Multiple sclerosis in Hispanics: a study of clinical disease expression.

BACKGROUND: Hispanics living with multiple sclerosis (MS) in the United States are not well defined. OBJECTIVE: To describe the clinical characteristics of MS among Hispanic Whites (HW) in Southern California with those of non-Hispanic Whites (NHW). METHODS: We performed a medical chart review to identify all cases of HW with MS (n = 125) who were treated at our institution during a 1-year period. We also identified cases of NHW with MS (100 NHW) treated at those clinics. All HW patients were interviewed to ascertain ancestry including detailed migration history. Disease progression was assessed by ambulatory disability and defined as Expanded Disability Status Scale (EDSS) score ≥6. RESULTS: Compared with NHW, HW were more likely to have a relapsing-remitting form of MS and a younger age of onset (28.4 ± 0.97 years) with presenting symptoms of optic neuritis and transverse myelitis. However, overall ambulatory disability did not differ between HW and NHW. Migration to the US at age >15 years was associated with increased risk of disability in HW. CONCLUSIONS: HW living in the USA may be at risk of developing MS at an earlier age compared with NHW. Migration history can play an important role in the management of HW with MS.

Defective post-thymic tolerance mechanisms during the chronic progressive stage of multiple sclerosis.

We have recently isolated a panel of T-cell clones from chronic progressive multiple sclerosis (MS) patients that are capable of functioning as antigen-presenting cells and of expressing the costimulatory molecules B7-1 and B7-2. In this report we show that these T-cell clones are resistant to inhibitory regulation, including the induction of anergy and sensitivity to tumor growth factor-beta (TGF-beta)-induced growth inhibition. The resistance to anergy induction was associated with expression of B7 costimulatory molecules. These data suggest that lack of responsiveness to peripheral inhibitory signals may account for the entry of autoimmune diseases into a chronic progressive phase.

Coronavirus induction of class I major histocompatibility complex expression in murine astrocytes is virus strain specific.

Neurotropic strains of mouse hepatitis viruses (MHV) such as MHV-A59 (A59) and MHV-4 (JHMV) cause acute and chronic encephalomyelitis and demyelination in susceptible strains of mice and rats. They are widely used as models of human demyelinating diseases such as multiple sclerosis (MS), in which immune mechanisms are thought to participate in the development of lesions in the central nervous system (CNS). The effects of MHV infection on target cell functions in the CNS are not well understood, but A59 has been shown to induce the expression of MHC class I molecules in glial cells after in vivo and in vitro infection. Changes in class I expression in infected cells may contribute to the immunopathogenesis of MHV infection in the CNS. In this communication, a large panel of MHV strains was tested for their ability to stimulate class I expression in primary astrocytes in vitro. The data show that the more hepatotropic strains, such as MHV-A59, MHV-1, MHV-2, MHV-3, MHV-D, MHV-K, and MHV-NuU, were potent inducers of class I expression in astrocytes during acute infection, measured by radioimmunoassay. The Kb molecule was preferentially expressed over Db. By contrast, JHMV and several viral strains derived from it did not stimulate the expression of class I molecules. Assays of virus infectivity indicated that the class I-inducing activity did not correlate with the ability of the individual viral strain to replicate in astrocytes. However, exposure of the viruses or the supernatants from infected astrocytes to ultraviolet light abolished the class I-inducing activity, indicating that infectious virus is required for class I expression. These data also suggest that class I expression was induced directly by virus infection, and not by the secretion of a soluble substance into the medium by infected astrocytes. Finally, analyses of A59/JHMV recombinant viral strains suggest that class I-inducing activity resides in one of the A59 structural genes.

Regeneration of oligodendroglia during recovery from demyelinating disease.

Infection of mice with the JHM strain of mouse hepatitis virus causes demyelination as a result of a cytolytic infection of oligodendroglia. In recovery, animals show remyelination, which could result either from surviving oligodendrocytes extending their territory or by generation of new oligodendroglia. Electron microscopic autoradiographic studies with 3H-labeled thymidine demonstrate that the cells associated with remyelination are newly generated oligodendroglia.

Virions from progressive multifocal leukoencephalopathy: rapid serological identification by electron microscopy.

Virions were extracted directly from the brain of a patient with progressive multifocal leukoencephalopathy (PML). They were treated with antiserum to SV40, with rabbit antiserum to previous PML isolates, or with serum from another patient with the same disease and observed directly by electron microscopy. This procedure could be used for the rapid identification of the antigenic nature of virions in cases of PML.

Mutational analysis of the transferrin receptor reveals overlapping HFE and transferrin binding sites.

