The role of granulocyte macrophage colony stimulating factor in hospitalized children with Mycoplasma pneumoniae pneumonia.

Abstract

Inappropriate inflammatory response in children with M. pneumoniae infection might be associated with disease severity. The role of Granulocyte macrophage colony stimulating factor (GM-CSF) in hospitalized children with Mycoplasma pneumoniae pneumonia (MPP) has not been fully discussed. Clinical and laboratory data of a total 40 children with MPP were collected. GM-CSF and myeloperoxidase (MPO) were detected by ELISAs. Meanwhile, normal human bronchial epithelium was infected by M.pneumoniae and neutrophils were stimulated by GM-CSF to explore GM-CSF and MPO release in supernatant, respectively. Compared to control group, a significant increased percentage of neutrophils and decreased percentage of macrophages in bronchoalveolar lavage fluid of children with MPP was observed (P<0.05). Children with MPP had significantly higher levels of GM-CSF (P=0.0047) and MPO (P=0.0002) in BALF compared to the controls. Level of GM-CSF in BALF was associated with duration of fever (r=0.42, P=0.007) and strongly correlated with level of MPO (r=0.075, P=0.0005). Levels of GM-CSF and MPO significantly decreased (both P<0.05) after treatment. Invitro, M.pneumoniae induced GM-CSF expression in a time-dependent manner during a 72-h period (P<0.05) and MPO secretion significantly increased by recombinant human GM-CSF stimulation at 24h (P<0.05). GM-CSF could be induced by M.pneumoniae infection in vivo and vitro. Childen with high level GM-CSF had longer duration of fever. GM-CSF probably plays a vital role in neutrophil inflammation in M.pneumoniae infection.