HIV-1 tropism evolution after short-term maraviroc monotherapy in HIV-1-infected patients.

We analyzed the evolution of viral tropism after 8 days of maraviroc monotherapy, i.e., we used the maraviroc clinical test (MCT), in 21 patients with and 14 without virological response to the drug (MCT(+) and MCT(-) patients, respectively). No increases in CXCR4 inferred viral loads (X4IVLs) were observed in MCT(+) patients, while X4IVLs increased only in MCT(-) patients, with X4IVLs of >2 log(10) HIV RNA copies/ml. These results shed light on the evolution of viral tropism under a CCR5 antagonist in vivo.

TROCAI (tropism coreceptor assay information): a new phenotypic tropism test and its correlation with Trofile enhanced sensitivity and genotypic approaches.

The only clinically validated assay available to determine HIV tropism is Trofile, an assay that possesses some limitations. Our first aim was to develop a new phenotypic tropism test (TROCAI [tropism coreceptor assay information]) and to categorize results generated by this test according to the virological response to a short-term exposure to the CCR5 receptor antagonist maraviroc (maraviroc clinical test). Our second aim was to compare TROCAI results to those obtained by Trofile enhanced sensitivity (ES) and to different genotypic algorithms. TROCAI assayed HIV tropism in 33 HIV-infected patient viral isolates obtained from a modified coculture, followed by multiple infection cycles of indicator cells. TROCAI obtained a reportable result in all patients with viral loads of >500 HIV RNA copies/ml and in 3/6 patients with <500 HIV RNA copies/ml (30/33 patients, 91.9%). Patients who responded to maraviroc had an X4-using virus proportion in indicator cell supernatant of 0 to 0.41%. Hence, we used the threshold of 0.5% to categorize TROCAI results as R5 (<0.5%) or dual/mixed (>0.5%). The concordance between TROCAI and Trofile (ES) was 22/24 (91.6%), and with genotypic approaches it was 22/26 (84.6%). TROCAI results, which were categorized in this study by the maraviroc clinical test, could be used as a test in addition to those currently used to select patients for treatment with CCR5 antagonists.

Association of heterozygous CCR5Δ32 deletion with survival in HIV-infection: A cohort study.

The role of a 32 base pair deletion in the CCR5 gene (CCR5Δ32) in HIV-disease progression and response to combined antiretroviral therapy (cART) is well established. However, the impact of CCR5Δ32 in the long-term survival pre-cART and after cART introduction in a large cohort of HIV-infected patients is unknown. We analyzed the association of CCR5Δ32 deletion in the long-term survival of HIV-infected patients recruited between June 1981 and October 2016 (n = 1006). Clinical and epidemiological variables were recorded and CCR5Δ32 deletion was assessed by PCR and electrophoretic analysis. The association of CCR5Δ32 deletion with the time to death was analyzed by Log-Rank tests and Cox Regression models. The CCR5 WT/Δ32 prevalence was 13.4% (n = 135). We did not find any homozygous subject for CCR5Δ32 deletion. AIDS (n = 85, 41.5%) and non-AIDS (n = 87, 42.4%) events were the main causes of 205 deaths. CCR5Δ32 deletion was independently associated with survival (p = 0.022; hazard ratio (HR): 0.572, confidence interval (CI) [0.354-0.923]), after adjusting by HIV diagnosis before 1997, age at diagnosis, being on cART, risk of transmission, nadir CD4+ T-cell counts and CDC stage C. This result was reproduced when the analysis was restricted to patients on cART (p = 0.045; HR: 0.530 [0.286-0.985]). These results confirm the protective role of CCR5Δ32, and extend it to the long-term survival in a large cohort of HIV-infected patients. Beyond its antiviral effect, CCR5Δ32 enhanced the long-term survival of patients on cART.

Maraviroc Clinical Test (MCT) as an alternative tool to decide CCR5-antagonists prescription in naïve HIV-infected patients.