The transferrin receptor (TfR) binds two proteins critical for iron metabolism: transferrin (Tf) and HFE, the protein mutated in hereditary hemochromatosis. Previous results demonstrated that Tf and HFE compete for binding to TfR, suggesting that Tf and HFE bind to the same or an overlapping site on TfR. TfR is a homodimer that binds one Tf per polypeptide chain (2:2, TfR/Tf stoichiometry), whereas both 2:1 and 2:2 TfR/HFE stoichiometries have been observed. In order to more fully characterize the interaction between HFE and TfR, we determined the binding stoichiometry using equilibrium gel-filtration and analytical ultracentrifugation. Both techniques indicate that a 2:2 TfR/HFE complex can form at submicromolar concentrations in solution, consistent with the hypothesis that HFE competes for Tf binding to TfR by blocking the Tf binding site rather than by exerting an allosteric effect. To determine whether the Tf and HFE binding sites on TfR overlap, residues at the HFE binding site on TfR were identified from the 2.8 A resolution HFE-TfR co-crystal structure, then mutated and tested for their effects on HFE and Tf binding. The binding affinities of soluble TfR mutants for HFE and Tf were determined using a surface plasmon resonance assay. Substitutions of five TfR residues at the HFE binding site (L619A, R629A, Y643A, G647A and F650Q) resulted in significant reductions in Tf binding affinity. The findings that both HFE and Tf form 2:2 complexes with TfR and that mutations at the HFE binding site affect Tf binding support a model in which HFE and Tf compete for overlapping binding sites on TfR.

Treatment of recurrent malignant gliomas with chronic oral high-dose tamoxifen.

The present clinical trial was undertaken to assess the clinical safety and possible efficacy of administering tamoxifen to patients with recurrent malignant glial tumors at dosages calculated to achieve levels sufficient to inhibit protein kinase C within the tumor cells. Chronic p.o. tamoxifen was administered in very high dosages to 32 patients (20 males and 12 females; age range, 26-75 years; mean, 49 years) with histologically verified malignant glioma [anaplastic astrocytoma (12 patients) or glioblastoma multiforme (20 patients)] who had demonstrated clinical and radiographical progression or recurrence following external beam radiation therapy (and additional chemotherapy in 11; immunotherapy in 2). The dosage of tamoxifen administered was 200 mg/day to males and 160 mg/day to females given in a twice daily schedule. Clinical and radiographical (defined as a greater than 50% decrease in volume of the enhancing lesion volume on magnetic resonance imaging and a decrease in metabolic activity on serial positron emission tomographic scans) response was noted in 8 patients (25%; 4/12 with anaplastic astrocytoma and 4/20 glioblastoma multiforme), with an additional 6 patients (19%) exhibiting stabilization of disease with minimal side effects. Median survival from the time of diagnosis for the entire cohort was 24 months (104 weeks), for the anaplastic astrocytoma group 42.5 months (185 weeks), and for the glioblastoma group 17.4 months (75.5 weeks). From the initiation of tamoxifen, median survival for the entire cohort was 10.1 months (44 weeks), for the anaplastic astrocytoma group 16 months (69 weeks), and for the glioblastoma group 7.2 months (31 weeks). The mean length of follow-up of all patients after initiating tamoxifen was 16 months (69 weeks), while the mean length of follow-up of alive patients is 22.6 months (98 weeks) (range up to 51 months). These data suggest that a subgroup of patients with malignant gliomas respond or stabilize with chronic high-dose tamoxifen therapy. This therapy may represent an alternative or adjuvant to existing chemotherapies for these tumors; further clinical trials are warranted.

Possible role of androgen receptors in amyotrophic lateral sclerosis. A hypothesis.

Androgen receptors have been demonstrated in both cranial nerve and spinal motor neurons. This article proposes that amyotrophic lateral sclerosis (ALS) may be a disease in which androgen receptors in motor neurons are lost or not functioning. This is suggested by the male-to-female ratio of the disease, the age of onset, and the sparing of neurons of cranial nerves III, IV, and VI that coincidentally lack androgen receptors. The hypothesis is that ALS may be due to a loss of androgen receptors that results in an inability to respond to a variety of insults including axonal damage.

Mouse hepatitis virus-induced recurrent demyelination. A preliminary report.

Four-week-old BALB/c mice inoculated intracerebrally with the JHM strain of mouse hepatitis virus developed an acute demyelinating disease followed by apparent recovery with remyelination. When surviving mice were examined 16 months later, small areas of active demyelination were still present. This is the first reported example, to our knowledge, of an experimental viral infection in which acute demyelination with recovery is followed by persisting or recurring demyelination.

Experimental arthrogryposis caused by viral myopathy.

