Integrating scRNA-Seq data derived from heterogeneous biopsies and purified immune populations enables assignment of hematopoietic lineage to each cell. (A) tSNE mapping of 8129 cells from a follicular lymphoma sample (LPJ128, gray dots) and of 2962 purified cells from 8 BEIL populations (colored dots). (B) RNA-Seq based assignment of all 11 091 cells to a hematopoietic lineage. Every single cell was compared with every BEIL representative. (C) Among the gray LPJ128 cells from panel (A), expression of an 18-gene signature of cell cycle progression is shown (colorbar legend) and was highest among B cells and Tregs. The scale shows the GSVA enrichment score¹⁹  per cell. (D-E) Overall cell type frequencies are quantified for the sample above, along with 5 additional follicular lymphoma samples. Sequencing-based (left) and FACS-based (right) cell type frequencies are shown in pairs for each specimen (D) and cell type (E). **Spearman r ≥ 0.95: *r ≥ 0.9.