Human immunodeficiency virus bDNA assay for pediatric cases

Area of Science:

• Virology
• Pediatric Infectious Diseases
• Clinical Diagnostics

Background:

• Antiretroviral therapy monitoring in adults with HIV relies on plasma HIV-1 RNA viral load (VL) quantification.
• Limited data exists on HIV VL quantification in pediatric populations, particularly in Argentina where new assays are being considered.

Purpose of the Study:

• To evaluate a pediatric protocol for the branched DNA (bDNA) assay for quantifying HIV-1 RNA viral load in HIV-infected children.
• To compare the sensitivity and performance of the pediatric protocol versus the standard bDNA assay in different age groups of children.

Main Methods:

• Twenty-five HIV-infected children's plasma samples were analyzed using the Quantiplex HIV RNA 2.0 Assay (Chiron Corporation).
• A pediatric protocol using 50 microliters of plasma (sensitivity: 10,000 copies/ml) was initially employed.
• Samples with undetectable results were re-tested using the standard 1 ml bDNA protocol (sensitivity: 500 HIV-RNA c/ml).
• Children were divided into two groups: under 12 months (group A, n=9) and over 12 months (group B, n=16).

Main Results:

• All infants under 12 months (group A) exhibited high HIV-RNA levels (median: 362,000 c/ml).
• In children over 12 months (group B), the pediatric protocol showed detectable HIV-RNA in only 25% of samples (median: <10,000 c/ml).
• The standard 1 ml protocol detected HIV-RNA in all children in group B (median: 23,300 c/ml), with levels ranging from 950 to 226,200 c/ml.

Conclusions:

• The pediatric protocol for the bDNA assay is potentially useful for HIV viral load monitoring in children under 12 months of age.
• For children over 12 months, the standard 1 ml bDNA protocol is necessary for accurate HIV RNA quantification.
• Undetectable HIV-RNA results in infants under one year using the pediatric protocol warrant confirmation with the standard protocol.