MicroRNA signature from extracellular vesicles of HCV/HIV co-infected individuals differs from HCV mono-infected

Hepatitis C virus (HCV) coinfection with human immunodeficiency virus (HIV) has a detrimental impact on disease progression. Increasing evidence points to extracellular vesicles (EVs) as important players of the host-viral cross-talk. The microRNAs (miRNAs), as essential components of EVs cargo, are key regulators of normal cellular processes and also promote viral replication, viral pathogenesis, and disease progression. We aimed to characterize the plasma-derived EVs miRNA signature of chronic HCV infected and HIV coinfected patients to unravel the molecular mechanisms of coinfection. EVs were purified and characterized from 50 plasma samples (21 HCV mono- and 29 HCV/HIV co-infected). EV-derived small RNAs were isolated and analyzed by massive sequencing. Known and de novo miRNAs were identified with miRDeep2. Significant differentially expressed (SDE) miRNA identification was performed with generalized linear models and their putative dysregulated biological pathways were evaluated. Study groups were similar for most clinical and epidemiological characteristics. No differences were observed in EVs size or concentration between groups. Therefore, HCV/HIV co-infection condition did not affect the concentration or size of EVs but produced a disturbance in plasma-derived EVs miRNA cargo. Thus, a total of 149 miRNAs were identified (143 known and 6 de novo) leading to 37 SDE miRNAs of which 15 were upregulated and 22 downregulated in HCV/HIV co-infected patients. SDE miRNAs regulate genes involved in inflammation, fibrosis, and cancer, modulating different biological pathways related to HCV and HIV pathogenesis. These findings may help to develop new generation biomarkers and treatment strategies, in addition to elucidate the mechanisms underlying virus-host interaction. KEY MESSAGES: HCV and HCV/HIV displayed similar plasma-EV size and concentration. EVs- derived miRNA profile was characterized by NGS. 37 SDE miRNAs between HCV and HCV/HIV were observed. SDE miRNAs regulate genes involved in inflammation, fibrosis and cancer.

HCV spontaneous clearers showed low senescence profile in people living with HIV under long ART

Coinfection with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) increases immune activation, inflammation, and oxidative stress that could lead to premature senescence. Different HCV infections, either acute or chronic infection, could lead to distinct premature cellular senescence in people living with HIV (PLWHIV). Observational study in 116 PLWHIV under antiretroviral treatment with different HCV status: (i) n = 45 chronically infected with HCV (CHC); (ii) n = 36 individuals who spontaneously clarify HCV (SC); (iii) n = 35 HIV controls. Oxidative stress biomarkers were analyzed at lipid, DNA, protein, and nitrates levels, as well as antioxidant capacity and glutathione reductase enzyme. Replicative senescence was evaluated by relative telomere length (RTL) measurement. Additionally, 26 markers of Senescence-Associated Secretory Phenotype (SASP) were analyzed by multiplex immunoassays (Luminex xMAP technology). Differences were evaluated by generalized linear model (GLMs) adjusted by most significant covariates. The SC group had a senescence signature similar to the HIV control group and slightly lower SASP levels. However, significant differences were observed with respect to the CHC group, where an increase in the nitrate concentration [adjusted arithmetic mean ratio, aAMR = 1.73 (1.27-2.35), p < 0.001, q = 0.009] and the secretion of 13 SASP-associated factors [granulocyte macrophage colony-stimulating factor (GM-CSF), interferon-β, interleukin (IL)-1β, IL-2, IL-8, IL-13, tumor necrosis factor (TNF)-α, IL-1α, IL-1RA, IL-7, IL-15, C-X-C motif chemokine ligand 10 (IP-10), stem cell factor (SCF); q < 0.1)] was detected. The CHC group also showed higher values of IL-1α, IP-10, and placental growth factor 1 (PIGF-1) than HIV controls. The SC group showed a slightly lower senescence profile than the HIV group, which could indicate a more efficient control of viral-induced senescence due to their immune strengths. Chronic HCV infection in PLWHIV led to an increase in nitrate and elevated SASP biomarkers favoring the establishment of viral persistence.

Dynamics of cellular senescence markers after HCV elimination spontaneously or by DAAs in people living with HIV

BACKGROUND

We identified that acute or chronic Hepatitis C (HCV) infection in people living with HIV (PLWHIV) results in different senescence profiles. However, variations in these profiles after HCV elimination, spontaneously or with direct-acting antivirals (DAAs), remain unclear.

METHODS

Longitudinal observational study (48 weeks) in 70 PLWHIV: 23 PLWHIV with active HCV-chronic infection (CHC) before and after HCV eradication with DAAs, 12 PLWHIV who spontaneously clarify the HCV (SC), and 35 controls (HIV). Oxidative stress was quantified at DNA, lipid, protein, and nitrate levels, as well as the antioxidant capacity and glutathione enzyme. The replicative senescence was evaluated by relative telomere length measurement by PCR and twenty-six factors related to Senescence-Associated Secretory Phenotype (SASP) were characterized by Luminex. Differences in senescence markers was evaluated by generalized linear models.

RESULTS

During follow-up, the SC group achieved a significant improvement in glutathione enzyme and lipid peroxidation. The secretion of SASP markers increased but was still lower than that of the HIV group. Overall, the CHC group reduced the levels of oxidative stress and SASP markers to levels like those of the HIV group. No significant differences in telomere shortening were observed between groups.

CONCLUSIONS

As the time since spontaneous resolution of HCV infection increased, patients had an improved senescence profile compared to the HIV group. Elimination of chronic HCV infection by DAAs led to a partial improvement of the senescent profile by restoring oxidative stress levels. However, although some SASP markers reached levels like those of the HIV group, others remained altered.

903 Protein Saver cards: the best alternative for dried blood spot storage at room temperature for HCV RNA

Hepatitis C virus (HCV) infection remains a global health problem, detected only in the early stages by molecular tests. Molecular tests detect HCV RNA, which is very prone to degradation by ribonucleases, reason why blood samples must be transported and stored at − 20 °C, or even − 70 °C for long-term storage. Flinders Technology Associates (FTA) cards are a useful sampling collecting device for dry blood spot (DBS) storage, especially for low and middle-income countries (LMIC). In this study, we analyzed viral HCV RNA integrity for long-term storage at room temperature compared to − 20 °C using two different types of cards for DBS: FTA Classic and 903 Protein Saver cards. For this purpose, DBS were prepared on these cards using blood or plasma samples from HCV infected patients, and samples were analysed by conventional RT-PCR. Our results showed that 903 Protein Saver cards are the best and cheapest alternative for DBS storage at room temperature. In these conditions, we found that HCV RNA integrity lasted for up to 9 months.

