Use of pathology-specific peripheral blood CD34 thresholds to predict leukapheresis CD34 content with optimal accuracy: a bicentric analysis of 299 leukaphereses

CD34+ cell counts in peripheral blood (PB) and corresponding numbers of CD3 4+ cells and colony-forming units-granulocyte/macrophage (CFU-GM) in 299 le ukapheresis products of 209 patients undergoing PB progenitor cell (PBPC) m obilization for autologous transplantation in two different centers were an alyzed and compared according to diagnosis: non-Hodgkin lymphoma (NHL, 94 l eukaphereses), multiple myeloma (MM, 75), Hodgkin's disease (HD, 37), solid tumors (35), and chronic myeloid leukemia (CML, 32). Without separating di sease entities, correlations between PB CD34+ cell counts and leukapheresis content of CD34+ cells (r>0.83, P<0.01) and CFU-GM (r>0.81, P<0.01) were e xcellent. In both centers, a PB CD34 threshold ensuring a leukapheresis yie ld > 10(6) CD34/kg was determined. This threshold was higher in center I th an in center 2, and its predictive accuracy (91.4%, i.e.. prediction correc t 91.4% of the time) was significantly lower than in center 2 (98.4%, P=0.0 2). When data were analyzed by pathology, PB CD34+ cell counts and leukaphe resis content of CD34+ cells and CFU-GM remained well correlated, and in bo th centers PB CD34 thresholds predictive of a yield >10(6) CD34/k-g per leu kapheresis could be determined for each pathology. For most patients, patho logy-specific PB CD34 thresholds could be obtained directly from the equati on of the PB CD34/leukapheresis CD34 correlation curve; they varied dependi ng on both pathology and center (range: 7-20x10(6) CD34/l). Pathology-speci fic thresholds predicted a leukapheresis yield greater than or equal to 10( 6) CD34/kg accurately 100% of the time for MM patients in center 2 and HD a nd solid tumor patients of both centers, resulting in overall rates of accu rate prediction of sufficient graft CD34 content of 96.6% in center 1 and 9 8.9% in center 2.