The reference panel was assembled with samples from four distinct cell types. A redundant set of well-known cell-type markers was selected from the literature [31, 55, 56] (Additional file 1: Table S3). Principal component analysis (PCA) was performed on the reference panel using R function prcomp (version 3.3.3) to verify that the expressions of these gene were clustering samples by their cell types (Additional file 1: Figure S1b; Additional file 1: Figure S2a).
