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PURPOSE: The Cancer Immune Monitoring and Analysis Centers - Cancer Immunologic Data Commons (CIMAC-CIDC) Network is supported by the National Cancer Institute to identify biomarkers of response to cancer immunotherapies across clinical trials using state-of-the-art assays. A primary platform for CIMAC-CIDC studies is cytometry by time-of-flight (CyTOF), performed at all CIMAC laboratories. To ensure the ability to generate comparable CyTOF data across labs, a multistep cross-site harmonization effort was undertaken.

EXPERIMENTAL DESIGN: We first harmonized standard operating procedures (SOPs) across the CIMAC sites. Because of a new acquisition protocol comparing original narrow - or new wide bore injector introduced by the vendor (Fluidigm), we also tested this protocol across sites before finalizing the harmonized SOP. We then performed cross-site assay harmonization experiments using 5 shared cryopreserved and one lyophilized internal control PBMCs with a shared lyophilized antibody cocktail consisting of 14 isotype-tagged antibodies previously validated, plus additional liquid antibodies. These reagents and samples were distributed to the CIMAC sites and the data were centrally analyzed by manual gating and automated methods (Astrolabe).

RESULTS: Average coefficients of variation (CVs) across sites for each cell population were reported and compared to a previous multisite CyTOF study. We reached an inter-site CV of under 20% for most cell subsets, similar to a previously published study.

CONCLUSIONS: These results establish the ability to reproduce CyTOF data across sites in multi-center clinical trials, and also highlight the importance of quality control procedures, such as the use of spike-in control samples, for tracking variability in this assay.