Our aim was to analyze the virological response to a combined antiretroviral therapy started after Maraviroc Clinical Test (MCT) in naïve HIV-infected patients. Forty-one patients were exposed to MCT, based on an 8-day MVC monotherapy. If undetectability or a viral load reduction >1 log10 HIV-RNA copies/ml was achieved, a MVC-containing cART was prescribed. Forty patients showed a positive MCT; undetectability after 48weeks on cART was achieved in 34/41 (82.9%) patients. The result of MCT was compared with a genotypic tropism method and with Trofile®, showing 10.7% and 18.75% discordance rates, respectively. MCT is a reliable tool to decide CCR5-antagonists prescription, also in the naïve scenario where most patients show a virological response to MVC independently the tropism result reported by genotypic or phenotypic methods.

Structural requirements for multimerization of the pathogen receptor dendritic cell-specific ICAM3-grabbing non-integrin (CD209) on the cell surface.

The myeloid C-type lectin dendritic cell-specific ICAM3-grabbing non-integrin (DC-SIGN, CD209) recognizes oligosaccharide ligands on clinically relevant pathogens (HIV, Mycobacterium, and Aspergillus). Alternative splicing and genomic polymorphism generate DC-SIGN mRNA variants, which have been detected at sites of pathogen entrance and transmission. We present evidence that DC-SIGN neck variants are expressed on dendritic and myeloid cells at the RNA and protein levels. Structural analysis revealed that multimerization of DC-SIGN within a cellular context depends on the lectin domain and the number and arrangement of the repeats within the neck region, whose glycosylation negatively affects oligomer formation. Naturally occurring DC-SIGN neck variants differ in multimerization competence in the cell membrane, exhibit altered sugar binding ability, and retain pathogen-interacting capacity, implying that pathogen-induced cluster formation predominates over the basal multimerization capability. Analysis of DC-SIGN neck polymorphisms indicated that the number of allelic variants is higher than previously thought and that multimerization of the prototypic molecule is modulated in the presence of allelic variants with a different neck structure. Our results demonstrate that the presence of allelic variants or a high level of expression of neck domain splicing isoforms might influence the presence and stability of DC-SIGN multimers on the cell surface, thus providing a molecular explanation for the correlation between DC-SIGN polymorphisms and altered susceptibility to HIV-1 and other pathogens.

Long-term virological outcome and resistance mutations at virological rebound in HIV-infected adults on protease inhibitor-sparing highly active antiretroviral therapy.

OBJECTIVE: To assess the durability of the undetectability of HIV plasma viraemia (pV) and to determine the factors associated with virological rebound (VR) in HIV-infected adults on protease inhibitor (PI)-sparing highly active antiretroviral therapy (HAART). The development of resistance mutations during virologically successful therapy and VR was also analysed. MATERIALS AND METHODS: One hundred and twenty-six HIV-infected adults on PI-sparing HAART were prospectively followed from April 1998 to December 2002: Group 1, naive for antiretroviral drugs (n = 26); Group 2, previously PI-HAART-exposed patients (n = 19); Group 3, previously exposed to suboptimal therapy (n = 81). Genotypic resistance tests on peripheral blood mononuclear cells or on plasma RNA (when feasible) were carried out when undetectable HIV pV was demonstrated for at least 48 weeks. Additionally, patients showing a therapy adherence >95% developing VR were also tested at rebound, at simplification and during previous suboptimal therapy exposure. RESULTS: The median follow-up time was 630 [329-903] days. VR was considered as two consecutive pV levels >50 copies/mL. Twenty-two (17.5%) patients developed VR. Only therapy adherence <95% was independently associated with VR (adjusted hazard ratio: 8.42; 95% CI: 3.33-21.27). Twenty (40%) of the 50 patients with pV < 50 copies/mL for at least 48 weeks showed at least one thymidine-associated mutation (TAM) but none had NNRTI-resistance mutations. Ten (83.3%) of 12 available adherent patients showing VR harboured NNRTI-resistance-associated mutations; 50% of them were considered as wild-type strains at simplification time. However, the TAM number and resistance mutations profile found on suboptimal exposure were very similar to those found at VR on simplification therapy. CONCLUSIONS: PI-sparing HAART allows maintenance of successful long-term control of HIV replication, adherence to therapy being the main factor associated with VR. However, a small proportion of patients on simplification regimen may develop VR regardless of therapy compliance. VR on PI-sparing HAART is characterized by the emergence of NNRTI cross-resistance mutations. Finally, TAMs 'archived' during previous suboptimal exposures are partially involved in subsequent VR on simplification HAART.