• Froggett, Steve
• Ngayo, Musa
• Majiwa, Maxwel
• Wamalwa, Dalton
• Emery, Sandra
• John-Stewart, Grace
• Overbaugh, Julie

Abstract

<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>The aim of this study was to develop an economical 'in-house' single round polymerase chain reaction (PCR) assay using filter paper-dried blood spots (FP-DBS) for early infant HIV-1 diagnosis and to evaluate its performance in an African setting.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>An 'in-house' single round PCR assay that targets conserved regions in the HIV-1 polymerase (<jats:italic>pol</jats:italic>) gene was validated for use with FP-DBS; first we validated this assay using FP-DBS spiked with cell standards of known HIV-1 copy numbers. Next, we validated the assay by testing the archived FP-DBS (N = 115) from infants of known HIV-1 infection status. Subsequently this 'in-house' HIV-1 <jats:italic>pol</jats:italic> PCR FP-DBS assay was then established in Nairobi, Kenya for further evaluation on freshly collected FP-DBS (N = 186) from infants, and compared with findings from a reference laboratory using the Roche Amplicor<jats:sup>®</jats:sup> HIV-1 DNA Test, version 1.5 assay.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The HIV-1 <jats:italic>pol</jats:italic> PCR FP-DBS assay could detect one HIV-1 proviral copy in 38.7% of tests, 2 copies in 46.9% of tests, 5 copies in 72.5% of tests and 10 copies in 98.1% of tests performed with spiked samples. Using the archived FP-DBS samples from infants of known infection status, this assay was 92.8% sensitive and 98.3% specific for HIV-1 infant diagnosis. Using 186 FP-DBS collected from infants recently defined as HIV-1 positive using the commercially available Roche Amplicor v1.5 assay, 178 FP-DBS tested positive by this 'in-house' single-round HIV-1 <jats:italic>pol</jats:italic> PCR FP-DBS PCR assay. Upon subsequent retesting, the 8 infant FP-DBS samples that were discordant were confirmed as HIV-1 negative by both assays using a second blood sample.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>HIV-1 was detected with high sensitivity and specificity using both archived and more recently collected samples. This suggests that this 'in-house' HIV-1 <jats:italic>pol</jats:italic> FP-DBS PCR assay can provide an alternative cost-effective, reliable and rapid method for early detection of HIV-1 infection in infants.</jats:p></jats:sec>

Topics

• size-exclusion chromatography