Clinical trials are increasingly incorporating flow cytometric immunological assays aimed at understanding mechanistic outcomes of treatment in study design, or defining biomarkers associated with disease progression. In order to improve data reproducibility and to increase the statistical power of independent trials all aspects of standardized assays must be harmonised between different labs. This includes sample collection timing, SOP training, processing, storage conditions, in addition to mAb panels, cytometer QC and data analysis.We instigated a cross-lab training process to harmonise a series of high-parameter flow cytometric assays. We then used these assays to test the safety of ustekinumab administration to 20 young adults (18-25yrs) with recent-onset Type 1 diabetes (T1D). T1D is characterised by T-cell-mediated destruction of insulin-producing pancreatic beta cells. Ustekinumab inhibits IL-12/23 p40 and thereby limits the function of IL-17 and/ or IFNγ secreting T-cells, which are implicated in TID pathogenesis. Our assays revealed a dose-dependent increase in the frequency of memory regulatory T-cells (Tregs; p<0.01) and a reduction in the frequency of IL-17 + IFNγ + Th17.1-cells (p<0.05) post treatment. Results from this trial indicated that changes in immune cell populations may predict a clinical response to ustekinumab therapy.
We have now harmonised these assays between labs in Canada and the UK for two randomized, placebo-controlled clinical trials to test the efficacy of ustekinumab in new- onset T1D. This study provides a template for integrating flow cytometric analyses in future immunotherapy trials.