final program.qxd - Parallels Plesk Panel

PP 3.23
Proviral DNA and plasma viral RNA resistance mutations in HIV1 naive patients
B. Kabamba Mukadi1, A. Dusquenne 1 , J. Ruelle 1 , J-C. Yombi 2 , B. Vandercam 2 ,
M. Bodéus 1 , P. Goubau 1 .
1
Laboratoire de référence SIDA,
2
Centre de prise en charge,
Université Catholique de Louvain,
Avenue Hippocrate 10, 1200 Bruxelles, Belgium.
Objectives
HIV mutations associated with antiretroviral drug resistance may be carried by
transmitted strains in therapy naive patients. At present, HIV-1 drug resistance mutations
are detected by analysing plasma viral RNA. The HIV-1 proviral DNA could be an
alternative marker, as it is known that proviral DNA persists in infected cells, even after
prolonged successful HAART.
Methods
This is a prospective study of the prevalence of HIV-1 drug mutations in proviral DNA from
purified CD4+ cells as compared to the plasma viral RNA in naive patients. The Forty tree
selected naive patients had a mean viral load of 5.27 log (2.6 - 5.87) with a mean CD4
lymphocyte value of 338/mm3 (6 - 1460). They include 58 % of Europeans and 42 % of
non-Europeans, mostly people from central Africa. Sequenced HIV-1 viruses comprise
39% and 61% of subtype B and non-B, respectively. Genotypic antiretroviral drug
resistance mutations were determined by an in house RT- PCR method applied on RT and
PR genes. Direct cycle sequencing was carried out on the ABI Prism 310 sequencer. In
case of PCR failure, samples were analysed by Versant HIV-1 Resistant Kit. Identified
mutations were those listed in the ARNS algorithm list (September 2005).
Results
Out of the 380 detected resistance mutations, 213 and 167 mutations were detected in
CD4+ cells and in the plasma, respectively. Fifty five percent of PR mutations and 22,5%
of RT mutations were simultaneously present in both CD4+ cells and plasma. The
prevalence of patients with viruses carrying at least 3 secondary PR mutations was 86,2%
and 74,4% in CD4+ cells and in the plasma, respectively. Forty percent of patients had at
least 1 RT mutation in CD4+ cells while 33% had at least 1 RT resistance mutation in the
plasma. The only detected proviral RT key mutations were M184V and M184I (5.3% of RT
mutations) in different patients, but not found in the plasma. The final resistance mutations
interpretation showed 93% of identical results in both CD4+ cells and plasma. One patient
had a virus with RT resistant profile (67N, 70R, 219Q) in both CD4+ cells and plasma.
Conclusion
We cannot exclude the presence of minority resistant viruses as a consensus sequence
was obtained and the sensitivity of sequencing to detect mixed populations is commonly
estimated to be between 20 and 50%. Although wild-type virus may overgrow any initial
resistant virus in patients with chronic asymptomatic HIV infection, a very low prevalence
of key mutations was detected. The only frequent mutations detected were protease
secondary mutations, which are less relevant for drug resistance. HIV1 proviral DNA
resistance testing may be useful in chronically infected individuals or in patients with
undectable viremia as more resistance mutations were detected in CD4+ cells.
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