Effect of Swine Glyco-humanized Polyclonal Neutralizing Antibody on Survival and Respiratory Failure in Patients Hospitalized With Severe COVID-19: A Randomized, Placebo-Controlled Trial

Background

We evaluated the safety and efficacy of XAV-19, an antispike glyco-humanized swine polyclonal neutralizing antibody in patients hospitalized with severe coronavirus disease 2019 (COVID-19).

Methods

This phase 2b clinical trial enrolled adult patients from 34 hospitals in France. Eligible patients had a confirmed diagnosis of severe acute respiratory syndrome coronavirus 2 within 14 days of onset of symptoms that required hospitalization for low-flow oxygen therapy (<6 L/min of oxygen). Patients were randomly assigned to receive a single intravenous infusion of 2 mg/kg of XAV-19 or placebo. The primary end point was the occurrence of death or severe respiratory failure between baseline and day 15.

Results

Between January 12, 2021, and April 16, 2021, 398 patients were enrolled in the study and randomly assigned to XAV-19 or placebo. The modified intention-to-treat population comprised 388 participants who received full perfusion of XAV-19 (199 patients) or placebo (189 patients). The mean (SD) age was 59.8 (12.4) years, 249 (64.2%) individuals were men, and the median time (interquartile range) from symptom onset to enrollment was 9 (7-10) days. There was no statistically significant decrease in the cumulative incidence of death or severe respiratory failure through day 15 in the XAV-19 group vs the placebo group (53/199 [26.6%] vs 48/189 [25.4%]; adjusted risk difference, 0.6%; 95% CI, -6% to 7%; hazard ratio, 1.03; 95% CI, 0.64-1.66; P = .90). In the safety population, adverse events were reported in 75.4% of 199 patients in the XAV-19 group and in 76.3% of 190 patients in the placebo group through D29.

Conclusions

Among patients hospitalized with COVID-19 requiring low-flow oxygen therapy, treatment with a single intravenous dose of XAV-19, compared with placebo, did not show a significant difference in terms of disease progression at day 15.

Impact de la pandémie de COVID-19 sur les populations sans domicile fixe : résultats d’une cohorte fermée rétrospective (mars–mai 2020)

Introduction

Les populations de sans domicile fixe ont un taux de mortalité supérieur à celui de la population générale. Ceci est en partie en lien avec des maladies chroniques non suivis, des problèmes d’addiction ainsi qu’une exposition plus forte aux maladies transmissibles, en particulier respiratoires. Nous avons réalisé une étude pour évaluer les taux d’attaque, d’hospitalisation et de mortalité liés à l’infection par le SARS-CoV-2 dans une population de résidents de centres d’hébergement pour sans-abri et du personnel à leur contact.

Matériels et méthodes

Une étude sérologique rétrospective a été réalisée sur l’ensemble des résidents et des membres du personnel de trois centres d’hébergement pour sans-abri entre mars et mai 2020 : 2 centres de lits halte soins santé (LHSS) et un dortoir de femmes. Nous avons inclus tous les adultes présents dans les centres d’hébergement ou décédés d’une infection avérée par le SARS-CoV-2. Les IgG anti-SARS-CoV-2 étaient détectés par le test ELISA « SARS-CoV-2 IgG Architect (Abbott) ». Un cas confirmé de SARS-CoV-2 était défini comme tout participant présentant une PCR ou une sérologie positive. Des sérologies de contrôle ont été prélevées quatre mois après la première sérologie positive.

Résultats

Nous avons inclus 100 résidents et 83 membres du personnel. Le taux de SARS-CoV-2 confirmé par PCR ou sérologie était de 72/100 (72,0 %) pour les résidents et de 17/83 (20,5 %) pour le personnel. Le taux d’hospitalisation chez les résidents était de 17/72 (25 %) et le taux de décès de 4/72 (5,6 %). Toutes les hospitalisations sauf une et tous les décès sont survenus chez des résidents des LHSS. Trente-quatre sur 68 (50 %) des résidents des LHSS présentaient au moins deux facteurs de risque de forme grave d’infection par le SARS-CoV-2. Les femmes hébergées dans le dortoir étaient plus jeunes, présentaient moins de comorbidité, avaient le taux d’attaque le plus élevé (90,6 %) et une morbidité-mortalité quasi nulle. Cinquante-deux sur 80 (63,4 %) des personnes ayant une première sérologie positive ont eu une sérologie de contrôle à 4 mois de la première sérologie et 8 mois environ de leur infection. Parmi eux, 44 (84,6 %) avaient conservé des sérologies positives.

