Granulocyte colony-stimulating factor protects control rats but not ethanol-fed rats from fatal pneumococcal pneumonia.

A model of chronic ethanol ingestion was used to study the effects of granulocyte colony-stimulating factor (G-CSF) on the pathogenesis of pneumococcal pneumonia in intoxicated rats. G-CSF or 5% dextrose in water (D5W) was administered subcutaneously to ethanol-fed and pair-fed control rats on days 6 and 7 of pair feeding. Rats were infected transtracheally with type 3 Streptococcus pneumoniae on day 8. In pair-fed control rats, G-CSF significantly increased the total number and percentage of polymorphonuclear leukocytes (PMNL) in the peripheral blood (P < .001), augmented PMNL recruitment to infected lungs (P < .01), and significantly increased survival from pneumococcal pneumonia (P = .01). In contrast, treatment of ethanol-fed rats with G-CSF did not enhance pulmonary PMNL delivery and did not increase survival following experimental pneumococcal pneumonia, despite a significant increase in the total number and percentage of circulating PMNL (P < .001). These data suggest that despite increasing the numbers of circulating PMNL, G-CSF is unable to provide protection against fatal pneumococcal pneumonia in ethanol-fed rats.