Glucocorticoid pulse therapy enhances peripheral blood monocyte Hb:Hp-uptake capacity in vivo. Fluorescent Hb:Hp₆₃₃-uptake capacity of peripheral blood leukocytes was measured ex vivo in routine blood samples from patients without glucocorticoid treatment (control) and from patients after glucocorticoid pulse therapy (GC). (A) A distinct cell population (red frame) with Hb:Hp₆₃₃-uptake capacity can be identified in the plot shown in the left panel. The CD14^high/CD163^high phenotype (red) of these cells (right) identifies the cell population as monocytes expressing the Hb scavenger receptor. Black indicates granulocytes, and gray indicates lymphocytes. (B) The mean FL4 (Hb:Hp₆₃₃) fluorescence of each cell population was extracted in the patient samples as shown in A. The CD14^high/CD163^high monocytes from individuals treated with a glucocorticoid pulse (n = 14) showed a significantly (P < .001) increased Hb:Hp-uptake capacity compared with nontreated individuals (n = 11).