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Quantification of Viral load and resistance tests of HIV-1 to ARVs from dried blood spots samples in Guinean patients undergoing antiretroviral treatment. Problem: As in several countries of the South, the virological monitoring of patients undergoing antiretroviral treatment (ARVT) in Guinea is low or non-existent in some locations. The aim of this study was to assess the technical and logistical feasibility of the use of (dried blood spots) DBSs in viral load (VL) and genotyping tests. Method: From September 2010 to October 2010, DBS were prepared from blood samples of adult patients under ARVT. The samples had to be sent to the reference laboratory within 30 days after the sample had been done at ambient temperature. The VL was quantified and the samples of patients with virological failure (CV ≥ 3 log10 copies/mL) were genotyped according to the ANRS protocol. The Stanford algorithm, version 6.0.8, was used to analyse and interpret the resistance mutations. Results: Amongst the 136 included patients, 129 and 7 were under first and second line treatment respectively, and monitored for an average of 35 months [IQR: 6-108]. Virological failure was noticed among 33 patients. Among them, 84.8% (n = 28/33) benefited from genotyping. The global resistance rate was 14% (n = 19/136). CRF02_AG was the most prevalent viral subtype (82%; n = 23). Conclusion: In addition to demonstrating the technical and logistic feasibility of VL and genotyping tests from DBSs, these results show the relevance of their use in the virological monitoring of patients under ARVT. Also, this study made it possible to provide information on virological failure, ARV resistance and the HIV-1 genetic diversity in Guinea.
RESUMEN
INTRODUCTION: Access to antiretroviral treatment (ART) becomes more and more effective in resource-limited settings (RLS). However, this global effort would be even more profitable if the access to laboratory services especially in decentralized settings was strengthened. We report the virological outcome and HIV-1 drug resistance in three West African countries using dried blood spots (DBS) samples. METHODS: We included HIV-1-infected adults on ART ≥6 months and followed up in capital cities and decentralized sites in Senegal, Mali and Guinea-Conakry. Patients were consecutively enrolled and DBS were collected in field conditions and kept at ambient temperature before transfer to the reference laboratory. Viral load (VL) was quantified using the NucliSENS EasyQ HIV-1 v1.2. Genotyping of HIV-1 pol gene was performed using in-house protocol. RESULTS: Of the 407 participants, 119, 152 and 136 were from Senegal, Mali and Guinea-Conakry, respectively. The median treatment duration was 36 months [IQR: 6-136]. Virological failure (VF) (VL≥3log10 copies/mL) was observed in 26% (95% confidence interval (CI), 18-35; n=31), 11% (95% CI, 6-17; n=16) and 24% (95% CI, 17-32; n=33) of patients in Senegal, Mali and Guinea-Conakry, respectively (p=0.001). Of samples presenting VL≥3log10 copies/mL (n=80), 70 were successfully genotyped. At least one drug resistance mutation (DRM) was detected in the following proportions: 70% (95% CI, 50-86; n=19), 93% (95% CI, 68-100; n=14) and 68% (95% CI, 48-84; n=19) in Senegal, Mali and Guinea-Conakry, respectively (p=0.22). Twenty-six per cent (26%; 95% CI, 16-38; n=18) of patients in VF harboured wild-type viruses, which is likely indicative of weak adherence. Phylogenetic analysis showed the predominance of CRF02_AG subtype (73%; 95% CI, 61-83; n=51). CONCLUSIONS: We describe the ART outcome in capital and rural settings of Senegal, Mali and Guinea-Conakry. Our results in all of the three countries highlight the need to reinforce the ART adherence in order to minimize the occurrence of drug resistance. In addition, these findings provide additional evidence that the use of DBS as a sampling support could assist virological monitoring of patients on ART in remote areas.