HIV This Week

Ngo-Giang-Huong N, Khamduang W, Leurent B, Collins I, Nantasen I, Leechanachai P, Sirirungsi W, Limtrakul A, Leusaree T, Comeau AM, Lallemant M, Jourdain G. Early HIV-1 Diagnosis Using In-House Real-Time PCR Amplification on Dried Blood Spots for Infants in Remote and Resource-Limited Settings. J Acquir Immune Defic Syndr. 2008. [Epub ahead of print]

In resource-limited settings, most perinatally HIV-1-infected infants do not receive timely antiretroviral therapy because early HIV-1 diagnosis is not available or affordable. To assess the performance of a low-cost in-house real-time polymerase chain reaction assay to detect HIV-1 DNA in infant dried blood spots. One thousand three hundred nineteen dried blood spots collected throughout Thailand from non-breast-fed infants born to HIV-1-infected mothers were shipped at room temperature to a central laboratory. In-house real-time DNA polymerase chain reaction results were compared with Roche Amplicor HIV-1 DNA test (Version 1.5) results. In addition, Ngo-Giang-Huong and colleagues verified the Roche test performance on dried blood spots sampled from 1218 other infants using as reference HIV serology result at 18 months of age. Real-time DNA polymerase chain reaction and Roche DNA polymerase chain reaction results were 100% concordant. Compared with HIV serology results, the Roche test sensitivity was 98.6% (95% confidence interval: 92.6% to 100.0%) and its specificity at 4 months of age was 99.7% (95% confidence interval: 99.2% to 99.9%). In-house real-time polymerase chain reaction performed as well as the Roche test in detecting HIV-1 DNA on dried blood spots in Thailand. Combined use of dried blood spots and real-time PCR assays is a reliable and affordable tool to expand access to early HIV-1 diagnosis in remote and resource-limited settings, enabling timely treatment for HIV-1-infected infants.

Editors’ note: After drying overnight, dried blood spots (DBS) of only 50 microlitres of blood, obtained through a heelstick procedure, can be sent through the mail from rural and remote settings. This first report of the excellent performance of an in-house real-time HIV DNA polymerase chain reaction (PCR) test, on DBS specimens from non-breast-fed infants of HIV-positive mothers, holds promise for early detection of HIV infection in infants. Real-time PCR assays have high sensitivity and specificity, provide results more rapidly, avoid crossover PCR contamination, and are increasingly affordable. All HIV-infected infants should start on antiretroviral treatment as soon as they are diagnosed because of very high mortality in the first year of life. This highlights the importance of rapid turnaround of DBS results from the testing laboratory back to the clinic.