Comparison of budesonide and fluticasone propionate on COPD macrophage phagocytosis and killing of bacteria

Inhaled glucocorticosteroids (ICS) are associated with an increased rate of pneumonia in COPD. The mechanism underlying this is unknown. However, recent data suggest that this is more prevalent in patients treated with fluticasone propionate (FP) than budesonide (BUD). Macrophages and monocyte-derived macrophages (MDM) from COPD patients are deficient in clearing bacteria and this might explain increased bacterial colonisation in COPD. It is possible that ICS could further suppress this response, therefore we examined the effect of BUD and FP on MDM phagocytosis and killing of Haemophilus influenzae (HI) and Streptococcus pneumoniae (SP). MDM from COPD patients (n=3-12) were pre-incubated with BUD or FP for 30 min after which phagocytosis of fluorescently labelled inert beads, or heat killed HI or SP, after 1 and 4 h were measured fluorimetrically. For bacterial killing, MDM were pre-incubated with BUD or FP prior to culture with HI or SP for 4 h, antibiotics were added and cells lysed and plated on agar plates. After 12 h, colonies were counted. Neither BUD nor FP altered MDM phagocytosis of beads or SP at any time point (n=10-12). FP (10 -5 M) suppressed phagocytosis of HI by ∼20% (p -9 M-10 -7 M suppressed phagocytosis by ∼10% (p These data suggest that macrophages may respond differently to FP compared to BUD with respect to phagocytosis of bacteria and may explain why FP is more likely than BUD to be associated with pneumonia in COPD patients.