JAC Advance Access originally published online on January 24, 2008
Journal of Antimicrobial Chemotherapy 2008 61(3):694-698; doi:10.1093/jac/dkm515
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Original research |
Subtype variability, virological response and drug resistance assessed on dried blood spots collected from HIV patients on antiretroviral therapy in Angola
1 Department of Infectious Diseases, Hospital Carlos III, Madrid, Spain 2 Faculty of Medicine and Department of Infectious Diseases, Hospital Santa María, Lisbon, Portugal 3 HIV Unit, Hospital Esperança, Luanda, Angola
Received 11 August 2007; returned 26 November 2007; revised 8 October 2007; accepted 5 December 2007
*Correspondence address. Department of Infectious Diseases, Hospital Carlos III, Sinesio Delgado 10, 28029 Madrid, Spain. Tel: +34-91-4532500; Fax: +34-91-7336614; E-mail: cmendoza{at}teleline.es
Background: Subtype variability may influence treatment response and selection of drug resistance mutations in HIV-positive patients on antiretroviral therapy.
Patients and 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.
Keywords: DBS , viral load , HIV subtypes , non-B subtypes