Blunted Response to Combination Antiretroviral Therapy in HIV Elite Controllers: An International HIV Controller Collaboration

Objective: HIV “elite controllers” (ECs) spontaneously control viral load, but some eventually require combination antiretroviral treatment (cART), due to a loss of viral control or a decline in CD4 T-cell counts. Here we studied the CD4 T-cell count dynamics after cART initiation among 34 ECs followed in U.S. and European cohorts, by comparison with chronically viremic patients (VIRs). Methods: ECs were defined as patients with at least ≥5 viral load (VL) measurements below 400 copies/mL during at least a 5-year period despite never receiving ART and were selected from the French ANRS CO18 cohort, the U.S. SCOPE cohort, the International HIV Controllers study and the European CASCADE collaboration. VIRs were selected from the ANRS COPANA cohort of recently-diagnosed (<1 year) ART-naïve HIV-1-infected adults. CD4 T-cell count dynamics after cART initiation in both groups were modelled with piecewise mixed linear models. Results: After cART initiation, CD4 T-cell counts showed a biphasic rise in VIRs with: an initial rapid increase during the first 3 months (+0.63/month), followed by +0.19/month. This first rapid phase was not observed in ECs, in whom the CD4Tc count increased steadily, at a rate similar to that of the second phase observed in VIRs. After cART initiation at a CD4 T-cell count of 300/mm3, the estimated mean CD4 T-cell gain during the first 12 months was 139/mm3 in VIRs and 80/mm3 in ECs (p = 0.048). Conclusions: cART increases CD4 T-cell counts in elite controllers, albeit less markedly than in other patients

Potential role for HIV-specific CD38-/HLA-DR+ CD8+ T cells in viral suppression and cytotoxicity in HIV controllers.

BACKGROUND:HIV controllers (HIC) are rare HIV-1-infected patients who exhibit spontaneous viral control. HIC have high frequency of CD38-/HLA-DR+ HIV-specific CD8+ T cells. Here we examined the role of this subset in HIC status. MATERIALS AND METHODS:We compared CD38-/HLA-DR+ CD8+ T cells with the classical CD38+/HLA-DR+ activated phenotype in terms of 1) their activation status, reflected by CD69, CD25, CD71, CD40 and Ki67 expression, 2) functional parameters: Bcl-2 expression, proliferative capacity, and IFN-γ and IL-2 production, and 3) cytotoxic activity. We also investigated how this particular profile is generated. RESULTS:Compared to CD38+/HLA-DR+ cells, CD38-/HLA-DR+ cells exhibited lower expression of several activation markers, better survival capacity (Bcl-2 MFI, 367 [134-462] vs 638 [307-747], P = 0.001), higher frequency of polyfunctional cells (15% [7%-33%] vs 21% [16%-43%], P = 0.0003), greater proliferative capacity (0-fold [0-2] vs 3-fold [2]-[11], P = 0.007), and higher cytotoxicity in vitro (7% [3%-11%] vs 13% [6%-22%], P = 0.02). The CD38-/HLA-DR+ profile was preferentially generated in response to low viral antigen concentrations. CONCLUSIONS:These data highlight the role of CD38-/HLA-DR+ HIV-specific CD8+ T cell cytotoxicity in HIC status and provide insights into the mechanism by which they are generated. Induction of this protective CD8+ subset may be important for vaccine strategies

Stimulation with a low antigen concentration induces the CD38⁻/HLA-DR⁺ phenotype on specific CD8⁺ T cells.

<p>(A) Graphs representing the frequency of (A) CD38⁻/HLA-DR⁺ cells (dark histograms) and (B) CD38⁺/HLA-DR⁺ cells (dark gray histograms) among activated EBV-specific healthy donor CD8⁺ T cells (i.e. those expressing CD38 and/or HLA-DR) after a four-day culture period (n = 8).</p

CD38 and HLA-DR expression on bulk and HIV-specific CD8⁺ T cells.

<p>(A) Proportions of bulk CD8⁺ T cells from HD (n = 16, light gray bars), HAART-treated patients (n = 19, mid gray bars), viremic patients (n = 21, dark gray bars) and HIC (n = 79, black bars) expressing CD38 and HLA-DR. (C) Proportions of HIV-specific CD8⁺ T cells from HAART-treated patients (n = 13, mid gray bars), viremic patients (n = 39, dark gray bars) and HIC (n = 80, black bars) expressing CD38 and HLA-DR. Pie charts representing CD38⁻/HLA-DR⁻ (white), CD38⁻/HLA-DR⁺ (black), CD38⁺/HLA-DR⁻ (light gray) and CD38⁺/HLA-DR⁺ (dark gray) cells among bulk (B) and HIV-specific CD8⁺ T cells (D). Statistical differences shown in the pie charts are based on the difference in the frequency of the CD38⁻/HLA-DR⁺ subset between the different groups. * <i>P</i><0.05, ** <i>P</i><0.01, *** <i>P</i><0.001.</p

Study population.

