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Current postulates support the idea that MS is triggered by an infectious agent or agents through an autoimmune reaction directed against brain antigens in genetically susceptible individuals. Evidence for an infectious etiology of MS is indirect. We have proposed that MS may, in some instances, be due to a zoonotic infection and that canine distemper virus, a measles-like virus in dogs, is a likely candidate in the causation of this disorder. The high homology between canine distemper and measles virus proteins has made it extremely difficult to distinguish distemper from measles antibodies serologically. We now provide evidence that humans can be infected with this neurotropic dog virus. Furthermore, a high titer of canine distemper virus antibodies is significantly associated with MS. Identification of the etiologic agent in MS may lead to the elucidation of disease pathogenesis and to disease prevention through appropriate public health and vaccination programs.

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Measles virus (MV) mRNA transcription and replication are thought to be controlled by cis-acting sequence elements contained within the terminal MV genomic noncoding nucleotides. To validate these promoter and regulatory signal assignments, cDNAs were constructed allowing synthesis of RNAs corresponding to a MV genome in which all coding and intercistronic regions were replaced by the chloramphenicol acetyl transferase (CAT) coding sequence. Transcript production by T7 polymerase starting and ending precisely with the MV genome terminal residues was achieved by fusing the T7 polymerase promoter and the hepatitis delta virus genome ribozyme followed by tandem T7 polymerase termination sequences to the MV genomic 5' and 3' ends, respectively. Transfection of these negative polarity transcripts, mimicking natural defective interfering RNAs of the internal deletion type, into MV-infected 293 cells gave rise to CAT activity which could be serially transferred and massively amplified together with progeny helper virus in fresh cells. Transfer was blocked only by antibodies able to neutralize MV infectivity, indicating that the chimeric RNA not only was encapsidated, transcribed, and replicated, but also packaged into virions. Sequence analyses confirmed that both the expected chimeric antigenome and mRNA products were transcribed and replicated with fidelity during serial passage. Minor changes introduced in the transcription promoter markedly compromised function. This system now can be exploited to examine MV genomic cis-acting regulatory elements and extended to the development of full-length MV cDNAs.

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Total lymphoid irradiation (TLI) has been reported to delay deterioration in patients with progressive multiple sclerosis and other autoimmune disorders. METHODS--In an open trial, the effect of TLI combined with a one year course of low dose prednisone was compared to the effect of sham TLI and TLI only in a prior double-blind study of patients with progressive multiple sclerosis. RESULTS--Twenty-seven patients receiving TLI combined with corticosteroids had significantly greater lymphocytopenia in the year post-therapy than those receiving TLI only or sham TLI and Kaplan Meier product-limit survival analysis showed significantly less progression in the TLI plus steroid group over 4 years of follow-up. No difference in lymphocytopenia or progression was found with TLI plus corticosteroid therapy when the spleen was removed from the field of irradiation. CONCLUSION--These results lend further support to the hypothesis that TLI may be effective in progressive MS, and indicates that adding low-dose prednisone may enhance this effect. The study also suggests that TLI may be equally effective whether or not the spleen is irradiated.

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Evidence for a viral cause of multiple sclerosis (MS) is indirect since no infectious agent has been reproducibly isolated from MS tissues nor has viral genome or antigen been consistently identified. The occurrence of spontaneous human and animal models of demyelination, serologic studies, and epidemiologic data provide persuasive circumstantial evidence for an infectious trigger in this disease. Potential mechanisms for viral induced demyelination include persistent infection of host tissues or immune mediated organ damage either in the presence or absence of the infectious agent. Any proposed viral candidate should cause demyelination in animals or man and the pattern of infection should be consistent with the unique geographic features of MS epidemiology. In addition, serologic studies should support an infection by the agent and/or viral genome should be detected in MS tissues. At this time no virus can be unequivocally linked to MS but cumulative evidence is more supportive of canine distemper virus than other viruses.

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Gestation is a period of decreased risk for a relapse of MS, whereas the 3 months postpartum is a period of high risk. Taken together, the pregnancy year may also be a period of higher risk for relapse than non-pregnancy periods. However, the lifetime risk rate does not appear to change because of pregnancy, and on the basis of current retrospective studies, long-term disability is not higher in pregnant women or even women experiencing relapses during the pregnancy year. MS has little or no effect on the course of pregnancy or delivery, although patients with severe MS may have difficulty fully caring for their newborns. The decision to become pregnant should be made by the patient and her husband after they are appropriately informed about the risks involved.

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We cloned the genomic RNA of canine distemper virus (CDV) and determined the nucleotide sequence of the large (L) protein-coding gene. The L gene is 6573 nucleotides long and contains a single open reading frame coding for a polypeptide of 2161 amino acids (MW 246,354). The precise 5' end of the viral genome consists of a 38-nucleotide leader region. The CDV L protein shows over 77% amino acid similarity with its morbilliform relative measles virus (MV) with nearly 67% of their amino acids conserved. The sequence homology of 11 negative strand viruses L proteins is compared and relatedness was found in the following decreasing order: CDV, MV, Sendai virus, parainfluenza virus type 3, simian virus 5, parainfluenza virus type 2, mumps virus, Newcastle disease virus, respiratory syncytial virus, vesicular stomatitis virus, rabies virus. The consensus sequence of proposed functional domains involved in L gene catalytic activities was well conserved in the CDV L protein.

