638 NEUTROPHIL CHEMOTAXIS, PHAGOCYTOSIS, AND BACTERICIDE ACTIVITY IN NORMAL VOLUNTEERS RECEIVING PREDNISONE

Abstract

To evaluate the in vivo effect of prednisone on neutrophil (PMN) functions, prednisone (40 mg./day) was given orally for 3 days to 8 normal volunteers. PMN chemotaxis toward activated serum and PMN random migration were measured in modified Boyden chambers. NBT reduction after stimulation by phorbol myristate acetate was measured by use of flow-cytophotometry. Phagocytosis and bactericidal activity of Staphylococcus aureus were determined by the method of Tan et al. Twenty-four hours and 72 hours after the first prednisone dose the average absolute number of PMNs increased by 64% and 41% respectively from the initial 3.31 ± 1.0 × 109/1 (mean ± 1 SD). Chemotaxis was significantly decreased after 24 hours (P < 0.005) while the 72-hour chemotaxis returned to normal values in 2 subjects and remained low in the remaining 4. The increased random migration of PMNs which was found in 2 volunteers was also suppressed during the study period. Although phagocytosis of Staphylococcus aureus remained unaffected, bactericidal activity 72 hours after the first prednisone dose was significantly diminished as compared to initial values or to the values of untreated paired controls (P < 0.02). This decrease in bactericidal activity was observed following 30 minutes but not 120 minutes of PMN-bacteria interaction. NBT reduction by PMNs was not impaired. Short-term treatment with prednisone interferes with PMN chemotaxis and bactericidal activity and may therefore compromise host-defense mechanisms.