Conclusion

Le taux d’attaque du SARS-CoV-2 était extrêmement élevé chez les résidents des centres d’hébergement pour sans-abri par rapport à la population générale. Le risque d’infection grave par le SARS-CoV-2 était fortement associé à la présence de comorbidités à un plus jeune âge. Cette population à risqué doit être considérée comme prioritaire dans les campagnes de vaccination dans l’accès aux logements individuels pour les plus vulnérables.

Characterization of viral rebounds on dual etravirine/raltegravir maintenance therapy (ANRS-163 ETRAL trial)

BACKGROUND

The ANRS-163 ETRAL trial, a switch study to an etravirine 200 mg/raltegravir 400 mg twice-daily regimen in 165 patients with HIV-1 infection, showed durable efficacy until Week 96. The aim of this work was to investigate in detail the virological rebounds (VRs), defined as at least one plasma HIV viral load (VL) >50 copies/mL.

METHODS

Quantification of HIV-DNA level was assessed at baseline, Week 48 and Week 96 (n = 157). VLs were measured in seminal plasma at Week 48 (n = 26). Genotypic resistance testing by ultra-deep sequencing (UDS) for reverse transcriptase (RT) and integrase regions was performed at baseline and at the time of VR.

RESULTS

In this study, 19 patients experienced VR, with 2 patients having virological failure (VF; two consecutive VLs >50 copies/mL). For the first patient with VF, UDS detected minority resistant variants only in RT (K103N, 9.6%; Y181C, 4.9%) at baseline. Some RT variants became dominant at VF (K101E, 86.3%; Y181C, 100.0%; G190A, 100.0%) and others emerged in integrase (Y143C, 2.4%; Q148R, 6.2%; N155H, 18.8%). For the second patient with VF, neither RT nor integrase mutations were detected at baseline and VF. Median HIV-DNA level was similar at baseline, Week 48 and Week 96 (2.17, 2.06 and 2.11 log10 copies/106 cells, respectively). Only one patient had a detectable seminal HIV VL (505 copies/mL).

CONCLUSIONS

The dual etravirine/raltegravir regimen as maintenance therapy was effective and the emergence of mutations in cases of VF was similar to that seen in other dual-regimen studies. No HIV-DNA level modification was evidenced by Week 96.

Factors associated with the emergence of integrase resistance mutations in patients failing dual or triple integrase inhibitor-based regimens in a French national survey

BACKGROUND

Successful 2-drug regimens (2DRs) for HIV were made possible by the availability of drugs combining potency and tolerability with a high genetic barrier to resistance. How these deal with resistance development/re-emergence, compared with 3DRs, is thus of paramount importance.

MATERIALS AND METHODS

A national survey including patients who were either naive or experienced with any 2DR or 3DR but failing integrase strand transfer inhibitor (INSTI)-containing regimens [two consecutive plasma viral load (VL) values >50 copies/mL] was conducted between 2014 and 2019. Genotypic resistance tests were interpreted with the v28 ANRS algorithm.

RESULTS

Overall, 1104 patients failing any INSTI-containing regimen (2DRs, n = 207; 3DRs, n = 897) were analysed. Five hundred and seventy-seven (52.3%) patients were infected with a B subtype and 527 (47.3%) with non-B subtypes. Overall, 644 (58%) patients showed no known integrase resistance mutations at failure. In multivariate analysis, factors associated with the emergence of at least one integrase mutation were: high VL at failure (OR = 1.24 per 1 log10 copies/mL increase); non-B versus B subtype (OR = 1.75); low genotypic sensitivity score (GSS) (OR = 0.10 for GSS = 2 versus GSS = 0-0.5); and dolutegravir versus raltegravir (OR = 0.46). Although 3DRs versus 2DRs reached statistical significance in univariate analysis (OR = 0.59, P = 0.007), the variable is not retained in the final model.

CONCLUSIONS

This study is one of the largest studies characterizing integrase resistance in patients failing any INSTI-containing 2DR or 3DR in routine clinical care and reveals factors associated with emergence of integrase resistance that should be taken into consideration in clinical management. No difference was evidenced between patients receiving a 2DR or a 3DR.

