SOURCES AND SEQUELAE OF BACTERIAL-CONTAMINATION OF HEMATOPOIETIC STEM-CELL COMPONENTS - IMPLICATIONS FOR THE SAFETY OF HEMATOTHERAPY AND GRAFT ENGINEERING

Background: It is important to compare the incidence of bacterial cont amination of components collected from the peripheral blood or bone ma rrow (BM), as well as of components processed with or without cell sel ection or depletion, and to evaluate the sequelae of such contaminatio n. Study Design and Methods: Bacterial contamination rates were compar ed in 1380 untreated autologous peripheral blood progenitor cells (PBP Cs), 291 untreated autologous BM samples, 916 monoclonal antibody (MoA b)-treated autologous and allogeneic BM samples, and in 45 autologous PBPC components from which the CD34+ cells were selected. Bacterial cu ltures were performed at sequential time points during the processing of MoAb-treated BM. Results: Bacterial contamination was documented in 44 of 2632 components from 1593 patients (1.67% of components, 2.76% of patients! before cryopreservation. Although only 0.65% of untreated PBPCs were contaminated before cryopreservation, each patient was mor e likely to have given a contaminated PBPC component than a contaminat ed BM component (2.41% vs. O%, p<0.01). Bacterial contamination of MoA b-treated BM was greater during or after manipulation than it was befo re (2.33% vs. 0.77%, p<0.05). At thawing, contamination was documented in 42 (1.97%) of 2136 components cultured. Ten (13.7%) of 73 patients who received hematopoietic progenitor cells that were contaminated be fore cryopreservation or at thawing developed fever or positive blood cultures within 48 hours of transfusion. Fever was associated with bac teremia in two cases, but no irreversible clinical sequelae were noted . Conclusion: These studies suggest that, despite careful attention to sterile procedures, low-level contamination of hematopoietic stem cel l components can be introduced before or during manipulation as well a s at thawing, and that standards for monitoring of the procedures for collection, processing, cryopreservation, thawing, and transfusion of hematopoietic progenitor cells are necessary.