Dynamics of viral replication in infants with vertically acquired human immunodeficiency virus type 1 infection.

About one-third of vertically HIV-1 infected infants develop AIDS within the first months of life; the remainder show slower disease progression. We investigated the relationship between the pattern of HIV-1 replication early in life and disease outcome in eleven infected infants sequentially studied from birth. Viral load in cells and plasma was measured by highly sensitive competitive PCR-based methods. Although all infants showed an increase in the indices of viral replication within their first weeks of life, three distinct patterns emerged: ( a ) a rapid increase in plasma viral RNA and cell-associated proviral DNA during the first 4\u20136 wk, reaching high steady state levels ( . 1,000 HIV-1 copies/10 5 PBMC and . 1,000,000 RNA copies/ml plasma) within 2\u20133 mo of age; ( b ) a similar initial rapid increase in viral load, followed by a 2.5\u201350-fold decline in viral levels; ( c ) a significantly lower ( . 10-fold) viral increase during the first 4\u20136 wk of age. All infants displaying the first pattern developed early AIDS, while infants with slower clinical progression exhibited the second or third pattern. These findings demonstrate that the pattern of viral replication and clearance in the first 2\u20133 mo of life is strictly correlated with, and predictive of disease evolution in vertically infected infants