Therefore, since the 1970s, there was great interest to improve the prognosis of persistently neutropenic patients suffering from severe infections with the administration of granulocytes, and the availability of recombinant hematopoietic growth factors such as granulocyte-colony stimulating factor (G-CSF) extended the use of this strategy even into the prophylactic setting (“adoptive immunotherapy”) [96]. This evidence concerns the gene CSF3 and infection.