Surveillance of HIV-1 primary infections in France from 2014 to 2016: toward stable resistance, but higher diversity, clustering and virulence?

OBJECTIVES

Patients with primary HIV-1 infection (PHI) are a particular population, giving important insight about ongoing evolution of transmitted drug resistance-associated mutation (TDRAM) prevalence, HIV diversity and clustering patterns. We describe these evolutions of PHI patients diagnosed in France from 2014 to 2016.

METHODS

A total of 1121 PHI patients were included. TDRAMs were characterized using the 2009 Stanford list and the French ANRS algorithm. Viral subtypes and recent transmission clusters (RTCs) were also determined.

RESULTS

Patients were mainly MSM (70%) living in the Paris area (42%). TDRAMs were identified among 10.8% of patients and rose to 18.6% when including etravirine and rilpivirine TDRAMs. Prevalences of PI-, NRTI-, first-generation NNRTI-, second-generation NNRTI- and integrase inhibitor-associated TDRAMs were 2.9%, 5.0%, 4.0%, 9.4% and 5.4%, respectively. In a multivariable analysis, age >40 years and non-R5 tropic viruses were associated with a >2-fold increased risk of TDRAMs. Regarding HIV diversity, subtype B and CRF02_AG (where CRF stands for circulating recombinant form) were the two main lineages (56% and 20%, respectively). CRF02_AG was associated with higher viral load than subtype B (5.83 versus 5.40 log10 copies/mL, P=0.004). We identified 138 RTCs ranging from 2 to 14 patients and including overall 41% from the global population. Patients in RTCs were younger, more frequently born in France and more frequently MSM.

CONCLUSIONS

Since 2007, the proportion of TDRAMs has been stable among French PHI patients. Non-B lineages are increasing and may be associated with more virulent CRF02_AG strains. The presence of large RTCs highlights the need for real-time cluster identification to trigger specific prevention action to achieve better control of the epidemic.

Evaluation of the safety and efficacy of XAV-19 in patients with COVID-19-induced moderate pneumonia: study protocol for a randomized, double-blinded, placebo-controlled phase 2 (2a and 2b) trial

BACKGROUND

Early inhibition of entry and replication of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a very promising therapeutic approach. Polyclonal neutralizing antibodies offers many advantages such as providing immediate immunity, consequently blunting an early pro-inflammatory pathogenic endogenous antibody response and lack of drug-drug interactions. By providing immediate immunity and inhibiting entry into cells, neutralizing antibody treatment is of interest for patient with COVID-19-induced moderate pneumonia. Convalescent plasma to treat infected patients is therefore a relevant therapeutic option currently under assessment (CORIMUNO-PLASM NCT04324047). However, the difficulties of collecting plasma on the long term are not adapted to a broad use across all populations. New polyclonal humanized anti-SARS-CoV2 antibodies (XAV-19) developed by Xenothera and administered intravenous. XAV-19 is a heterologous swine glyco-humanized polyclonal antibody (GH-pAb) raised against the spike protein of SARS-CoV-2, blocking infection of ACE-2-positive human cells with SARS-CoV-2.

METHODS

Pharmacokinetic and pharmacodynamic studies have been performed in preclinical models including primates. A first human study with another fully representative GH-pAb from Xenothera is ongoing in recipients of a kidney graft. These studies indicated that 5 consecutive administrations of GH-pAbs can be safely performed in humans. The objectives of this 2-step phase 2 randomized double-blinded, placebo-controlled study are to define the safety and the optimal XAV-19 dose to administrate to patients with SARS-CoV-2 induced moderate pneumonia, and to assess the clinical benefits of a selected dose of XAV-19 in this population.

DISCUSSION

This study will determine the clinical benefits of XAV-19 when administered to patients with SARS-CoV-2-induced moderate pneumonia. As a prerequisite, a first step of the study will define the safety and the dose of XAV-19 to be used. Such treatment might become a new therapeutic option to provide an effective treatment for COVID-19 patients (possibly in combination with anti-viral and immunotherapies). Further studies could later evaluate such passive immunotherapy as a potential post-exposure prophylaxis.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04453384 , registered on 1 July 2020, and EUDRACT 2020-002574-27, registered 6 June 2020.

