False I50V resistance readings of HIV isolates: co-amplification of NASBA HIV-1 RNA QT internal calibrators and HIV-1 patient isolates may lead to a false I50V mutation resistance reading in genotypic tests

Arch Virol. 2008;153(8):1489-94. doi: 10.1007/s00705-008-0138-2. Epub 2008 Jul 4.

Abstract

The I50V protease inhibitor (PI) resistance mutation was found in 87.4% of protease gene fragments sequenced from 199 nucleic acid isolates extracted using an NASBA virus load assay, performed between 1997 and 2001 in Brazil. This mutation is an amprenavir-related mutation, and at that particular time this PI was seldom used in Brazil. This mutation was found both in patients with and without therapeutic success. Q calibrators showed the PI resistance mutation I50V when directly amplified and sequenced from the 423-bp PCR product targeting protease gene. The majority of the patients' samples had a mixture of I50I and I50V; however, this artifact was nor seen when a 989-bp PCR product was used. These results show that RNA extracted using virus load kits need to be critically evaluated before being used in home-brew genotypic tests.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-HIV Agents / pharmacology
  • Anti-HIV Agents / therapeutic use
  • Drug Resistance, Viral / genetics
  • False Positive Reactions*
  • HIV Infections / genetics
  • HIV Infections / virology
  • HIV Protease / genetics
  • HIV Protease / metabolism
  • HIV Protease Inhibitors / pharmacology*
  • HIV Protease Inhibitors / therapeutic use
  • HIV-1 / drug effects
  • HIV-1 / genetics*
  • Humans
  • Mutation
  • RNA, Viral / analysis
  • Reagent Kits, Diagnostic / standards*
  • Reagent Kits, Diagnostic / statistics & numerical data
  • Viral Load

Substances

  • Anti-HIV Agents
  • HIV Protease Inhibitors
  • RNA, Viral
  • Reagent Kits, Diagnostic
  • HIV Protease