Objective: To study the effect of inhaled glucocorticoids on white blood cell count (WBC) and elucidate the mechanisms involved.
Background: WBC is commonly used as an aid in diagnosis of infectious diseases. It is well established that systemic glucocorticoids increase the number of circulating leukocytes and neutrophils. However, although inhaled glucocorticoids are commonly used, their effect on WBC has not been clarified.
Methods: The comparative prospective study included 60 healthy adults. We compared the effects of budesonide (given by aerosol or inhalation), fluticasone (aerosol) and saline inhalation (control) on WBC and absolute neutrophil counts (ANC). Blood samples were taken at time zero and at six hours. Neutrophil MAC-1(CD11b) expression, L-selectin (CD62L) expression and G-CSF serum levels were measured to elucidate the mechanisms involved.
Results: Following a single dose inhalation of budesonide, 23.4% increase (95% CI 11.3-35.4) in mean WBC and 30.1% increase (95% CI 7.2-53.0) in mean ANC were observed at 6 hours. Inhaled fluticasone increased WBC and ANC by 12.6% (95% CI 1.5-23.7) and 22.7% (95% CI 6.2-39.2), respectively (p<0.01 for both).
A significant decrease in Neutrophil MAC-1 was detected 6 hours after inhalation in the budesonide and fluticasone groups with 30.9% (p<0.01) and 39.8% decrease, respectively, (p=0.01) and for L-selectin expression in the budesonide group (30.9%, p=0.02), with no significant changes in G-CSF levels.
Conclusions: Glucocorticoid inhalation increases significantly ANC. It appears that the primary mechanism is a decrease inthe adhesion molecules expression on neutrophils` membrane. Physicians should be aware of these changes which might affect clinical decisions.
