bluuebunny/crossref_metadata_2025 huggingface dataset:
Are mutations in HIV type-1 reverse transcriptase 245 codon predictive of abacavir hypersensitivity reaction?
Authors: Bracciale Laura , Santangelo Rosaria , Fanti Iuri , Prosperi Mattia , Colafigli Mauela , Di Giambenedetto Simona , Marchetti Simona , Di Franco Aldo , Cauda Roberto , De Luca Andrea
Published: April 2022

Background

HLA-B*5701 is strongly related to abacavir hypersensitivity reactions (HSRs). Polymorphisms at position 245 of HIV type-1 (HIV-1) reverse transcriptase (RT) show an association with HLA-B*5701 suggesting that viral genotyping performed for antiretroviral drug resistance testing could reduce human leukocyte antigen (HLA) screening necessity to prevent abacavir HSR.

Methods

To further test the validity of 245 codon analysis results for predicting HSR, we analysed 1,179 sequences from 752 HIV-1-infected patients.

Results

Mutant amino acid residues in RT 245 were found in 30.6% of sequences. Among 239 patients with multiple longitudinal genotypes, 245 residues varied in 37 (15.5%) from wild type to mutant and/or vice versa. All these changes appeared during antiretroviral treatment. A total of 15 out of 229 (6.5%) abacavir-treated patients developed a clinically confirmed HSR: all carried B subtypes. There was no significant difference in the prevalence of 245 mutants between abacavir-treated patients with HSR (27%) and those without (29%), even after limiting the analysis to subtype B carriers.

Conclusions

The significant intraindividual variability of 245 residues and the lack of their association with clinically confirmed HSR argue against their use as viral genetic markers to exclude patients at risk for HSR.
Absence of a relation between efavirenz plasma concentrations and toxicity-driven efavirenz discontinuations in the EuroSIDA study
Authors:   on behalf of the EuroSIDA study group, van Luin Matthijs , Bannister Wendy P , Mocroft Amanda , Reiss Peter , Perri Di Giovanni , Peytavin Gilles , Molto José , Karlson Anders , Castagna Antonella , Beniowski Marek , Lundgren Jens D , Burger David M
Published: April 2022

Background

Conflicting data exist regarding the effect of efavirenz (EFV) plasma concentrations on central nervous system (CNS) toxicity. We aimed to determine whether patients with high EFV plasma concentrations have an increased likelihood of toxicity-driven EFV discontinuations.

Methods

EFV plasma concentrations were measured from patients in the EuroSIDA study starting EFV after 1 January 1999. Patients with a plasma concentration available were divided into those that discontinued EFV because of any toxicity or by the choice of the patient or physician within 2 years (TOXPC group) and those that continued EFV for ≥2 years (no toxicity group). Multivariable logistic regression modelling was used to investigate the effects of the EFV plasma concentration and those of other potentially relevant factors on the risk of toxicity-induced EFV discontinuations.

Results

A total of 843 patients were included. Of these patients, 138 patients (16.4%) discontinued EFV because of TOXPC and 705 (83.6%) patients continued EFV for ≥2 years. A total of 20 (14.5%) patients in the TOXPC group had high EFV plasma concentrations (>4.0 mg/l) compared with 99 (14.0%) patients in the no toxicity group ( P=0.890). A positive hepatitis C status ( P=0.026), but not the EFV plasma concentration, was an independent predictor of toxicity-driven EFV discontinuations.

Conclusions

No association was found between EFV plasma concentrations and the risk of EFV discontinuations because of (CNS) toxicity. This result questions the designation of EFV plasma concentrations >4.0 mg/l as being ‘toxic’, at least when defined by treatment discontinuation.
Human single-chain antibodies that neutralize homologous and heterologous strains and clades of influenza a virus subtype H5N1
Authors: Maneewatch Santi , Thanongsaksrikul Jeeraphong , Songserm Thaweesak , Thueng-In Kanyarat , Kulkeaw Kasem , Thathaisong Umaporn , Srimanote Potjanee , Tongtawe Pongsri , Tapchaisri Pramuan , Chaicumpa Wanpen
Published: April 2022

Background

Human antibodies that interfere with the biological activity of haemagglutinins (HAs) of influenza viruses have high potential as an antiviral agent.

Methods

Human single-chain antibody fragments (HuScFv) to recombinant and native HAs of the influenza virus H5N1 subtype were produced using a human antibody phage display library with the intention to increase the therapeutic arsenal against this highly pathogenic virus.

Results

The HuScFv inhibited HA activity and neutralized infectivity of both homologous and heterologous strains and clades of the H5N1 subtype in Madin–Darby canine kidney cell cultures. Intraperitoneally injected HuScFv also mediated immunotherapeutic protection in mice that were intranasally challenged with highly pathogenic H5N1 viruses belonging to different strains and clades.

Conclusions

Our data indicate that it might be worth pursuing these HuScFv further for future consideration as candidates for influenza intervention and treatment.
Mutations in the thumb–connection and RNase H domain of HIV type-1 reverse transcriptase of antiretroviral treatment-experienced patients
Authors: Waters Joshua M , O'Neal Wesley , White Kirsten L , Wakeford Charles , Lansdon Eric B , Harris Jeanette , Svarovskaia Evguenia S , Miller Michael D , Borroto-Esoda Katyna
Published: April 2022

Background

Antiretroviral therapy that targets HIV type-1 (HIV-1) reverse transcriptase (RT) can be linked to mutations in the thumb–connection (amino acids [AA] 241–426) and RNase H (AA 427–560) domains, which could affect drug resistance.

