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Biomedical subjects

M P Lunn

Publications and source records attributed to M P Lunn.

6 recordsLinked to original sources

Immunotherapy for IgM anti-Myelin-Associated Glycoprotein paraprotein-associated peripheral neuropathies.

BACKGROUND: Serum monoclonal anti-Myelin Associated Glycoprotein antibodies may be pathogenic in some patients with IgM paraprotein and demyelinating neuropathy. Immunotherapies aimed at reducing the level of these antibodies might be expected to be of benefit in the treatment of the neuropathy. Many potential therapies have been described in small trials, uncontrolled studies and case reports. OBJECTIVES: To examine the efficacy of any form of immunotherapy in reducing disability and impairment resulting from IgM anti-Myelin Associated Glycoprotein paraprotein-associated demyelinating peripheral neuropathy. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group register (August 2002) and MEDLINE (January 1966 - August 2002) and EMBASE (January 1980 - August 2002) for controlled trials, checked the bibliographies to identify other controlled trials and contacted authors and other experts in the field. SELECTION CRITERIA: Types of studies: randomised or quasi-randomised controlled trials. TYPES OF PARTICIPANTS: patients of any age with anti-Myelin Associated Glycoprotein antibody associated demyelinating peripheral neuropathy with monoclonal gammopathy of undetermined significance of any severity. Types of interventions: any type of immunotherapy. Types of outcome measures: Primary: improvement in the Neuropathy Disability Score or Modified Rankin Scale six months after randomisation Secondary: Neuropathy Disability Score and/or the Modified Rankin Score 12 months after randomisation. Ten metre walk time, subjective clinical scores and electrophysiological parameters at six and 12 months after randomisation. IgM paraprotein levels and anti-Myelin Associated Glycoprotein antibody titres six months after randomisation. Adverse effects of treatments. DATA COLLECTION AND ANALYSIS: We identified six randomised controlled trials of which five were included after discussion between the authors. One author extracted the data and the other checked them. No missing data could be obtained from authors. MAIN RESULTS: The five eligible trials used four of the many available immunotherapy treatments. Only two had comparable interventions and outcomes but these were only short-term studies. There were no significant benefits of the treatments used in the predefined outcomes. However intravenous immunoglobulin showed benefits in terms of improved Modified Rankin Scale at two weeks and 10 metre walk time at four weeks. Serious adverse effects of intravenous immunoglobulin are known to occur from observational studies but none were encountered in these trials. REVIEWER'S CONCLUSIONS: There is inadequate reliable evidence from trials of immunotherapies in anti-Myelin Associated Glycoprotein paraproteinaemic neuropathy to recommend any particular immunotherapy treatment. Intravenous immunoglobulin is relatively safe and may produce some short-term benefit. Large well designed randomised trials are required to assess the efficacy of promising new therapies.

Demyelinating Diseases↗

High-affinity anti-ganglioside IgG antibodies raised in complex ganglioside knockout mice: reexamination of GD1a immunolocalization.

Gangliosides, sialic acid-bearing glycosphingolipids, are highly enriched in the vertebrate nervous system. Anti-ganglioside antibodies are associated with various human neuropathies, although the pathogenicity of these antibodies remains unproven. Testing the pathogenic role of anti-ganglioside antibodies will be facilitated by developing high-affinity IgG-class complement-fixing monoclonal anti-bodies against major brain gangliosides, a goal that has been difficult to achieve. In this study, mice lacking complex gangliosides were used as immune-naive hosts to raise anti-ganglioside antibodies. Wild-type mice and knockout mice with a disrupted gene for GM2/GD2 synthase (UDP-N-acetyl-D-galactosamine : GM3/GD3 N-acetyl-D-glactosaminyltransferase) were immunized with GD1a conjugated to keyhole limpet hemocyanin. The knockout mice produced a vigorous anti-GD1a IgG response, whereas wildtype littermates failed to do so. Fusion of spleen cells from an immunized knockout mouse with myeloma cells yielded numerous IgG anti-GD1a antibody-producing colonies. Ganglioside binding studies revealed two specificity classes; one colony representing each class was cloned and characterized. High-affinity monoclonal antibody was produced by each hybridoma : an IgG1 that bound nearly exclusively to GD1a and an IgG2b that bound GD1a, GT1b, and GT1aalpha. Both antibodies readily readily detected gangliosides via ELISA, TLC immune overlay, immunohistochemistry, and immunocytochemistry. In contrast to prior reports using anti-GD1a and anti-GT1b IgM class monoclonal antibodies, the new antibodies bound avidly to granule neurons in brain tissue sections and cell cultures. Mice lacking complex gangliosides are improved hosts for raising high-affinity, high-titer anti-ganglioside IgG antibodies for probing for the distribution and physiology of gangliosides and the pathophysiology of anti-ganglioside antibodies.

