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

Abstract

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.

FIG. 1.

Representative example of flow cytometry data and gating strategy. A representative example for some of the antibody panels used is shown. (A) Expression of CD45RA and CD27 on CD4 and CD8 T cells to define the differentiation stage of these cells. (B, C) Expression of activation markers CD38 and HLA-DR on different subsets of CD4 (B) and CD8 (C) T cells as defined by CD45RA and CD27 expression. (D, E) Annexin binding on different subsets of CD4 (D) and CD8 (E) T cells as defined by CD45RA and CD27 expression. (F) Expression of exhaustion markers PD-1 and Tim-3 on CD4 and CD8 T cells. (G) Gating strategy used to define T regulatory (Treg) CD4 cells as CD127⁻CD25⁺FoxP3⁺. Numbers inside plots or histograms represent the percentage of positive events in each quadrant or region.

FIG. 2.

Box-plot graphs showing baseline (light gray boxes) and week 48 (dark gray boxes) levels of different T cell subsets in the whole population of patients. Vertical axes represent the proportion of cells and horizontal axes the different CD4 and CD8 T cells subsets. (A) Differentiation stage (coexpression of CD45RA and CD27) of CD4 and CD8 T cells. (B) Activation (coexpression of CD38 and HLA-DR) of different CD4 and CD8 T cells subsets. (C) Senescence (CD57 expression), exhaustion (PD1 expression), and apoptosis (Annexin binding) of different CD4 and CD8 T cell subsets. In this graph the right vertical axis applies only to senescence of CD4 T cells subsets. (D) CD127 expression, thymic function (CD31 expression), and Treg cells (defined as CD4⁺CD127⁻CD25⁺FoxP3⁺). In this graph the right vertical axis applies only to Treg cells. Levels of statistical significance for the pairwise comparison (Wilcoxon signed rank test) between baseline and week 48 values are as follows: p<0.05 (*); p<0.01 (**); p<0.001 (***). N, naive; CM, central memory; EM, effector memory; Ef, effector.

FIG. 3.

Box-plots showing the variation (delta value) in the level of different subsets of T cells after 48 weeks of successful antiretroviral therapy in patients treated with an efavirenz (EFV)-based combined antiretroviral treatment (cART) regimen (light gray boxes) and in patients treated with a lopinavir/r (LPV/r)-containing cART regimen (dark gray boxes). Positive delta values reflect an increase and negative values reflect a decrease in the level of the T cell subset. The y-axis scale on the right applies only to the last subset shown on the x-axis. The dotted line marks the zero delta value. Only T cell subsets with statistically significant differences (p≤0.05) or showing a trend (p≤0.1) between EFV and LPV/r groups of patients are shown. CM, central memory T cells; EM, effector memory T cells; Ef, effector T cells.

FIG. 4.

(A) Box-plots showing the variation in the level of collagen deposition as measured as percentage of lymphoid tissue occupied by collagen at baseline before any antiretroviral therapy and after 48 weeks of therapy. Patients on LPV/r and EFV-containing regimens are shown together (n=8). (B) Box-plots showing the variation in the level of thymic volume at baseline before any antiretroviral therapy and after 48 weeks of therapy. Patients on LPV/r and EFV-containing regimens are shown together (n=11).