Biomarkers for assessing the immune state in rheumatoid arthritis and their application in a cellular therapy clinical trial

Background
Rheumatoid arthritis (RA) is caused by a loss of immune tolerance to self. Current clinical biomarkers assess inflammation but, as we treat earlier to prevent or cure disease, it will be increasingly important to assess the immune 'state'. For example, we have developed a novel therapeutic approach with tolerogenic dendritic cells (tolDC) that switch pathogenic self-reactive T-cells into regulatory/anergic T-cells. Our phase I clinical trial showed this therapy to be safe, and our forthcoming trial will compare different administration routes for efficacy. In order to demonstrate appropriate pharmacodynamic effects of tolDC, we will develop assays that assess the immune state, particularly the functional capabilities of autoreactive T-cells. Such surrogate outcome measures are the only way to provide true 'proof of concept' for such treatments.

Objectives
1) to validate existing and novel immunomonitoring tools for the characterisation of autoreactive T-cells in clinical samples from RA patients
2) to apply these tools to probe changes in autoreactive-T-cells with tolDC treatment
3) To define biomarkers for T-cell tolerance
4) To extrapolate our findings to other clinical RA scenarios

Novelty
The novelty lies in combining state-of-the-art techniques to enrich autoreactive T-cells (including the use of HLA/peptide tetramers) and analysing those cells at single cell level, ultimately studying T-cells from our forthcoming tolDC clinical trial to demonstrate therapeutic immune modulation.

Timeliness
A number of antigen-specific tolerogenic therapies for autoimmune diseases are currently under development, for treatment and prevention. These include cell-based (e.g. tolDC) as well as nanoparticle-based strategies. However, suitable pharmacodynamic biomarkers are currently lacking, but will be essential outcome measures in clinical trials to demonstrate immune modulation.

Experimental approach
The student will validate established techniques (multi-colour flow cytometry, ELISPOT, in vitro proliferation assay, single cell sequencing) alongside techniques we have developed to enrich autoreactive T-cells (HLA/peptide tetramers, activation-induced marker (AIM) assay) for use as immunomonitoring tools for clinical samples. These assays will then be applied to samples from the tolDC trial which include peripheral blood mononuclear cells, as well as lymph node aspirates, taken before and after tolDC administration. As a contingency, these novel tools can also be applied to probe the phenotype and function of autoreactive T-cells in other relevant scenarios, for example, from RA patients as they enter remission with standard-of-care treatment such as methotrexate, providing invaluable new insights into immune mechanisms of disease and their modulation by treatment.