Highly diversified multiply drug-resistant HIV-1 quasispecies in PBMCs: a case report.
BACKGROUND
Although drug resistance is a major challenge in HIV therapy, the effect of drug resistance mutations on HIV evolution in vivo is not well understood. We have now investigated genetic heterogeneity in HIV-1 by performing drug resistance genotyping of the PR-RT regions of viruses derived from plasma and peripheral blood mononuclear cells (PBMCs) of a single patient who had failed multiple regimens of anti-retroviral therapy.


RESULTS
Patterns of drug resistance mutations showed that the viral populations in PBMCs were more heterogeneous than in plasma. Extensive analysis of HIV from infected PBMCs in this patient showed that high-level diversity existed among 109 cloned PR-RT sequences and that the majority of mutations were related to drug resistance. Moreover, the PBMCs included archival species that reflected the treatment history of the patient while those in plasma were mainly related to the most recent treatment. Some of the proviral clones contained single or multiple mutations in various combinations. Approximately eighteen percent of the proviral clones derived from infected PBMCs were defective, i.e. 5.5% contained single nucleotide deletions (frameshift mutations) and 12.8% encoded in-frame stop codons (nonsense mutations). Amino acid substitutions in PR and the polymerase region of RT occurred in 12-15% of cases but were much less frequent in the RNase H region of RT, which might not have been under drug selection pressure.


CONCLUSIONS
Selective drug pressure can yield multiple drug-resistant quasispecies that include archival and replication-incompetent species in PBMC reservoirs.
Quan
Yudong
Y
McGill University AIDS Centre, Lady Davis Institute-Jewish General Hospital, 3755 Cote Ste-Catherine Road, Montreal, Quebec, H3T 1E2, Canada. yudongquan@yahoo.com
Brenner
Bluma G
BG
Dascal
André
A
Wainberg
Mark A
MA
D019943:Amino Acid Substitution / Q000235:genetics; D019380:Anti-HIV Agents / Q000627:therapeutic use; D018389:Codon, Nonsense; D004252:DNA Mutational Analysis; D024882:Drug Resistance, Viral / Q000235:genetics*; D016368:Frameshift Mutation; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology*; D016333:HIV Protease / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology*; D020125:Mutation, Missense; D010949:Plasma / Q000821:virology*; D011110:Polymorphism, Genetic; D011533:Proviruses / Q000235:genetics; D012641:Selection, Genetic; D017384:Sequence Deletion
D019380:Anti-HIV Agents; D018389:Codon, Nonsense; D054303:HIV Reverse Transcriptase; D016333:HIV Protease