Eosinophil Kinetics in Two Patients with Eosinophilia

Leukocyte kinetics were studied in two individuals with marked eosinophilia. Blood leukocytes, labeled in vitro with Na₂⁵¹CrO₄, disappeared from the circulation at different rates in the two subjects during the first eight hours after infusion. In one, label disappeared exponentially with a T/2 of 4.5-5.0 hours; in the other, the level of radioactivity remained constant. In both, however, a significant rise in radioactivity appeared during the second 24 hours, suggesting recirculation of the eosinophils. Blood leukocyte DNA-³²P labeling was similar in both subjects and closely resembled neutrophil DNA-³²P labeling observed in normal individuals. Hydrocortisone infusion produced an exponential decrease in circulating eosinophils in one subject and, for reasons unknown, a linear decrease in the other; the drug exhibited no effect on eosinophils in vitro.