Analysis of the GM-CSF and GM-CSF/IL-3/IL-5 receptor common beta chain in a patient with pulmonary alveolar proteinosis.
OBJECTIVE
To investigate the expression of the granulocyte-macrophage colony-stimulating factor (GM-CSF) and GM-CSF/IL-3/IL-5 receptor common beta chain (beta c receptor) in an adult patient with idiopathic pulmonary alveolar proteinosis (PAP), so as to demonstrate the possible association of the GM-CSF and beta c receptor with the pathogenesis of human PAP.


METHODS
The GM-CSF levels were measured with a commercial ELISA kit (sensitivity 5 pg/ml) and the beta c receptor expression on the cell surface was detected by flow cytometry analysis. Reverse transcription polymerase chain reaction (RT-PCR) analysis was employed to detect the expression of the GM-CSF mRNA and the beta c receptor mRNA in peripheral blood mononuclear cells and alveolar macrophages. The entire coding regions of the GM-CSF cDNA and the beta c receptor cDNA were sequenced by the Sanger dideoxy-mediated chain termination method to detect possible mutations.


RESULTS
The patient with PAP failed to release the GM-CSF protein either from circulating mononuclear cells or from alveolar macrophages. The expression of the GM-CSF mRNA was normal after the stimulation of lipopolysaccharide, whereas a point mutation at position 382 of the GM-CSF cDNA from "T" to "C" was revealed by cDNA sequencing, which caused a change in amino acid 117 of the protein from isoleucine to threonine. The beta c receptor expression on the cell surface was normal, and the beta c receptor mRNA expression and the sequence of the entire coding region of the beta c receptor were also normal.


CONCLUSIONS
The decreased GM-CSF production is associated with the pathogenesis of human PAP. A point mutation of the GM-CSF cDNA may contribute to the decreased GM-CSF production in our adult PAP patient. The mutation of the beta c receptor in some of paediatric patients with PAP may not be a common problem in adult patients.
Wang
Xuanding
X
Department of Pulmonology, Second Affiliated Hospital of Medical School, Zhejiang University, Hangzhou 310009, China. xudwang@mail.hz.zj.cn
Liu
Fuguang
F
Bewig
Burkhard
B
D018076:DNA, Complementary / Q000737:chemistry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000032:analysis / Q000096:biosynthesis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011649:Pulmonary Alveolar Proteinosis / Q000209:etiology / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D018121:Receptors, Cytokine / Q000096:biosynthesis* / Q000235:genetics
D018076:DNA, Complementary; D012333:RNA, Messenger; D018121:Receptors, Cytokine; C114668:beta C receptor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor