Secondary measures of immunologic efficacy in clinical trials

Purpose of reviewSince type 1 diabetes mellitus is a T lymphocyte-mediated disease, numerous T cell-centric strategies aimed at either interfering with pathogenic effector T cells, or promoting regulatory ones, are at the stage of planned clinical trials or beyond. The feasibility of measuring reductions in activity or number of pathogenic T cells and/or equivalent increases in regulatory cells is the focus of this review. Recent findingsThe design of surrogate T cell markers for trial monitoring has been facilitated by the recent deployment of new assay technologies, a greater knowledge of islet-specific T cell targets and a greater understanding of the T cell-dominated pathogenic process leading to islet destruction, as well as the regulatory pathways designed to prevent it. SummaryAdvances in technologies designed to measure the anticipated low frequency of autoreactive T cells, as well as recent discoveries in the field of regulatory T cells and the creation of clinical trial consortia, have set the stage for the implementation of large-scale clinical trials in type 1 diabetes in which the measurement of T cell reactivity is viewed as a key mechanistic outcome.