Animals↗

Cytomegalovirus is not associated with IgM anti-myelin-associated glycoprotein/sulphate-3-glucuronyl paragloboside antibody-associated neuropathy.

Monoclonal antibodies reactive with the HNK-1 epitope of myelin-associated glycoprotein (MAG) and the sulphate-3-glucuronyl paragloboside (SGPG)-like glycolipids are often found in the serum of patients with IgM paraprotein-associated demyelinating neuropathy. The presence of such antibodies in patients with chronic polyneuropathy has recently been associated with evidence of active cytomegalovirus (CMV) infection by the polymerase chain reaction. We wished to test these findings and examined sera from patients with MAG-reactive or MAG-nonreactive paraproteinemic neuropathy and patients with paraproteinemia only for the presence of CMV DNA and anti-CMV antibodies. CMV DNA was not detected in sera from any patient group. Furthermore, anti-CMV antibody prevalence was normal and similar in all 3 groups. We therefore report no evidence of an association between CMV infection and anti-MAG/SGPG antibodies associated with paraproteinemic peripheral neuropathy.

Aged↗

Successful treatment of IgM paraproteinaemic neuropathy with fludarabine.

OBJECTIVES: To evaluate the response of four patients with IgM paraproteinaemic neuropathy to a novel therapy-pulsed intravenous fludarabine. BACKGROUND: The peripheral neuropathy associated with IgM paraproteinaemia usually runs a chronic, slowly progressive course which may eventually cause severe disability. Treatment with conventional immunosuppressive regimens has been unsatisfactory. Fludarabine is a novel purine analogue which has recently been shown to be effective in low grade lymphoid malignancies. METHODS: Four patients were treated with IgM paraproteinaemic neuropathy with intravenous pulses of fludarabine. Two of the four patients had antibodies to MAG and characteristic widely spaced myelin on nerve biopsy and a third had characteristic widely spaced myelin only. The fourth had an endoneurial lymphocytic infiltrate on nerve biopsy and a diagnosis of Waldenström's macroglobulinaemia. RESULTS: In all cases subjective and objective clinical improvement occurred associated with a significant fall in the IgM paraprotein concentration in three cases. Neurophysiological parameters improved in the three patients examined. The treatment was well tolerated. All patients developed mild, reversible lymphopenia and 50% mild generalised myelosuppression, but there were no febrile episodes. CONCLUSION: Fludarabine should be considered as a possible treatment for patients with IgM MGUS paraproteinaemic neuropathy.

Aged↗

Chronic inflammatory demyelinating polyradiculoneuropathy: a prevalence study in south east England.

Although there are now widely accepted diagnostic criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) there are few epidemiological data. A prevalence study was performed in the four Thames health regions, population 14 049 850. The prevalence date was 1 January 1995. Data were from a national consultant neurologist surveillance programme and the personal case series of two investigators. A diagnosis of CIDP was made according to definite, probable, possible, or suggestive diagnostic criteria. A wide difference in prevalence rates between the four health regions was noted, probably due to reporting bias. In the South East Thames Region, from which the data were most comprehensive the prevalence for definite and probable cases was 1.00/100 000; the highest total prevalence (if possible and suggestive cases were included) would have been 1.24/100 000. On the prevalence date 13% of patients required aid to walk and 54% were still receiving treatment.

Adolescent↗