Methods

Genotypical and statistical analyses were performed on HIV-1 RT from 100 antiretroviral treatment-naive and 248 antiretroviral treatment-experienced patients, the majority of whom were infected with HIV-1 subtype B. The RT region was analysed in three parts: the polymerase (AA 1–240), thumb–connection (AA 241–426) and RNase H (AA 427–560) domains.

Results

The polymerase domain had statistically significant changes between the two groups at 24 AA positions that are known resistance sites. Within the thumb–connection domain, R284 and N348 had statistically significant changes between the groups ( P=0.007 and P≤0.001, respectively). In treatment-experienced patients, 17.3% had R284K, whereas 24.5% had N348I substitutions. Both R284 and N348 were 100% conserved in treatment-naive patients. Within the RNase H domain, only K451 showed a statistically significant change ( P≤0.001), with K451R present in 11% of treatment-experienced patients but remaining 100% conserved among treatment-naive patients.

Conclusions

RT mutations at three positions outside of the polymerase region were associated with antiretroviral therapy: R284K, N348I and K451R. Both R284K and K451R interact with the phosphate backbone of the template or primer in HIV-1 RT crystal structures and could potentially influence the positioning of the primer strand, thus affecting polymerization, the efficiency of nucleoside reverse transcriptase inhibitor excision and/or RNase H activity.
Identification of nonsense mutations in hepatitis B virus S gene in patients with hepatocellular carcinoma developed after lamivudine therapy
Authors: Lai Ming-Wei , Huang Shiu-Feng , Hsu Chao-Wei , Chang Mei-Hui , Liaw Yun-Fan , Yeh Chau-Ting
Published: April 2022

Background

Lamivudine is widely used in patients with chronic hepatitis B virus (HBV) infection. In cirrhotic patients, long-term lamivudine therapy significantly reduced the risk of hepatocellular carcinoma (HCC). However, in a small but substantial portion of patients, HCC still developed despite lamivudine therapy. Prolonged usage of lamivudine led to mutations in the polymerase gene, where concurrent nonsense mutations in the HBV S gene occasionally occurred. The significance of such mutations in hepatocarcinogenesis remains elusive. Here, we aimed to understand the oncogenicity of HBV pre-S/S nonsense mutations identified in patients with HCC that developed after lamivudine therapy.

Methods

Of 141 consecutive hepatitis B surface antigen-positive HCC patients, 8 developed HCC after receiving lamivudine therapy. The HBV pre-S/S sequences in their serum and tissue samples were analysed. A sex-and age-matched group of HCC patients who never received lamivudine therapy were included as controls. Site- directed mutagenesis experiments were performed to generate identified pre-S/S nonsense mutations in expression vectors for tumourigenicity analysis.

Results

Seven of eight patients in the lamivudine-treated group harboured nonsense mutations in the S gene compared with none in the control group ( P<0.001). Site- directed mutagenesis and transient transfection experiments revealed that these mutants could transactivate oncogene promoters. NIH3T3 cells stably expressing sL21*, sW156* and sW172* pre-S/S mutants had increased tumourigenicity in nude mice.

Conclusions

HCCs developed in lamivudine-treated patients who frequently carried nonsense mutations in the S gene. Such pre-S/S mutants are potentially oncogenic and might counteract the effect of lamivudine in preventing hepatocarcinogenesis.
CD4+ T-cell percentage is an independent predictor of clinical progression in AIDS-free antiretroviral-naive patients with CD4+ T-cell counts >200 cells/mm3
Authors: Guiguet Marguerite , Kendjo Eric , Carcelain Guislaine , Abgrall Sophie , Mary-Krause Murielle , Tattevin Pierre , Yazdanpanah Yazdan , Costagliola Dominique , Duval Xavier
Published: April 2022

Background

The aim of this study was to evaluate the clinical prognostic value of the CD4+ T-cell percentage (%CD4), the CD4+/CD8+ T-cell ratio or the CD8+ T-cell count, in addition to the CD4+ T-cell count and viral load (VL) in antiretroviral-naive HIV- infected patients with CD4+ T-cell counts >200 cells/ mm3.

Methods

Antiretroviral-naive patients ( n=9,740) who were AIDS-free and had a CD4+ T-cell count >200 cells/ mm3 at their first visit after January 1997 were followed-up until treatment initiation or clinical progression (mean follow- up 17 months and 13,660 person-years). Poisson regression was used for statistical analyses.

Results

Progression to AIDS-defining events (ADEs), serious ADEs and death occurred in 228 patients (crude rate 1.69 per 100 person-years), 105 patients (0.77 per 100 person-years) and 67 patients (0.49 per 100 person-years), respectively. Regarding progression to ADE, the data fit was improved when the model also included the %CD4 (Akaike's information criteria [AIC] 2,049) and, to a lesser extent, the CD4+/CD8+ T-cell ratio (AIC 2,053), in addition to CD4+ T-cell count and VL (AIC 2,056). After adjustment for VL and baseline characteristics, patients with CD4+ T-cell counts of 350–500 cells/mm3 and %CD4<15% had an estimated incidence of ADE of 3 per 100 person-years, similar to that in patients with CD4+ T-cell counts of 200–350 cells/mm3 and %CD4>15%. The %CD4 was also significantly associated with the risk of serious ADE. By contrast, %CD4, CD4+/CD8+ T-cell ratio or CD8+ T-cell count had no additional prognostic value for the risk of death.

Conclusions

In antiretroviral-naive HIV-infected patients with CD4+ T-cell counts >200 cells/mm3, the %CD4 was predictive of the risk of clinical progression independently of CD4+ T-cell count and VL.
Long-term hepatitis C internal ribosome entry site-dependent gene expression mediated by phage φC31 integrase in mouse model
Authors: Sun Zhidong , Wang Yi , Fu Qiuxia , Zhou Yong , Jia Shuaizheng , Du Juan , Peng Jianchun , Wang Yingli , Yang Shuhua , Zhan Linsheng
Published: April 2022

Background

The lack of a robust small animal model for hepatitis C virus (HCV) has hindered the development of novel drugs, including internal ribosome entry site (IRES) inhibitors. Phage φC31 integrase has emerged as a potent tool for achieving long-term gene expression in vivo. This study utilized φC31 integrase to develop a stable, reproducible and easily accessible HCV IRES mouse model.

