Franco Moretti

This 8-year longitudinal study was aimed to analyze the HIV-1 gp120-C2V3C3 sequence dynamics, their phylogenetic relationships and tropism evolution in patients under HAART. Such viral analysis comprised two compartments: plasma and PBMC. Fifty gp120-C2V3C3 genomic sequences were characterized from 16 patients: 41 from plasma when viremia was measurable and 9 from PBMCs if plasma viral load was undetectable. The vast majority of HIV isolates (43 out of 50) were ascribed to BF subtype, irrespective of the compartment (plasma or mononuclear-cells) analyzed. A statistically well-supported clustering phenomenon was observed for each patient sampling data. Each cluster comprised viral sequences from both compartments analyzed. In the vast majority of cases, the viral sequences obtained along active production periods were intermingled with those identified from proviral sequences. A substantial stability of co-receptor tropism for the HIV BF subtype was observed over an 8-year followup.

The evolution of hepatitis C virus (HCV) quasispecies in patients with HIV-1 coinfection is not fully understood. The HCV-1a quasispecies heterogeneity was analyzed at inter and intra-host levels along 7.6 years in 21 coinfected patients that showed different virological and immunological responses to highly active antiretroviral therapy (HAART). Two to nine serial samples were subjected to direct and clonal sequence analyses of the envelope glycoprotein 2 (E2) gene. E2-based phylogenies, intra-host HCV evolution and evolutionary rates, as well as dynamics of the quasispecies heterogeneity parameters were evaluated. Bayesian coalescent phylogenies indicated complex evolutionary histories, revealing some viral lineages that persisted along the follow up and others that were detectable at a single or some sampling times, suggesting the occurrence of emergence-extinction cycles. HCV quasispecies underwent very rapid evolution in HAART-treated patients (~3.1×10(-2) sub/site/year) follow...

Chronic coinfection with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) is among the greatest challenges facing public health worldwide. In this population, the response to hepatitis C therapy by treatment with pegylated interferon plus ribavirin (PEG-IFN+RBV) is lower than in HCV-monoinfected patients, particularly in those infected by HCV genotype 1. A PKR/eIF-2α phosphorylation homology domain (PePHD) within the E2 protein has been found to interact with PKR and inhibit PKR in vitro, suggesting a possible mechanism for HCV to evade the antiviral effects of IFN. The aim of this work was to analyze the amino acid conservation in the HCV-E2-PePHD and quasispecies diversity among HCV-HIV-coinfected patients exhibiting sustained virological response, non-response, or partial response with viral relapse to PEG-IFN+RBV by ultra-deep pyrosequencing. For this purpose, HCV-E2-PePHD PCR products were generated and sequenced directly for four patients with a sustained response, seven patients with no virological response, and four patients with viral relapse before and after treatment with PEG-IFN+RBV. HCV-E2-PePHD amino acid sequences were obtained for isolates from serum collected before and during treatment (24 h, 4 weeks, and 12 weeks). Quasispecies analysis of the HCV-E2-PePHD and flanking genomic regions was performed using 454/Roche pyrosequencing, analyzing 39,364 sequence reads in total. The HCV-E2-PePHD sequence at the amino acid and nucleotide level was highly conserved among HCV genotype 1 strains, irrespective of the PEG-IFN+RBV response. This high degree of amino acid conservation and sporadic mutations in the HCV-E2-PePHD domain do not appear to be associated with treatment outcome. The HCV-E2-PePHD sequence before or during treatment cannot be used to predict reliably the outcome of treatment in patients coinfected with HCV genotype 1 and HIV.

The South American HIV-1 epidemic is characterized by the co-circulation of subtype B and BF recombinant variants. Together with the B and BF genotypes, HIV-1 subtype C (HIV-1C), F1, and several other recombinants have been reported. The epidemiological significance and immune correlates of these "non-B-non-BF" strains circulating in South America are still uncertain and therefore are increasingly attracting the interest of the scientific community. In this study, the South American HIV-1C epidemic was studied using new technologies for the phylogenetic analysis of large datasets. Our results indicate that there is a major clade encompassing most of the South American HIV-1C strains. These analyses also agreed that some strains do not group inside this major clade, suggesting that there could be HIV-1C sequences of different origins circulating in South America. Others have proposed different hypotheses about the origins of HIV-1C strains from South America. This study shows that an exact single origin cannot be determined, a fact that could be attributed to sampling problems, phylogenetic uncertainty, and the shortage of historical and epidemiological data. Currently, the reported data indicate that HIV-1C strains were introduced in Brazil and afterward spread to other regions of South America. By using character optimization on the obtained phylogenetic trees, we observed that Argentina could also be a point in which the HIV-1C epidemic entered South America.

We studied drug resistance mutations (DRMs) in 2623 pol sequences. Out of 94,828 amino acid substitutions that were detected, 8749 corresponded to nucleoside reverse transcriptase inhibitor (NRTI), 3765 to nonnucleoside reverse transcriptase inhibitor (NNRTI), and 7141 to protease inhibitor (PI) resistance-associated mutations. The most common DRMs were L10I, I54V, L90M, V82A, A71V, L10V, M46I, M184V, M41L, T215Y, D67N, L210W, K70R, N348I, V118I, K103N, Y181C, G190A, K101E, V108I, L100I, V90I, K101Q, and A98G. As expected, DRMs frequencies depended on viral genotype. The amounts of NRTI and PI resistance mutations among B and BF sequences from children were higher than among sequences from adults. The frequencies of PI and NRTI resistance mutations among B and BF sequences from adult men were higher than among sequences from women. Some of these observations can be explained in light of the available epidemiological information, but some cannot, indicating that further studies are needed to understand the antiretroviral resistance epidemics in Argentina.