Stable prevalence of transmitted drug resistance mutations and increased circulation of non-B subtypes in antiretroviral-naive chronically HIV-infected patients in 2015/2016 in France

OBJECTIVES

We estimated the prevalence of transmitted-drug-resistance-associated mutations (TDRAMs) in antiretroviral-naive chronically HIV-1-infected patients.

PATIENTS AND METHODS

TDRAMs were sought in samples from 660 diagnosed HIV-1-infected individuals in 2015/2016 in 33 HIV clinical centres. Weighted analyses, considering the number of patients followed in each centre, were used to derive representative estimates of the percentage of individuals with TDRAMs. Results were compared with those of the 2010/2011 survey (n = 661) using the same methodology.

RESULTS

At inclusion, median CD4 cell counts and plasma HIV-1 RNA were 394 and 350/mm3 (P = 0.056) and 4.6 and 4.6 log10 copies/mL (P = 0.360) in the 2010/2011 survey and the 2015/2016 survey, respectively. The frequency of non-B subtypes increased from 42.9% in 2010/2011 to 54.8% in 2015/2016 (P < 0.001), including 23.4% and 30.6% of CRF02_AG (P = 0.004). The prevalence of virus with protease or reverse-transcriptase TDRAMs was 9.0% (95% CI = 6.8-11.2) in 2010/2011 and 10.8% (95% CI = 8.4-13.2) in 2015/2016 (P = 0.269). No significant increase was observed in integrase inhibitor TDRAMs (6.7% versus 9.2%, P = 0.146). Multivariable analysis showed that men infected with the B subtype were the group with the highest risk of being infected with a resistant virus compared with others (adjusted OR = 2.2, 95% CI = 1.3-3.9).

CONCLUSIONS

In France in 2015/2016, the overall prevalence of TDRAMs was 10.8% and stable compared with 9.0% in the 2010/2011 survey. Non-B subtypes dramatically increased after 2010. Men infected with B subtype were the group with the highest risk of being infected with a resistant virus, highlighting the need to re-emphasize safe sex messages.

Resistance to integrase inhibitors: a national study in HIV-1-infected treatment-naive and -experienced patients

OBJECTIVES

To describe integrase strand transfer inhibitor (INSTI) resistance profiles and factors associated with resistance in antiretroviral-naive and -experienced patients failing an INSTI-based regimen in clinical practice.

METHODS

Data were collected from patients failing an INSTI-containing regimen in a multicentre French study between 2014 and 2017. Failure was defined as two consecutive plasma viral loads (VL) >50 copies/mL. Reverse transcriptase, protease and integrase coding regions were sequenced at baseline and failure. INSTI resistance-associated mutations (RAMs) included in the Agence Nationale de Recherches sur le SIDA genotypic algorithm were investigated.

RESULTS

Among the 674 patients, 359 were failing on raltegravir, 154 on elvitegravir and 161 on dolutegravir therapy. Overall, 90% were experienced patients and 389 (58%) patients showed no INSTI RAMs at failure. The strongest factors associated with emergence of at least one INSTI mutation were high VL at failure (OR = 1.2 per 1 log10 copies/mL increase) and low genotypic sensitivity score (GSS) (OR = 0.08 for GSS ≥3 versus GSS = 0-0.5). Patients failing dolutegravir also had significantly fewer INSTI RAMs at failure than patients failing raltegravir (OR = 0.57, P = 0.02) or elvitegravir (OR = 0.45, P = 0.005). Among the 68 patients failing a first-line regimen, 11/41 (27%) patients on raltegravir, 7/18 (39%) on elvitegravir and 0/9 on dolutegravir had viruses with emergent INSTI RAMs at failure.

CONCLUSIONS

These results confirmed the robustness of dolutegravir regarding resistance selection in integrase in the case of virological failure in routine clinical care.

