Reverse transcriptase activity for quantitation of HIV-1 subtype C in plasma: Relation to RNA copy number and CD4 T-cell count

• Published in: Journal of medical virology Vol. 78; no. 2; pp. 161 - 168
• Main Authors: Seyoum, Elizabeth, Wolday, Dawit, Girma, Mulu, Malmsten, Anders, Meselle, Tsehaynesh, Gronowitz, J. Simon, Britton, Sven
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-02-2006; Wiley-Liss
• Subjects: Biological and medical sciences; CD4 Lymphocyte Count; CD4 T-cell count; enzyme activity; Ethiopia; Fundamental and applied biological sciences. Psychology; HIV Infections - immunology; HIV Infections - metabolism; HIV Infections - virology; HIV Reverse Transcriptase - blood; HIV-1 - genetics; HIV-1 - isolation & purification; HIV-1 - metabolism; HIV-1 subtype C; Human immunodeficiency virus 1; Human viral diseases; Humans; Infectious diseases; Medical sciences; Medicin och hälsovetenskap; Microbiology; Miscellaneous; Prospective Studies; reverse transcriptase; RNA, Viral - blood; Viral diseases; Viral Load; Virology; Ethiopia; Africa; RNA-directed DNA polymerase; HIV-1 virus; Enzyme; Copy number; reverse transcriptase; Transferases; Retroviridae; Lentivirus; Virus; Nucleotidyltransferases; HIV-1 subtype C; enzyme activity; T-Lymphocyte; Human immunodeficiency virus; Viral load; Subtype; CD4 T-cell count; Ethiopia; Quantitative analysis
• ISSN: 0146-6615; 1096-9071
• DOI: 10.1002/jmv.20523

The present study monitored the changes in human immunodeficiency virus (HIV) viral load using a reverse transcriptase (RT) assay and an HIV‐1 RNA based assay, and relates these data to the dynamics of CD4 cell counts. The samples examined originate from a prospective study of HIV‐1 subtype C infected, untreated Ethiopians followed twice yearly over a period of up to 5 years. The ExaVir Load test, version 1, was used for isolation and quantitation of HIV‐1 RT in plasma. The RT activities recovered were compared to the HIV‐1 RNA copy numbers, which had been determined previously by the NucliSens HIV‐1 QT Test. There was a significant correlation between the data obtained in the two tests (r = 0.65, P < 0.0001). During follow‐up, the median RT and RNA levels increased more or less in parallel up to approximately four times the values at admittance. CD4 cell counts, which had also been determined previously, decreased slowly but continuously from approximately 310 to 190 CD4 cells/ml. In the majority of individual patients, there was an inverse correlation between CD4 T‐cell counts and RT activity, and with the RNA copy number, and the data obtained by either test could be used to predict CD4 T‐cell counts. The ExaVir Load test thus provides data equivalent to the estimation of the number of HIV‐1 RNA copies for the prediction of CD4 T‐cell counts. It is based on a simple technique, can be run in any routine diagnostic laboratory, and is a competitive alternative for use in resource limited settings. J. Med. Virol. 78:161–168, 2006. © 2005 Wiley‐Liss, Inc.