Bacterial contamination of peripheral blood progenitor cells for transplantation

Abstract

Peripheral blood progenitor cells (PBPC) were obtained from 128 apheresis harvests on 64 patients and were tested in duplicate for microbiological contamination (1) after collection and (2) after thawing, following processing and cryopreservation. In this study we have attempted to improve the monitoring of contamination in peripheral blood progenitor cell collections by identifying exogenous contamination that probably originated from the testing laboratory and is therefore not clinically significant. We found no contamination in 82% of harvests, 1.6% of harvests to be significantly contaminated and organisms were isolated from 16.4% that were assessed as clinically nonsignificant. Our experience indicates that the choice of microbiological methods will influence the results and their clinical relevance. No samples were positive by direct culture. We recommend that sampling should be performed at more than one stage during the procedure and that initially only the post-thaw samples be analysed. Testing should be performed by enrichment culture in duplicate only and if positive to aid interpretation the post-collection sample should then be cultured. No patient given nonsignificantly contaminated graft without antibiotic cover suffered infection from the identified organism. The incidence of significant contamination was low and we recommend that in these cases PBPC grafts can be infused safely provided prophylactic antibiotic cover is given.

CD34+ selection of hematopoietic blood cell collections and autotransplantation in lymphoma: overnight storage of cells at 4°C does not affect outcome

“…18 These results, however, were inconsistent with previous reports which have indicated that storage of PBPC for periods up to 5 days has minimal effect on cell count, cell viability, and CFU-GM. [29][30][31][32] More importantly, other investigators have reported that overnight storage prior to processing had no effect on platelet recovery after transplant. 33,34 We attribute the differences in these two reports to the fact that our initial trial was not randomized and patient characteristics were not balanced.…”

Microbial contamination of hematopoietic progenitor cell products: clinical outcome

“…All autologous transplant patients had neutrophil recovery at a median of 10 days (range, [8][9][10][11][12][13][14]. Among the allogeneic transplant patients, all but one engrafted in a median of 13 days (range, 5-21).…”

“…7,8 Several small studies have reported favorable outcomes after infusion of contaminated products with minimal clinical consequences. [9][10][11] The US Food and Drug Administration (FDA) has recently established new rules for 'current good tissue practice for manufacturers of human cellular and tissue-based products', in which they describe a risk of 2.4% for contamination and raise concerns that there was a high rate of morbidity and mortality after receiving a contaminated product. 12 In this report, we retrospectively studied the outcomes of transplantation involving contaminated HPC product infusions performed during a 6-year period in a single institution.…”

Evaluation of optimal survival of primitive progenitor cells (LTC-IC) from PBPC apheresis products after overnight storage

“…Recommendations concerning this issue exist but vary among the different centers and are primarily based on analyses of viable cell counts, measurement of CD34-positive cells and/or colony-forming cells (CFC) after ON storage. [1][2][3][4][5] In addition, many of these analyses were performed on bone marrow progenitors and the conclusions drawn from these experiments were translated to PBPC without re-evaluation. Recent animal data suggest that primitive progenitor cells are not only important for long-term engraftment but also contribute significantly to the early phase of hematopoietic engraftment after myeloablative therapy.…”