The Response of Peripheral Blood Stem Cells to Standard Chemotherapy for Lymphoma

Peripheral blood stem cells (PBSC) represent an alternative to bone marrow for autologous transplantation. These progenitors are found in the blood in greatly increased numbers after chemotherapy for acute leukaemia and after high dose cyclophosphamide when they can be harvested. We have assessed the response of colony forming units-granulocyte monocyte (CFU-GM) and colony forming units-granulocyte, erythroid, monocyte, megakaryocyte (CFU-GEMM) in 46 patients with lymphoma undergoing standard chemotherapy. Seventeen out of 18 patients with non Hodgkin's lymphoma (NHL) receiving CHOP had a 6.9 fold increase over baseline in CFU-GM and a 5 fold increase in CFU-GEMM occurring on day 19. In 3 patients with NHL, ALL type therapy induced a 17.5 and 16 fold increase in these progenitors occurring on day 21. Only 4 of the 10 patients with Hodgkin's disease (HD) treated with ChIVPP demonstrated a rise in progenitors and only to 3.3 and 2.7 fold in CFU-GM and CFU-GEMM respectively. ABVD similarly produced increases in only 5/9 patients and MOPP in 3/5. HOPE-bleo increased circulating CFU-GM 16.3 fold and CFU-GEMM 12.4 fold. Bone marrow involvement significantly reduced the peak levels of CFU-GM (p = 0.0017) as did second or subsequent line chemotherapy (p = 0.0001). Thus standard chemotherapy regimes for lymphoma can induce a rise in circulating progenitors in the majority of patients. Peripheral blood stem cell harvesting should be performed during first line chemotherapy as blood counts are recovering and should be repeated after each cycle.