Development and validation of a high-parameter mass cytometry workflow to decipher immunomodulatory changes in celiac disease.

The advent of time-of-flight mass cytometry (CyTOF) has enabled high dimensional and unbiased examination of the immune system to simultaneous interrogate a multitude of parameters and gain a better understanding of immunologic data from clinical trial samples. Here we describe the development and validation of a 33-marker mass cytometry workflow for measuring gastrointestinal (GI) trafficking peripheral blood mononuclear cells (PBMCs) in patients with celiac disease (CeD). This panel builds upon identification of well-characterized immune cells and expands to include markers modulated in response to gluten challenge in patients with CeD. The CeD panel was optimized and validated according to accepted industry practice for validation of flow cytometry assays and builds upon established sample processing workflows for mass cytometry studies. Several critical parameters were evaluated during the assay development phase of this study including optimization of the sample processing steps, antibody specificity, and ensuring the panel as a whole performed to expectation. The panel was then validated using a fit-for-purpose approach tailored to the intended use of the data in the clinical trial. Validation included assessment of analytical parameters essential to understanding the reliability and robustness of the CeD panel such as intra-assay precision, inter-assay precision, inter-operator precision and sample processing stability. Together, this validated mass cytometry workstream provides robust and reproducible high-dimensional analysis of human peripheral blood immune cells to characterize patient samples from clinical trials.