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Sequences critical for the transcription and replication functions of canine distemper virus (CDV) RNA polymerase were analyzed. The sequence was obtained from polymerase chain reaction (PCR) products using either c-DNA clones from a genomic library as template or in most instances genomic CDV RNA. Clones coding for the precise 3'- and 5'-ends of the CDV genome were sequenced and the results confirmed by additional PCR experiments. The virtual identity of terminal sequences and spacing at the two noncoding ends speak to the importance of these areas in replication and transcription. The sequence for each of the CDV gene boundaries was defined and all were compared to related viruses. This report completes the sequence determination of the CDV genome.

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Multiple sclerosis (MS) is an acquired inflammatory demyelinating disease of the central nervous system (CNS) believed to be of autoimmune pathogenesis. Progressive MS is a common cause of disability in young adults in the United States. Although several immunomodulating therapies have been tested in clinical and animal studies, there is no known treatment that prevents further progression and disability. Current research efforts are being focused on the development of novel, safe immunospecific treatments. Until such therapies become available, a major component of patient management should be to relieve symptoms, prevent complications, and maximize function in activities of daily living. A team approach involving health care professionals of various specialties is ideal for the management of patients with progressive MS.

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In an attempt to prevent disease exacerbations, intravenous gamma globulin (500 mg to 2 g/kg) plus methylprednisolone was administered monthly to 14 patients with progressive multiple sclerosis, 11 of whom were steroid dependent. Seventeen exacerbations of disease activity were seen in 11 patients over a mean follow-up period of 7.8 months. Four exacerbations occurred in 3 patients within one month of receiving 1.6 to 2.0 g/kg of intravenous gamma globulin (IVGG). Most exacerbations occurred within 2 weeks of steroids being tapered; thus a steroid sparing effect of IVGG could not be demonstrated. We conclude that IVGG plus methylprednisolone can be given safely at monthly intervals for a prolonged period but in the dosage administered did not prevent exacerbations in 80% of patients with progressive multiple sclerosis.

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An autopsy study was performed on spinal cords from 18 children who died with HIV-1 infection, using standard histopathologic techniques as well as in situ hybridization and immunocytochemistry for HIV-1. Of 16 spinal cords examined by histology, nine had inflammatory cell infiltrates and six had multinucleated cells; both types of lesion are associated with the presence of HIV-1 in central nervous system tissue. HIV-1 type lesions were often present in the spinal cord and brain from the same patient. Pallor of myelin in corticospinal tracts in the cord was present in half of the cases; this change correlated with diffuse myelin pallor in the corresponding brains, but not with the HIV-1 associated changes in the cords. In situ hybridization for HIV-1 nucleic acid sequences gave positive results in seven of 18 spinal cords, with hybridizing signal usually localized to inflammatory cell infiltrates and multinucleated cells. Positive in situ hybridization, on frozen sections, correlated with the presence of HIV-1 associated changes on paraffin sections from the same cases. Immunocytochemistry for p25 core protein of HIV-1, using a monoclonal antibody on frozen sections, was positive in multinucleated cells, macrophages, and microglia. In this series there were two cases of vacuolar myelopathy, one a 30-month-old boy who had concomitant measles virus in the spinal cord grey matter, and the other nine-year-old girl who had severe HIV-1 infection of the cord. Other than the single case of measles virus, there were no opportunistic infections in the cords in this series. HIV-1 frequently involves the spinal cord in children with AIDS, while opportunistic infections are rare. Vacuolar myelopathy occurs in children with HIV-1 infection, although its occurrence is much less frequent than in adults with AIDS.

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Twenty-seven young patients with multiple sclerosis (MS) were studied to determine if they had received prior measles vaccination. Fourteen patients whose immunization records were available had received measles vaccine in childhood. Eight other patients gave a history of receiving measles vaccine. These results suggest that infection by measles virus is probably not the sole cause of MS and that, unlike subacute sclerosing panencephalitis and postmeasles encephalitis, MS may not be preventable by measles vaccination given at an appropriate age.

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T lymphocyte subset percentages were determined in 16 total lymphoid irradiation (TLI) treated and 18 sham treated control patients with chronic progressive multiple sclerosis. During the first year after treatment, the ratio of T helper/inducer to T suppressor/cytotoxic cells (Th/Ts ratio) was significantly higher in sham treated multiple sclerosis patients who worsened clinically compared with TLI treated and sham treated multiple sclerosis patients who remained clinically stable. TLI caused a fall in the percentage of T helper cells in treated patients, while the percentage of T suppressor cells remained stable during the first year after treatment. In contrast, the percentage of T suppressor cells fell in sham treated multiple sclerosis patients who worsened clinically.

