Processing cord blood from premature infants into autologous red-blood-cell products for transfusion.

BACKGROUND AND OBJECTIVES: The use of umbilical cord blood (UCB) for transfusion purposes has gained interest the past years. UCB transfusion could serve premature infants, who often need transfusions early in life. MATERIAL AND METHODS: We investigated the suitability of different storage media. UCB was collected after 25 0/7--35 6/7 gestational weeks and centrifuged to concentrate red cells subsequently stored in saline-adenine-glucose-mannitol (SAGM), or in additive solution-3 (AS-3), or stored as whole blood in citrate-phosphate-dextrose-adenine-1. Quality parameters were measured at 7 day intervals during 35 days and compared to the standard RBC product. RESULTS: White-blood-cell- and platelet counts were higher in the UCB products. In the fractionated units, haemolysis remained below 1·0% in 64% after 14 days, and in 30% after 21 days. Storage in SAGM or AS-3 showed similar quality. Whole blood UCB showed better pH and haemolysis rates after 21 days. CONCLUSION: UCB can be processed into autologous products for premature infants. Shelf-life is limited to 14-21 days and compares unfavourably to stored whole blood. Considering the early transfusion needs in these infants, a short shelf-life would not be a practical objection.

Microbial contamination of cord blood stem cells.

BACKGROUND AND OBJECTIVES: After storage, low levels of contaminating bacteria in standard blood components can reach bacteraemic levels, causing severe transfusion-associated sepsis. For cord blood (CB), the significance of low levels of contaminating bacteria and the optimal detection method is unknown and not supported by available guidelines. MATERIALS AND METHODS: Spiking experiments and testing of various subfractions of CB units were used to determine the behaviour of bacteria during centrifugation, freezing and thawing. For routine testing of CB, different volumes were compared for the detection of potential pathogens and micro-organisms of low pathogenicity. RESULTS: Centrifugation, as applied to CB fractionation, does not show concentration of bacteria in any particular fraction and supports the possibility of culture of waste fractions. Dimethylsulphoxide (DMSO) and freezing does not affect the viability of bacteria under the conditions used in this study. Owing to the low contamination level, a large sample volume of 20 ml was more sensitive than a 10-ml sample volume. Eighty five per cent of the isolated strains can be considered to be of low pathogenicity. CONCLUSION: When an optimal waste fraction sample volume of 20 ml was cultured, the contamination rate of CB was found to be approximately 13%, with low levels of < 1 colony-forming unit (CFU)/ml. Such levels of bacteria of low pathogenicity are expected to be of clinical importance only when CB is expanded in vitro for a prolonged period of time.

Hemopoietic stem and precursor cell analysis in umbilical cord blood using the Sysmex SE-9000 IMI channel.

Circulating hematopoietic progenitor cells (HPCs) are routinely measured by flow cytometry using CD34 expression. As an alternative, the "immature information" (IMI) channel measurement of the automated hematology analyzer Sysmex SE machines was developed. We tested the IMI channel HPC method with umbilical cord blood specimens. The IMI-HPCs were compared with CD34 counts and numbers of colony-forming units (CFUs). The IMI-HPC data were reproducible and dilution experiments yielded a log-linear relationship. The mean percentage of CD34(+) cells in 50 umbilical cords was 0.43 versus 0.11 of HPCs in the IMI channel (correlation coefficient r = 0.67). Absolute numbers yielded 96.79 x 10(6)/L CD34(+), 33.17 x 10(6)/L IMI-HPC, and 35.04 x 10(6)/L CFU-HPC. Receiver operating characteristics curves were made at various cutoff levels for CD34(+) cells to visualize sensitivity and specificity profiles. With median values of 13.56 x 10(6)/L for IMI-HPC and 20 x 10(6)/L for CD34(+) as cutoff points (the levels used in the laboratory to start stem cell pheresis), the percentage of false-negative observations was 70.4%. To exclude the influence of storage time, tests were repeated until 72 h after umbilical cord collection. Total white blood cell count decreased in most cases, whereas absolute number of IMI-HPC tended to increase in time. In conclusion, if HPC measurements in the IMI channel are used to monitor circulating stem cells during mobilization, one has to be aware of a very low correlation between these results and those of other methods such as CD34(+) analysis and colony growth. False-negative results do occur, but if events are seen in the IMI channel, this simple monitoring technique is useful to predict the presence of circulating stem cells.

Association of stress during delivery with increased numbers of nucleated cells and hematopoietic progenitor cells in umbilical cord blood.

OBJECTIVE: Umbilical cord blood can be used as a source of bone marrow repopulating cells for allogeneic stem cell transplantation. Large variations in the frequencies of white blood cells and hematopoietic progenitor cells have been found for umbilical cord blood. These variations may be due in part to specific circumstances during labor and delivery. STUDY DESIGN: In this study we analyzed the relationship between stress factors occurring during parturition and the frequencies of nucleated cells, leukocyte subsets, CD34(+) cells, and hematopoietic progenitor cells, as determined in semisolid medium cultures of umbilical cord blood. RESULTS: We observed that a prolonged first stage of labor resulted in increases in the numbers of nucleated cells, granulocytes, CD34(+) cells, and hematopoietic progenitor cells in umbilical cord blood. Evaluation of parameters that indicate stress of the infant during delivery demonstrated higher numbers of nucleated cells, granulocytes, CD34(+) cells, and hematopoietic progenitor cells in umbilical cord blood from children with lower venous pH. CONCLUSION: Longer duration stress during delivery increased the numbers of nucleated cells, granulocytes, CD34(+) cells, and hematopoietic progenitor cells, possibly by causing mobilization of various cell populations by endogenous cytokines. As long as umbilical cord blood harvesting does not interfere with the delivery, umbilical cord blood collected after stressful deliveries may provide optimal units for hematopoietic stem cell transplantation.