Cross-Recognition of SARS-CoV-2 B-Cell Epitopes with Other Betacoronavirus Nucleoproteins

The B and T lymphocytes of the adaptive immune system are important for the control of most viral infections, including COVID-19. Identification of epitopes recognized by these cells is fundamental for understanding how the immune system detects and removes pathogens, and for antiviral vaccine design. Intriguingly, several cross-reactive T lymphocyte epitopes from SARS-CoV-2 with other betacoronaviruses responsible for the common cold have been identified. In addition, antibodies that cross-recognize the spike protein, but not the nucleoprotein (N protein), from different betacoronavirus have also been reported. Using a consensus of eight bioinformatic methods for predicting B-cell epitopes and the collection of experimentally detected epitopes for SARS-CoV and SARS-CoV-2, we identified four surface-exposed, conserved, and hypothetical antigenic regions that are exclusive of the N protein. These regions were analyzed using ELISA assays with two cohorts: SARS-CoV-2 infected patients and pre-COVID-19 samples. Here we describe four epitopes from SARS-CoV-2 N protein that are recognized by the humoral response from multiple individuals infected with COVID-19, and are conserved in other human coronaviruses. Three of these linear surface-exposed sequences and their peptide homologs in SARS-CoV-2 and HCoV-OC43 were also recognized by antibodies from pre-COVID-19 serum samples, indicating cross-reactivity of antibodies against coronavirus N proteins. Different conserved human coronaviruses (HCoVs) cross-reactive B epitopes against SARS-CoV-2 N protein are detected in a significant fraction of individuals not exposed to this pandemic virus. These results have potential clinical implications.

Persistent low-Level viremia in persons living with HIV undertreatment: An unresolved status

Antiretroviral therapy (ART) allows suppressed viremia to reach less than 50 copies/mL in most treated persons living with HIV (PLWH). However, the existence of PLWH that show events of persistent low-level viremia (pLLV) between 50 and 1000 copies/mL and with different virological consequences have been observed. PLLV has been associated with higher virological failure (VF), viral genotype resistance, adherence difficulties and AIDS events. Moreover, some reports show that pLLV status can lead to residual immune activation and inflammation, with an increased risk of immunovirological failure and a pro-inflammatory cytokine level which can lead to a higher occurrence of non-AIDS defining events (NADEs) and other adverse clinical outcomes. Until now, however, published data have shown controversial results that hinder understanding of the true cause(s) and origin(s) of this phenomenon. Molecular mechanisms related to viral reservoir size and clonal expansion have been suggested as the possible origin of pLLV. This review aims to assess recent findings to provide a global view of the role of pLLV in PLWH and the impact this status may cause on the clinical progression of these patients.

Diarrhoea-causing enteric protist species in intensively and extensively raised pigs (Sus scrofa domesticus) in Southern Spain. Part II: Association with Hepatitis E virus susceptibility

Enteropathogenic parasites can infect a wide range of mammals, including humans, supposing an important zoonotic risk. Hepatitis E virus (HEV) is an emerging foodborne pathogen of increasing public health relevance, affecting both humans and animal populations. Because both microorganisms share faecal-oral transmission route they may constitute an excellent model to evaluate the interplay between them. Thus, we aim to evaluate the viral-parasite interactions at the enteric interface in swine. We included pigs of two different breeds farming in South Spain under different production systems. We compared the HEV prevalence by the presence of Giardia duodenalis, Cryptosporidium spp., Balantioides coli, Blastocystis sp. and Enterocytozoon bieneusi in faecal samples. The HEV prevalence was 13.1 (62 out 475, 95% CI: 10.2-16.4). Those pigs infected with Cryptosporidium spp. showed a higher prevalence of HEV (30.8 vs. 12%; p = .012). In the same way, animals bearing E. bieneusi seem to have a higher rate of HEV infection (24.2 vs. 12.2%; p = .06). According to their location in the gut, animals bearing intracellular enteroparasites showed a higher HEV prevalence than those uninfected (29.6 vs. 12.7%; p = .038), meanwhile those carrying extracellular enteroparasites had a lower likelihood to be infected by HEV than those uninfected (12.1 vs. 23.1%; p = .071). Those animals bearing both types of enteroparasites showed a similar prevalence of HEV infection than those exhibiting negative for both (20.8 vs. 26.1%; p = .763). Our study provides evidence that intracellular and extracellular enteroparasites modulate the susceptibility to HEV infection in pigs. Meanwhile, the presence of extracellular enteroparasites shows a protective effect on the risk of HEV acquisition in swine, whereas intracellular enteroparasites seems to have the opposite effect, favouring the HEV infection.

HCV eradication with DAAs differently affects HIV males and females: A whole miRNA sequencing characterization

Gender-specific consequences after HCV eradication are unexplored. MicroRNAs (miRNAs) play a crucial role in the immune response against viral infections. However, few have highlighted miRNA role in sex-biased disease or therapy response. We aim to assess gender differences reflected in the miRNA expression of HIV/HCV-coinfected patients who achieve sustained virological response (SVR) with direct acting antivirals (DAAs). We conducted a prospective study of miRNA expression in PBMCs from 28 chronic HIV/HCV-coinfected patients (HIV/HCV) at baseline and after achieving SVR with DAAs. Sixteen HIV-monoinfected patients (HIV) and 36 healthy controls (HC) were used as controls. Identification of significant differentially expressed (SDE) miRNAs was performed with generalized linear model and mixed GLMs. We also explored putative dysregulated biological pathways. At baseline, the HIV/HCV patients showed differences in the miRNA profile concerning the HIV group (165 and 102 SDE miRNAs for males and females, respectively). Gender-stratified analysis of HIV/HCV group at baseline versus at SVR achievement showed higher differences in males (80 SDE miRNAs) than in females (55 SDE miRNAs). After SVR, HIV/HCV group showed similar values to HIV individuals, especially in females (1 SDE miRNA). However, ten miRNAs in males remained dysregulated, which were mainly involved in cancer, fatty acid, and inflammatory pathways. Taken together, our results show gender-biased dysregulation in the miRNA expression profile of PBMCs after HCV eradication with DAAs. These differences were normalized in females, while miRNA profile and their target-related pathways in males lack of normalization, which may be related to a high-risk of developing liver-related complications.

Diarrhoea-causing enteric protist species in intensively and extensively raised pigs (Sus scrofa domesticus) in Southern Spain. Part I: Prevalence and genetic diversity

Numerous protist species are shared between humans and pigs. Among those, Giardia duodenalis, Cryptosporidium spp. and Balantioides coli have a clear public and animal health significance. For others such as Enterocytozoon bieneusi and Blastocystis sp., their impact on animal health has not been fully established. Little information is currently available on the molecular diversity of these protists in swine populations. To fill this gap, we molecularly assessed G. duodenalis, Cryptosporidium spp., B. coli, Blastocystis sp. and E. bieneusi in faecal samples from Iberian and Large White pigs raised under different (intensive and/or extensive) management systems in southern Spain. A total of 151 extensively raised Iberian pigs, 140 intensively raised Iberian pigs, and 184 intensively raised Large White pigs were investigated. Blastocystis sp. was the agent most prevalently found (47.8%), followed by B. coli (45.5%), G. duodenalis (10.7%), E. bieneusi (6.9%), and Cryptosporidium spp. (5.5%). Blastocystis sp. was significantly less prevalent in intensively raised Iberian pigs (22.9%) than in their extensively raised counterparts (51.0%) or in intensively raised Large White pigs (64.1%). A significantly higher prevalence was found for G. duodenalis, Cryptosporidium spp., and E. bieneusi in Large White pigs than Iberian pigs. Balantioides coli was similarly distributed (40.0-51.1%) in all three investigated swine populations. Sequence analyses revealed the presence of G. duodenalis assemblage E, two Cryptosporidium species (Cryptosporidium scrofarum and Cryptosporidium suis), B. coli (genotypes A and B), Blastocystis sp. (ST1, ST3, and ST5), and E. bieneusi (EbpA, EbpC, EbpD, O, and a novel genotype named PigSpEb2). Novel genotype PigSpEb2 was found alone or in combination with EbpA. Data suggest a widespread exposure to protist enteroparasites in domestic pig populations irrespectively of breed and raising management system. Many of the species/genotypes identified have a zoonotic potential and might represent a public health concern.