Methods

φC31 integrase plasmid and the reporter vector, HCV-IRES–luciferase expression cassette (containing an attB site), was codelivered to murine livers using high pressure tail vein injection. HCV IRES-dependent translation refected by luciferase expression was accurately monitored in vivo by bioluminescence imaging. Genomic integration of the transgene was confirmed by partial hepatectomy and nested PCR. An HCV IRES-targeted short hairpin RNA (shRNA) expression plasmid, sh184, was hydrodynamically transfected into mouse liver to study its inhibition efficacy in vivo.

Results

φC31 integrase mediated intramolecular recombination between wild-type attB and attP sites in mice. The expression of luciferase was stable after 30 days post-transfection and remained so for 300 days only in the livers of mice that were coinjected with the integrase-encoding plasmid. Luciferase levels reduced dramatically after hydrodynamic transfection of sh184.

Conclusions

These results indicate that this mouse model provides a powerful tool for accurate and long-term evaluation of potential anti-IRES compounds in vivo.
Clinical and Virological Responses to Clevudine Therapy in Chronic Hepatitis B Patients: Results at 1 Year of an Open-Labelled Prospective Study
Authors: Ko Soon Young , Kwon So Young , Choe Won Hyeok , Kim Byung Kook , Kim Kyun-Hwan , Lee Chang Hong
Published: April 2022

Background

A previous clinical study of oral clevudine monotherapy for 24 weeks demonstrated that it has potent sustained antiviral effects without inducing drug resistance. The aim of this study was to evaluate the antiviral effects and safety of clevudine monotherapy for 12 months.

Methods

In this open-labelled prospective study, 45 treatment-naive chronic hepatitis B patients treated with 30 mg clevudine once daily for 12 months were monitored at baseline and at 3-month intervals during treatment.

Results

At baseline, the mean age of patients was 42 years, 32 were hepatitis B e antigen (HBeAg)-positive and 15 had liver cirrhosis. After 12 months of clevudine therapy, the mean serum hepatitis B virus (HBV) DNA level in HBeAg-positive patients had decreased by 4.6 log10 IU/ ml. Serum HBV DNA was undetectable in 68.7% of patients. HBeAg loss or seroconversion was observed in five patients (15.6%) and serum alanine aminotransferase (ALT) level had normalized after 12 months of treatment in 75% of patients. In all 13 HBeAg-negative patients, serum HBV DNA level was undetectable after 12 months of therapy and ALT level was normal in 61.5% of patients. Viral breakthrough occurred in one patient after 9 months of clevudine treatment. This patient had an HBV polymerase mutation, rtM204I. There were no serious adverse events.

Conclusions

One-year clevudine therapy is effective for suppressing serum HBV DNA level and for normalization of ALT level. Viral breakthrough associated with the rtM204I mutation in the HBV polymerase gene occurs during long-term clevudine treatment.
Virological response at 4 weeks to predict outcome of hepatitis C treatment with pegylated interferon and ribavirin
Authors: Martinot-Peignoux Michelle , Maylin Sarah , Moucari Rami , Ripault Marie-Pierre , Boyer Nathalie , Cardoso Ana-Carolina , Giuily Nathalie , Castelnau Corinne , Pouteau Michèle , Stern Christiane , Aupérin Anne , Bedossa Pierre , Asselah Tarik , Marcellin Patrick
Published: April 2022

Background

Viral kinetics during therapy provides information on how to individualize treatment. To determine the benefit of assessing positive predictive values (PPVs) and negative predictive values (NPVs) of rapid virological responses (RVRs) and early virological responses (EVRs), on-treatment outcomes in chronic hepatitis C patients were examined.

Methods

A total of 408 patients (221 treatment-naive) treated with pegylated interferon-α2b and ribavirin were included. Hepatitis C virus (HCV) RNA was measured at baseline, 4 weeks and 12 weeks. RVR was defined as undetectable HCV RNA at 4 weeks and EVR as ≥2 log10 decrease in HCV RNA at 12 weeks. The additive value of RVR on predicting sustained virological response (SVR) was assessed with receiver operating characteristic (ROC) curves.

Results

SVR, RVR and EVR were observed in 46%, 23% and 78% of patients, respectively. PPVs of RVR were 96%, 100% and 100% in treatment-naive patients, relapsers and non-responders, respectively. NPVs of failure to achieve EVR were 97%, 75% and 91%, in treatment- naive patients, relapsers and non-responders, respectively. At 4 weeks, patients with RVR had the highest probability to achieve SVR (odds ratio 44.98 in the entire population and 32.95 in treatment-naive patients). ROC curves showed the area under the ROC curve to be 0.758 versus 0.832 in the entire population and 0.795 versus 0.858 in treatment-naive patients at baseline versus week 4, respectively.

