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Biomedical subjects

R M Malmgren

Publications and source records attributed to R M Malmgren.

6 recordsLinked to original sources

A case-control study of multiple sclerosis.

We conducted a study of 145 persons with multiple sclerosis who had been identified in a 1970 survey and 145 friend controls, to investigate whether the development of MS was associated with exposure to uncommon viruses or an older age at infection with 1 or more common viruses. The most striking finding was a strong positive association for history of infectious mononucleosis (IM), suggesting older age at exposure to Epstein-Barr virus, the most common etiologic agent of IM. We also found significant positive associations for number of different domiciles before adulthood and for visits outside the United States; both would be compatible with an increased likelihood among cases of exposures to uncommon viruses or to multiple strains of a common agent. Cases were younger at menarche, increasing the probability of viral exposure after puberty.

Adolescent

Genetic susceptibility to multiple sclerosis.

Previous studies of histocompatibility (HLA) types in multiple sclerosis (MS) families did not provide convincing proof of an HLA-linked susceptibility factor. In 12 families we studied, all MS cases in each family shared at least one chromosome. The probability of this occurring in the absence of genetic linkage is approximately 0.001. The estimated penetrance is 5 percent, implying that the genetic susceptibility factor may be a necessary but not a sufficient cause of MS. Additional studies are needed to identify other differences between affected and unaffected susceptible individuals.

Female

HLA types and immunity in multiple sclerosis.

HLA types and levels of humoral and cell-mediated immune responses to several antigens were studied in a large group of patients with multiple sclerosis, and in controls. Patients were more likely than controls to have the DRw2 antigen. They had higher mean antibody titers to measles but not to cytomegalovirus, herpes 1, or herpes 2, and had less competent cell-mediated responses. Antibody titers to measles were lower and cell-mediated immune responses were more effective in patients with the DRw2 antigen in patients than in patients without it. This apparent specificity for measles suggests that the etiology of multiple sclerosis is related to the immune response to measles or related viruses.

Antibodies, Viral

Evidence for lower susceptibility to multiple sclerosis in Japanese-Americans.

A search for cases of multiple sclerosis (MS) was carried out among the 120,066 Japanese-American residents and the 3,060,366 Caucasian residents native to state of residence in King and Pierce Counties, Washington, and Los Angeles County, California. Although 48 cases would have been expected among Japanese-Americans in both areas (on the basis of the prevalence among Caucasians in these two areas), only eight cases were found who were residents on prevalence day -- all were American-born residents of Los Angeles County. The age-, sex-adjusted prevalence of MS among Japanese-Americans in both areas was 5.9 per 100,000. The lower prevalence of multiple sclerosis among Japanese-Americans than among Caucasians has been interpreted as evidence of a lower susceptibility to factors causing multiple sclerosis.

Humans

Latitude, migration, and the prevalence of multiple sclerosis.

Prevalence of multiple sclerosis (MS) was determined in three groups of Caucasians in King and Pierce Counties (Washington) and in Los Angeles County (California): natives (born in study state), migrants from high-risk states (North), and migrants from low risk states (South). A diagnosis of definite or probable MS (excluding migrants with onset before migration) was established in 1816 of the persons found. The prevalence in Los Angeles County natives and in migrants from the South to either Los Angeles County or King-Pierce Counties were relatively low, while prevalence in King-Pierce Counties among natives and migrants from the North were high. The prevalence in migrants from the North to Los Angeles was intermediate. The results suggest that some degree of protection is provided to migrants by residence in low-prevalence areas, either early or later in life.

California