Different HCV Exposure Drives Specific miRNA Profile in PBMCs of HIV Patients

Micro RNAs (miRNAs) are essential players in HIV and HCV infections, as both viruses modulate cellular miRNAs and interact with the miRNA-mediated host response. We aim to analyze the miRNA profile of HIV patients with different exposure to HCV to explore specific signatures in the miRNA profile of PBMCs for each type of infection. We massively sequenced small RNAs of PBMCs from 117 HIV+ infected patients: 45 HIV+ patients chronically infected with HCV (HIV/HCV+), 36 HIV+ that spontaneously clarified HCV after acute infection (HIV/HCV-) and 36 HIV+ patients without previous HCV infection (HIV). Thirty-two healthy patients were used as healthy controls (HC). Differential expression analysis showed significantly differentially expressed (SDE) miRNAs in HIV/HCV+ (n = 153), HIV/HCV- (n = 169) and HIV (n = 153) patients. We found putative dysregulated pathways, such as infectious-related and PI3K signaling pathways, common in all contrasts. Specifically, putatively targeted genes involved in antifolate resistance (HIV/HV+), cancer-related pathways (HIV/HCV-) and HIF-signaling (HIV) were identified, among others. Our findings revealed that HCV strongly influences the expression profile of PBMCs from HIV patients through the disruption of its miRNome. Thus, different HCV exposure can be identified by specific miRNA signatures in PBMCs.

Epidemic history and baseline resistance to NS5A-specific direct acting drugs of hepatitis C virus in Spain

Hepatitis C virus (HCV) infection remains a global health problem. Previously, the prevalence of NS5A resistance-associated substitutions (RASs) to elbasvir, a new direct-acting antiviral (DAA) against the NS5A viral protein was assessed by our group before its introduction into clinical use in Spain. However, the origin, epidemic history, transmission dynamics, diversity and baseline RASs to NS5A direct-acting agents of HCV-GT1a in Spain remain unknown. A nationwide cross-sectional survey of individuals chronically-infected with HCV-G1a and DAAs-naïve was performed. HCV population sequencing, phylogenetic analysis and Bayesian methods were used. GT1a clade II was more prevalent than clade I (82.3% vs. 17.7%; P < 0.001) and older (estimated origin in 1912 vs. 1952). Clade II epidemic is currently declining whereas clade I epidemic has reached equilibrium. A total of 58 single RASs were identified, which account for the moderate level (10%) of baseline resistance observed. When considering the regional data, marked differences were observed, with thirteen regions showing an intermediate level (5–15%) and one a high level (20%) of resistance. Current HCV-GT1a epidemic in Spain is driven by clade I which seem to have different dissemination routes relative to clade II. A moderate level of baseline RASs to NS5A-DAAs with marked differences among regions was observed. Close surveillance of response to treatment with DAAs will be important.

Comparison of methods and characterization of small RNAs from plasma extracellular vesicles of HIV/HCV coinfected patients

Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) hijack the host exosomal machinery as an additional mechanism of infection and evasion of the immune system, modifying the small RNA (smRNA) cargo during infection. We characterized the surface epitopes of extracellular vesicles (EVs) from plasma HIV/HCV-coinfected patients and their smRNA cargo profile, by comparing different isolation procedures. Six EVs isolation procedures were compared: ultracentrifugation, and five different polyethylene glycol-based methods (commercial, combined with a column purification step and two custom); and two RNA commercial kits (phenol and non-phenol based) were used. High-throughput sequencing of smRNAs was performed. Exosomal surface epitopes were analyzed by the MACSPlex Exosome Kit. Four miRNAs displayed differences among protocols (hsa-miR-205-5p and hsa-let-7a/b/f-5p). The selection of RNA isolation kit impacted on the detection of miRNAs and other smRNAs, where the phenol-based RNA isolation kit performed acceptably. EVs surface was enriched with HLA-DR/DP/DQ, CD81, and CD8. There were three liver-specific miRNAs overexpressed (let-7a-5p, miR-21-5p and hsa-miR-122-5p), thus, EVs cargo might reflect liver disease evolution. Other smRNAs such as piwi-interacting RNAs were also detected for the first time. Custom polyethylene glycol precipitation-based methods combined with an RNA phenol-based kit yielded the higher number of smRNAs for EVs isolated from plasma HIV/HCV patients.

Enterocytozoon bieneusi (Microsporidia): Identification of novel genotypes and evidence of transmission between sympatric wild boars (Sus scrofa ferus) and Iberian pigs (Sus scrofa domesticus) in Southern Spain

Microsporidia is a phylum of obligate emergent intracellular protist-like fungi pathogens that infect a broad range of hosts including vertebrates and invertebrates. Enterocytozoon bieneusi is the most common cause of microsporidiosis in humans, affecting primarily immunosuppressed patients but also reported in immunocompetent individuals. Epidemiological information on the presence and molecular diversity of E. bieneusi in livestock and wildlife in Spain is limited. Therefore, the occurrence of this microsporidia was investigated in sympatric extensively reared Iberian pigs (n = 186) and free ranging wild boars (n = 142) in the province of Córdoba, Southern Spain. Forty-two Iberian pigs (22.6%) and three wild boars (2.1%) were found E. bieneusi positive by PCR. In Iberian pigs, occurrence of E. bieneusi was significantly higher in sows than in fattening pigs (31.6% vs. 11.4%; p = .001). Five genotypes were identified in Iberian pigs, four previously reported (EbpA, PigEb4, O, Pig HN-II) and a novel genotype (named PigSpEb1), while only two genotypes were identified in wild boars, EbpA and novel genotype PigSpEb1. All five genotypes identified belong to Group 1 suggesting zoonotic potential. This study constitutes the first report on the occurrence and molecular characterization of E. bieneusi in Iberian pigs and wild boars. The identification of two genotypes with zoonotic potential in sympatric Iberian pigs and wild boars suggests that E. bieneusi can be potentially transmitted between those two hosts, but also implies that they may act as natural sources of microsporidia infection to other hosts including humans.

Protist enteroparasites in wild boar (Sus scrofa ferus) and black Iberian pig (Sus scrofa domesticus) in southern Spain: a protective effect on hepatitis E acquisition?

BACKGROUND

Several studies have independently evaluated the occurrence of hepatitis E virus (HEV) and enteroparasites in swine, but no surveys have been conducted to jointly assess the prevalence and genetic diversity of enteroparasites in pigs and wild boars, their sympatric transmission between hosts, and their potential interaction with HEV.

METHODS

We prospectively collected serum and faecal samples from black Iberian domestic pigs and wild boars from southern Spain between 2015‒2016. We evaluated for HEV in serum and faeces, and for the presence of enteroparasites (Giardia duodenalis, Cryptosporidium spp., Blastocystis sp., Neobalantidium coli and Strongyloides spp.) in the same faecal samples. The prevalence of each intestinal parasite species was calculated.

