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Integrase-strand-transfer inhibitors (INSTIs) are known to rapidly reduce HIV-1 plasma viral load, replication cycles, and new viral integrations, thus potentially limiting viral evolution. Here, we assessed the role of INSTIs on HIV-1 V3 evolution in a cohort of 89 HIV-1-infected individuals starting an INSTI- (N = 41, [dolutegravir: N = 1; elvitegravir: N = 3; raltegravir: N = 37]) or a non-INSTI-based (N = 48) combined antiretroviral therapy (cART), with two plasma RNA V3 genotypic tests available (one before [baseline] and one during cART). V3 sequences were analysed for genetic distance (Tajima-Nei model) and positive selection (dN/dS ratio). Individuals were mainly infected by B subtype (71.9%). Median (interquartile-range, IQR) plasma viral load and CD4 + T cell count at baseline were 4.8 (3.5–5.5) log10 copies/mL and 207 (67–441) cells/mm3, respectively. Genetic distance (median, IQR) between the V3 sequences obtained during cART and those obtained at baseline was 0.04 (0.01–0.07). By considering treatment, genetic distance was significantly lower in INSTI-treated than in non-INSTI-treated individuals (median [IQR]: 0.03[0.01–0.04] vs. 0.05[0.02–0.08], p = 0.026). In line with this, a positive selection (defined as dN/dS ≥ 1) was observed in 36.6% of V3 sequences belonging to the INSTI-treated group and in 56.3% of non-INSTI group (p = 0.05). Multivariable logistic regression confirmed the independent correlation of INSTI-based regimens with a lower probability of both V3 evolution (adjusted odds-ratio: 0.35 [confidence interval (CI) 0.13–0.88], p = 0.027) and positive selection (even if with a trend) (adjusted odds-ratio: 0.46 [CI 0.19–1.11], p = 0.083). Overall, this study suggests a role of INSTI-based regimen in limiting HIV-1 V3 evolution over time. Further studies are required to confirm these findings.

Intrahepatic total HBV DNA (it-HBV DNA) level might reflect the size of virus reservoir and correlate with the histological status of the liver. To quantitate it-HBV DNA in a series of 70 liver biopsies obtained from hepatitis B chronic patients, a modified version of the COBAS®Ampliprep/COBAS®TaqMan HBV test v2.0 was used for this purpose. The linearity and reproducibility of the modified protocol was tested by quantifying serial dilutions of a full-length HBV containing plasmid and it-HBV DNA from a reference patient. A good linear trend between the expected values and those generated by the assay was observed at different concentrations of both plasmid and reference patient (R 2 = 0.994 and 0.962, respectively). Differences between the values obtained in two independent runs were ≤0.3 log IU for the plasmid and ≤0.6 log IU/mg for the reference patient, showing a high inter-run reproducibility. In the 70 liver biopsies, it-HBV DNA level ranged from 1.4 to 5.4 log IU/mg, with a good linearity and reproducibility between the values obtained in two runs [R 2 = 0.981; median (IQR) difference of it-HBV DNA 0.05 (0.02-0.09) IU/mg]. The modified COBAS®Ampliprep/COBAS®TaqMan HBV test v2.0 allows an accurate quantitation of it-HBV DNA. Its determination may have prognostic value and may be a useful tool for the new therapeutic strategies aimed at eradicating the HBV infection.

Background HBV reactivation is associated with high mortality rates in hematopoietic stem cell transplantation (HSCT) and prophylactic lamivudine (LMV) treatment is suggested to prevent this phenomenon. However, the duration of LMV treatment in HSCT patients is not fully defined and the time of immune recovery is considered the best parameter for a drug to be safely interrupted. In patients undergoing allogeneic HSCT, the time of immune recovery is not easy to define and may take years after transplantation and prolonged LMV treatments, which can lead to drug-resistant viral strains. Case presentation An anti-HBc-positive hematological patient who was undergoing prolonged immunosuppression and who experienced HBV reactivation 3 months after the suspension of a prolonged LMV prophylaxis is described. HBV-DNA matching an atypical serological profile characterized by HbsAg negativity and anti-HBs positivity was detected in the patient. The genotypic analysis of the HBV strain identified T127P, F170FL and S204R mutations of HbsAg, which can hinder HBsAg recognition in a diagnostic assay. Conclusions HBV reactivation in the HSCT host can be sustained by HBsAg viral variants with characteristics of altered immunogenicity that cannot be detected by usual laboratory tests. This clinical case description suggests the importance of screening for serum HBV-DNA levels in the diagnosis of HBV reactivation and monitoring HBV-DNA after prophylaxis suspension, particularly in HSCT subjects who have undergone prolonged periods of LMV treatment.

Altres ajuts: This work was supported by the FIS project 07/0418 (to CC), the Spanish AIDS network, "RIS, Red Temática Cooperativa de Investigación en SIDA (RD06/0006)" and the CHAIN European Consortium. C. Cabrera and J. Blanco are researchers from Fundació Institut de Recerca en Ciències de la Salut Germans Trias i Pujol supported by the Health Department of the Catalan Government (Generalitat de Catalunya). F. Cunyat is supported by the FIS project 07/0418 and VS is supported by grants from CHAIN, Collaborative HIV and Anti-HIV Drug-Resistance Network, Integrated Project no.223131, funded by the European-Commission Framework-7 Program. MC is supported by a RIS contract. This work is part of the PhD thesis of F. Cunyat at Universitat Autònoma de Barcelona, Barcelona, Spain. Resistance to the fusion inhibitor enfuvirtide (ENF) is achieved by changes in the gp41 subunit of the HIV envelope glycoprotein (Env). Specific ENF-associated mutational pathways correlate with immunological recovery, even after virological failure, suggesting that the acquisition of ENF resistance alters gp41 pathogenicity. To test this hypothesis, we have characterized the expression, fusion capability, induction of CD4 + T cell loss and single CD4 + T cell death of 48 gp41 proteins derived from three patients displaying different amino acids (N, T or I) at position 140 that developed a V38A mutation after ENF-based treatment. In all cases, intra-patient comparison of Env isolated pre- or post-treatment showed comparable values of expression and fusogenic capacity. Furthermore, Env with either N or T at position 140 induced comparable losses of CD4 + T-cells, irrespective of the residue present at position 38. Conversely, Env acquiring the V38A mutation in a 140I background induced a significantly reduced loss of CD4 + T cells and lower single-cell death than did their baseline controls. No altered ability to induce single-cell death was observed in the other clones. Overall, primary gp41 proteins with both V38A and N140I changes showed a reduced ability to induce single cell death and deplete CD4 + T cells, despite maintaining fusion activity. The specificity of this phenotype highlights the relevance of the genetic context to the cytopathic capacity of Env and the role of ENF-resistance mutations in modulating viral pathogenicity in vivo, further supporting the hypothesis that gp41 is a critical mediator of HIV pathogenesis.