Conclusions

RVR is a strong predictor of SVR (PPV>96%) and failure to achieve EVR is a strong predictor of non-SVR (NPV>75%), independent of patients’ pretreatment status. Added to baseline characteristics, RVR increased the accuracy to predict SVR. The combination of RVR and EVR provided complementary information, and thus provides a key opportunity to individualize treatment and improve the benefit/risk ratio of therapy.
Hypophosphataemia: An Easy Strategy for Diagnosis and Treatment in HIV Patients
Authors: Bagnis Corinne Isnard , Karie Svetlana , Deray Gilbert , Essig Marie
Published: April 2022

Because HIV infection has become a chronic disease, it is crucial that metabolic complications secondary to HIV infection or prolonged therapy be diagnosed and managed appropriately over time. Therefore the optimal follow-up becomes complex and time consuming. Our review aimed to provide physicians in charge of HIV-infected patients with key data helping them to diagnose and understand hypophosphataemia in HIV patients. Hypophosphataemia is frequent and sometimes secondary to renal phosphate wasting. It is very rarely a component of a complex proximal tubular disorder, such as Fanconi syndrome. When isolated, hypophosphataemia is easy to rule out and treat. In rare cases, prolonged hypophosphataemia, when related to renal phosphate wasting and tubular dysfunction, might have potential consequences on bone outcome, however, more studies are needed. HIV infection by itself might be a risk factor for bone metabolism abnormalities; antiretroviral drugs might also be involved. Therefore, it seems valuable for patients that the minimal screening should be performed routinely, in order to prevent long-term disabilities.
The effects of HIV type-1 viral suppression and non-viral factors on quantitative proteinuria in the highly active antiretroviral therapy era
Authors: Gupta Samir K , Smurzynski Marlene , Franceschini Nora , Bosch Ronald J , Szczech Lynda A , Kalayjian Robert C ,   for the AIDS Clinical Trials Group Longitudinal Linked Randomized Trials Study Team
Published: April 2022

Background

Proteinuria is associated with progressive renal disease and overall mortality in HIV-infected patients; however, the prevalence and correlates of quantitative pro-teinuria in the highly active antiretroviral therapy era are unknown.

Methods

Spot urine protein to creatinine (P/Cr) ratios, an accepted measure of quantitative daily proteinuria, were measured annually since 2002 in participants of the AIDS Clinical Trials Group Longitudinal Linked Randomized Trials cohort. We used linear regression models with general estimating equations to identify factors associated with the abnormal P/Cr thresholds of ≥0.2 and ≥1.0.

Results

Of the 2,857 participants (most of whom were receiving antiretroviral therapy) analysed, 16% and 3% had P/Cr levels ≥0.2 and ≥1.0, respectively, at first measurement. P/Cr levels did not change during a median follow-up of 3 years (interquartile range 2–4). Factors associated with P/Cr≥0.2 at any measurement included greater age, lower glomerular filtration rate, female sex, antiretroviral therapy prior to entry into parent randomized trial, HIV type-1 RNA level ≥400 copies/ ml, lower CD4+ T-cell count and history of hypertension, diabetes or hepatitis C coinfection (all P<0.04). Black race and higher non-high-density lipoprotein cholesterol levels were associated with P/Cr levels ≥1.0, but not with P/ Cr levels ≥0.2. Hepatitis B coinfection and current use of adefovir, indinavir and tenofovir were not associated with either of the P/Cr thresholds.

Conclusions

Both HIV-1 and non-HIV-1-related factors are associated with abnormal levels of proteinuria and identify those who are at a greater risk of worse clinical outcomes. Several of these factors are differentially associated with lower and higher proteinuria thresholds.
Immunological and mutagenic actions of ribavirin monotherapy preceding combination therapy with interferon for patients with chronic hepatitis C
Authors: Ogawa Koji , Hige Shuhei , Nakanishi Mitsuru , Yamamoto Yoshiya , Chuma Makoto , Nagasaka Atsushi , Asaka Masahiro
Published: April 2022

Background

We aimed to investigate the effects of ribavirin on hepatitis C virus (HCV). Immunological and virological effects were analysed in patients undergoing treatment with ribavirin monotherapy prior to the initiation of combination therapy with interferon-α.

Methods

A total of 25 patients with chronic HCV infection were enrolled in this study. All patients received ribavirin for 4 weeks during monotherapy; subsequently, interferon-α2b was additionally given as combined therapy. Patients were divided into two groups according to virological response. A rapid viral responder (RVR) was defined as a patient in whom HCV RNA became undetectable within 4 weeks after combination therapy. The changes of the T-helper (Th)1/Th2 subset of peripheral blood CD4+ T-cells, serum cytokine levels and the alignment of the interferon sensitivity- determining region (ISDR) during ribavirin monotherapy were analysed by flow cytometry, ELISAs and sequencing methods.

Results

A total of 17 patients were classed as RVR. In the RVR group, the mean ±sd serum alanine aminotransferase levels significantly decreased (before treatment 103 ±92 IU/l and after treatment 57 ±46 IU/l; P<0.05) during ribavirin monotherapy. The mean ±sd Th1/Th2 ratio significantly increased (before treatment 13.9 ±5.1 and after treatment 16.7 ±6.2; P<0.05), but did not change in the non-RVR group. The levels of Th2 cytokines (interleukin-10 and soluble CD30) significantly decreased, especially in the RVR group. The mean ±sd mutation rates of ISDR at the nucleotide level increased in the RVR group (before treatment 2.6 ±0.9 sites/clone and after treatment 3.9 ±1.6 sites/clone; P<0.05), but did not change in the non-RVR group.

Conclusions

Ribavirin administration might increase the efficacy of interferon therapy for patients with chronic hepatitis C by stimulating the host immune system and promoting HCV gene mutation.
In vivo selection by enfuvirtide of HIV type-1 env quasispecies with optimal potential for phenotypic expression of HR1 mutations
Authors: Goubard Armelle , Clavel François , Mammano Fabrizio , Labrosse Béatrice
Published: April 2022

Background

HIV type-1 (HIV-1) resistance to enfuvirtide (ENF) is mediated by mutations in the HR1 domain of gp41. We have previously shown that some of these mutations are selected in the context of env backgrounds that are not dominant before exposure to ENF, suggesting that particular env environments could facilitate phenotypic expression of HR1-mediated ENF resistance.

