The function of FLT3LG (fms related receptor tyrosine kinase 3 ligand, Ensembl gene identifier ENSG00000090554) is as follows. Stimulates the proliferation of early hematopoietic cells by activating FLT3. Synergizes well with a number of other colony stimulating factors and interleukins. Required for the development of B cells, and dendritic cells (DCs). .