RESULTS

A total of 328 animals (56.7% black Iberian pigs and 43.3% wild boars) were included in the study. The overall global prevalence of HEV in serum was 16.8%. The overall global prevalence of each enteroparasite species was 19.5% for G. duodenalis, 8.2% for Cryptosporidium spp., 41.8% for Blastocystis sp., 31.4% for N. coli, and 8.8% for Strongyloides spp. HEV-infected animals showed a significantly lower prevalence of G. duodenalis (3.2 vs 20%; P = 0.002) and Blastocystis sp. (38.7 vs 80%; P < 0.001) than those uninfected by HEV. Animals carrying G. duodenalis and Blastocystis sp. infections showed a significantly lower rate of HEV infection than those not harbouring these enteroparasites (P < 0.001).

CONCLUSIONS

Our study found a high prevalence of enteroparasites in black Iberian pigs and wild boars in southern Spain, suggesting a sympatric co-transmission of some of the species investigated. It is suggested that extracellular G. duodenalis and Blastocystis sp. might have a protective effect on HEV acquisition in swine.

Epidemiological trend of hepatitis C-related liver events in Spain (2000-2015): A nationwide population-based study

OBJECTIVE

Analysis the epidemiological trends of hospital admissions, intra-hospital deaths, and costs related to chronic hepatitis C (CHC) taking into account four major clinical stages [compensated cirrhosis (CC), end-stage liver disease (ESLD), hepatocellular carcinoma (HCC), and liver transplantation (LT)] in Spain.

METHODS

Retrospective study in patients with chronic hepatitis C and a hospital admission in the Spanish Minimum Basic Data Set from 2000 to 2015. Outcome variables were admission, death, length of hospital stay and costs.

RESULTS

A total of 868,523 hospital admissions with CHC (25.5% CC, 25.3% ESLD, 8.6% HCC, and 2.5% LT) were identified. Overall rates of admission and mortality increased from 2000-2003 to 2004-2007, but after 2008, these rates stabilized and/or decreased. An upward trend was found for hospitalization percentage in CC (from 22.3% to 30%; p < 0.001), ESLD (from 23.9% to 27.1%; p < 0.001), HCC (from 7.4% to 11%; p < 0.001), and LT (from 0.07% to 0.10%; p = 0.003). An upward trend was also found for case fatality rate, except in ESLD (p = 0.944). Gender and age influenced the evolution of hospitalization rates and mortality differently. The length of hospital stay showed a significant downward trend in all strata analyzed (p < 0.001). Cost per patient had a significant upward trend (p < 0.001), except in LT, and a decrease from 2008-2011 to 2012-2015 in CC (p = 0.025), HCC (p < 0.001), and LT (p = 0.050) was found.

CONCLUSION

The initial upward trend of the disease burden in CHC has changed from 2000 to 2015 in Spain, improving in many parameters after 2004-2007, particularly in the 2012-2015 calendar period.

Nanotechnology: A reality for diagnosis of HCV infectious disease

Hepatitis C virus (HCV) is the primary etiologic agent of liver cirrhosis or hepatocellular carcinoma. HCV elevated infection rates are mostly due to the lack of an accurate and accessible screening and diagnosis, especially in low- and middle-income countries. Conventional HCV diagnostic algorithm consists of a serological test followed by a nucleic acid test. This sequence of tests is time consuming and not affordable for low-resource settings. Nanotechnology have introduced new promising tests for the diagnose of infectious diseases. Based on the employment of nanoparticles and other nanomaterials which lead to highly sensitive and specific nanoscale tests, most of them target pathogen genome. Implementation of nanoscale tests, which are affordable, portable and easy to use by non-specialized personal, would improve HCV diagnosis algorithm. In this review, we have summed up the current emerging nanotechnology tools, which will improve actual screening and treatment programs, and help to reach HCV elimination proposal.

HCV-coinfection is related to an increased HIV-1 reservoir size in cART-treated HIV patients: a cross-sectional study

In HIV-1/HCV-coinfected patients, chronic HCV infection leads to an increased T-lymphocyte immune activation compared to HIV-monoinfected patients, thereby likely contributing to increase HIV-1 reservoir that is the major barrier for its eradication. Our objective was to evaluate the influence of HCV coinfection in HIV-1 viral reservoir size in resting (r) CD4+ T-cells (CD25-CD69-HLADR-). Multicenter cross-sectional study of 97 cART-treated HIV-1 patients, including 36 patients with HIV and HCV-chronic co-infection without anti-HCV treatment, 32 HIV patients with HCV spontaneous clearance and 29 HIV-monoinfected patients. rCD4+ T-cells were isolated and total DNA was extracted. HIV viral reservoir was measured by Alu-LTR qPCR. Differences between groups were calculated with a generalized linear model. Overall, 63.9% were men, median age of 41 years and Caucasian. Median CD4+ and CD8+ T-lymphocytes were 725 and 858 cells/mm³, respectively. CD4+ T nadir cells was 305 cells/mm³. Proviral HIV-1 DNA size was significantly increased in chronic HIV/HCV-coinfected compared to HIV-monoinfected patients (206.21 ± 47.38 vs. 87.34 ± 22.46, respectively; P = 0.009), as well as in spontaneously clarified HCV co-infected patients when compared to HIV-monoinfected individuals (136.20 ± 33.20; P = 0.009). HIV-1/HCV co-infected patients showed a larger HIV-1 reservoir size in comparison to HIV-monoinfected individuals. This increase could lead to a greater complexity in the elimination of HIV-1 reservoir in HIV-1/HCV-coinfected individuals, which should be considered in the current strategies for the elimination of HIV-1 reservoir.

Epidemic history of hepatitis C virus genotypes and subtypes in Portugal

Any successful strategy to prevent and control HCV infection requires an understanding of the epidemic behaviour among the different genotypes. Here, we performed the first characterization of the epidemic history and transmission dynamics of HCV subtypes in Portugal. Direct sequencing of NS5B was performed on 230 direct-acting antiviral drugs (DAA)-treatment naïve patients in Lisbon. Phylogenetic analysis was used for subtyping and transmission cluster identification. Bayesian methods were used to reconstruct the epidemic history of HCV subtypes. Sequences were analysed for resistance-associated substitutions (RAS). The majority of strains were HCV-GT1 (62.6%), GT3 (18.3%, all subtype 3a) and GT4 (16.1%). Among GT1, the most frequent were subtypes 1a (75.5%) and 1b (24.5%). Polyphyletic patterns were found in all but 12 lineages suggesting multiple introductions of the different subtypes in this population. Five distinct epidemics were identified. The first significant HCV epidemic in Portugal occurred between 1930s and 1960s, was caused almost exclusively by GT1b and was likely associated with blood transfusions. Rapid expansion of GT3a occurred in the 1960s and GT1a in the 1980s, associated with intravenous drug use. The most recent epidemics were caused by GT4a and GT4d and seem to be associated with the resurgence of opioid use. The C316N substitution was found in 31.4% of GT1b-patients. Close surveillance of patients bearing this mutation and undergoing dasabuvir-based regimens will be important to determine its impact on treatment outcome.

