Liquid Preservation of Granulocytes

Granulocytes can be expected to have a life span of up to four days after collection. The number of morphologically normal cells declines by 10 to 15 per cent per day during the first two days. Phagocytosis, bacterial killing and metabolic activities related to the hexose monophosphate shunt remain essentially unchanged during the first day of storage, but chemotaxis ATP levels and the ability of the granulocytes to circulate are reduced after storage. Preliminary information suggests that chemotaxis and ATP may be better maintained at room temperature, although studies in rabbits suggest that in vivo function may be better maintained by refrigerator storage. Granulocytes collected by ordinary phlebotomy, CFCL and IFCL behave in general, similarly during storage. However, in our experience, FL granulocytes have a greater loss of bactericidal capacity and chemo‐tactic responsiveness during storage. Although others have been able to better maintain in vitro function of FL granulocytes, these cells may be more susceptible to damage during storage unless scrupulous collection technique is used. The influence of many other storage variables including: pH, composition of container, agitation, surface to volume ratio, cell concentration, nutrient requirements, presence of other cells such as red cells or platelets is not yet established. Agitation during storage at room temperature causes reduced chemotactic response. Granulocyte chemiluminescence is maintained when the storage pH is 6.5 to 8.0, however a narrower range may be needed for maintenance of chemotactic response. Other studies indicate that storage in polyvinyl chloride containers may be preferable to polyolefin or ethylenevinyl acetate. Although storage of granulocytes should be possible, the conditions are not yet sufficiently well defined to justify this practice. Granulocytes should be transfused as soon as possible after collection.