None of these myelin antigens functioned as immunodominant T cell antigen characteristic for optic neuritis or multiple sclerosis. The autoimmune T cell repertoire was not more restricted in optic neuritis (as an example of early multiple sclerosis). The autoreactive T cell repertoires differed in blood compared with CSF in individual patients with optic neuritis and multiple sclerosis. No relations were found between specificity or quantity of autoreactive T cells in blood or CSF, and clinical variables of optic neuritis or multiple sclerosis, or occurrence of oligoclonal IgG bands in CSF. The role of raised MBP, PLP, and MAG reactive Th1-like cells found in optic neuritis and multiple sclerosis remains unexplained.

Adolescent↗