Effects of leukoreduction on N-methylhistamine concentration in stored units of canine whole blood

OBJECTIVE To determine the effects of leukoreduction on N-methylhistamine ( NMH; a stable histamine metabolite) concentration in units of canine whole blood during storage and incubation at room temperature ( approx 22 degrees C) to simulate temperature conditions during transfusion. ANIMALS 8 healthy adult Walker Hounds. PROCEDURES A standard unit of blood (450 mL) was obtained from each dog twice, with at least 28 days between donations. Blood units collected from 4 dogs during the first donation underwent leukoreduction, whereas the blood units collected from the other 4 dogs did not undergo leukoreduction, prior to storage at 4 degrees C. The alternate treatment was applied to blood units collected during the second donation. A sample from each unit was obtained for determination of plasma NMH concentration the day of donation (before and after leukoreduction when applicable) and before and after incubation at room temperature for 5 hours on days 14 and 28 of storage. RESULTS Units that underwent leukoreduction had substantially lower leukocyte and platelet counts than nonleukoreduced units. Plasma NMH concentration increased immediately after leukoreduction but did not change significantly during the subsequent 28 days of storage, nor did it differ between units that did and did not undergo leukoreduction. CONCLUSIONS AND CLINICAL RELEVANCE Leukoreduction and simulated transfusion temperature did not affect the histamine load in units of canine whole blood during the first 28 days of storage. Further research is necessary to determine whether histamine contributes to the development and severity of blood transfusion reactions in dogs.