The use of nystatin to restore the flow properties of time-expired stored erythrocytes.

Human erythrocytes stored for more than 21 days in citrate phosphate dextrose with adenine (CPDA-1) exhibited a marked reduction in volume following incubation for 24 h at 37 degrees C in fresh autologous plasma. This incubation apparently mimics the effects of reinfusion of the stored cells in vivo. These shrunken stored cells have a decreased filterability as measured by their increased transit times through a 5-microns diameter Nuclepore filter. The polyene antifungal agent nystatin was used to reinflate these shrunken cells with different concentrations of potassium ions. A concentration of 90 mM potassium chloride was found to reinflate the shrunken stored cells so that their mean cell volume, mean corpuscular haemoglobin concentration and average densities were the same as those of fresh cells. This reinflation also restored the filterability of the shrunken stored cells so as to be similar to that of fresh cells.