Lymphocyte subsets in children younger than 2 years old: normal values in a population at risk for human immunodeficiency virus infection and diagnostic and prognostic application to infected children.

Data were collected prospectively from 116 children younger than 2 years old who were seen at the Duke Pediatric AIDS Clinical Trials Unit for known human immunodeficiency virus seropositivity. Forty-six (40%) of these children were human immunodeficiency virus-infected and 70 were not infected. Using 3-month blocks, 10th, 50th and 90th percentiles were calculated for the CD4+ and CD8+ cell counts, percentage of lymphocytes positive for CD4 and CD8 and T4:T8 ratios. Results from the infected and uninfected children were compared. By 3 to 6 months of age the infected patients had significantly lower CD4+ counts, percentage CD4+ cells and T4:T8 ratios, whereas the percentage of CD8+ lymphocytes was significantly higher. Absolute CD8+ counts were approximately the same in infected and uninfected children through age 2 years. Most infected children had one or more abnormal lymphocyte subset results (less than the 10th percentile for uninfected patients) by age 2: 83% had an abnormal CD4+ percentage; 78% had an abnormal T4:T8 ratio; and 67% had an abnormal CD4+ count. All 13 children who had an opportunistic infection (at any age) had an abnormal CD4+ percentage before age 2 years, and 12 of 13 had a low absolute CD4+ count or T4:T8 ratio. Among patients who died 10 of 11 had 1 or more low CD4+ count, 9 of 11 had an abnormal CD4+ percentage and 8 of 11 an abnormal T4/T8 ratio.