A<unk>  is a medical procedure in which<unk> s (a type of white blood cell) are infused into a person's blood.<unk> s were historically used to prevent and treat infections in people with neutropenia (an abnormally low level of neutrophils), but the practice declined in popularity in the 1980s. Interest in the procedure increased in the 1990s due to the development of more effective methods for harvesting<unk> s and a growing population of people with severe neutropenia from chemotherapy. However, the treatment's efficacy remains poorly understood and its use is controversial.<unk> s are most often collected through leukapheresis, a process that separates the donor's white blood cells from their red blood cells and plasma. Donors may be given corticosteroids or<unk>  colony-stimulating factor to increase their<unk>  count prior to the blood collection.<unk> s have a short shelf life and it is recommended that they are transfused within hours of collection. Adverse effects from<unk> s include fever, chills, respiratory symptoms, transfusion-transmitted infections, and the development of antibodies against human leukocyte antigens, which can interfere with subsequent transfusions.
Granulocyte transfusion
Platelet transfusion
Exchange transfusion
Precipitate delivery
Transfusion therapy 
Packed red blood cells
Autologous blood therapy
Blood transfusion