Abstract
The effect of methotrexate on the phagocytosis and killing of Staphylococcus aureus by granulocytes from healthy blood donors was investigated in vitro. A concentration of methotrexate of 2.2 × 10—4 mol/l (100 μg/ml), which is readily obtained on high dose intravenous administration did not decrease the phagocytosis and intracellular killing of Staph. aureus. In addition, granulocytes isolated from patients after termination of 6 h and 24 h high-dose methotrexate infusions showed normal phagocytic activity.