OBJECTIVE: To investigate the expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) protein and mRNA in four patients with pulmonary alveolar proteinosis (PAP).METHODS: GM-CSF levels were measured with a commercial ELISA kit. RT-PCR was employed to detect the expression of the GM-CSF mRNA in peripheral blood mononuclear cells (PBMC) and alveolar macrophages. To discover the possible mutations, the entire coding region of the GM-CSF cDNA was sequenced by the Sanger dideoxy-mediated chain termination method.RESULTS: All patients, except for the one with secondary PAP showed no release of GM-CSF either from PBMC or from alveolar macrophages. The expression of the GM-CSF mRNA was normal in all patients, whereas a point mutation at position 382 of the GM-CSF cDNA from "T" to "C" was revealed by cDNA sequencing in one idiopathic PAP patient, which caused a change from isoleucine to threonine in amino acid 117 of the protein.CONCLUSIONS: Decreased GM-CSF production is associated with the pathogenesis of idiopathic PAP. A point mutation of the GM-CSF cDNA may partly contribute to the decreased GM-CSF production.
Adult Enzyme-Linked Immunosorbent Assay