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Performance of a Modified In-House HIV-1 Avidity Assay among a Cohort of Newly Diagnosed HIV-1 Infected Individuals and the Effect of ART on the Maturation of HIV-1 Specific Antibodies

[ Vol. 17 , Issue. 2 ]

Author(s):

Diviya Alex, Tennison Inba Raj Williams, Jaiprasath Sachithanandham, Swaminathan Prasannakumar, John Paul Demosthenes, Veena Vadhini Ramalingam, Punitha John Victor, Priscilla Rupali, Gnanadurai John Fletcher and Rajesh Kannangai*   Pages 134 - 145 ( 12 )

Abstract:


Background: Viral kinetics impact humoral immune response to HIV; antibody avidity testing helps distinguish recent (<6 months) and long-term HIV infection. This study aims to determine the frequency of recent HIV-1 infection among clients attending ICTC (Integrated Counselling and Testing Centre) using a commercial EIA, to correlate it with a modified in-house avidity assay and to study the impact of ART on anti-HIV-1 antibody maturation.

Methods: Commercial LAg Avidity EIA was used to detect antibody avidity among 117 treatment naïve HIV-1 infected individuals. A second-generation HIV ELISA was modified for in-house antibody avidity testing and cutoff was set based on Receiver Operating Characteristic (ROC) analysis. Archived paired samples from 25 HIV-1 infected individuals before ART and after successful ART; samples from 7 individuals responding to ART and during virological failure were also tested by LAg Avidity EIA.

Results: Six individuals (5.1%) were identified as recently infected by a combination of LAg avidity assay and HIV-1 viral load testing. The modified in-house avidity assay demonstrated sensitivity and specificity of 100% and 98.2%, respectively, at AI=0.69 by ROC analysis. Median ODn values of individuals when responding to ART were significantly lower than pre-ART [4.136 (IQR 3.437– 4.827) vs 4.455 (IQR 3.748–5.120), p=0.006] whereas ODn values were higher during virological failure [4.260 (IQR 3.665 – 4.515) vs 2.868 (IQR 2.247 – 3.921), p=0.16].

Conclusion: This modified in-house antibody avidity assay is an inexpensive method to detect recent HIV-1 infection. ART demonstrated significant effect on HIV-1 antibody avidity owing to changes in viral kinetics.

Keywords:

Avidity assay, LAg avidity assay, HIV, recent infection, ART, India.

Affiliation:

Department of Clinical Virology, Christian Medical College, Vellore, Tamil Nadu, 632004, Department of Infectious Diseases, Christian Medical College, Vellore, Tamil Nadu, 632004, Department of Clinical Virology, Christian Medical College, Vellore, Tamil Nadu, 632004, Department of Clinical Virology, Christian Medical College, Vellore, Tamil Nadu, 632004, Department of Clinical Virology, Christian Medical College, Vellore, Tamil Nadu, 632004, Department of Clinical Virology, Christian Medical College, Vellore, Tamil Nadu, 632004, Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, 632004, Department of Infectious Diseases, Christian Medical College, Vellore, Tamil Nadu, 632004, Department of Clinical Virology, Christian Medical College, Vellore, Tamil Nadu, 632004, Department of Clinical Virology, Christian Medical College, Vellore, Tamil Nadu, 632004

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