Dashed hopes

By Philip Cohen BABIES who somehow rid themselves of HIV infection shortly after birth have intrigued AIDS researchers for about ten years. If the secret behind these infants’ ability to shake off the virus could be uncovered, it might lead to new drugs or vaccines. But now a team of researchers in the US has come to a startling conclusion about these so-called transient HIV infections—they never actually happened. Instead, in every case they have examined, they believe that sloppy testing probably resulted in an uninfected newborn being misdiagnosed as HIV-positive. Months later, when the test was repeated, the child appeared to have fought off the virus (This Week, 8 April 1995, p 6). “Our initial goal was to prove transient infections were real and then get a clue to how these people cleared the infection,” says Lisa Frenkel of the University of Washington in Seattle. Frenkel and her colleagues started by trying to confirm previous cases of transient infection. Diagnosing HIV infection in infants is notoriously hard. The standard adult test for anti-HIV antibodies doesn’t work, because maternal antibodies persist in the blood for over a year after birth. So doctors use other techniques such as looking for viral proteins directly, or by using the polymerase chain reaction (PCR) to amplify one viral gene in a sample so there are millions of copies that can be detected. In the current issue of Science (vol 280, p 1073), the researchers report their analysis of 42 instances of transient infection in infants and one unusual case in a new mother. In each case they discovered something suspicious. In six cases they analysed human instead of viral genes and found the HIV-positive samples belonged to another child. In 17 instances, the virus in the babies’ blood was unrelated to the mother’s infection, which suggested the sample was infected in the lab. In 20 cases, they couldn’t detect a full set of viral genes in the blood sample. That suggests the original tests were false positives or had been contaminated during PCR. The researchers conclude that there are problems with these complicated tests for infants and their mothers. “Anyone who has used them knows how problematic they can be,” says Frenkel. In this study they went to great lengths to avoid contamination. For instance, samples from mothers and infants were analysed by different people in different buildings a mile apart. Frenkel adds that it is still possible there are real cases of transient infections. “This just emphasises the need to document them carefully,
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