<p>Median values [1^st–3^rd interquartile range] are shown for age, time since diagnosis, CD4⁺ and CD8⁺ T cell counts, and HIV RNA viral loads.</p>a<p>Viremic and HAART-treated patients' RNA viral loads were measured using an assay with a quantification limit of <50 copies/ml, while values in HIC were obtained with ultrasensitive assays.</p

High antigen sensitivity is associated with a high frequency of CD38⁻/HLA-DR⁺ cells in HIC.

<p>The antigen sensitivity of HIV-specific CD8⁺ T cells was measured in ELISpot assays with serial limiting dilutions of antigenic peptides (from 10⁻⁵ to 10⁻¹¹ M) and was expressed as the log molar concentration of peptide yielding 50% of the maximum response (EC_50%). Correlations between the proportion of CD38⁻/HLA-DR⁺ (A) or CD38⁺/HLA-DR⁺ (B) and the antigen sensitivity of HIV-specific CD8⁺ T cells from HIC. Correlations were evaluated using the Spearman rank correlation coefficient. The Spearman r correlation and the Pearson correlation curve are indicated for significant correlations (n = 47).</p

Influence of stimulatory conditions on the activation phenotype of specific CD8⁺ T cells.

<p>(A) Representative dot plots of HLA-DR and CD38 expression in unstimulated conditions (upper graph), after IFN-α stimulation (middle graph) or peptide stimulation (2 µM, lower graph) among specific (dark dots) and non-specific (gray dots) CD8⁺ T cells from healthy donors after a four-day culture period. CD38 and HLA-DR expression on bulk (C left panel) and specific CD8⁺ T cells (B and C right panel). (B) Flow cytometry histograms showing representative results for cells from one individual in unstimulated conditions (dark lines), after IFN-α stimulation (light gray histograms) or peptide stimulation (dark gray histograms). (C) Surface expression of CD38 (white bars) and HLA-DR (gray bars) on bulk and specific CD8⁺ T cells (n = 4).</p

Qualitative features of CD38⁻/HLA-DR⁺ and CD38⁺/HLA-DR⁺ HIV-specific CD8⁺ T cell subsets in HIC.

<p>(A) Bcl-2 expression on CD38⁻/HLA-DR⁺ and CD38⁺/HLA-DR⁺ HIV-specific CD8⁺ T cells (n = 11). (B) Proportion of CD38⁻/HLA-DR⁺ and CD38⁺/HLA-DR⁺ HIV-specific CD8⁺ T cells producing both IFN-γ and IL-2 among HIV-specific CD8⁺ T cells producing IFN-γ or IL-2 (n = 35). (C) Fold increase in CD38⁻/HLA-DR⁺ and CD38⁺/HLA-DR⁺ HIV-specific CD8⁺ T cell numbers after 5 days of culture with HIV peptides (2 µM) (n = 7). (D–E) Proportion of CD38⁻/HLA-DR⁺ and CD38⁺/HLA-DR⁺ HIV-specific CD8⁺ T cells producing perforin (D) and granzyme B (E) (n = 35). (F) Graphs representing percentage cytotoxicity (measured as granzyme-B-mediated intracellular cleavage of a fluorogenic substrate) of CD38⁻/HLA-DR⁺ and CD38⁺/HLA-DR⁺ HIV-specific CD8⁺ T cells (n = 11). * <i>P</i><0.05, ** <i>P</i><0.01, *** <i>P</i><0.001.</p

Blunted response to combination antiretroviral therapy in HIV elite controllers: an international HIV controller collaboration.

ObjectiveHIV "elite controllers" (ECs) spontaneously control viral load, but some eventually require combination antiretroviral treatment (cART), due to a loss of viral control or a decline in CD4 T-cell counts. Here we studied the CD4 T-cell count dynamics after cART initiation among 34 ECs followed in U.S. and European cohorts, by comparison with chronically viremic patients (VIRs).MethodsECs were defined as patients with at least ≥5 viral load (VL) measurements below 400 copies/mL during at least a 5-year period despite never receiving ART and were selected from the French ANRS CO18 cohort, the U.S. SCOPE cohort, the International HIV Controllers study and the European CASCADE collaboration. VIRs were selected from the ANRS COPANA cohort of recently-diagnosed (ResultsAfter cART initiation, CD4 T-cell counts showed a biphasic rise in VIRs with: an initial rapid increase during the first 3 months (+0.63√CD4/month), followed by +0.19√CD4/month. This first rapid phase was not observed in ECs, in whom the CD4Tc count increased steadily, at a rate similar to that of the second phase observed in VIRs. After cART initiation at a CD4 T-cell count of 300/mm(3), the estimated mean CD4 T-cell gain during the first 12 months was 139/mm(3) in VIRs and 80/mm(3) in ECs (p = 0.048).ConclusionscART increases CD4 T-cell counts in elite controllers, albeit less markedly than in other patients

Characteristics at baseline and at cART initiation in 34 elite Controllers (ECs) and 478 chronically viremic (VIRs) patients from the ANRS COPANA Cohort.

<p>Data are median [IQR] or n (%);</p><p>According to own cohort’s definitions of ECs;</p><p>SSA/Car/BA = Sub-Saharan African, Caribbean or African-American origin.</p