Study of the genotypic-resistant pattern in plasma of a group of HIV-infected Cameroonian pregnant women and children

Abstract number: 1734_191

Turriziani O., Russo G., Lichtner M., Bucci M., Stano A., Sauzullo I., Mengoni F., Ialungo A., Vullo V., Antonelli G.

Objective: To study the genotypic resistance pattern in plasma-HIV RNA derived from HIV-1 infected Cameroonians pregnant women and children.

Patients The samples used in this study derived from a cohort of HIV infected mothers and their children who participated in a PMTCT programme (Prevention mother to child transmission) based on HIV-NET protocol. 49 Cameroonians HIV-1 infected pregnant women and 7 HIV-1 infected children.

Methods: RNA was extracted from 140 mL of plasma using a QIAmp Viral RNA kit (Qiagen, Milan, Italy) following the manufacturer's instructions. Sequencing was undertaken using CLIP, a DNA sequencing technique for direct sequencing of small quantities of amplified template (TruGene HIV-1, Bayer Diagnostics).

Results: Eight out of 49 pregnant women examined and 4 out of 7 children who underwent the treatment develop resistance to NVP. Three of the 4 children harbour a resistant virus different from that of the mothers who indeed harbour a wild variant of the virus. This indicates that the virus has not been transmitted by the mothers but they develop resistance after the treatment received after birth. Since the mothers and children have been treated once and with a single dose of nevirapine, the data also show that NNRTI resistant variants persist also in absence of the drugs.

The sequence analysis of the protease region also revealed the presence of minor PI mutations in 44 of 49 mother's samples studied (median 5 mutations; range 0–7). Interestingly the PR sequence from children revealed the same PI substitutions in 4 cases, while in 3 children the mutations detected were different from those revealed in mother's samples.

Conclusions: These data confirm that one dose of NVP is sufficient to select NNRTI resistant variant which can persist for long time also in the absence of the selective drug. Furthermore our results show that HIV-1 from Cameroonian patients seems to display a peculiar pattern of minor substitution associated to PI resistance. Further studies are needed to verify whether the use of PIs in Cameroon may result in the rapid emergence of PI resistant strain.