The researchers re-analyzed the infant specimens that had tested positive for HIV-1 and the mothers' specimens. They performed tests to study the genetic code in the babies' and mothers' specimens, to determine whether the virus in the baby's specimen was related to the mother's virus. "The test results in the case where both the mother and baby were positive and later showed no evidence of infection showed that none of their five specimens with HIV-1 had viruses that were related," said Frenkel. "These viruses looked genetically different enough that they did not come from the same source. Also, one of the viruses was a known strain used in laboratories."
In 20 of the other 41 cases, the researchers could not find the envelope gene -- the outside coating of the virus used to evaluate the relatedness of the genes -- which suggested that the patients' specimens had become contaminated with HIV-1 in the laboratory.
In another six cases, they found there was a mix-up in the specimens, since the infant's human gene markers did not match the gene markers found in two or more of the same infant's other virus-negative specimens.
Where they did find envelope virus in the infant specimen, they analyzed the gene sequence of the envelope virus and compared it with that of the mother. In 17 cases, they showed that the envelope virus in the child's specimen was not related to the envelope virus in the mother.
"Our hypothesis was that transient infection could occur," Frenkel said.
"By using a rigorous genetic standard in examining all the supposed cases we
could find fr
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Contact: Laurie McHale
lmchale@u.washington.edu
(206) 543-3620
University of Washington
14-May-1998