title: High concordance between HIV-1 drug resistance genotypes generated from plasma and dried blood spots in antiretroviral-experienced patients.
abstract: OBJECTIVE
  Dried blood spots (DBS) are a convenient alternative to plasma for drug resistance testing in resource-limited settings. We investigated the correlation between resistance genotypes generated from DBS and plasma.
  
  
  METHODS
  Sixty DBS specimens from HIV-1 subtype B-infected antiretroviral-experienced (n = 58) and naive patients (n = 2) were tested. DBS were prepared using 50 mul blood and were stored with desiccant at -20 degrees C.
  
  
  METHODS
  Resistance genotypes from DBS were obtained using the ViroSeq HIV-1 assay and were compared with genotypes derived from plasma. The frequency of amplification of proviral DNA from DBS was evaluated using an in-house nested polymerase chain reaction assay.
  
  
  RESULTS
  : Fifty of the 60 DBS specimens were successfully genotyped including all 38 specimens collected from patients with plasma viral loads greater than 2000 copies/ml and 12 of 22 DBS (54.5%) from patients with viral loads less than 2000 copies/ml. HIV-1 DNA was detected in 44.4% of the DBS. Despite the presence of DNA, genotypes from DBS and plasma were highly concordant. Of the 316 mutations found in plasma sequences, 306 (96.8%) were also found in DBS. Discrepancies were mostly caused by mixtures at minor protease positions or unusual amino acid changes, and in only two cases were caused by major protease (M46L) or reverse transcriptase (K103N) mutations absent in DBS sequences.
  
  
  CONCLUSIONS
  : We demonstrated a high concordance between resistance genotypes from plasma and DBS, and that resistance testing from DBS can achieve sensitive levels similar to those seen using plasma. Our results indicate that DBS may represent a feasible alternative to plasma for drug resistance testing in treated individuals.
authors.affiliation: Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
authors.forename: Silvina
authors.initials: S
authors.lastname: Masciotra
authors.forename: Carolina
authors.initials: C
authors.lastname: Garrido
authors.forename: Ae S
authors.initials: AS
authors.lastname: Youngpairoj
authors.forename: Amanda
authors.initials: A
authors.lastname: McNulty
authors.forename: Natalia
authors.initials: N
authors.lastname: Zahonero
authors.forename: Angelica
authors.initials: A
authors.lastname: Corral
authors.forename: Walid
authors.initials: W
authors.lastname: Heneine
authors.forename: Carmen
authors.initials: C
authors.lastname: de Mendoza
authors.forename: J Gerardo
authors.initials: JG
authors.lastname: García-Lerma
mesh_terms: D000293:Adolescent; D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D001800:Blood Specimen Collection / Q000379:methods*; D018791:CD4 Lymphocyte Count; D004279:DNA, Viral / Q000235:genetics; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology / Q000821:virology*; D016333:HIV Protease / Q000235:genetics; D017320:HIV Protease Inhibitors / Q000627:therapeutic use; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010802:Phylogeny; D011533:Proviruses / Q000235:genetics; D015203:Reproducibility of Results; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use; D019562:Viral Load; D014766:Viremia / Q000276:immunology / Q000821:virology
chemical_list: D019380:Anti-HIV Agents; D004279:DNA, Viral; D017320:HIV Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors; D054303:HIV Reverse Transcriptase; D016333:HIV Protease