Methods

Envelope clones, representing the viral quasispecies present in the longitudinal follow-up of a patient who failed ENF-based salvage therapy, were tested for ENF susceptibility and Env-related replicative capacity. ENF resistance mutations in HR1 were introduced or back-mutated in representative clones to evaluate their phenotypic effect in different genetic contexts.

Results

The ENF resistance levels produced by the introduction of mutation V38A in pretherapeutic env sequences were significantly lower than those of env clones harvested after viral escape, and in which V38A was naturally selected. Back-mutation of V38A from these clones resulted in a strong loss in ENF resistance, but these clones retained significant residual resistance, again strongly suggesting the role of determinants outside of HR1 in HIV-1 resistance to ENF. By contrast with changes in resistance, addition or removal of HR1 mutations in env clones had little effect on viral replicative capacity.

Conclusions

The development of ENF resistance in vivo is a concerted coevolutionary process whereby HR1 mutations are selected within env variants that permit their optimal phenotypic expression.
Transmitted antiretroviral drug resistance among acute and recent HIV infections in North Carolina from 1998 to 2007
Authors: Hurt Christopher B , McCoy Sandra I , Kuruc JoAnn , Nelson Julie AE , Kerkau Melissa , Fiscus Susan , McGee Kara , Sebastian Joseph , Leone Peter , Pilcher Christopher , Hicks Charles , Eron Joseph
Published: April 2022

Background

Transmitted drug resistance (TDR) limits antiretroviral options and thus complicates the management of HIV-positive patients. HIV disproportionately affects the southern US, but available national estimates of TDR prevalence principally reflect large metropolitan centres outside this region.

Methods

The Duke/UNC Acute HIV Program has collected data on acute or recent HIV infections (ARHI) in North Carolina since 1998. Acute infections represent antibody-negative, RNA-positive patients. Recent infection was determined by history of HIV testing or concordance between detuned ELISA and antibody avidity assays. Genotypic sequence data from the earliest collected pretreatment plasma samples were analysed with the Stanford HIV Database and screened for surveillance drug resistance mutations (SDRMs).

Results

A total of 253 individuals with ARHI between May 1998 and May 2007 had complete genotypic sequence data for analysis; 39.5% were acute infections, 78.7% were male, 64.8% were non-White and 53.8% were men who have sex with men. The overall prevalence of TDR was 17.8%, with SDRMs for non-nucleoside/ nucleotide reverse transcriptase inhibitors (NNRTIs) in 9.5% of the cohort. Mutations for nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) were detected in 7.5% and for protease inhibitors (PIs) in 3.2%. K103N was the most common mutation (7.5%). Thymidine analogue mutations were found in 4.7% of samples; the most common PI SDRM was L90M (2.4%). Dual- or triple-class antiretroviral resistance was rare, encountered in only six (2.4%) samples.

Conclusions

The prevalence of TDR in North Carolina is similar to estimates from the US metropolitan areas. These findings have implications for initial regimen selection and secondary prevention efforts outside of large, metropolitan HIV epicentres.
Variability of reverse transcriptase and overlapping S gene in hepatitis B virus isolates from untreated and lamivudine-resistant chronic hepatitis B patients
Authors: Pollicino Teresa , Isgrò Graziella , Di Stefano Rosa , Ferraro Donatella , Maimone Sergio , Brancatelli Santa , Squadrito Giovanni , Marco Vito Di , Craxì Antonio , Raimondo Giovanni
Published: April 2022

Background

The high degree of diversity of the hepatitis B virus (HBV) quasispecies in chronically infected individuals raises the possibility that HBV genetic variants favouring resistance to nucleoside/nucleotide analogues (NAs) might pre-exist to treatment. The aim of this study was to investigate the genetic variability of the entire HBV reverse transcriptase (RT) domain and of the overlapping S gene in a large series of untreated hepatitis B surface antigen carriers and in lamivudine (3TC)-resistant patients.

Methods

Sequencing analysis of the entire HBV RT domain of isolates from 100 untreated (treatment- naive group) and 59 3TC-resistant (3TC-resistant group) consecutive patients with chronic hepatitis B was performed.

Results

In the treatment-naive group, primary mutations known to cause resistance to NAs were not detected, but variably combined secondary/compensatory mutations were found in 46 (46%) patients. Moreover, four patients carried mutations that modified the S protein antigenicity. In the 3TC-resistant group, besides the primary 3TC-resistant mutations, various combinations of primary and secondary mutations conferring resistance to other NAs were detected in 41/59 (69.5%) patients. Importantly, the RT mutations induced by 3TC provoked stop codons in the overlapping S gene in two patients and modified the S protein antigenicity in another nine.

Conclusions

This study shows that HBV mutants associated with resistance to NAs might already be present as the major infecting population in untreated patients, and that variants emerging under 3TC might also carry mutations favouring resistance to other NAs and/or potentially altering the S protein immunoreactivity.
Rescue Monotherapy in Lamivudine-Resistant Hepatitis B e Antigen-Positive Chronic Hepatitis B: Adefovir versus Entecavir
Authors: Lee Jung Min , Kim Hyung Joon , Park Jun Yong , Lee Chun Kyon , Kim Do Young , Kim Ja Kyung , Lee Hyun Woong , Paik Yong Han , Lee Kwan Sik , Han Kwang-Hyub , Chon Chae Yoon , Hong Sun Pyo , Nguyen Tin , Ahn Sang Hoon
Published: April 2022

Background

The efficacy of adefovir dipivoxil (ADV) or entecavir (ETV) rescue monotherapy has not been directly compared in hepatitis B e antigen (HBeAg)- positive patients with lamivudine (3TC)-resistant chronic hepatitis B (CHB). We compared the efficacy of ADV and ETV rescue monotherapy in HBeAg-positive patients with confirmed genotypic 3TC resistance.

