Background: Traditionally in pediatric HIV, the CD4+ T-lymphocyte percent is used to monitor disease progression because of the variability in absolute CD4+ T-lymphocyte numbers. Because of the high cost of equipment, sophisticated and delicate technology, most laboratories in resource-limited settings use simple protocols that enumerate only the absolute CD4+ T-lymphocyte counts. We assessed the use of absolute CD4+ T-lymphocyte count as a surrogate marker of pediatric HIV disease progression.
Methods: We analyzed the CD4+ T-lymphocytes and HIV viral load over a 10-year period (1996–2006) of 97 HIV-infected children enrolled in the Yale Prospective Longitudinal Pediatric HIV Cohort using generalized linear mixed models. Both CD4+ T-lymphocytes and HIV viral load were assessed at baseline and every 2–3 months. The modeling approach used in this study allows the intercept and the rate at which outcome variables change over time to vary across participants.
Results: We determined that absolute CD4+ T-lymphocytes count was just as reliable at monitoring pediatric HIV as CD4+ T-lymphocyte percentage. Antiretroviral treatment, regardless of the regimen used, was associated with higher CD+ T-lymphocytes count (P < 0.01). Race was significantly associated with CD4+ T-lymphocytes counts (with lower values for blacks compared with nonblacks; P < 0.01). The presence of other infections was associated with lower CD4+ T-lymphocyte count (P = 0.01) and higher viral load (P < 0.01), respectively.
Conclusions: In situations where determination of CD4+ T-lymphocyte percentages is not readily available, the absolute count may provide an affordable and accessible laboratory surrogate marker of HIV disease progression in children.
From the Departments of *Pediatrics and †Pharmacology, Yale University School of Medicine, New Haven, CT; ‡Pediatric AIDS Care Program, Yale-New Haven Hospital, New Haven, CT; and the §Department of Biostatistics, Harvard University School of Public Health, Boston, MA.
Accepted for publication January 16, 2008.
This study was supported by the grants from the National Institute of Child Health and Human Development (5 N01 HD 3-3345), National Institute of Allergy and Infectious Disease (AI32397 and AI39015), and by Child Health Research Center Award K12HD001401-08 (to E.P.).
Address for correspondence: Elijah Paintsil, MD, Departments of Pediatrics and Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520. E-mail: email@example.com.