Prevalence of relevant NS5A resistance-associated substitutions to elbasvir in genotype 1a hepatitis C virus patients in Spain

Resistance-associated substitutions (RASs) to the new HCV NS5A inhibitor elbasvir may limit its efficacy and lead to virological failure in HCV-GT1a-infected patients. There are no data outside clinical trials evaluating their prevalence and impact in grazoprevir/elbasvir in GT1a-infected patients in Spain. A multicentre cross-sectional study of 632 initial patients was conducted. In 13 of these patients, the sample could not be amplified or a consensus sequence by Sanger sequencing could not be performed. Ultimately, 617 HCV-G1a-infected individuals treated at 84 Spanish hospitals from the 17 autonomous communities plus the 2 autonomous cities of Spain were analysed. HCV population sequencing was used to identify RAS to elbasvir and the mutational pattern and drug sensitivity were confirmed by geno2pheno[HCV]. Viruses bearing RASs to elbasvir were present in 6.2% of HCV-G1a infected patients. The most common RASs were the Y93C/H/N and Q30E/H/R (2.4% and 2.3%, respectively). Only 3.4% of the identified RASs to elbasvir conferred reduced susceptibility to elbasvir by geno2pheno[HCV], which exclusively identified the positions Q30H/R (n=7) and Y93C/H/N (n=8) as single mutations and Q30H+Y93H (n=4) and Q30R+Y93H (n=2) as double mutations as the major RASs to elbasvir. A lower prevalence of RASs to elbasvir was observed in our HCV-G1a Spanish cohort than reported previously in clinical trials evaluating patients from the USA. This information may be essential to guide the implementation of grazoprevir/elbasvir in Spain and to manage G1a-infected patients.

NS3 Resistance-Associated Variants (RAVs) in Patients Infected with HCV Genotype 1a in Spain

Background

Resistance-associated variants have been related to treatment failure of hepatitis C virus (HCV) therapy with direct-acting antiviral drugs. The aim of our study was to analyze the prevalence of clinically relevant resistance-associated variants within NS3 in patients infected with HCV genotype 1a (GT1a) in Spain.

Methods

We performed a cross-sectional study on 2568 patients from 115 hospitals throughout Spain (2014–2015). The viral NS3 protease gene was amplified by nested polymerase chain reaction and sequenced by Sanger sequencing using an ABI PRISM 377 DNA sequencer. Additionally, clade information for genotype 1a was obtained by using the software geno2pheno (http://hcv.geno2pheno.org/).

Results

In total, 875 out of 2568 samples were from human immunodeficiency virus (HIV)/HCV-coinfected patients. Q80K was the main RAV found in our patients (11.1%) and the rest of the resistance-associated variants had a lower frequency, including S122G (6.23%), T54S (3.47%), V55A (2.61%), and V55I (2.15%), which were among the most frequent after Q80K. Overall, 286 samples had the Q80K polymorphism (11.1%) and 614 (23.9%) were GT1a clade I. HIV/HCV-coinfected patients had a higher frequency of Q80K and GT1a clade I than HCV-monoinfected patients (12.9% vs. 9.6% [p = 0.012] and 28.5% vs. 21.4% [p<0.001], respectively). Both the prevalence of Q80K and GT1a clade I were not uniform throughout the country (p<0.001), which ranged from 7.3%-22.2% and 15.7%-42.5%, respectively. The frequency of the Q80K polymorphism was far higher in patients infected with GT1a clade I than in patients infected with GT1a clade II (41.5% vs. 1.6%; p<0.001).

Conclusions

The prevalence of most resistance-associated variants in NS3 was low in patients infected with HCV GT1a in Spain, except for Q80K (11.1%), which was also notably higher in HIV/HCV-coinfected patients. The vast majority of Q80K polymorphisms were detected in GT1a clade I.

Off-label use of rilpivirine in combination with emtricitabine and tenofovir in HIV-1-infected pediatric patients: A multicenter study

To assess the safety and efficacy of rilpivirine in combination with emtricitabine and tenofovir (RPV/FTC/TDF) as a once-daily single-tablet regimen (STR) in HIV-1-infected children and adolescents we performed a multicenter case series study of HIV-1-infected patients. Inclusion criteria were initiation of therapy with RPV/FTC/TDF before the age of 18. Patients were divided into undetectable viral load (uVL) group, HIV-1 RNA < 20 copies/mL on stable combined antiretroviral therapy (cART), and detectable viral load (dVL) group, HIV-1 RNA ≥ 20 copies/mL at RPV/FTC/TDF initiation. Patients were monitored from the date of RPV/FTC/TDF initiation until June 30, 2015, RPV/FTC/TDF discontinuation or failure to follow-up. Seventeen patients (8 in uVL and 9 in dVL group) with age between 11.6 and 17.6 were included. Reasons for switching were toxicity (n = 4) and simplification (n = 4) in uVL; viral failure (n = 8) and cART initiation (n = 1) in the dVL group. After a median follow-up of 90 (uVL) and 40 weeks (dVL), 7/8 (86%) patients maintained and 8/9 (89%) achieved and maintained HIV-1 suppression. Median CD4 count increased from 542 to 780/μL (uVL, P = 0.069) and 480 to 830/μL (dVL, P = 0.051). Five patients (2 in uVL and 3 in dVL) improved their immunological status from moderate to no immunosuppression. Serum lipid profiles improved in both groups; cholesterol dropped significantly in the dVL group (P = 0.008). Grade 1 laboratory adverse events (AEs) were observed in 3 patients. No clinical AEs occurred. Adherence was complete in 9 patients (5 in uVL and 4 in dVL); 1 adolescent interrupted treatment. Once-daily STR with RPV/FTC/TDF may be a safe and effective choice in selected HIV-1-infected adolescents and children.

Molecular modeling studies demonstrate key mutations that could affect the ligand recognition by influenza AH1N1 neuraminidase

The goal of this study was to identify neuraminidase (NA) residue mutants from human influenza AH1N1 using sequences from 1918 to 2012. Multiple alignment studies of complete NA sequences (5732) were performed. Subsequently, the crystallographic structure of the 1918 influenza (PDB ID: 3BEQ-A) was used as a wild-type structure and three-dimensional (3-D) template for homology modeling of the mutated selected NA sequences. The 3-D mutated NAs were refined using molecular dynamics (MD) simulations (50 ns). The refined 3-D models were used to perform docking studies using oseltamivir. Multiple sequence alignment studies showed seven representative mutations (A232V, K262R, V263I, T264V, S367L, S369N, and S369K). MD simulations applied to 3-D NAs showed that each NA had different active-site shapes according to structural surface visualization and docking results. Moreover, Cartesian principal component analyses (cPCA) show structural differences among these NA structures caused by mutations. These theoretical results suggest that the selected mutations that are located outside of the active site of NA could affect oseltamivir recognition and could be associated with resistance to oseltamivir.

Toll-like receptor 8 (TLR8) polymorphisms are associated with non-progression of chronic hepatitis C in HIV/HCV coinfected patients

Toll-like receptor 8 (TLR8) polymorphisms have been related to hepatitis C virus (HCV) infection. The aim was to estimate the association of TLR8 polymorphisms with HCV-related outcomes in HIV/HCV coinfected patients. We performed a cross-sectional study of 220 patients who underwent a liver biopsy. TLR8 polymorphisms were genotyped using GoldenGate® assay. The outcome variables were non-fibrosis (F0), mild-inflammation (A0/A1), and non-steatosis [fatty hepatocytes (FH) <10%]. Logistic regression analysis was used to compare the outcome variables according to TLR8 polymorphisms. Four polymorphisms were analyzed (rs1013151, rs5744069, rs17256081 and rs3764880rs1013151). Female patients had higher frequency of TLR8 major alleles at rs17256081 and rs101315, and minor alleles at rs3764880 and rs5744069. Male patients had higher frequency of TLR8 minor alleles except for rs3764880, where major alleles were higher (p<0.01). Two TLR8 polymorphisms (rs1013151 and rs5744069) were significantly associated with non-fibrosis (F0) [adjusted odds ratio (aOR)=4.42 (95% of confidence interval (95%CI)=1.54; 12.68) (p=0.006) and aOR=4.76 (95%CI=1.69; 13.37) (p=0.003); respectively]. When data were stratified by gender, rs1013151 and rs5744069 polymorphisms remained significant for male patients [adjusted odds ratio (aOR)=4.49 (95%CI=1.08; 18.62) (p=0.039) and aOR=6.17 (95%CI=1.45; 26.20) (p=0.014); respectively]. When data were stratified by major HCV genotypes, patients infected with HCV genotype 1 (GT1) had significant values for both rs1013151 and rs5744069 polymorphisms [aOR=5.79 (95%CI=1.44; 23.32) (p=0.013) and aOR=8.01 (95%CI=2.16; 35.65) (p=0.005); respectively]. Finally, none of the TLR8 polymorphisms were significantly associated with mild-inflammation or non-steatosis. In conclusion, TLR8 polymorphisms seem to be related to non-progression of liver fibrosis in HIV/HCV coinfected patients, particularly in males and those patients infected with GT1.

