White cells protect donor blood against bacterial contamination

Abstract

The possible beneficial role of white cells (WBCs) in donor blood has been investigated with respect to their capacity to remove bacteria. Preparations of buffy coat and whole blood, containing as well as reduced of WBCs, were inoculated with Staphylococcus epidermidis, S. aureus, Escherichia coli, Pseudomonas aeruginosa, and Propionibacterium species. Upon storage at room temperature, the presence of WBCs resulted in a reduction of the bacterial content. Units inoculated with S. epidermidis and E. coli were completely cleared of bacteria within 5 to 24 hours. On the other hand, S. aureus, after an initial reduction in number, started to multiply. In WBC-reduced units, the initial bacterial content remained unchanged for 5 hours, but the bacteria then exhibited vigorous growth within 48 hours in buffy coat and slower growth in whole blood. Propionibacterium sp. did not grow with or without WBCs. P. aeruginosa did not grow in buffy coat but showed a growth pattern similar to that of S. aureus in whole blood. The presence of WBCs in the donor blood during the first hours after collection thus seems to rid the blood of at least some species of bacteria. These results indicate that it would be favorable not to perform WBC reduction during blood collection and that several hours of contact can be needed to obtain sterility.

Clinical Impact of Bioactive Substances in Blood Components: Implications for Leukocyte Filtration

“…Prestorage leukofiltration had no influence on erythrocyte counts [134], and similarly platelet counts in platelet-rich plasma appeared to be unaffected by prestorage filtrations [68]. It has been suggested that bacterial contamination of blood components may be protected by leukocytes present in various blood components [135]. Moreover, it is now widely accepted that prestorage removal of leukocytes before their disintegration and the subsequent release of engulfed bacteria during storage contributes to the safety of blood components.…”

Transfusion-related bacterial sepsis

“…Hogman and coworkers reported that buffy coats that were leukodepleted before inoculation with S. epidermidis, S. aureus, E. coli, P. aeruginosa, and Propionibacterium sp. had higher titers during storage than unfiltered buffy coats (62).…”

“…Interpolated data from values presented by Hogman and coworkers suggest that Staphylococcus aureus and Pseudomonas aeruginosa can undergo 1 to 2 doublings in whole blood held for 8 h at room temperature (62). Currently, erythrocytes can be prepared from whole blood that is held at room temperature for up to 8 h after collection or from chilled (1 to 6°C) whole blood units stored for up to 3 days.…”

“…One experiment involving filtration and bacterial growth has been carried out with buffy coats (the interface layer between erythrocytes and plasma following centrifugation of whole blood) (62). Buffy coats are currently being used in some European blood centers as an alternative way to prepare platelet concentrates.…”

Preparation of Leukocyte–Poor Platelet Concentrates via a Short, Hard Spin of a Pool of Buffy Coats

“…Many blood banks store whole–blood units or BCs before component preparation, because a certain holding time, between 3 and 24 h, is needed to achieve maximal platelet recovery [5, 6, 7]. In the time between phlebotomy and platelet production, leukocytes may phagocytose microorganisms that could possibly be present [8, 9]. …”