CD4 T-lymphocyte counts and Pneumocystis carinii pneumonia in pediatric HIV infection.

The relationship between CD4 T-lymphocyte counts and infection with the human immunodeficiency virus (HIV) is retrospectively investigated for 266 HIV-infected and uninfected children who were born to infected women, including 39 with Pneumocystis carinii pneumonia (PCP), in a population-based surveillance study. Of 21 perinatally HIV-infected children with PCP only 10 (48%) had CD4 T-lymphocyte counts that were less than 500 x 10(6) cells/L (500 cells/mm3), compared with all 18 who were infected via blood transfusions or clotting factors. Among 68 children who were 1 year or younger, 18 (90%) of 20 PCP cases had CD4 T-lymphocyte counts that were less than 1500 x 10(6) cells/L (1500 cells/mm3) compared with only five (10%) of 48 children who did not have the acquired immunodeficiency syndrome (odds ratio, 77.4; 95% confidence interval, 19.7 to 313.4). The mean CD4 T-lymphocyte count was lower for the 39 PCP cases when compared with the 188 children who were at different stages of HIV infection and did not have the acquired immunodeficiency syndrome (AIDS) independent of age. The majority of perinatally HIV-infected children with PCP were 6 months or younger and 50% were previously unknown to be infected. Thus, HIV-positive children should be identified early and followed closely. CD4 T-lymphocyte counts may be useful in monitoring HIV-positive children and determining when to begin PCP prophylaxis.