Immobilization of the embryo has been postulated to cause the joint deformities in arthrogryposis multiplex congenita (AMC). Experimental damage to the motor neurons or pharmacologic blockade of neuromuscular transmission has previously resulted in typical joint changes of AMC. In the present investigation, we have studied the effects of paralysis produced by a viral myopathy on joint development. Coxsackievirus A2 was injected intravenously into chick embryos on the seventh day of incubation. Within 48 hours, severe myositis and paralysis resulted. Electron microscopical and immunofluorescence techniques demonstrated virus in muscle cells. Within three to four days after infection, the muscle had virtually disappeared. Ankylosis of joints, corresponding to that seen in human AMC, occurred. This study shows that primary myopathy with paralysis can produce arthrogrypotic joint deformities. The possibility of a viral etiologic factor in some human cases of AMC should be considered.

Experimental neuropathology of chronic demyelination induced by a JHM virus variant (DS).

A small plaque variant of JHM virus has a markedly reduced ability to kill mice following intracerebral inoculation. Spinal cords of mice surviving 13 to 16 months following acute infection with this variant were examined ultrastructurally. Multiple subpial areas of demyelination in the anterior and lateral white matter were found in five of 13 mice. The lesions had more gliosis, fewer oligodendrocytes, and less remyelination than has been described following other infections with JHM virus. No conclusive evidence of active demyelination or viral-like particles was found. The pathogenesis of the lesions observed may be due to a persistent, attenuated infection of oligodendrocytes or to immunologic processes. These lesions were similar to chronic multiple sclerosis plaques. Therefore, this variant should prove to be a useful tool for studying the long-term effects of viral-induced demyelinating diseases.

Antigenic assessment of coronaviruses isolated from patients with multiple sclerosis.

Many studies have either supported or discounted the role of coronaviruses as etiologic agents in multiple sclerosis (MS). Two new approaches were applied to investigate this controversy. First, monoclonal antibodies specific for either murine coronaviruses (mouse hepatitis viruses) or human coronaviruses were used to characterize the antigenic features of MS-derived coronaviruses SK and SD. Both isolates were found to have a mouse hepatitis virus-type profile. Second, serum and cerebrospinal fluid antibodies to different coronaviruses, including SD, were measured in MS and control groups. No significant difference in antibody level to coronaviruses was found between MS and control samples. The results of these antigenic studies do not support a specific association between MS and coronaviruses.

Chronic central nervous system demyelination in mice after JHM virus infection.

The pathogenesis of murine hepatitis virus, strain JHM, was studied in 6- and 12-week-old C57/BL mice. There was 100% mortality in the 6-week-old mice after intracerebral inoculation. The lesions were characterized by necrotizing encephalomyelitis, without demyelination. Intracerebral inoculation of 12-week-old animals, however, resulted in no morbidity or mortality. The 12-week-old animals showed transient virus replication in the brain, spinal cord, and liver, which was cleared by day 14. Histologic examination showed evidence of ongoing demyelination, concomitant remyelination, and hydrocephalus ex vacuo. Although viral antigen was demonstrated by immunofluorescence in the central nervous system of these animals, no infectious virus was recovered, and immunosuppression regimens did not potentiate the disease.

Isolation and characterization of autoreactive proteolipid protein-peptide specific T-cell clones from multiple sclerosis patients.

During the course of multiple sclerosis (MS), myelin proteins are likely antigenic targets for autoreactive T cells. Although most studies have implicated myelin basic protein as a potent encephalitogenic myelin component, proteolipid protein (PLP) appears also to be a possible target antigen in the autoimmune response in MS. In this report, we investigated the human T-cell responses to PLP by using PLP104-117 and PLP142-153 synthetic peptides as target antigens in limiting dilution. One hundred twenty-five CD4+, T-cell receptor (TCR) alpha beta+ T-cell clones (TCCs) were established from the peripheral blood of seven MS patients and five control subjects. Despite the use of enriched cultures no gamma delta TCCs were obtained. Recognition of both PLP epitopes occurred in the context of multiple HLA-DR alleles. We found no differences in restriction element usage between MS patients and control subjects. TCR variable beta-region (V beta) usage was assessed by flow cytometry using a panel of monoclonal antibodies defining different V beta elements. In both MS patients and control subjects, there was a marked heterogeneity in the TCR V beta repertoire. Furthermore, sequential evaluation of MS patients during acute attacks and clinical remissions showed even more broadening of the TCR V beta repertoire. These data demonstrate that a heterogeneous T-cell response to PLP concerning HLA restriction and TCR usage is present in both MS patients and normal subjects.

Attempts to demonstrate virus in amyotrophic lateral sclerosis.

Neurons were isolated from the brain and spinal cord of five patients with clinical and pathologic evidence of amyotrophic lateral sclerosis (ALS). The following studies were carried out to detect the presence of infectious virus. Homogenates of isolated neurons were passaged in several cell lines at different temperatures; isolated neurons were cultured; and supernatant fluids were passaged on the cell lines. Neurons were also cocultivated and fused with continuous cell lines and subsequently passaged; isolated neurons were examined by electronmicroscopy and immunofluorescent techniques, using sera from ALS patients. No evidence of virus was found by these methods.