An NS5A single optimized method to determine genotype, subtype and resistance profiles of Hepatitis C strains

The objective was to develop a method of HCV genome sequencing that allowed simultaneous genotyping and NS5A inhibitor resistance profiling. In order to validate the use of a unique RT-PCR for genotypes 1-5, 142 plasma samples from patients infected with HCV were analysed. The NS4B-NS5A partial region was successfully amplified and sequenced in all samples. In parallel, partial NS3 sequences were analyzed obtained for genotyping. Phylogenetic analysis showed concordance of genotypes and subtypes with a bootstrap >95% for each type cluster. NS5A resistance mutations were analyzed using the Geno2pheno [hcv] v0.92 tool and compared to the list of known Resistant Associated Substitutions recently published. In conclusion, this tool allows determination of HCV genotypes, subtypes and identification of NS5A resistance mutations. This single method can be used to detect pre-existing resistance mutations in NS5A before treatment and to check the emergence of resistant viruses while undergoing treatment in major HCV genotypes (G1-5) in the EU and the US.

Antiretroviral-naive and -treated HIV-1 patients can harbour more resistant viruses in CSF than in plasma

OBJECTIVES

The neurological disorders in HIV-1-infected patients remain prevalent. The HIV-1 resistance in plasma and CSF was compared in patients with neurological disorders in a multicentre study.

METHODS

Blood and CSF samples were collected at time of neurological disorders for 244 patients. The viral loads were >50 copies/mL in both compartments and bulk genotypic tests were realized.

RESULTS

On 244 patients, 89 and 155 were antiretroviral (ARV) naive and ARV treated, respectively. In ARV-naive patients, detection of mutations in CSF and not in plasma were reported for the reverse transcriptase (RT) gene in 2/89 patients (2.2%) and for the protease gene in 1/89 patients (1.1%). In ARV-treated patients, 19/152 (12.5%) patients had HIV-1 mutations only in the CSF for the RT gene and 30/151 (19.8%) for the protease gene. Two mutations appeared statistically more prevalent in the CSF than in plasma: M41L (P=0.0455) and T215Y (P=0.0455).

CONCLUSIONS

In most cases, resistance mutations were present and similar in both studied compartments. However, in 3.4% of ARV-naive and 8.8% of ARV-treated patients, the virus was more resistant in CSF than in plasma. These results support the need for genotypic resistance testing when lumbar puncture is performed.

A cohort study of treatment-experienced HIV-1-infected patients treated with raltegravir: factors associated with virological response and mutations selected at failure

This study aimed to identify factors associated with virological response (VR) to raltegravir (RAL)-containing regimens in 468 treatment-experienced but integrase inhibitor-naive HIV-1 patients receiving a RAL-containing regimen. VR was defined at Month 6 (M6) as HIV-1 RNA viral load (VL) <50 copies/mL. The impacts on VR of baseline integrase mutations, VL, CD4 count, genotypic sensitivity score for nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors and protease inhibitors, and the number of new antiretrovirals used for the first time associated with RAL were investigated. For patients with VL >50 copies/mL at M6, integrase mutations selected were characterised. Median baseline VL was 4.2 log(10)copies/mL (IQR 3.3-4.9 log(10) copies/mL) and CD4 count was 219 cells/mm(3) (IQR 96-368 cells/mm(3)). At M6, 71% of patients were responders. In multivariate analysis, baseline VL and CD4 count and ≥ 2 new antiretrovirals among darunavir, etravirine, maraviroc and enfuvirtide were associated with VR to RAL. Neither HIV-1 subtype nor baseline integrase polymorphisms were associated with VR to RAL. Among 63 failing patients at M6, selection of ≥ 1 change in the integrase gene was observed in 49 (77.8%), and 27/63 (42.9%) were considered as RAL-associated resistance mutations. Factors independently associated with the occurrence of ≥ 1 RAL-associated resistance mutation were VL at failure >3 log(10) and having no new drugs associated with RAL. RAL showed great potency in treatment-experienced patients. The number of new drugs associated with RAL was an important factor associated with VR. HIV-1 subtype and baseline integrase polymorphisms do not influence the RAL VR.

Seroprevalence and Molecular Characterisation of Human Hepatitis A virus in Serum Samples of Tunisian Patients with Clinical Symptoms of Viral Hepatitis

The aim of the present study was to investigate the seroprevalence of Hepatitis A virus antibodies in patients with clinical symptoms of viral hepatitis and molecular characterization of the detected isolates. The present study deals with the seroprevalence and the genetic diversity of HAV in 400 Tunisian patients presenting in dispensaries (160 patients) and in University Hospitals (240 patients) with hepatitis symptoms between 2006 and 2008. The patients with acute hepatitis were mainly from rural regions. However, the total number of patients was decreased over time. The collected samples were from patients with hepatitis symptoms occurring mainly during January-March (36.7, 26, and 35.5%) and September-December (39.4, 43.4, and 35.5%) during the three years of study, respectively. However, HAV infection was established for only 110 among 400 patients. The detected isolates were clustered within sub-genotype IA. The present study constituted another report of the continued surveillance of HAV infection in the region of Monastir and the molecular characterisation of the detected strains.