Methods

A total of 160 HBeAg-positive patients with confirmed 3TC resistance underwent switch therapy (91 ADV and 59 ETV). Parameters assessed included alanine aminotransferase (ALT) normalization, HBeAg serocon-version, undetectable serum hepatitis B virus (HBV) DNA by PCR (lower detection limit <300 copies/ml), virological breakthrough and initial virological response (IVR) at 3 (IVR-3) and 6 (IVR-6) months.

Results

Following 52 weeks of treatment in the ADV and ETV groups, serum HBV DNA became undetectable in 25 (27.5%) and 21 (35.6%; P=0.292) patients, ALT normalization occurred in 67/78 (85.9%) and 43/47 (91.5%; P=0.351), HBeAg seroconversion in 4 (4.4%) and 1 (1.7%; P=1.000), IVR-3 in 19 (20.9%) and 18 (30.5%), IVR-6 in 40 (44.0%) and 25 (42.4%) and virological breakthrough in 2 (2.2%) and 1 (1.7%; P=1.000) patients, respectively.

Conclusions

ADV and ETV revealed comparable efficacy after 52 weeks of treatment in HBeAg-positive patients with 3TC resistance. Undetectable HBV DNA in serum following 52 weeks of treatment was predictable with IVR-3 and IVR-6 in both groups.
Inhibition of Epstein–Barr virus replication by small interfering RNA targeting the Epstein–Barr virus protease gene
Authors: Larrat Sylvie , Morand Patrice , Bas Ariane , Vigne Solenne , Crance Jean-Marc , Boyer Véronique , Nicod Sandrine , Grossi Laurence , Buisson Marlyse , Burmeister Wim P , Seigneurin Jean-Marie , Germi Raphaële
Published: April 2022

Background

The Epstein–Barr virus (EBV) protease (PR), coded by the BVRF2 gene, is essential for the maturation of the viral capsid and viral DNA packaging during the late stage of the EBV lytic cycle. Like the other herpesvirus serine PRs, EBV PR could be a target for the inhibition of EBV replication. To date, no data have been reported on the inhibition of EBV PR messenger RNA (mRNA) by small interfering RNA (siRNA).

Methods

In this study, siRNAs targeting EBV PR were delivered to the epithelial 293 cell line stably transfected with the complete B95-8 EBV episome. EBV DNA and PR mRNA were quantified by real-time PCR in cells and supernatant, protein expression was assessed by immunoblotting, and production of EBV infectious particles in the culture medium was measured by Raji cell superinfection.

Results

The EBV PR mRNA within the cells was reduced by 73%, the PR protein by 35% and the amount of virus in the cell supernatant was drastically decreased by 86% or 95%, depending on the method.

Conclusions

The strong effect of the siRNA targeting EBV PR on EBV replication attests to the crucial role played by EBV PR in the production of infectious particles and suggests that targeting this enzyme can be a new strategy against EBV-associated diseases where virus replication occurs.
Combination of baseline parameters and on-treatment hepatitis B virus DNA levels to start and continue patients with lamivudine therapy
Authors: Yuen Man-Fung , Fung James , Seto Wai-Kay , Wong Danny Ka-Ho , Yuen John Chi-Hang , Lai Ching-Lung
Published: April 2022

Background

This study aimed to identify the baseline hepatitis B virus (HBV) DNA, alanine aminotransferase (ALT) levels and on-treatment HBV DNA levels for favourable outcome in patients receiving 5-year lamivudine.

Methods

Virological, serological and biochemical parameters were assessed in 74 hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients at year 5 of therapy.

Results

Patients with baseline HBV DNA levels <9 log10 copies/ml and ALT≥2x the upper limit of normal (ULN) had a significantly higher chance of HBV DNA suppression to <4 log10 copies/ml (76.5%) and HBeAg seroconversion (82.4%), and a lower chance of YMDD mutations (35.3%) compared with patients with HBV DNA<9 log10 copies/ml and ALT<2xULN and patients with HBV DNA≥9 log10 copies/ml (all P<0.05). All patients with these two baseline parameters plus week 4 HBV DNA<4 log10 copies/ml achieved HBV DNA<35 copies/ml, HBeAg seroconversion and ALT normalization without YMDD mutations at year 5. When these two baseline parameters were combined with week 24 HBV DNA<3 log10 copies/ml, 60%, 80% and 90% of patients had HBV DNA<35 copies/ml, <3 log10 copies/ml and <4 log10 copies/ml, respectively at year 5. Overall, 90% of patients had HBeAg seroconversion and only 10% had YMDD mutations.

Conclusions

For HBeAg-positive patients with baseline HBV DNA<9 log10 copies/ml and ALT≥2xULN, lamivudine could be initiated. For those with HBV DNA<4 log10 copies/ml at week 4 or <3 log10 copies/ml at week 24, continuation of lamivudine treatment would be more likely to result in a good long-term response.
Cytomegalovirus resistance in solid organ transplant recipients treated with intravenous ganciclovir or oral valganciclovir
Authors: Boivin Guy , Goyette Nathalie , Rollag Halvor , Jardine Alan G , Pescovitz Mark D , Asberg Anders , Ives Jane , Hartmann Anders , Humar Atul
Published: April 2022

Background

The rate of cytomegalovirus (CMV) mutations conferring ganciclovir resistance was assessed in a trial comparing intravenous ganciclovir and oral valganciclovir for treatment of CMV disease in solid organ transplant (SOT) recipients.

Methods

Viral genes ( UL97 and UL54) conferring ganciclovir resistance were amplified and sequenced from blood samples collected at days 0 (before therapy), 21 (end of induction) and 49 (end of maintenance).