Lipoamide dehydrogenase: rapid heat inactivation in platelets of patients with recessively inherited ataxia.

The activity of lipoamide dehydrogenase was abnormally heat-labile in homogenized platelets from seven patients with as recessive ataxia conforming to the syndrome of Friedreich ataxia or clinical variants. Taken together, the abnormality and previous findings of low activity and abnormal kinetic properties are compatible with a change in the conformation of the enzyme in these patients.

Multiple sclerosis flares associated with recombinant granulocyte colony-stimulating factor.

Four of 10 patients who were enrolled on protocols of high-dose immunosuppression with peripheral blood stem cell rescue for MS experienced neurologic worsening while receiving recombinant human granulocyte colony-stimulating factor. There was improvement when methylprednisolone was given to three of the patients, but one patient died of respiratory failure. The mechanism of the neurologic worsening is uncertain.

Extended use of glatiramer acetate (Copaxone) is well tolerated and maintains its clinical effect on multiple sclerosis relapse rate and degree of disability. Copolymer 1 Multiple Sclerosis Study Group.

When 251 relapsing-remitting patients with multiple sclerosis were randomized to receive daily subcutaneous injections of glatiramer acetate, previously called copolymer 1 (Copaxone; n = 125) or placebo (n = 126) for 24 months, there were no laboratory abnormalities associated with glatiramer acetate treatment and it was well tolerated with few side effects. Patients receiving glatiramer acetate had significantly fewer relapses and were more likely to be neurologically improved, whereas those receiving placebo were more likely to worsen. This study was extended for 1 to 11 months (mean of 5.2 months for the glatiramer acetate group and 5.9 months for the placebo group). The blinding and study conditions used during the core 24-month study were unchanged throughout the extension. The results of this extension study confirm the excellent tolerance and safety profile of glatiramer acetate for injection. The clinical benefit of glatiramer acetate for both the relapse rate and for neurologic disability was sustained at the end of the extension trial.

Beta-endorphin enhances interleukin-2 (IL-2) production in murine lymphocytes.

Beta-endorphin has been reported to enhance T lymphocyte proliferation and cytolytic activity. In this report, it is demonstrated that beta-endorphin enhances the production of the T cell lymphokine, interleukin-2, from mitogen-stimulated, unfractionated murine splenocytes, as well from a cloned T cell line. The enhancement is naloxone irreversible and dependent on the integrity of the C-terminal amino acids, though the N-terminal amino acids appear to contribute to the potency of the enhancement. The data suggest that beta-endorphin interacts with a nonopioid receptor that has specificity characteristics similar to a nonopioid beta-endorphin receptor described in the central nervous system.

Human CD8+ TCR-alpha beta(+) and TCR-gamma delta(+) cells modulate autologous autoreactive neuroantigen-specific CD4+ T-cells by different mechanisms.

To investigate the regulatory interactions among autologous T-cells during the course of multiple sclerosis (MS), proteolipid protein peptide-specific CD4+ T-cell clones (TCCs) were irradiated and used as immunogens to stimulate purified populations of autologous CD8+ TCR-alpha beta+ and TCR-gamma delta+ T-cells isolated from the peripheral blood of MS patients, patients with other non-inflammatory neurological diseases, and healthy blood donors. The resulting blasts were expanded in the presence of hIL-2 and then cloned by limiting dilution. Two different groups of CD8+ TCCs were revealed. A first group of CD8+ TCCs recognized autologous CD4+ T-cells based in their TCRV beta structures (anti-idiotypic responsiveness). A second group of CD8+ TCCs recognized Ag activated autologous CD4+ TCCs irrespective of their Ag specificity or TCRV beta expression (anti-ergotypic responsiveness). Both groups showed MHC class I restricted cytotoxicity against CD4+ T-cells and were able to secrete IFN-gamma, TNF alpha/beta and TGF-beta. TCR-gamma delta+ TCCs isolated in response to stimulation with autologous peptide-specific CD4+ TCCs showed only anti-ergotypic cytotoxicity, which was not inhibited by anti-MHC class Ia monoclonal antibodies. Moreover, they were able to secrete IFN-gamma and TNF alpha/beta, but not TGF-beta. These data demonstrate that regulatory mechanisms among human autologous T-cells can be mediated by cytolytic interactions or by the release of specific cytokines. Furthermore, they provide evidence that CD8+ TCR-alpha beta+ and TCR-gamma delta+ cells differ in their patterns of recognition and in their abilities to modulate the immune response mediated by autologous autoreactive CD4+ T-cells.