Mobilization of CD34+ cells in elderly patients (≥ 70 years) with multiple myeloma: influence of age, prior therapy, platelet count and mobilization regimen

The mobilization of peripheral blood stem cells was studied in 984 multiple myeloma patients, including 106 patients aged >/= 70 years. Increasing age correlated inversely with CD34+ yield (P /= 12 months of prior standard chemotherapy (P = 0.0001), /= 200 x 10(9)/l premobilization as favourable variables (both P /= 4 x 10(6)/kg CD34+ cells in a median of one collection. The effect of age was incremental with no age threshold showing acceleration in the decline of CD34+ yield. Chemotherapy significantly increased CD34+ yield compared with growth factors only. However, the subgroup of patients with > 12 months prior therapy and premobilization platelet count /= 50 x 10(9)/l) if /= 4 x 10(6)/kg CD34+ cells. Increasing age adversely affected CD34+ yield even with limited premobilization therapy, indicating that early collection is important in elderly patients.