An immunological comparison of third companion in advanced drug-naive HIV-infected patients

Do Combination Antiretroviral Therapy Regimens for HIV Infection Feature Diverse T-Cell Phenotypes and Inflammatory Profiles?

Immune abnormalities featuring HIV infection persist despite the use of effective combination antiretroviral therapy (cART) and may be linked to the development of noninfectious comorbidities. The aim of the present narrative, nonsystematic literature review is to understand whether cART regimens account for qualitative differences in immune reconstitution. Many studies have reported differences in T-cell homeostasis, inflammation, coagulation, and microbial translocation parameters across cART classes and in the course of triple vs dual regimens, yet such evidence is conflicting and not consistent. Possible reasons for discrepant results in the literature are the paucity of randomized controlled clinical trials, the relatively short follow-up of observational studies, the lack of clinical validation of the numerous inflammatory biomarkers utilized, and the absence of research on the effects of cART in tissues. We are currently thus unable to establish if cART classes and regimens are truly accountable for the differences observed in immune/inflammation parameters in different clinical settings. Questions still remain as to whether an early introduction of cART, specifically in the acute stage of disease, or newer drugs and novel dual drug regimens are able to significantly impact the quality of immune reconstitution and the risk of disease progression in HIV-infected subjects.

T-cell phenotype and function following a first cART regimen containing either a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor in HIV-infected late presenters: results from a retrospective, ex vivo study

BACKGROUND

We aimed to comparatively assess darunavir/ritonavir (DRV/r) and efavirenz (EFV)-based first-line cART regimens in the reconstitution of T-cell phenotype and function in HIV-infected, late presenter subjects.

METHODS

Retrospective, ex vivo study on stored peripheral blood mononuclear cell samples of cART-naive, HIV-infected individuals with CD4(+) T-cell counts <50>250/µl upon cART initiation with either DRV/r or EFV as third drugs of standard antiretroviral regimens. CD4(+) and CD8(+) T-cell maturation (CCR7/CD45RA) and proliferation (Ki67), CD8(+) T-cell activation (CD38/HLA-DR) as well as HIV- and cytomegalovirus (CMV)-specific responses (CD4/CD8/IL-2/IFN-γ) were studied by flow cytometry at baseline (T0), T3, T6 and T12 months. Soluble inflammatory markers (IL-6 and sCD14) were measured in plasma at T0 and T12. Wilcoxon and Mann-Whitney tests were used for statistics.

RESULTS

A total of 19 patients started DRV/r and 15 EFV. Both regimens accounted for suppression of the HIV RNA load (<40 copies/ml), reconstitution of absolute CD4(+) T-cells and CD4(+)/CD8(+) T-cell ratio. All study participants displayed a significant decrease of activated HLA-DR(+)CD38(+) CD8(+) T-cells at all study time points, yet no differences were found between study groups in T-cell activation and maturation phenotype. From a functional standpoint, only individuals receiving DRV/r displayed transitory recovery of HIV-specific IL-2(+)IFN-γ(-) CD4(+) T-cells (T3: P=0.006) and IL-2(-)IFN-γ(+) CD8(+) T-cells (T3: P=0.032).

CONCLUSIONS

DRV/r- and EFV-based regimens have an equal effect on T-cell phenotype and function in HIV late presenters. A temporary restoration of HIV-specific T-cell immunity early in the course of therapy with DRV/r possibly implies a more effective control over HIV in the first months following a PI/r-based regimen, even at late stage of disease.

The role of baseline HIV-1 RNA, drug resistance, and regimen type as determinants of response to first-line antiretroviral therapy

The factors influencing virological response to first-line combined antiretroviral therapy (cART) in an Italian cohort of HIV-1-infected patients were examined. Eligible patients were those enrolled in a national prospective observational cohort (Antiretroviral Resistance Cohort Analysis), starting first-line cART between 2001 and 2011 and who had at least one follow-up of HIV-1 RNA. The primary endpoint was virological success, defined as the first viral load <50  copies/ml. Time to events were analyzed by Kaplan-Meier analysis and Cox proportional hazard model. One thousand three hundred five patients met the study inclusion criteria. In a multivariable model adjusting for transmission mode, presence of transmitted drug resistance, baseline CD4(+) cell count, viral subtype, and type of NRTI backbone employed, independent predictors of virological success were higher baseline viral load (≥500,000 vs. <100,000 HR 0.52; P < 0.001), a weighted genotypic susceptibility score (wGSS) <3 (HR 0.58; P = 0.003), male sex (HR 0.76 P = 0.001), and type of initial third drug employed (integrase inhibitor vs. boosted protease inhibitors HR 3.23; P < 0.001). In the subset with HIV-1 RNA >100,000  copies/ml, virologic success was only associated with the use of integrase inhibitors in the first cART regimen. Independent predictors of immunological success were baseline CD4(+) cell count and wGSS <3. High baseline HIV-1 RNA, predicted activity of the first-line regimen based on genotypic resistance testing, gender, and use of new agents were found to predict time to achieve virological success. The type of initial nucleoside analog backbone was not found to predict virological response.

Immunological function restoration with lopinavir/ritonavir versus efavirenz containing regimens in HIV-infected patients: a randomized clinical trial

CD4(+) count increase has been reported to be different with lopinavir/r (LPV/r) and efavirenz (EFV)-containing regimens. The different effect of these two regimens on other immune function parameters and the relationship with the gain of CD4(+) count have not been assessed in a randomized clinical trial. Fifty antiretroviral treatment (cART) naïve HIV-infected individuals were randomized to receive LPV/r or EFV both with tenofovir/emtricitabine for 48 weeks. A substudy of immunological function restoration was performed in 22 patients (LPV/r n=10 and EFV n=12). Activation, thymic function, apoptosis, senescence, exhaustion, Treg cells, interleukin (IL)-7-receptor/IL-7 system, thymic volume, and lymphoid tissue fibrosis were evaluated at baseline and at week 48. Both groups experienced a CD4(+) count increase that was higher in the EFV group (ΔCD4(+) 88 vs. 315 cells/μl LPV/r vs. EFV, respectively, p<0.001). Despite this difference in CD4(+) gain, the change in other immune function parameters was similar in both treatment groups. Most of parameters evaluated tended to normalize after 48 weeks of cART. A significant decrease in levels of activation, senescence, exhaustion, and apoptosis on CD4(+) and CD8(+) T cells (p<0.001 for all) and a significant increase in markers of thymic function, IL-7 receptor, and in the levels of central memory CD4(+) T cells and naive subsets of CD8(+) T cells (p<0.001 for all) with respect to baseline values were observed without any difference between groups. These data indicate that the differences in CD4(+) gain with different cART regimens are not immunologically meaningful and might explain the similar clinical efficacy of these regimens.