No increase in hepatitis B virus (HBV)-specific CD8+ T cells in patients with HIV-1-HBV coinfections following HBV-active highly active antiretroviral therapy

Abstract

Following treatment of hepatitis B virus (HBV) monoinfection, HBV-specific T-cell responses increase significantly; however, little is known about the recovery of HBV-specific T-cell responses following HBV-active highly active antiretroviral therapy (HAART) in HIV-HBV coinfected patients. HIV-HBV coinfected patients who were treatment naïve and initiating HBV-active HAART were recruited as part of a prospective cohort study in Thailand and followed for 48 weeks (n = 24). Production of gamma interferon (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) in both HBV- and HIV-specific CD8(+) T cells was quantified using intracellular cytokine staining on whole blood. Following HBV-active HAART, the median (interquartile range) log decline from week 0 to week 48 for HBV DNA was 5.8 log (range, 3.4 to 6.7) IU/ml, and for HIV RNA it was 3.1 (range, 2.9 to 3.5) log copies/ml (P < 0.001 for both). The frequency of HIV Gag-specific CD8(+) T-cell responses significantly decreased (IFN-gamma, P < 0.001; TNF-alpha, P = 0.05). In contrast, there was no significant change in the frequency (IFN-gamma, P = 0.21; TNF-alpha, P = 0.61; and IFN-gamma and TNF-alpha, P = 0.11) or magnitude (IFN-gamma, P = 0.13; TNF-alpha, P = 0.13; and IFN-gamma and TNF-alpha, P = 0.13) of HBV-specific CD8(+) T-cell responses over 48 weeks of HBV-active HAART. Of the 14 individuals who were HBV e antigen (HBeAg) positive, 5/14 (36%) lost HBeAg during the 48 weeks of follow-up. HBV-specific CD8(+) T cells were detected in 4/5 (80%) of patients prior to HBeAg loss. Results from this study show no sustained change in the HBV-specific CD8(+) T-cell response following HBV-active HAART. These findings may have implications for the duration of treatment of HBV in HIV-HBV coinfected patients, particularly in HBeAg-positive disease.

FIG. 1.

ICS for HBV-specific CD8⁺ T cells. CD8⁺ T cells were identified by forward and side scatter and expression of CD8-PE. Data from at least 8,000 CD8⁺ T cells were collected for analysis. The percentage of HBV-specific T cells was defined as the percentage of cytokine-producing CD8⁺ T cells. A positive response was considered to be >0.05% cytokine⁺ CD8⁺ T cells above background (the response to stimulation with DMSO and costimulatory molecules alone) and also at least 2-fold above background. The positive control included pokeweed mitogen/staphylococcal enterotoxin (PWM/SEB). A representative example from an HIV-HBV-coinfected patient with production of either TNF-α or IFN-γ or both cytokines from CD8⁺ T cells to DMSO, PWM/SEB, HBV precore protein, and HIV Gag peptides is shown.

FIG. 2.

Magnitude, frequency, and specificity of antigen-specific CD8⁺ T-cell responses following HBV-active HAART. The magnitude and frequency of the antigen-specific CD8⁺ T-cell response as measured by IFN-γ (left panels), TNF-α (middle panels), or both IFN-γ and TNF-α (right panels) production are shown for the HBV-specific CD8⁺ T-cell response in all patients (top row), HBeAg-negative patients (second row), and HBeAg-positive patients (third row) (A) and for the HIV Gag-specific CD8⁺ T cell-response in all patients (B). The magnitude of cytokine production (percent cytokine-positive CD8⁺ T cells; black circles and left axis) and the frequency of patient responses (percentage of patients who had a response above zero/total evaluable responses; gray columns and right axis) are shown. (C) Specificity of the HBV peptide pool response. The mean magnitude of the positive HBV-specific responses to each HBV gene product (precore, X, surface, and polymerase) is shown. In panel B, P values for frequency (chi-square test for trend in frequencies) are indicated using solid lines, and significant changes in magnitude (GEE) are shown using dotted lines.

FIG. 3.

Changes in clinical parameters and HBV-specific CD8⁺ T cells in patients who underwent HBeAg seroconversion or hepatic flare. (A) Five HBeAg-positive patients lost HBeAg and/or developed HBeAb during the 48-week treatment period. (B) Two patients had a hepatic flare including, one patient who had both a flare and HBeAg seroconversion (1339). (C) The median peak TNF-α response of the HBeAg-positive seroconverters (n = 5) and the remaining nonseroconverting patients (n = 19). Patient numbers are indicated above the graphs, and symbols and units are identified along the vertical axes. In the bottom rows of panels A and B, the bars represent the following: white, IFN-γ; black, TNF-α; gray, TNF-α and IFN-γ. The lower limit of detection for HIV RNA was 50 copies/ml. Patient 1336 died at week 12 and therefore did not complete 48 weeks of follow-up. NT, not tested (due to patient death [x] or no sample available); NER, no evaluable response (due to no response to the mitogen-positive control).