Factors affecting recovery after peripheral blood stem cell transplantation

To determine the factors that might be involved in successful engraftment following administration of autologous peripheral blood stem cells (PBSC) obtained by leukapheresis to replace bone marrow after ablation therapy for malignant disease, four patients were examined in detail. One who had had pelvic radiation as well as chemotherapy had a prolonged, gradual but complete recovery. One who received granulocyte-macrophage-colony stimulating factor (GM-CSF) following PBSC infusion showed a rapid recovery phase, but developed high fever (culture negative) associated with arrested hematopoiesis and died with central nervous system (CNS) symptoms after 120 days. Two other patients recovered without major incident. Concentration of PBSC was analyzed by: (1) approximation by counting mononuclear cells (MNC); (2) CD34 cells by flow cytometric analysis; and (3) colony forming units-granulocyte macrophage (CFU-GM) by colony formation in microtiter plates. The time to BM recovery (retics > 1.0 percent, neutrophils > 500 per cumm, platelets > 50,000 per cumm) was determined by following daily counts. Engraftment appeared to depend upon an adequate minimum dose of PBSC, but ultimate recovery of the patient seemed to be determined by ancillary factors, especially CNS infection. These patients illustrate that while rapidity of bone marrow (BM) recovery may be related to PBSC dose, other factors, particularly infection, influence patient outcome.