High-dose therapy with autologous stem cell rescue is an increasingly applied treatment for younger patients (o65 years). In patients with recurrent chemotherapy-sensitive low-grade non-Hodgkin’s lymphoma (NHL), or CLL, high rates of complete remission and moderate rates of durable disease control can be attained.

For an autograft to be successful, a minimum number of stem cells must be obtained from a mobilization procedure, to ensure an acceptable rate of haemopoietic recovery and a low rate of graft failure. Patients with lymphoid malignancies, particularly those with ‘low-grade’histology, have a higher rate of collection failure. 1 Many of these patients may have received multiple prior courses of potentially myelotoxic therapy. In a number of studies of this patient group, prior treatment with the purine analogue fludarabine has been associated with impaired mobilization. 2–5 Ketterer et al2 examined 200 patients with lymphoid malignancies and identified prior exposure to fludarabine as the most significant predictor of a sub-optimal stem cell collection (P= 0.0008). Given that fludarabine is a potent cytotoxic agent in both initial and salvage therapy of patients with lymphoproliferative disorders and is becoming more widely used in this setting, the problem of impaired stem cell mobilization may become an increasingly frequent clinical issue. Only one previous study4 has specifically examined the factors contributing to poor stem cell yield in fludarabine-exposed patients, and was restricted to patients with CLL. We therefore analysed our own experience with peripheral blood stem cell (PBSC) mobilization in patients