title: Establishment and evaluation of a loop-mediated isothermal amplification (LAMP) assay for the semi-quantitative detection of HIV-1 group M virus.
abstract: The past decade has witnessed a dramatic increase of anti-retroviral treatment of human immunodeficiency virus (HIV) infected patients in many African countries. Due to costs and lack of currently available commercial viral load assays, insufficient attention has been paid to therapy monitoring through measurement of plasma viral load. This challenge of patient monitoring by tests as viral load, CD4 cell count, and finally HIV drug resistance could reverse achievements already made against HIV/AIDS infection. Loop-mediated isothermal amplification (LAMP) has been shown to be simple, rapid and cost-effective, characteristics which make this assay suitable for viral load monitoring in resource limited settings. This paper describes a revised LAMP assay using primers in the HIV-1 integrase region. The assay can be used for semi-quantitative measurement of HIV-1 group M viral load. The lower limit of detection (LLOD) was determined as 1200copies/mL and lower limit of quantitation (LLOQ) at 9800copies/mL. Sensitivities of 82 and 86% (in 135 and 99 plasma samples respectively from Kenya) and 93% (in 112 plasma samples from Germany) and specificities of 99 and 100% were realized. HIV-1 group O and HIV-2 virus samples were not detected. This LAMP assay has the potential for semi-quantitation of HIV-1 group M viral load in resource limited countries. There is still a need for further improvement by refinement of primers in respect to detection of HIV-1 group M non-B virus.
authors.affiliation: Max von Pettenkofer-Institute for Hygiene and Medical Microbiology (MVPI), Ludwig-Maximilians-University, Pettenkofer Strasse 9a, 80336 Munich, Germany; Center for International Health (CIH) at the Ludwig-Maximilians-University, Leopoldstraße 7, 80802 Munich, Germany; Department of Medical Microbiology, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62 000, 00200 Nairobi, Kenya. Electronic address: Kodarie04@yahoo.com.
authors.forename: Eddy Okoth
authors.initials: EO
authors.lastname: Odari
authors.affiliation: Kenya Medical Research Institute (KEMRI), Mbagathi, P.O. Box 54840, Nairobi, Kenya.
authors.forename: Alex
authors.initials: A
authors.lastname: Maiyo
authors.affiliation: Kenya Medical Research Institute (KEMRI), Mbagathi, P.O. Box 54840, Nairobi, Kenya.
authors.forename: Raphael
authors.initials: R
authors.lastname: Lwembe
authors.affiliation: Max von Pettenkofer-Institute for Hygiene and Medical Microbiology (MVPI), Ludwig-Maximilians-University, Pettenkofer Strasse 9a, 80336 Munich, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Gurtler
authors.affiliation: Max von Pettenkofer-Institute for Hygiene and Medical Microbiology (MVPI), Ludwig-Maximilians-University, Pettenkofer Strasse 9a, 80336 Munich, Germany.
authors.forename: Josef
authors.initials: J
authors.lastname: Eberle
authors.affiliation: Max von Pettenkofer-Institute for Hygiene and Medical Microbiology (MVPI), Ludwig-Maximilians-University, Pettenkofer Strasse 9a, 80336 Munich, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Nitschko
mesh_terms: D016903:Drug Monitoring / Q000379:methods; D005838:Genotype; D005858:Germany; D015658:HIV Infections / Q000821:virology*; D015497:HIV-1 / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007630:Kenya; D012680:Sensitivity and Specificity; D019562:Viral Load / Q000379:methods*
keywords: HIV-1 integrase primer; Kenya; LAMP assay; Semi-quantitative; Viral load