Non-Hodgkin lymphoma (NHL) patients are no more likely than healthy people to have been exposed to or infected by simian virus 40 (SV40), a macaque polyomavirus that contaminated poliovirus vaccines in the mid-20th century, according to a new study in the September 15 issue of the Journal of the National Cancer Institute. SV40 has been suggested as a cause of human cancers, including NHL.
In the United States between 1955 and 1962, SV40 frequently contaminated poliovirus vaccines, which were grown in monkey kidney tissue. Several groups have reported detection of SV40 in the tumor tissue of 15% to 43% of NHL patients, and the virus causes leukemia and lymphoma in laboratory rodents. However, other research groups did not detect SV40 in NHL tumors, and recent evidence has suggested that it cannot infect human lymphocytes. Moreover, epidemiologic studies have failed to find an increase in the risk of NHL among people exposed to SV40-contaminated poliovirus vaccine.
To examine the possible association between exposure to SV40 and NHL, Eric A. Engels, M.D., M.P.H., of the National Cancer Institute, and colleagues conducted a population-based case–control study of 724 NHL patients and 622 control subjects. In the study, two independent laboratories tested for antibodies to SV40 in all of the subjects using two similar tests that utilize SV40 virus-like particles.
SV40 seropositivity--the presence of antibodies to SV40 virus-like particles--was detected in 7% to 10% of NHL case patients and 10% to 11% of control subjects. When the researchers accounted for cross-reactivity with the related human polyomaviruses BK and JC, they found SV40-specific antibody in less than 2% of both case patients and control subjects. The researchers thus found no association between SV40 exposure or infection and an increased risk of NHL.
"Based on the assumption that SV40 infection would have resulted in a measurable immune response to virion proteins, the results presented in this report do not support the idea that SV40 is a common infection of humans or a major cause of NHL. In the future, it will be of interest to develop additional serological assays for SV40 infection for studies of persons with cancer and the general population," the authors write.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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