Dysfunctional phenotypes of CD4+ and CD8+ T cells are comparable in patients initiating ART during early or chronic HIV-1 infection

Abstract

Early initiation of antiretroviral therapy (ART) is becoming a common clinical practice according to current guidelines recommending treatment to all HIV-1-infected patients. However, it is not known whether ART initiated during the early phase of infection prevents the establishment of abnormal phenotypic features previously reported in CD4+ and CD8+T cells during chronic HIV-1 infection. In this cross-sectional study, blood specimens were obtained from 17 HIV-1-infected patients who began ART treatment shortly after infection (early ART [EA]), 17 age-matched HIV-1-infected patients who started ART during chronic phase of infection (late ART [LA]), and 25 age-matched non-HIV-1-infected controls. At collection of specimens, patients in EA and LA groups had received ART for comparable periods of time. Total HIV-1 DNA was measured in white blood cells by quantitative PCR. The concentration of 9 inflammatory parameters and 1 marker of fibrosis, including sCD14 and β-2 microglobulin, was measured in plasma. Furthermore, expression of markers of abnormal immune activation (human leukocyte antigen - antigen D related [HLA-DR] and CD38), exhaustion (programmed death 1, CD28, CD57) and terminal differentiation (CD127) was measured on CD4+ and CD8+T cells. T-cell proliferation was measured through Ki67 expression. The copies of total HIV-1 DNA in blood were significantly lower (P = 0.009) in EA compared with that in LA group. Only the expression of HLA-DR on naïve CD4+ T cells distinguished EA from LA, whereas expression of 3 surface markers distinguished T-cell populations of HIV-1-infected patients from controls. These included HLA-DR distinguishing CD4+ T cells from EA compared with controls, and also CD38 and CD127 on CD4+ and CD8+ T cells, respectively, distinguishing both groups of patients from controls. The sCD14 levels were significantly higher in EA patients, and β-2 microglobulin levels were higher in LA group compared with that in controls. Our results demonstrate an equivalent abnormal expression of activation (HLA-DR and CD38 on CD4+ T cells) and terminal differentiation (CD127 on CD8+ T cells) markers in T cells from both EA and LA patients. The size of total HIV-1 DNA copies in blood of EA was lower compared with LA patients. These findings suggest that some abnormalities taking place in the T-cell compartment during primary HIV-1 infection may not be corrected by early ART.

Figure 1

CD4+ T-cell counts and CD4+/CD8+ ratio in the blood of individuals treated during primary (EA) and chronic (LA) phases of HIV-1 infection. CD4+ T-cell counts (cells/μL) and the ratio between CD4+ T cells and CD8+ T cells (CD4+/CD8+ ratio) were measured in the blood of subjects belonging to both EA (n = 17) and LA (n = 17) study groups. The measurements were performed before ART initiation (baseline [BL]), at 12 months (12 m) after ART and at sampling (S). The statistical difference in the values between the time points was calculated using ANOVA. Median values are shown in the figures. ^∗P < 0.05, ^∗∗P < 0.01, ^∗∗∗P < 0.001, and ^∗∗∗∗P < 0.0001. ANOVA, analysis of variance; ART, antiretroviral therapy; EA, early ART; LA, late ART.

Figure 2

Frequency of CD4+ and CD8+ T cells and their subsets in PBMCs. The frequency of total CD4+ and CD8+ T cells, among CD3+ T cells, and the T-cell subsets naive, CM, EM, and TEMRA calculated out of total CD4+ or total CD8+ T cells are shown. The data are presented for all 3 groups studied: EA (n = 17), LA (n = 17), and C (n = 25). The line in the figures represents median values and the statistics were calculated using ANOVA. ^∗P < 0.05, ^∗∗P < 0.01, and ^∗∗∗P < 0.001. ANOVA, analysis of variance; ART, antiretroviral therapy; CM, central memory; EA, early ART; EM, effector memory; LA, late ART; TEMRA, terminally differentiated effector memory cells.

Figure 3

Frequency of CD38++ CD4+, HLA-DR+ CD4+, and CD127− CD8+ T-cell subsets. The frequency of CD38++ and HLA-DR+ cells among total, naive, CM, EM, and TEMRA CD4+ T cells is shown together with the frequency of CD127− total, naive, CM, EM, and TEMRA CD8+ T cells. The data are presented for the 3 groups studied: EA (n = 17), LA (n = 17), and C (n = 25). The line in the figures represents the median values and the statistics were calculated using ANOVA. ^∗P < 0.05, ^∗∗P < 0.01, and ^∗∗∗P < 0.001. ANOVA, analysis of variance; ART, antiretroviral therapy; CM, central memory; EA, early ART; EM, effector memory; HLA-DR, human leukocyte antigen - antigen D related; LA, late ART; TEMRA, terminally differentiated effector memory cells.

Figure 4

The frequency of Ki67 expressing CD4+ and CD8+ T cells. The frequency of Ki67-positive total CD4+ and CD8+ T cells and CD4+ T cells and CD8+ T-cell subsets (naive, CM, EM, and TEMRA) in the 3 groups studied are shown. The line represents median values and the differences between the groups have been calculated using ANOVA. ^∗P < 0.05 and ^∗∗P < 0.01. ANOVA, analysis of variance; ART, antiretroviral therapy; CM, central memory; EM, effector memory; TEMRA, terminally differentiated effector memory cells.

Figure 5

Size of total HIV-1 DNA copies and its correlation to T-cell subpopulations and surface markers. Copies of HIV-1 DNA in 10⁶ PBMCs from EA and LA patients (A). The line represents median values and the differences between the groups have been calculated using ANOVA (^∗∗P < 0.01). In specimens from EA patients, the number of HIV-1 DNA copies was shown to directly correlate with the frequencies of CD8+ EM and CD8+ total HLA-DR+ T cells, whereas a negative correlation was shown between the virus reservoir and the frequency of CD8+ TEMRA T cells (B). In specimens from LA patients, the number of HIV-1 DNA copies, directly correlated to the frequency of CD8+ CM PD-1+ T cells and indirectly to the CD8+ TEMRA CD38++. Correlation coefficients and their significance were calculated using Spearman rank correlation. ANOVA, analysis of variance; ART, antiretroviral therapy; CM, central memory; EA, early ART; EM, effector memory; HLA-DR, human leukocyte antigen - antigen D related; LA, late ART; PD-1, programmed death 1; TEMRA, terminally differentiated effector memory cells.