Results

The overall risk of developing a confirmed or probable ganciclovir resistance mutation during treatment was similar for patients treated with ganciclovir (2.3%) and valganciclovir (3.6%; P=0.51). A persistent viral load at day 21 was associated with a significant risk of ganciclovir resistance by day 49 (odds ratio 11.83; P=0.022). In multivariate analyses, presence of a confirmed ganciclovir resistance mutation was independently associated with virological failure (viral load ≥600 copies/ml) at days 21 and 49. One-third (3/9) of patients with confirmed CMV resistance mutations had recurrent CMV disease. The plasma half-life of confirmed ganciclovir-resistant UL97 mutants was significantly longer than that of wild-type strains, polymorphic variants and strains with mutations of unknown significance ( P=0.045). Multiple UL54 mutations of unknown significance were found in clinical strains. Viral kinetic analysis of these latter strains revealed no effect (negative or positive) on in vivo viral fitness.

Conclusions

Treatment with oral valganciclovir or intravenous ganciclovir results in similar and low rates of resistance mutations in SOT recipients. Patients with drug-resistant CMV strains often have virological failure and might have unfavourable clinical outcomes.
Dried Fluid Spots for HIV Type-1 Viral Load and Resistance Genotyping: A Systematic Review
Authors: Hamers Raph L , Smit Pieter W , Stevens Wendy , Schuurman Rob , Rinke de Wit Tobias F
Published: April 2022

Background

Dried spots on filter paper made of whole blood (dried blood spots; DBS), plasma (dried plasma spots; DPS) or serum (dried serum spots) hold promise as an affordable and practical alternative specimen source to liquid plasma for HIV type-1 (HIV-1) viral load determination and drug resistance genotyping in the context of the rapidly expanding access to antiretroviral therapy (ART) for HIV-1-infected individuals in low- and middle-income countries. This report reviews the current evidence for their utility.

Methods

We systematically searched the English language literature published before 2009 on Medline, the websites of the World Health Organization and US Centers for Disease Control and Prevention, abstracts presented at relevant international conferences and references from relevant articles.

Results

Data indicate that HIV-1 viral load determination and resistance genotyping from DBS and DPS is feasible, yielding comparable test performances, even after storage. Limitations include reduced analytical sensitivity resulting from small analyte volumes (approximately 3.5 log10 copies/ ml at 50 ml sample volume), nucleic acid degradation under extreme environmental conditions, impaired efficiency of nucleic acid extraction, potential interference of archived proviral DNA in genotypes obtained from DBS and the excision of spots from the filters in high-volume testing.

Conclusions

This technology offers the advantages of a stable specimen matrix, ease of sample collection and shipment. The current sensitivity in drug resistance testing is appropriate for public health surveillance among pretreatment populations. However, consistently improved analytical sensitivity is needed for their routine application in the therapeutic monitoring of individuals receiving ART, particularly at the onset of treatment failure.
Maraviroc: Pharmacokinetics and drug Interactions
Authors: Abel Samantha , Back David J , Vourvahis Manoli
Published: April 2022

Maraviroc is a potent selective CCR5 antagonist and is the first of this new class of oral agents to be approved for the treatment of CCR5-tropic HIV type-1. Maraviroc is extensively metabolized by CYP3A4, with renal clearance accounting for approximately 23% of total clearance. The half-life of maraviroc is approximately 16 h. Maraviroc does not inhibit any of the major CYP450 enzymes at clinically relevant doses and it has not shown any clinically relevant effects on plasma concentrations of other agents; hence, no dose adjustments of coadministered agents are required. Maraviroc exposure is altered by agents that modulate the activity of CYP3A4 and, in some circumstances, maraviroc dose adjustment is necessary. This article aims to review all pharmacokinetic and drug interaction data available for maraviroc, and to provide a comprehensive summary of the dose adjustment recommendations for maraviroc when coadministered with agents from all classes of antiretroviral therapy as well as other commonly coadministered agents.
Management of Antiretroviral Therapy for HIV Infection: Modelling when to Change Therapy
Authors: D'Amato Rebecca M , D'Aquila Richard T , Wein Lawrence M
Published: April 2022

Objective

To evaluate four strategies for monitoring plasma HIV RNA levels and/or resistance genotypes to decide when to change antiretroviral therapy. The strategies include: (i) 1997 guidelines recommending a therapy switch when plasma RNA exceeds a threshold level; (ii) a viral load policy, using a fixed increase in viral load as the trigger; (iii) a genotype policy, requiring a smaller viral rebound than (ii) and detection of genotypic resistance before switching; and (iv) a proactive policy, switching drug regimens at a predetermined time if viral load has not rebounded.

Design and setting

A Monte Carlo simulation tracks patients’ viral loads and presence of opportunistic infection during therapy. The model uses clinical and virological data and statistical variation in patient parameters for the evaluation of therapeutic strategies. Main outcome measures: To determine which strategies minimize viral rebound detection delay while maintaining a low (prespecified) probability of switching therapy before rebound.

Results

1997 Guidelines and the viral load policy create lengthy delays in detection of rebound, particularly when patients are drug-naive and the detection limit of the viral load assay is 500 copies/ml. A detection limit of 20 copies/ml decreases this delay substantially. Genotyping achieves only minor additional delay reductions. Of the strategies tested, the proactive policy leads to the shortest delays.

