Effect of flow rate on adherence of unlabeled and indium-111 oxine-labeled leukocytes

Uptake of radioactively labeled leukocytes has been observed in ischemic noninfected regions. Since this may be a flow-related phenomenon, the authors investigated the effect of flow rate on adherence of indium-111 oxine-labeled leukocytes with a model based on the elution patterns of radioactivity and granulocytes from nylon fiber columns. Relative radioactivity adherence (%RA) and relative granulocyte adherence (%GA) agreed closely, indicating that radioactivity retained by the columns is predominantly in the form of viable labeled granulocytes, and that labeled and unlabeled granulocytes have the same adherence characteristics. When other conditions were held constant, but passage speed was varied, %GA and %RA were related to the flow rate in an inverse linear fashion. Decrease in flow rate can lead to increased accumulation of leukocytes.