The effect of bilirubin on the phagocytic activity of mouse peripheral granulocytes and monocytes in vivo.

Using an in vitro phagocytic assay with synthetic 2-hydroxyethylmethacrylate copolymer particles, the phagocytic activity of leukocytes of bilirubin-treated mice (85 and 170 mumol/L in 0.5 mL intraperitoneally) was studied. Bilirubin treatment significantly stimulated the phagocytosis of both peripheral blood granulocytes and monocytes; the increase of phagocytosis persisted for 6 h after bilirubin injection. The potential immunostimulating and/or immunotoxic effect of bilirubin is discussed.