Effects of granulocyte colony-stimulating factor in cirrhotic rats with pneumococcal pneumonia

A rat model was used to study the effects of granulocyte colony-stimulating factor (G-CSF) on the pathogenesis of pneumococcal pneumonia in cirrhosis. G-CSF or 5% dextrose in water was administered subcutaneously to cirrhotic and control rats before or after transtracheal infection with type 3 Streptococcus pneumoniae. In both groups, G-CSF significantly increased the total number and percentage of polymorphonuclear leukocytes (PMNL) in peripheral blood (P < .002) and bronchoalveolar lavage fluid (P < .01). An in vivo phagocytosis assay revealed no increase in uptake of pneumococci by PMNL within the lungs of cirrhotic or control rats receiving G-CSF. G-CSF administered before infection did not protect cirrhotic or control rats, but G-CSF treatment after infection significantly reduced mortality in control (P = .04) but not cirrhotic rats. These data suggest that despite increasing numbers of circulating and pulmonary PMNL, G-CSF does not protect against fatal pneumococcal pneumonia in cirrhotic rats.