Single-cell RNA sequencing (scRNAseq) allows the identification, characterization, and quantification of cell types in a tissue. When focused on the adaptive immune system’s T and B cells, scRNAseq carries the potential to track the clonal lineage of each analyzed cell through the unique rearranged sequence of its antigen receptor (TCR or BCR, respectively), and link it to the functional state inferred from transcriptome analysis. Computational approaches to infer clonality and maturation status (for BCR only) from scRNAseq datasets of T and B cells have been developed but there are cumbersome and not costly effective. The inventors have now developed a FACS-based 5’-end RNAseq method, in particular a FACS-based 5’-end scRNAseq method, for cost effective integrative analysis of B and T cell transcriptome and paired BCR and TCR repertoire in phenotypically defined B and T cell subsets. In particular, the method of the present invention includes a reverse transcription step that uses a number of different well specific template switching oligonucleotides (TSO) to introduce a well-specific DNA barcode in the 5’-end of cDNAs.