To identify known immune cell populations in PBMCs, we used the Seurat package to perform unbiased clustering on the 2.7k PBMCs from Zheng et al., following the publicly available Guided Clustering Tutorial17, 53. The FindAllMarkers function was then used to find the top 20 markers for each of the 8 identified cell types. Cluster averages were calculated by taking the average raw count across all cells of each cell type. For each cell, we calculated the Spearman correlation of the raw counts of the marker genes and the cluster averages, and assigned each cell to the cell type to which it had maximum correlation.