Development of water-soluble polyanionic carbosilane dendrimers as novel and highly potent topical anti-HIV-2 microbicides

The development of topical microbicide formulations for vaginal delivery to prevent HIV-2 sexual transmission is urgently needed. Second- and third-generation polyanionic carbosilane dendrimers with a silicon atom core and 16 sulfonate (G2-S16), napthylsulfonate (G2-NS16) and sulphate (G3-Sh16) end-groups have shown potent and broad-spectrum anti-HIV-1 activity. However, their antiviral activity against HIV-2 and mode of action have not been probed. Cytotoxicity, anti-HIV-2, anti-sperm and antimicrobial activities of dendrimers were determined. Analysis of combined effects of triple combinations with tenofovir and raltegravir was performed by using CalcuSyn software. We also assessed the mode of antiviral action on the inhibition of HIV-2 infection through a panel of different in vitro antiviral assays: attachment, internalization in PBMCs, inactivation and cell-based fusion. Vaginal irritation and histological analysis in female BALB/c mice were evaluated. Our results suggest that G2-S16, G2-NS16 and G3-Sh16 exert anti-HIV-2 activity at an early stage of viral replication inactivating the virus, inhibiting cell-to-cell HIV-2 transmission, and blocking the binding of gp120 to CD4, and the HIV-2 entry. Triple combinations with tenofovir and raltegravir increased the anti-HIV-2 activity, consistent with synergistic interactions (CIwt: 0.33-0.66). No vaginal irritation was detected in BALB/c mice after two consecutive applications for 2 days with 3% G2-S16. Our results have clearly shown that G2-S16, G2-NS16 and G3-Sh16 have high potency against HIV-2 infection. The modes of action confirm their multifactorial and non-specific ability, suggesting that these dendrimers deserve further studies as potential candidate microbicides to prevent vaginal/rectal HIV-1/HIV-2 transmission in humans.

CXCL9, CXCL10 and CXCL11 polymorphisms are associated with sustained virologic response in HIV/HCV-coinfected patients

BACKGROUND

The CXCL9, CXCL10 and CXCL11 (CXCL9-11) chemokines play a critical role in eradication of hepatitis C virus (HCV), although HCV-specific immunity often fails to eradicate the HCV, allowing the chronicity of hepatitis C.

OBJECTIVE

To examine the association between CXCL9-11 polymorphisms and the sustained virological response (SVR) following hepatitis C virus (HCV) therapy with pegylated-interferon-alpha plus ribavirin in HIV/HCV-coinfected patients.

STUDY DESIGN

We performed a retrospective study in 176 naïve patients who started HCV treatment. The CXCL9 rs10336, CXCL10 rs3921 and CXCL11 rs4619915 polymorphisms were genotyped by GoldenGate(®) assay. Genetic data were analyzed under recessive inheritance model. The SVR was defined as undetectable HCV viremia through 24 weeks after the end of HCV treatment.

RESULTS

In the intention-to-treat analysis, the SVR rate was higher in HCV genotype 1/4 (GT1/4) patients carrying rs10336 TT (p=0.042), rs3921 GG (p=0.021), and rs4619915 AA (p=0.024) genotypes; and they had higher likelihood of achieving SVR (adjusted odds ratio (aOR)=3.26 (p=0.038), aOR=4.21 (p=0.019), and aOR=4.08 (p=0.022), respectively). For CXCL haplotype analysis (CXCL9/rs10336, CXCL10/rs3921, and CXCL11/rs4619915), the TGA haplotype (favorable alleles) had better odds of achieving SVR than the CCG haplotype (unfavorable alleles) in GT1/4patients (OR=2.69; p=0.003). No significant results were found in GT2/3 patients. Moreover, similar results were obtained in the on-treatment analysis.

CONCLUSIONS

The presence of homozygous for the minor allele of CXCL9 rs10336, CXCL10 rs3921 and CXCL11 rs4619915 was related to higher likelihoods of achieving the HCV clearance after pegIFNα/ribavirin therapy in HIV infected patients coinfected with HCV GT1/4.

Determinants of highly active antiretroviral therapy duration in HIV-1-infected children and adolescents in Madrid, Spain, from 1996 to 2012

OBJECTIVES

To investigate the duration of sequential HAART regimens and predictors of first-line regimen discontinuation among HIV-1 vertically infected children and adolescents.

DESIGN

Multicentre survey of antiretroviral-naïve patients enrolled in the HIV-Paediatric Cohor,t CoRISpeS-Madrid Cohort, Spain.

METHODS

Patients with a follow-up of ≥ 1 month spent on HAART, with available baseline CD4 count and HIV-viral load (VL) were included. Time spent on sequential HAART regimens was estimated and multivariable regression was used to identify predictors of time to first-line regimen discontinuation.

RESULTS

104 patients were followed for a median 8 years after starting HAART among 1996-2012; baseline %CD4 was 21.5 (12.3-34.0)and viral load was 5.1 (4.6-5.6) log10 copies/mL. Patients received a mean of 1.9 regimens. Median time on first-line HAART (n = 104) was 64.5 months; second HAART (n = 56) 69.8 months; and third HAART (n = 21) 66.5 months. Eleven (11%) patients were lost to follow-up while on first-line HAART and 54% discontinued (cumulative incidence of 16% and 38% by 1 and 3-year, respectively). The main predictor of first-line regimen discontinuation was suboptimal adherence to antiretrovirals (AHR: 2.60; 95% CI: 1.44-4.70).

CONCLUSIONS

Adherence to therapy was the main determinant of the duration of the first-line HAART regimen in children. It is important to identify patients at high risk for non-adherence, such as very young children and adolescents, in provide special care and support to those patients.

