Viable lymphocytes in frozen washed blood

Samples of glycerolized, frozen, packed cells, were washed by each of three systems and then were cultrued for viable lymphocytes using the short-term culture method. Of the 39 samples, 17 (43.6%) showed definite evidence of growth of lymphocytes. Of the 17, 11(64.7%) were washed by Elutramatic, two (11.8%) by Haemonetics, and four (23.5%) by IBM. The 4 C prefreeze (two to five days) as well as the -80 C (21 To 40 days) storage times were the same for both positive and negative specimens. In all samples, clumps of distorted granulocytes with pyknotic nuclei were seen in addition to a number of well-preserved mononucleated white cells. In the 17 specimens which showed growth, incorporation of 3H-thymidine was seen only in the PHA-induced blast cells; typical mitotic figures were seen in some cultures. These observations demonstrate that lymphocytes remain viable in frozen blood stored at -80 C up to 40 days. The significant difference in removal of viable lymphocytes noted in specimens washed by different instruments requires further evaluation.