The authors compared the results of standard and large-volume leukapheresis (LVL) separations in patients with a good response to mobilization therapy as well as in patients with an inadequate effect of mobilization. These comparisons should help to evaluate the effectiveness of separation procedures and the assessment of indication criteria for different procedures. With regard to the higher yields of the LVL technique it would be useful to apply LVL separation always when the patient is able to tolerate these procedures. LVL procedures should be also preferred in patients with an inadequate effect of mobilization where this technique is at present the only possibility how to achieve at least the minimal recommended dose of CD34+ cells for transplantation. The LVL technique is suitable also under conditions when an exceptionally high dose of CD 34+ is required either to ensure tandem transplan- tation of the patient or before subsequent manipulations with a PBPC graft when significant losses of the original cell content occur. The higher efficiency of the LVL technique makes it possible to reduce the number of separations needed to obtain an adequate amount of progenitor cells. This reduces the time of administration of cytokines, which are given to patients daily during mobilization and throughout the period of separation.

        Key words: haematopoietic progenitor cells from peripheral blood (PBPC), CD 34+ cells, separation of PBPC