Methods of freezing cord blood hematopoietic stem cells

Authors

  • Jolanta Antoniewicz-Papis,

    Corresponding author
    1. Department of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
    2. Department of Diagnostics for Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
    • Address reprint requests to: Jolanta Antoniewicz-Papis, PhD, Institute of Hematology and Transfusion Medicine, Indiry Gandhi Street 14, 02-776 Warsaw, Poland; e-mail: jpapis@ihit.waw.pl.

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  • Elżbieta Lachert,

    1. Department of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
    2. Department of Diagnostics for Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
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  • Jolanta Woźniak,

    1. Department of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
    2. Department of Diagnostics for Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
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  • Karolina Janik,

    1. Department of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
    2. Department of Diagnostics for Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
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  • Magdalena Łętowska

    1. Department of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
    2. Department of Diagnostics for Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
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  • Supported by the Institute of Hematology and Transfusion Medicine.

Abstract

Background

Cord blood (CB) is a valuable source of hematopoietic stem cells (HSCs). Extended storage of CB is possible provided that validated cryopreservation procedures are used. The study objective was to determine optimal methods of CB cryopreservation.

Study Design and Methods

In the study we 1) compared the effect of two-step cryopreservation and controlled-rate freezing method on the postthaw quality of CB (Study A) and 2) evaluated the postthaw quality of HSC fractions isolated from CB with various methods and frozen with controlled-rate freezing method (Study B). The same cryoprotectant mixture was used for 20 CB units (Study A) and 122 CB units (Study B).

Results

In Study A, 13.79 × 108 and 13.29 × 108 initial white blood cell (WBC) counts decreased to 6.38 × 108 and 6.02 × 108 after thaw for the two methods, respectively. The mononuclear cell (MNC) counts decreased from 5.90 × 108 to 3.71 × 108 and from 5.64 × 108 to 3.47 × 108 dependent on the method. MNC viability decreased from 99.0% to 97.4% for the former and from 98.5% to 97.2% for the latter method. The differences were insignificant. In Study B, postthaw WBC recovery in HSC fractions was 74.4% to 103.5%, MNC recovery 106.4% to 118.5%, CD34+ cell recovery 102.5% to 150.2%, and MNC viability 94.1% to 97.4%.

Conclusion

Neither the cryopreservation procedure nor the freezing of isolated HSCs affected product quality, which may indicate that various freezing methods can be used for cell banking provided the they follow recommendations of good manufacturing practice and Directive 2004/33/EC.

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