Age-related standards for T lymphocyte subsets based on uninfected children born to human immunodeficiency virus 1-infected women

The T lymphocyte subsets in the peripheral blood of 459 uninfected children born to white human immunodeficiency virus 1-infected women included in the European Collaborative Study were measured at regular intervals from birth. More than 2400 observations were used to create smooth age-related reference ranges for CD4 and CD8 counts and percentages, CD4:CD8 ratio and absolute lymphocyte count. Standards are presented for children up to 4 years of age. CD4, CD8 and absolute lymphocyte count rose after birth, peaked at around 6 to 9 months of age and then declined toward adult values. CD4 percentage and CD4:CD8 ratio declined steadily from birth onwards. Centile lines for CD4 count and CD4:CD8 ratio converged markedly with age. For the CD4 values, only 3 to 5% of the variation was attributable to differences between the 10 participating centers. These standards allow T lymphocyte abnormalities to be used more effectively as markers for disease progression and assist in the clinical follow up of human immunodeficiency virus 1-infected children. They also provide a basis for initiating antiretroviral treatment or antimicrobial prophylaxis.