Dendritic cell immunotherapy followed by cART interruption during HIV-1 infection induces plasma protein markers of cellular immunity and neutrophil recruitment

Abstract

Objectives: To characterize the host response to dendritic cell-based immunotherapy and subsequent combined antiretroviral therapy (cART) interruption in HIV-1-infected individuals at the plasma protein level.

Design: An autologous dendritic cell (DC) therapeutic vaccine was administered to HIV-infected individuals, stable on cART. The effect of vaccination was evaluated at the plasma protein level during the period preceding cART interruption, during analytical therapy interruption and at viral reactivation. Healthy controls and post-exposure prophylactically treated healthy individuals were included as controls.

Methods: Plasma marker ('analyte') levels including cytokines, chemokines, growth factors, and hormones were measured in trial participants and control plasma samples using a multiplex immunoassay. Analyte levels were analysed using principle component analysis, cluster analysis and limma. Blood neutrophil counts were analysed using linear regression.

Results: Plasma analyte levels of HIV-infected individuals are markedly different from those of healthy controls and HIV-negative individuals receiving post-exposure prophylaxis. Viral reactivation following cART interruption also affects multiple analytes, but cART interruption itself only has only a minor effect. We find that Thyroxine-Binding Globulin (TBG) levels and late-stage neutrophil numbers correlate with the time off cART after DC vaccination. Furthermore, analysis shows that cART alters several regulators of blood glucose levels, including C-peptide, chromogranin-A and leptin. HIV reactivation is associated with the upregulation of CXCR3 ligands.

Conclusions: Chronic HIV infection leads to a change in multiple plasma analyte levels, as does virus reactivation after cART interruption. Furthermore, we find evidence for the involvement of TBG and neutrophils in the response to DC-vaccination in the setting of HIV-infection.

Fig 1. Study setup.

Eligible HIV+ individuals were recruited into the study. They were given 4 autologous dendritic cell vaccinations at 4 week intervals, followed by analytical treatment interruption (ATI). Plasma analytes were measured before vaccination (‘PreVac’), after the third vaccination (Vac#3), just after commencing ATI, and when plasma virus loads become detectable again (ATI+PVL). The bar indicates the phases around the sampling points that were used for summarizing the neutrophil counts (N1-5).

Fig 2. PCA of all samples.

Missing values were removed by either excluding the analytes that contain missing values, or patients that have missing values.

Fig 3. Heatmap of analyte measurements in DC-TRN trial participants.

All measurements were corrected for patient effect. Three sample clusters are observed, which have been labelled A-C. The DCTRN trial stage at which the sample was taken in indicated by the left-most colour bar.

Fig 4. Differential expression analysis of analytes.

The names of analytes that are differentially expressed are depicted in circles for HIV infection stable on treatment vs healthy controls (‘HIV+’), cART treatment being treated HIV negative vs health control (‘treatment’) and virus reactivation as seen after stop cART, i.e., ATI.PVL—ATI (called ‘reactivation’). Up- and down-regulated analytes are depicted in red or green, respectively. ITAC is up-regulated during virus reactivation and down-regulated in during HIV infection.

Fig 5. Neutrophil counts over the course of the trial.

All data available for all patients is shown. The DC-TRN trail phases are indicated in Fig 1. The regression lines are annotated with significance levels and R-squared values.