What is the difference between gene therapy and cell therapy?

Gene therapy involves the transfer of genetic material in a carrier or vector and the uptake of the gene into targeted cells.  Cell therapy involves the transfer of cells with relevant/desired function into the patient. There are some protocols that use both gene and cell therapy: stem cells are isolated from the patient, genetically modified in culture to express a new gene, typically using a viral vector, expanded to sufficient numbers and then returned to the patient.