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To determine whether immunosuppression by total lymphoid irradiation (TLI) slowed deterioration of chronic progressive multiple sclerosis (MS), functional impairment score and blood lymphocyte counts were compared at 6-month intervals through 4 years following treatment of MS patients by either TLI (n = 27) or sham irradiation (n = 21). At each interval, 20 to 30% fewer TLI-treated patients had deteriorated (p less than 0.05 at 6, 12, and 18 months), and the difference in mean functional impairment score between groups became progressively greater (p less than 0.01 at 42 and 48 months). Benefit accrued principally to the 17 TLI-treated patients with absolute blood lymphocyte counts less than 900/mm3 3 months after treatment, whose mean functional impairment score remained within 0.6 units of baseline (p = NS), whereas the ten TLI patients with higher post-treatment lymphocyte counts had progressive deterioration (p less than 0.05 to p less than 0.001 versus TLI-treated patients with lower lymphocyte counts at all intervals except 30 months) and had deteriorated by more than 5 functional scale units by 42 and 48 months. Side effects were minor and complications rare in TLI-treated patients, but one TLI-treated patient developed staphylococcal sepsis. Thus, TLI slows deterioration of chronic progressive MS, with what appears to be enduring benefit through 4 years compartmented to patients with greater induced lymphopenia. Modification of lymphoid irradiation regimens to increase the proportion of MS patients who achieve a favorable degree of lymphopenia and to avert functional hyposplenism may further improve the benefit/risk ratio.

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Sequences critical for the activity of the measles virus (MV) RNA polymerase in transcription and replication were analyzed using a MV genomic cDNA library containing overlapping clones encompassing the entire MV genome. Clones corresponding to the 3' and 5' ends of the MV genome were identified and sequenced, and these sequences were confirmed by primer extension experiments. Neither (+) nor (-) strand leader RNAs were detected in MV-infected cell extracts, using high specific activity riboprobes made form these clones. Clones representing each of the MV gene boundaries were also sequenced, and variations including point mutations, insertions, and deletions were noted. Together with the sequence of the MV L gene region, this report completes the sequence determination of the MV genome.

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We have determined the nucleotide sequence of the measles virus (MV) L gene using a cDNA library encompassing the entire MV genome (J. Crowley et al. (1987) Intervirology, 28, 65-77). The L gene is 6639 nucleotides in length, and contains a single long open reading frame that could code for a protein of 247,611 kDa. Both the L gene and in particular the predicted L protein of MV bear substantial homology to their counterparts in Sendai virus and Newcastle disease virus, suggesting that the multifunctional nature of paramyxovirus L proteins imposes strong evolutionary constraints. The predicted MV L protein also contains distinct elements of a postulated ancestral RNA polymerase.

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Annual incidence rates of multiple sclerosis (MS) in the Shetland Islands have been updated from 1938 to 1986. These reveal a significant decline in MS incidence beginning between 1951 and 1968. No significant change in prevalence, age-specific prevalence, duration of MS, or mean age of the MS population in Shetland has been found since the last survey in 1974, although a trend towards an older MS population was noted.

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Although chemical immunosuppression has been shown to benefit patients with chronic progressive multiple sclerosis (MS), it appears that chemotherapy has an appreciable oncogenic potential in patients with multiple sclerosis. Accordingly, we developed a modified total lymphoid irradiation (TLI) regimen designed to reduce toxicity and applied it to a randomized double blind trial of TLI or sham irradiation in MS. Standard TLI regimens were modified to reduce dose to 1,980 rad, lowering the superior mantle margin to midway between the thyroid cartilage and angle of the mandible (to avert xerostomia) and the lower margin of the mantle field to the inferior margin of L1 (to reduce gastrointestinal toxicity by dividing abdominal radiation between mantle and inverted Y), limiting spinal cord dose to 1,000 rad by custom-made spine blocks in the mantle and upper 2 cm of inverted Y fields, and also protecting the left kidney even if part of the spleen were shielded. Clinical efficacy was documented by the less frequent functional scale deterioration of 20 TLI treated patients with chronic progressive MS compared to to 20 sham-irradiated progressive MS patients after 12 months (16% versus 55%, p less than 0.03), 18 months (28% versus 63%, p less than 0.03), and 24 months (44% versus 74%, N.S.). Therapeutic benefit during 3 years follow-up was related to the reduction in lymphocyte count 3 months post-irradiation (p less than 0.02). Toxicity was generally mild and transient, with no instance of xerostomia, pericarditis, herpes zoster, or need to terminate treatment in TLI patients. However, menopause was induced in 2 patients and staphylococcal pneumonia in one. Our data suggest that this modified TLI regimen has clinical efficacy and sufficiently low toxicity to make it suitable for investigative immunosuppressive treatment of patients with progressive MS or other non-malignant conditions.

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