Frozen cells were thawed  in water bath at 37 C for 3 minutes. Cells were centrifuged at 500 x g for 5 minutes, and washed in RPMI + 10 % Fetal Bovine Serum. Finally, cell pellets were resuspended in PBS + BSA 0.04% and processed with the 10x Genomics single cell 5' system according to manufacturer's instructions. scRNA-seq libraries were prepared with the Chromium Next GEM Single Cell V(D)J Reagent Kits v1.1 as described by the manufacturer's instructions. 10x Genomics scRNA-seq 5' library construction kit