Characterization of outbreak hepatitis a isolates in five Tunisian childcare centers

In the present study, epidemiological survey and molecular characterization of hepatitis A virus during an outbreak in five Tunisian childcare centers in El-Mahres during October and November 2006 were carried out. Five well-water and five drinking water samples were included in the present study. Serological investigation and molecular characterization were carried out. All patients were IgM seropositive and the viral genome was detected in all clinical and well-water samples whereas it was not detected in drinking water from the five childcare centers. Sequence analysis showed that all Tunisian strains belong to sub-genotype IA. The genetic profile of the VP1/2A junction showed that the outbreak isolates underwent an amino acid substitution which was absent in virus’s strains detected previously in Tunisia. Further studies need to be conducted to evaluate the emergence of the virus’s strains in clinical and water samples and more epidemiological data need to be collected about the risk factors which may contribute to acute hepatitis.

Genetic analysis of HAV strains in Tunisia reveals two new antigenic variants

To evaluate the genetic variability of hepatitis A virus (HAV) isolates in Tunisia, serum samples were collected from 99 patients in different Tunisian areas in 2003 containing 92 cases with acute hepatitis, five with severe acute hepatitis and two with fulminant hepatitis. The entire VP1 gene was amplified and sequenced. Sequences were then aligned and a phylogenetic analysis was performed. Additionally, the amino acid (aa) sequence of the VP1 was determined. The analysis of Tunisian HAV isolates revealed that all the isolates were sub-genotype IA with 96.4%-99.8% of identity and showed the emergence of two novel antigenic variants. The Tun31-03 antigenic variant, with a 38 aa deletion containing Met156, Val171, Leu174 and Ala176 and located between 150 and 187 aa of the VP1 protein where neutralization escape mutations, was found. The second antigenic variant, Tun36-03, was isolated from a patient with fulminant hepatitis and presented a substitution of Thr by Pro at position 10 of the VP1 protein. This amino acid is located in a peptide presenting an antigenically reactive epitope of the VP1 protein. This substitution has never been described previously.

A 1-year study of the epidemiology of hepatitis A virus in Tunisia

This 1-year (September 2000 to August 2001) prospective study investigated the presence of hepatitis A virus (HAV) in the population of Monastir, Tunisia (86 serum samples), in the influents and effluents of two wastewater treatment plants, and in shellfish harvested in the coastal areas of Monastir, Bizerte and Sfax (January 2001 to May 2001). The virus was detected by RT-PCR using primers targeted at the VP3-VP1 region. An epidemic of HAV infection was observed during the winter months, with a peak in January. The presence of the virus was relatively constant in the influents and effluents of the wastewater treatment plants, and the virus was found in shellfish from the Monastir area during the months of January and February. The genotype IA strain was recovered most frequently from human serum and wastewater samples. The observation that the peak of the epidemic was during the winter months suggests that transmission of HAV is related to climatic factors and, presumably, to shellfish consumption.

Hepatitis A in Tunisia: phylogenetic analysis of hepatitis A virus from 2001 to 2004

Tunisia is a highly endemic area for hepatitis A virus (HAV) infection. In the present study, the phylogenetic characterization of the VP1 gene (882 nucleotides) and of the VP1/2A junction (336 nucleotides) of Tunisian strains were examined. One hundred strains isolated from patient with anti-HAV IgM from 2001 to 2004 were amplified by RT-PCR, sequenced at the VP1 and at the VP1/2A junction and aligned with the published sequences to establish phylogenetic analysis. All Tunisian strains belong to genotype I with a greater presence of sub-genotype IA (98%) originate from most of Tunisian regions and 2% of sub-genotype IB. In addition, sub-genotype IA and IB strains formed 25 different clusters. Genetically similar strains were also identified between 2001 and 2004 isolated from the southern and the central part of Tunisia, suggesting that an indigenous strain has been circulating in the Tunisia. The genetic profile of the VP1 region showed that Tun159-02 and Tun40-03 clustered respectively in the IB and IA sub-genotype, however, analysis of VP1/2A junction revealed in contrast that Tun159-02 and Tun40-03 clustered respectively in IA and IB. This is the first report to identify sub-genotype IA in Tunisia and provides new data on the genetic relatedness of HAV from Tunisia and the distribution of sub-genotype IA in this part of the world.

