title: Subtype variability, virological response and drug resistance assessed on dried blood spots collected from HIV patients on antiretroviral therapy in Angola.
abstract: BACKGROUND
  Subtype variability may influence treatment response and selection of drug resistance mutations in HIV-positive patients on antiretroviral therapy.
  
  
  METHODS
  A retrospective study was performed on specimens collected on dried blood spots (DBS) from HIV-positive individuals receiving antiretroviral therapy in Luanda, Angola. HIV-RNA, drug resistance mutations and subtypes were examined in 294 HIV-positive patients treated with two nucleoside analogues (NA) plus one non-nucleoside reverse transcriptase inhibitor (NNRTI).
  
  
  RESULTS
  Overall, 217 (74%) had <1000 HIV-RNA copies/mL after a median of 12 months (range 7-24) of therapy. CD4 count was significantly higher in subjects with undetectable viraemia compared with viraemic patients (294 versus 220 cells/mm3; P = 0.003). Reverse transcriptase and/or gp41 genes could be genotyped in only 45 (58%) of viraemic patients, probably due to poor storage conditions of DBS. The most frequent resistance mutations were M184V (70%) and K103N (39%); 65% had mutations conferring resistance to both NA and NNRTI. Only five patients did not show resistance mutations. A wide HIV-1 subtype heterogeneity was found: 6 C (18.2%), 2 F (6%), 2 H (6%), 1 D (3%), 1 G (3%), 8 CRF02_AG (24.2%), 2 CRF06 (6%), 1 CRF01_AE (3%), 1 CRF14_BG (3%), 1 CRF25 (3%) and 1 CRF19 (3%). HIV clade could not be assigned in 7 (21%).
  
  
  CONCLUSIONS
  Nearly three-quarters of HIV-positive individuals who began an NNRTI-based triple regimen in Angola showed undetectable viraemia after a median of 12 months of therapy, a rate similar to that reported in Western countries. Specimens collected on DBS may allow monitoring of treatment response in resource-limited regions, although adequate temperature and humidity storage conditions are important to ensure RNA stability and further successful testing.
authors.affiliation: Department of Infectious Diseases, Hospital Carlos III, Madrid, Spain.
authors.forename: Carolina
authors.initials: C
authors.lastname: Garrido
authors.forename: Natalia
authors.initials: N
authors.lastname: Zahonero
authors.forename: Diana
authors.initials: D
authors.lastname: Fernándes
authors.forename: Dulcelina
authors.initials: D
authors.lastname: Serrano
authors.forename: Ana Rita
authors.initials: AR
authors.lastname: Silva
authors.forename: Nelia
authors.initials: N
authors.lastname: Ferraria
authors.forename: Francisco
authors.initials: F
authors.lastname: Antúnes
authors.forename: Juan
authors.initials: J
authors.lastname: González-Lahoz
authors.forename: Vincent
authors.initials: V
authors.lastname: Soriano
authors.forename: Carmen
authors.initials: C
authors.lastname: de Mendoza
mesh_terms: D000328:Adult; D000810:Angola / Q000453:epidemiology; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D015658:HIV Infections / Q000097:blood* / Q000188:drug therapy / Q000235:genetics*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics*; D006801:Humans; D008297:Male; D012189:Retrospective Studies