Abstract
The appearance of atypical lymphocytes in post-transfusion blood, their incorporation of tritiated thymidine in tissue culture and the elimination of cytotoxic antibody production, have been used as markers to show that frozen red cells are the least immunogenic when compared with dextran sedimented blood and whole blood donations. The absence of atypical lymphocytes and failure to produce lymphocytotoxic antibodies after transfusion of frozen cells is highly significant (P is less than 0.001) when compared with whole blood donations.