Diagnostic value of viral culture,Polymerase Chain Reaction and Western Blot for HIV-1 infection in 218 infants born to HIV-infected mothers and examined at different ages

In a prospective longitudinal 10-year (1988 to 1998) study, 308 sequential blood samples from 218 infants born to HIV-1 seropositive women were examined by blood culture, polymerase chain reaction (PCR) and Westerb Blot (WB) for HIV-1 infection within the first month of life (no. 47 specimens), at 2-6 (no. 125), 7-18 (no. 80), and > 18 (no 56) months after Birth. Clinical status at follow-up after the initial diagnosis of HIV infection was also evaluated. Vertically transmitted HIV infection was diagnosed in 45 children (24 children were diagnosed before 18 months of age), whereas 173 found to be uninfected (transmission rate 20.6%). Sensitivities of viral culture, PCR and WB were 95.2%, 97.8%, 94.4% and specificities were 99.5%, 97.6% and 20.7%, respectively. Thus, cululative positive predictive values (PPV) of blood culture, PCR and WB were 97.5%, 88.2% and 23.4%, while negative predictive values (NPV) were 99.0%, 99.6% and 100.0%, respectively. In view of defining the optimal time of sampling for a correct diagnosis of HIV infection, a PPV of 100.0% was achieved earlier by viral culture (2-6 months of age) than by PCR (7-18 months of age). Meanwhile, a NPV of 100% was obtained earlier by PCR (within the first month of age) than by viral culture (2-6 months). These results indicate that a combination test strategy requiringtwo blood samples analyzed by viral culture and PCR may confirm or exclude HIV perinatal infection within the first 2 months of life rather than being delayed to later times. Clinical follow-up was performed in 35 children, of whom 7 developed a repidly progressive disease, 23 showed a slow progression, while 5 children are still younger than 5 years and do not present severe clinical symptoms.