Effect of WBC reduction and storage temperature on PLTs frozen with 6 percent DMSO for as long as 3 years

Abstract

Background: PLTs frozen with 6 percent DMSO can be stored at -80 degrees C for 2 years, while those frozen with 5 percent DMSO at -150 degrees C can be stored for at least 3 years. The more rapid deterioration seen in PLTs frozen at -80 degrees C may be due to the presence of granulocytes. The effects of storage temperature and WBC reduction on PLTs frozen with DMSO and the breakage of the PVC plastic bags stored at -80 and -135 degrees C were assessed.

Study design and methods: Apheresed PLT-rich plasma (PRP) was either divided into two equal volumes where one volume was WBC-reduced and the other volume was not or filtered or not and then divided into two equal volumes. PLTs frozen with 6 percent DMSO were stored in PVC plastic bags at either -80 or -135 degrees C for as long as 3 years.

Results: After 2 years of storage at -80 degrees C, the PLTs exhibited satisfactory freeze-thaw-wash values regardless of whether or not they were WBC-reduced, but after 2 to 3 years of storage at -80 degrees C, the PLTs had significantly reduced freeze-thaw-wash values. Freeze-thaw-wash values were not reduced in PLTs stored at -135 degrees C for up to 3 years.

Conclusions: WBC reduction did not improve freeze-thaw-wash recovery values in PLTs stored at -80 or -135 degrees C for up to 3 years, but reducing the storage temperature from -80 to -135 degrees C did. Breakage of PVC plastic bags stored at -135 degrees C was excessive.