Predictors of attrition and immunological failure in HIV-1 patients on highly active antiretroviral therapy from different healthcare settings in Mozambique

In Mozambique, the evaluation of retention in HIV care and ART programmes is limited. To assess rate and predictors of attrition (no retention in care) and HAART effectiveness in HIV-1 infected patients who pay for medication and laboratory testing in Mozambique, we conducted a multicenter survey of HIV-1-infected patients who started HAART during 2002–2006. Cox proportional hazard models were used to assess risk of attrition and of therapy failure. Overall, 142 patients from 16 healthcare centers located in the capital city Maputo were followed-up for 22.2 months (12.1–46.7). The retention rate was 75%, 48% and 37% after one, two and three years, respectively. Risk of attrition was lower in patients with higher baseline CD4 count (P = 0.022) and attending healthcare center 1 (HCC1) (P = 0.013). The proportion of individuals with CD4 count ≤200 cells/µL was 55% (78/142) at baseline and decreased to 6% (3/52) at 36 months. Among the patients with available VL, 86% (64/74) achieved undetectable VL levels. The rate of immunologic failure was 17.2% (95% CI: 12.6–22.9) per 100 person-years. Risk of failure was associated to higher baseline CD4 count (P = 0.002), likely reflecting low adherence levels, and decreased with baseline VL ≥10,000 copies/mL (P = 0.033). These results suggest that HAART can be effective in HIV-1 infected patients from Mozambique that pay for their medication and laboratory testing. Further studies are required to identify the causes for low retention rates in patients with low CD4 counts and to better understand the association between healthcare setting and attrition rate.

Validation of a generation 4 phosphorus-containing polycationic dendrimer for gene delivery against HIV-1

Gene therapy, in which oligomeric genetic material is carried into cells by nano-sized gene delivery vehicles to interfere with gene expression, represents a promising approach for preventive therapy against HIV/AIDS pandemic. Herein, we evaluate the usefulness of a phosphorus-containing dendrimer G4(NH+Et2Cl-)96 as a delivery agent of ODNs and siRNAs. G4(NH+Et2Cl-)96 formed stable complexes with ODNs or siRNAs and exhibited very low cytotoxicity in Sup T1 cells or PBMC. Functional validation was performed by using specific siRNA against HIV-1 Nef, siNEF to interfere in HIV-1 replication. G4(NH+Et2Cl-)96/siNEF dendriplex showed a high efficiency in Nef silencing. Furthermore, in vitro treatment of HIV-infected PBMC with G4(NH+Et2Cl-)96/siNEF dendriplex significantly reduced the viral replication. Our results prove the usefulness of phosphorus-containing dendrimers to deliver and transfect siRNA into CD4-T cells as a potential alternative therapy in the HIV-1 infection.

Molecular distribution of amino acid substitutions on neuraminidase from the 2009 (H1N1) human influenza pandemic virus

The pandemic influenza AH1N1 (2009) caused an outbreak of human infection that spread to the world. Neuraminidase (NA) is an antigenic surface glycoprotein, which is essential to the influenza infection process, and is the target of anti-flu drugs oseltamivir and zanamivir. Currently, NA inhibitors are the pillar pharmacological strategy against seasonal and global influenza. Although mutations observed after NA-inhibitor treatment are characterized by changes in conserved amino acids of the enzyme catalytic site, it is possible that specific amino acid substitutions (AASs) distant from the active site such as H274Y, could confer oseltamivir or zanamivir resistance. To better understand the molecular distribution pattern of NA AASs, we analyzed NA AASs from all available reported pandemic AH1N1 NA sequences, including those reported from America, Africa, Asia, Europe, Oceania, and specifically from Mexico. The molecular distributions of the AASs were obtained at the secondary structure domain level for both the active and catalytic sites, and compared between geographic regions. Our results showed that NA AASs from America, Asia, Europe, Oceania and Mexico followed similar molecular distribution patterns. The compiled data of this study showed that highly conserved amino acids from the NA active site and catalytic site are indeed being affected by mutations. The reported NA AASs follow a similar molecular distribution pattern worldwide. Although most AASs are distributed distantly from the active site, this study shows the emergence of mutations affecting the previously conserved active and catalytic site. A significant number of unique AASs were reported simultaneously on different continents.

Etravirine-based highly active antiretroviral therapy in HIV-1-infected paediatric patients

BACKGROUND

We evaluated the efficacy, safety and tolerability of etravirine in paediatric patients vertically infected with HIV-1.

METHODS

A multicentre retrospective study of 23 multidrug-resistant paediatric patients (five children and 18 adolescents) enrolled in the study from 1 September 2007 to 28 February 2010 was carried out. We performed a longitudinal analysis of immunological, virological and clinical data.

RESULTS

The median age of the patients was 14.2 years [interquartile range (IQR) 12.5-15.8 years]. At baseline, the median HIV-1 RNA was 29 000 (4.5 log(10) ) HIV-1 RNA copies/mL (range 4300-83 000 copies/mL), the median CD4 T-cell count was 445 cells/μL (range 221-655 cells/μL) and the median CD4 percentage was 19.6% (IQR 13.0-31.0). Remarkably, 16 of 23 patients (70%) harboured one or more etravirine-associated resistance mutations. The backbone regimen included at least two fully active drugs in 91% of patients. After etravirine-based therapy, 20 patients (87%) achieved HIV-1 RNA<400 copies/mL and 18 of 23 (78%) achieved HIV-1 RNA<50 copies/mL: three (13%) within the first month, seven (30%) within the first 4 months, and six (26%) between the 5th and 8th months. CD4 T-cell recovery was observed in 19 patients (83%). The median follow-up time was 48.4 weeks (IQR 35.7-63.4 weeks); four patients (17%) were exposed to etravirine for >120 weeks. Three mild/short-term and two moderate skin rashes were observed in the adolescents. Laboratory abnormalities included hypercholesterolaemia (11 of 23 patients), hypertriglyceridaemia (eight of 23 patients), and reduced high-density lipoprotein cholesterol (10 of 23 patients). Adherence was complete in seven patients (30%). No patients showed complete resistance to etravirine after follow-up. However, three of 21 patients (14%) who initially showed intermediate resistance interrupted etravirine treatment because of virological failure.

CONCLUSIONS

We observed a sustained antiviral response and improved immunological parameters in multidrug-resistant paediatric patients, most of whom had received etravirine as part of salvage regimens with at least two fully active drugs.

Short communication: evaluation of the effect of enfuvirtide in 11 HIV-1 vertically infected pediatric patients outside clinical trials

The effect of enfuvirtide (ENF) in 11 HIV-1 heavily antiretroviral-experienced children and adolescents enrolled in the HIV-1 Paediatric Spanish cohort was further investigated. Patients who received ENF with novel drugs (etravirine, darunavir, and/or tipranavir) reached and maintained undetectable plasma HIV-1 RNA levels and showed immunological recovery within the first 3 months of therapy that was maintained during the follow-up. Viremia was not fully suppressed in patients who did not combine ENF with novel drugs but interestingly, immunological benefit was observed in half of these patients. Therefore, ENF showed a greater and more stable efficacy when administrated with novel drugs.

Raltegravir and etravirine are active against HIV type 1 group O

Abstract The activity of raltegravir and etravirine was assessed in vitro in HIV-1 group O isolates. Despite the presence of some natural polymorphisms associated with resistance to raltegravir (V72I, L74I, S153A, V201I, and T206S) and etravirine (G190A), both drugs showed significant antiviral activity. Subsequently, the clinical benefit was shown in an HIV-1 group O-infected individual in whom enfuvirtide was replaced by raltegravir. Therefore, individuals infected with HIV-1 group O might benefit from raltegravir and/or etravirine therapy.

Impact of antiretroviral therapy on chemokine (C-C motif) receptor 5 expression in HIV patients followed for over 2 years

Suppression of HIV replication using highly active antiretroviral therapy (HAART) might influence chemokine (C-C motif) receptor 5 expression on infected cells and therefore modulate the activity of chemokine (C-C motif) receptor 5 antagonists. Chemokine (C-C motif) receptor 5 expression was examined longitudinally in 26 HIV-infected adults who initiated HAART. Long-term suppression of plasma HIV-RNA did not significantly influence chemokine (C-C motif) receptor 5 expression on T lymphocytes. Therefore, the activity of chemokine (C-C motif) receptor 5 antagonists should not differ before and following HIV suppression on HAART.

