Clearance of HIV Infection in Infant

Date: March 29, 1995
Source: National Institutes of Health (NIH)
Author: National Institute of Allergy and Infectious Diseases (NIAID)

Federally supported investigators at the University of California at Los Angeles (UCLA) School of Medicine, report in the March 30 The New England Journal of Medicine about an infant who cleared HIV infection. All information about the study, funded by the National Institutes of Health (NIH), is embargoed until 6 p.m. Eastern Time, Wednesday, March 29, 1995.

The infant reported is the first virologically well-studied patient who clearly had HIV that is now undetectable, says NIH-grantee Yvonne Bryson, M.D., lead author of the article. Small numbers of other HIV-infected children whose infections seem to have disappeared have been reported, but these cases were not well documented and in the absence of definitive explanation usually were attributed to laboratory errors.

The child, now five years old, was born to an HIV-infected mother. Scientists could not find HIV in the child's blood when the child was born, but viral culture tests at day 19 and day 51 did reveal the virus. Later attempts to find HIV using HIV-culture techniques, polymerase chain reaction and antigen searches did not reveal any virus. Today, the child is healthy and has no evidence of HIV infection.

Increased knowledge of when and how HIV is eliminated from the body could have profound implications for the prevention of HIV transmission as well as treatment and vaccine development, according to NIH scientists. This child's experience fits into one of the categories that could also be an outcome of HIV exposure after immunization--transient infection with no later evidence of virus or disease. Also, these data and additional studies may further understanding of why approximately 70 percent of infants born to HIV-infected mothers in the United States escape infection.

Scientists from the National Institute of Allergy and Infectious Diseases (NIAID), which helped support the study, caution that although the report provides new and encouraging information showing that, in rare instances, infants may clear HIV, the data do not suggest that HIV infection in infants will automatically disappear.

Rather, the findings raise numerous questions about the frequency and mechanism of transient HIV infections, the implications for pregnant women and their children, and the HIV disease process and the body's immune response.

Investigators do not know how HIV is cleared in such children. A number of possible explanations may suggest how the transient HIV infection reported in the NEJM article may have occurred. The theories, all of which require more evidence and testing, include that the infant had an immune response to HIV that either eliminated or is totally supressing the virus. The immune response could come from maternal antibodies passed during pregnancy and/or from the infant's immune system. Another theory is that the child may have been infected with a defective form of HIV that could not adequately replicate. The UCLA study does not offer data that could clarify either the type of immune response this child had or the viral characteristics beyond its genetic fingerprint.

NIH-supported researchers are developing interventions based on active and passive immunization to prevent infected pregnant women from transmitting HIV to their children. This approach is analogous to the highly successful strategy to prevent hepatitis B in newborns, which uses a combination of hyperimmune globulin (a protein solution containing high concentrations of antibodies to hepatitis B) given at birth and a series of vaccinations given at birth and during infancy. Currently, phase I studies are evaluating the ability of available candidate HIV vaccines to stimulate immune responses in HIV-infected pregnant women and in their infants. The NIH also supports efficacy trials in the United States and other countries to evaluate passive immunization for the prevention of perinatal transmission.

In addition to the NIAID, other supporters of the UCLA study include the National Institute of Child Health and Human Development (NICHD), Fogarty International Center (FIC), the National Center for Research Resources (NCRR) and the Leukemia Society of America. NIAID, NICHD, FIC and NCRR are part of NIH, the federal focal point for biomedical and health research.

To pursue stories on this or related topics please call the NIAID Office of Communications at (301) 402-1663 or the NICHD Office of Research Reporting at (301) 496-5133