Conclusions

This model indicates that prolonged periods may be required for viral load to rebound to detectable levels following prolonged suppression. Proactive switching produces the best outcome in our model because it may reduce the duration of viral replication under pressure of a failing regimen before detection of viral rebound. This strategy should be evaluated in clinical trials.
Genotypic and Phenotypic Resistance to Stavudine after Long-Term Monotherapy
Authors: Holguín Africa , Dietrich Ursula , Immelmann Andreas , Soriano Vincent ,   The BMS-020 Spanish Study Group, Dietrich U , Immelmann A , Gil-Aguado A , Echevarría S , Clotet B , Ocaña I , Santamaría J , Bouza E , Bonora V , Alcácer F , Soriano V , Holguín A , Villalba N , González-Lahoz J
Published: April 2022

Protocol BMS 020 was a double-blind, prospective clinical trial in which two different doses of stavudine (20 and 40 mg twice daily) were compared in human immunodeficiency virus (HlV)-infected patients with previous exposure to zidovudine for longer than 16 weeks. Genotypic and phenotypic resistance to both zidovudine and stavudine were examined after at least 2 years of stavudine monotherapy. None of 35 tested individuals harboured the codon 50 and/or 75 mutations previously described to be associated with stavudine resistance. However, more than 80% of the individuals carried mutations associated with zidovudine resistance, despite all these patients having stopped zidovudine at least 2 years earlier. Significant phenotypic resistance to stavudine was observed only in 2 of 5 tested individuals, although IC50 values were increased only 6.6- and 9.2–fold, respectively. These two patients had suffered a decline in their CD4 count, and one of them had high levels of plasma viraemia. The sequence analysis of the reverse transcriptase (RT) gene (aa 30 to 240) in these five patients revealed no changes that could be involved in stavudine resistance. In contrast, and despite having stopped treatment with zidovudine more than 2 years before, phenotypic resistance to zidovudine was observed in all five subjects, with IC50 values raised by more than 75-fold in all of them. Moreover, all harboured codon substitutions within the RT gene associated with zidovudine resistance, and these mutations remained in viral genomes examined after virus co-culture, suggesting that they provided some biological advantage to mutants, even in the absence of drug pressure. In conclusion, both genotypic and phenotypic resistance to stavudine seem to be a rare event in patients exposed to the drug, even after long periods of exposure.
Prediction of HIV-1 RNA Suppression and its Durability during Treatment with Zidovudine/Lamivudine
Authors: Opravil Milos , Hill Andrew M , DeMasi Ralph , Dawson Debra
Published: April 2022

To predict the probability of long-term viral suppression during treatment with zidovudine and lamivudine, human immunodeficiency virus type 1 (HIV-1) RNA values were retrospectively pooled for 1083 patients from six randomized, double-blind clinical trials. All analyses of HIV-1 RNA were obtained using the Roche Amplicor assay or its earlier prototype. Time to loss of response was evaluated by Kaplan-Meier analysis; Cox proportional hazards models were used to assess the influence of baseline variables. Among 523 patients with ≤6 months of prior zidovudine treatment, the probability of HIV-1 RNA suppression below 400 copies/ml at 48 weeks was 71% in those with baseline HIV-1 RNA <5000 copies/ml, but only 14% in those with HIV-1 RNA between 50000 and 200000 copies/ml. Among 560 patients with >6 months of prior zidovudine treatment, the rates of sustained viral suppression were lower, but also significantly associated with the baseline HIV-1 RNA. Multivariate analyses showed no independent effect of CD4 cell count, age, sex, race, or CDC disease stage on the probability of sustained HIV-1 RNA suppression. When patients with ≤6 months of prior therapy were stratified based on the magnitude of HIV-1 RNA nadir achieved during treatment, those who reached a nadir of <400 copies/ml retained this response for significantly longer time periods than the ones who only achieved partial viral suppression. In conclusion, baseline HIV-1 RNA levels and the duration of prior zidovudine therapy strongly predict the antiretroviral efficacy of zidovudine/lamivudine. The baseline parameters should influence the choice of the antiretroviral regimen.
Low Plasma Concentrations of Indinavir are Related to Virological Treatment Failure in HIV-1-Infected Patients on Indinavir-Containing Triple Therapy
Authors: Burger David M , Hoetelmans Richard MW , Hugen Patricia WH , Mulder Jan W , Meenhorst Pieter L , Koopmans Peter P , Brinkman Kees , Keuter Monique , Dolmans Wil , Hekster Yechiel A
Published: April 2022

All human immunodeficiency virus type 1 (HIV-1)-infected patients who started to use indinavir (800 mg three times a day) as part of their triple drug regimen were included in a study to determine the importance of low plasma concentrations of indinavir as a cause of virological treatment failure. The indinavir concentration and a number of patient characteristics at baseline were tested as risk factors for virological treatment failure (defined as a viral load above 200 copies/ml after 24 weeks of treatment) in univariate and multivariate analyses; 65 patients were included. Virological treatment failure occurred in 36.9% of the patients. Multivariate analysis showed that a low plasma concentration of indinavir (odds ratio 0.1), a high viral load at baseline (odds ratio 2.6) and pretreatment with another protease inhibitor (odds ratio 10.0) were independent factors related to virological treatment failure. Monitoring of indinavir plasma concentrations may be an important tool for the optimization of triple drug combination therapy.
Cytomegalovirus Drug Resistance
Authors: Emery VC
Published: April 2022

Clinical resistance of cytomegalovirus (CMV) against the currently licensed antiviral drugs is becoming an increasingly recognized problem. This review focuses on the molecular basis of resistance and describes mutations in the UL54 DNA polymerase leading to resistance against cidofovir, foscarnet and ganciclovir. The review highlights two important developments in our appreciation of resistance. Firstly, the use of more rapid molecular based assays to detect genotypic resistance and secondly, the relationship between resistance profiles in multiple organ systems of the same host. Finally, the changing face of CMV disease in the era of highly active antiviral chemotherapy is considered with respect to its impact on the frequency of CMV resistance in the clinic.