Prevalence of X4 tropic HIV-1 variants in patients with differences in disease stage and exposure to antiretroviral therapy

Viral tropism plays an important role in HIV pathogenesis. However, its correlation with the clinical outcome and following exposure to antiretroviral drugs are still unclear. HIV-1 co-receptor usage was examined in 206 infected individuals: 67 seroconverters, 52 chronically drug-naïve, and 87 antiretroviral-experienced patients. The V3 loop was sequenced from plasma HIV-RNA and co-receptor usage was inferred using a phenotype predictor software (http://genomiac2.ucsd.edu:8080/wetcat/v3.html), which classifies V3 sequences as R5 or X4. The overall prevalence of X4 viruses was 26.2%, with significant differences among groups: 13.4% in seroconverters, 25% in drug-naïve, and 36.8% in antiretroviral- experienced patients (P = 0.001). The presence of X4 variants in the latter group was associated with higher viral load (P = 0.002) but not with lower CD4 counts. There was no association between HIV tropism and gender, transmission route or age. Neither with the CCR5 Delta32 genotype. Moreover, no association was found between HIV-1 tropism and drug resistance mutations nor with failure to regimens based on either protease inhibitors or non-nucleoside reverse transcriptase inhibitors. Finally, no significant association was found between IL-7 plasma levels with HIV-1 tropism. In summary, X4 viruses are particularly frequent among antiretroviral-experienced patients with high viral loads, irrespective of the CD4 count. Thus, CCR5 antagonists should be used with special caution in this subset of patients.

Prevalence of darunavir resistance mutations in HIV-1-infected patients failing other protease inhibitors

BACKGROUND

To estimate to what extent darunavir might be effective in patients failing distinct protease inhibitors (PIs), the genotypic resistance scores recently reported for the drug were examined in a large clinical HIV-1 drug resistance database.

METHODS

All clinical specimens from HIV-infected patients failing PI-based regimens referred for drug resistance testing between 1999 and 2007 to a reference centre in Madrid were analysed. Darunavir-specific resistance mutations listed by the September 2006 IAS-USA panel update were considered.

RESULTS

A total of 1021 genotypes from patients failing lopinavir (39.2%), nelfinavir (28.1%), saquinavir (14.5%), indinavir (13.7%), atazanavir (6.6%), fosamprenavir (5.3%) and tipranavir (1.1%) were identified. The prevalence of major darunavir resistance mutations was I50V 2.1%, I54M 1.3%, L76V 2.7% and I84V 14.5%. For minor darunavir resistance mutations, the rates were V11I 3.3%, V32I 3.9%, L33F 11%, I47V 2.1%, I54L 2.3%, G73S 12.8% and L89V 2.4%. Overall, 6.7% (n = 68) of the genotypes had three or more darunavir resistance mutations, which corresponded to a mean total number of PI resistance mutations of 12.3 +/- 1.9. In the multivariate analysis, prior fosamprenavir failure, prior saquinavir failure, the total number of PI resistance mutations and the number of prior PIs used were all independently associated with having more darunavir resistance mutations.

CONCLUSIONS

The prevalence of darunavir resistance mutations is low in patients failing other PI-based regimens, although prior failure to amprenavir and saquinavir might produce more cross-resistance to darunavir. Thus, darunavir may be a good option for patients who have failed other PI-based regimens.

Correlation between a phenotypic assay and three bioinformatic tools for determining HIV co-receptor use

The predictive value of three genotypic methods to determine HIV-1 co-receptor usage was assessed in 83 plasma specimens taking as reference the results obtained using a recombinant phenotypic assay (Phenoscript). The best concordance was found for webPSSM, followed by geno2pheno and wetcat (85.9, 71.8 and 70.5%, respectively). Less than 5.1% of phenotypic X4 viruses were missed by genotypic tools. The genotypic prediction of HIV-1 co-receptor usage can thus assist therapeutic decisions for using CCR5 antagonists.

Successful rescue therapy with darunabir (TMC114) in HIV-infected patients who have failed several ritonavir-boosted protease inhibitors

Darunabir, formerly TMC114, is a new protease inhibitor (PI) under clinical development designed to be active against HIV strains resistant to currently available PI. The virological and immunological response to ritonavir-boosted darunabir was assessed in four heavily antiretroviral-experienced patients who had failed enfuvirtide and two or more previous ritonavir-boosted PI regimens, including tipranavir in one instance. All four patients reached undetectable plasma HIV-RNA levels within 8 weeks of therapy and experienced significant CD4 cell count gains.

[HIV entry into the cells--mechanisms and therapeutic possibilities]

Human immunodeficiency virus (HIV) entry into cells is the first step in the viral replication cycle, which has been explored as a new therapeutic target. A better knowledge of the mechanisms involved in the entry process has led to the development of agents, which may inhibit each of the different steps of the viral entry process: attachment of the gp120 to the CD4 cell receptor; binding of the gp120 to CCR5 or CXCR4 coreceptors; and the fusion of viral and cell membranes. Entry inhibitors are the latest family of antiretroviral compounds, being enfuvirtide, a fusion inhibitor, the first approved. Several other entry inhibitors are currently in clinical development and hopefully soon will be part of the therapeutic armamentarium against HIV.

HIV entry inhibitors: mechanisms of action and resistance pathways

Entry inhibitors represent a new generation of antivirals for the treatment of HIV infection. Several compounds which block the attachment of HIV gp120 to either the CD4 T cell receptor or the CCR5/CXCR4 co-receptors are currently in clinical development. Most of these compounds have different molecular structures and specific mechanisms of action. These agents are eagerly awaited by a growing number of patients carrying viruses resistant viruses to many of the current available reverse transcriptase and protease inhibitors. For enfuvirtide, the first and, so far, only entry inhibitor approved for clinical use, the main mechanism of resistance is the selection of changes within a 10 amino acid segment encompassing residues 36-45 within the HR1 region of gp41. For other entry inhibitors, multiple changes in different gp120 domains (V1, V2, V3, C2 and C4) have been associated with loss of susceptibility to these agents, although in most cases with limited cross-resistance.

Enfuvirtide, the first fusion inhibitor to treat HIV infection

Entry inhibitors are a new class of drugs for the treatment of HIV infection. Enfuvirtide is the first compound of this family to be approved for clinical use. It blocks HIV fusion to host cells. It is a synthetic peptide that mimics an HR2 fragment of gp41, blocking the formation of a six-helix bundle structure which is critical in the fusion process. Enfuvirtide is a good therapeutic option as rescue therapy in combination with other active antiretrovirals and works against different HIV-1 variants, including all group M subtypes and group O. However, it is not active against HIV-2. The main mechanism of resistance to enfuvirtide depends of the selection of changes in a 10-amino acid domain between residues 36 to 45 in the HR1 region of gp41. Single and double mutations in this region have been shown to result in high-level resistance to enfuvirtide. A negative impact of enfuvirtide-resistance mutations on viral fitness has been postulated, since resistance mutations tend to disappear soon after drug discontinuation and because immunologic benefits have been noticed despite virologic failure in patients undergoing enfuvirtide treatment.