FLOW-CYTOMETRY USING ANNEXIN-V CAN DETECT EARLY APOPTOSIS IN PERIPHERAL-BLOOD STEM-CELL HARVESTS FROM PATIENTS WITH LEUKEMIA AND LYMPHOMA

Quantifying progenitor cells in peripheral blood stem cell (PBSC) harv ests by Row cytometric enumeration of CD34(+) cells does not account f or cell viability. Cell membrane asymmetry in early apoptosis exposes phosphatidylserine on the cell surface, This can be detected by staini ng with annexin V FITC, Apoptosis in 30 autologous PBSC harvests mobil ised by cyclophosphamide + G-CSF or standard chemotherapy + G-CSF was analysed immediately after collection by dual-colour flow cytometry wi th CD34 PE and annexin V FITC. Harvests contained a median of 3.4 x 10 (6)/kg (range 0.3-91.8) CD34(+) cells, Of these 87.6% (range 30-96.5) were annexin V-. In 10% of harvests more than 50% of CD34(+) cells wer e apoptotic, Differences in PBSC mobilisation or collection could not explain the variation in annexin V binding, Cyclophosphamide + G-CSF s ignificantly increased the yield of CD34(+) cells but did not increase apoptosis. Comparison of consecutive harvests showed no difference in the numbers of CD34(+) cells collected but found a significant decrea se in apoptotic CD34(+) cells through multiple collections, Analysis o f annexin V binding in PBSC harvests is a simple flow cytometry techni que which gives additional information on the status of CD34(+) progen itor cells.