Multicenter evaluation of the NucliSens EasyQ HIV-1 v1.1 assay for the quantitative detection of HIV-1 RNA in plasma

The Nuclisens EasyQ HIV-1 v1.1 assay (Biomerieux) is a real-time detection method combined with NASBA technology designed to measure plasma HIV-RNA. Its performance was assessed in 1008 clinical specimens collected from individuals infected with clade B (774) and non-B (234) HIV-1 variants at four European laboratories. The results were compared with those obtained using three other commercial viral load assays: Cobas Amplicor Monitor HIV-1 v1.5 (Roche), Versant HIV-1 RNA assay (Bayer) and Nuclisens HIV-1 QT (Biomerieux). Overall, the linearity, specificity and reproducibility of the EasyQ assay was comparable with that from the other tests. The correlation coefficient (R) between methodologies was 0.85 for Amplicor; 0.87 for Versant; and 0.91 for Nuclisens. The specificity of the assay was 99.4%. Of note, Versant missed 17% of specimens with non-B subtypes which could be detected by EasyQ, while Amplicor provided similar results than EasyQ. HIV-1 group O specimens were only detected by the EasyQ assay. In conclusion, the performance of the EasyQ assay seems to be similar to that of other HIV-1 viral load tests currently on the market, but it is more sensitive than Versant for HIV-1 non-B subtypes and shows a wider dynamic range than Amplicor. Moreover, as it incorporates the advantage of real-time detection procedures, it facilitates high throughput and short turnaround time.

Viral and clinical factors associated with the fulminant course of hepatitis A infection

Fulminant hepatitis is a severe complication of hepatitis A virus infection. Its mechanism is unknown. Liver transplantation can be necessary, but spontaneous recovery is frequent. There are no data on the level of viral replication according to the clinical form of hepatitis A. We reviewed the files of 50 patients with acute hepatitis A. Nineteen patients had fulminant hepatitis (defined by encephalopathy and factor V <50%), and, from them, 10 patients underwent transplantation. Hepatitis A virus (HAV) RNA was quantified by real-time PCR on sera obtained at admission. The genotype was determined by phylogenetic analysis of HAV RNA. HAV RNA was detected in serum by RT-PCR in 39 out of 50 patients. Encephalopathy and low factor V level were significantly related to female gender, HAV PCR negativity (9/19 vs. 5/31, respectively; P =.03), a low serum HAV RNA level (log, 3.6 +/- 0.6 vs. 4.4 +/- 0.9, respectively; P =.02), genotypes other than IA, and acetaminophen intake. In multivariate analysis, low or undetectable HAV viral load and a high bilirubin level were independently associated with both low factor V levels and fulminant hepatitis and also with death or transplantation. In conclusion, HAV-related liver failure is due to an excessive host response associated with a marked reduction in viral load. Serum HAV RNA assay could be of help in the management of severe hepatitis A.

Genetic variability of hepatitis A virus in South America reveals heterogeneity and co-circulation during epidemic outbreaks

Genetic analysis of selected genome regions of hepatitis A virus (HAV) suggested that distinct genotypes of HAV could be found in different geographical regions. In order to gain insight into the genetic variability and mode of evolution of HAV in South America, an analysis was performed of sequence data obtained from the VP1 amino terminus and the VP1/2A region of HAV strains isolated over a short period of time in Uruguay, Argentina and Chile. Sequences obtained from 22 distinct HAV isolates were compared with published sequences from 21 different strains isolated all over the world. Phylogenetic analysis revealed that all strains isolated belong to a unique sub-genotype (IA). Strains isolated during an outbreak period showed a higher degree of heterogeneity than anticipated previously and the co-circulation of different isolates. The genetic variability among strains isolated in this region seems to be higher in comparison with strains isolated in other regions of the world.