may even prolong life (McKinney et al., 1990; Pizzo, 1990).1 Zidovudine now constitutes standard therapy for children with AIDS. In addition, clinical trials of zidovudine among asymptomatic HIV-infected adults (with CD4+ cell counts below 500) suggest that early intervention delays the progression of disease (Volberding et al., 1990). Whether such benefits will be found among asymptomatic HIV-infected children, especially newborns, is unknown. The short-or long-term therapeutic risks for infants and children may also be different from those for adults. Similar uncertainty surrounds prophylactic therapy for Pneumocystis carinii pneumonia (PCP), one of the most common and devastating opportunistic infections affecting perinatally infected children (Scott, 1989). PCP prophylaxis has been effective for HIV-infected adults (CDC, 1989b) and for pediatric cancer patients (Hughes et al., 1977, 1987); there is reason to believe that HIV-infected children may derive comparable benefits, although this assumption is unconfirmed at this point.

Limitations in HIV Diagnostic Technology for Infants

Even if early therapeutic intervention confers some benefit to HIV-infected infants, deciding who to treat in early infancy is problematic, HIV-antibody tests are currently the most appropriate instrument for screening purposes, but these tests do not differentiate truly infected neonates from those who are uninfected. (All babies born to HIV-infected mothers carry passively acquired maternal antibodies, which may persist for up to 15 months of age; only about one-third of such infants are actually infected.) Both HIV p24 antigen tests and virus culture have been used to diagnose HIV infection in adults and children; however, their relative insensitivity in young infants makes them inappropriate for use as screening tools.2 Several other tests are under investigation (e.g., assays for IgM and IgA HIV antibodies, which do not cross the placenta [Weiblen et al., 1990]; in vitro HIV antibody production [Amadori et al., 1988]; polymerase chain reaction [Rogers et al., 1989]) that may eventually be useful in the early diagnosis of HIV infection in infants, but these tests require more extensive development and evaluation before they are ready

1  

 In May 1990, the Food and Drug Administration (FDA) granted marketing approval of zidovudine for use in HIV-infected children over three months of age who had HIV-related symptoms or who were asymptomatic with laboratory evidence of significant HIV-related immunosuppression.

2  

 The presence of p24 antigen indicates infection with HIV; however, it is not commonly measurable in young infants and therefore is not sufficiently sensitive in neonatal diagnosis. Similarly, although a positive virus culture in infants confirms HIV infection, a negative culture is not sufficient to exclude it (Husson et al., 1990; Pizzo, 1990).



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