Ex vivo expansion of umbilical cord blood CD34 cells in a closed system: a multicentric study.

BACKGROUND AND OBJECTIVES: The Dideco 'Pluricell System' is a CE-marked medical device allowing haematopoietic stem cell (HSC) expansion. It comprises a kit of cGMP cytokines and reagents, a closed-cell expansion chamber and a cell-washing set. We tested the system in a multicentric study by expanding CD34(+) cells from eight fresh umbilical cord blood (UCB) samples. MATERIALS AND METHODS: During culture, the mean nucleated cell (NC) count, the mean CD34(+) cell count, fold expansion, viability and apoptosis were measured. Clonogenic assays and immunophenotypical characterization were performed on days 0, 7 and 12. On the expanded cellular product, in three cases cell genotyping, endotoxin level and mycoplasma detection (by polymerase chain reaction) were performed. RESULTS: The mean CD34(+) cell expansion on days 7 and 12 was sevenfold and 12-fold respectively and the mean NC expansion was 69-fold and 180-fold. The mean NC viability on day 12 was 96.9% (94.4-99.1). After 12 days, granulocyte-macrophage colony-forming units (GM-CFU) showed a 20-fold increase: a slight increase in CD34(+) cell apoptosis was observed during culture. In all of three cases neither chromosomal alterations nor mycoplasma contamination was detected. No significant endotoxin levels were detected after expansion. CONCLUSIONS: The device allows the ex vivo expansion of NC and CD34(+) cells in a closed system. The expanded cellular product is a mixture of progenitors (CD34(+) cells) and differentiated (mainly myeloid and megakaryocytic) cells. To reduce cell apoptosis, more frequent cell feeding during culture should be tested.

The impact of rufloxacin given as prophylaxis to patients with cancer on their oral and faecal microflora.

A single dose of 200 mg/day rufloxacin was investigated for preventing infection and for its impact on the commensal flora in a pilot study of 62 patients undergoing cytotoxic treatment for cancer. No infection caused by Gram-negative bacilli occurred among 54 assessable patients but prophylaxis was replaced by empirical treatment for fever in 19 cases and because of an adverse event, in a further three cases. The remaining 32 patients completed prophylaxis. The number of oral Branhamella spp., faecal Enterobacteriaceae and Bacteriodes spp. were significantly reduced whereas there was little effect of rufloxacin on the numbers of the other oral and faecal microflora. However, resistance to rufloxacin increased among both oral viridans streptococci, coagulase negative staphylococci and the faecal enterococci. These preliminary data suggest that selective oral antimicrobial prophylaxis for patients with cancer might be achieved with once-daily rufloxacin.