Presence of Promyelocytes in Peripheral Blood as a Novel Predictor of Optimal Timing for Single-Step Peripheral Blood Stem Cell Collection.

Abstract

Because peripheral blood stem cell (PBSC) collection places a burden on the patient and should ideally be completed in a single procedure, a convenient clinical predictive factor is needed. This retrospective study included 72 patients who underwent autologous PBSC collection. A median volume of 3.9 × 106 CD34-positive cells/kg (range: 0.3-47.4 × 106 cells/kg) was collected on the first day. We defined failure as inability to collect 2.0 × 106 cells/kg on the first day. PBSC collection was classified as failed (n = 25, 34.7%) and successful (n = 47, 65.3%), and patient clinical characteristics were analyzed. The success group had significantly more cases in which a differential white blood cell count in peripheral blood on the day of PBSC collection detected promyelocytes (n = 34 [72.3%] vs. n = 11 [44.0%] in the failure group; P = 0.008). Sixty-two patients underwent autologous PBSC transplantation (median number of transplanted cells, 5.6 × 106/μL; range: 1.60-47.4 × 106 cells/μL). Among transplanted patients, the success and failure groups did not significantly differ in relation to the interval until neutrophil, platelet, or red blood cell engraftment. The presence of promyelocytes in peripheral blood may be a useful indicator of the optimal timing for single-step PBSC collection.