Background. It is known that plasma or serum viral load is high in vertically HIV-infected children during the first year of life, but the changes in these titers after the first birthday have not been described. Information on the natural history of circulating extracellular virus will be useful in elucidating the pathogenesis of pediatric HIV infection and in using viral load measurement to guide prognosis and therapy.
Methods. We measured serum RNA by reverse transcriptase-polymerase chain reaction and immune complex-dissociated p24 antigen enzyme-linked immunosorbent assay over time in 48 unselected children followed in our clinics and analyzed the findings in relation to age and clinical outcome.
Results. In first-available samples from the 48 children there was a gradual reduction in HIV RNA values with increasing age, with a slope of -0.21 log copy/ml/year (P < 0.001, R2 = 0.6022). This downward trend was seen in subsets of children with all degrees of immunodeficiency. The mean slope of repeated HIV RNA measurements in individual children was similarly in a downward direction (slope -0.11 (P = 0.007 for difference from zero)). The slope was more negative in children who were younger at baseline. Immune complex-dissociated p24 antigen values were much less predictable and predictive.
Conclusions. Viral load in vertically infected children, measured by reverse transcriptase-polymerase chain reaction, falls very gradually over time, descending from very high titers at the end of the first year, and reaching values seen in horizontally infected adults at ≈5 years of age.
From the Division of Infectious Diseases, Children's Hospital (KM, DZ, NK, SKB), Harvard School of Public Health (AS), and DuPont Medical Products (PC), Boston, MA; Children's Hospital Oakland Research Institute, Oakland, CA (JK); and Ludwig-Boltzman Institut for AIDS Research, University of Innsbruck, Clinic of Pediatrics, Innsbruck A-6020 Austria (DZ).
Accepted for publication Aug. 7, 1996.
Address for reprints: Kenneth McIntosh, M.D., Division of Infectious Diseases, Children's Hospital, 300 Longwood Avenue, Boston MA 02115. Fax 617-355-8387; E-mail firstname.lastname@example.org.