Abstract
Background aims. Cord blood (CB) banking is becoming more and more commonplace throughout the medical community, both in the USA and elsewhere. It is now generally recognized that storage of CB samples in multiple aliquots is the preferred approach to banking because it allows the greatest number of uses of the sample. However, it is unclear which are the best methodologies for cryopreservation and storage of the sample aliquots. In the current study we analyzed variables that could affect these processes. Methods. CB were processed into mononuclear cells (MNC) and frozen in commercially available human serum albumin (HSA) or autologous CB plasma using cryovials of various sizes and cryobags. The bacteriophage phiX174 was used as a model virus to test for cross-contamination. Results. We observed that cryopreservation of CB in HSA, undiluted autologous human plasma and 50% diluted plasma was equivalent in terms of cell recovery and cell viability. We also found that cryopreservation of CB samples in either cryovials or cryobags displayed equivalent thermal characteristics. Finally, we demonstrated that overwrapping the CB storage container in an impermeable plastic sheathing was sufficient to prevent cross-sample viral contamination during prolonged storage in the liquid phase of liquid nitrogen dewar storage. Conclusion. CB may be cryopreserved in either vials or bags without concern for temperature stability. Sample overwrapping is sufficient to prevent microbiologic contamination of the samples while in liquid-phase liquid nitrogen storage.
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Acknowledgments
The authors wish to acknowledge Dr B. Fane, University of Arizona, for provision of the phiX174 as well as assistance in methods used for the determination of phage numbers. We also acknowledge the assistance of all the nurses and physicians involved in the collection of the CB samples.
The project described was supported in part by grant #5R01AG038021-02 from the National Institute of Aging. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Aging or the National Institutes of Health.
Disclosure of interests: None.