Gene expression of interleukin-3 and granulocyte macrophage colony-stimulating factor in circulating CD4+ T cells in acute severe asthma.
BACKGROUND
Interleukin (IL)-3 and granulocyte macrophage colony-stimulating factor (GM-CSF) may influence the inflammatory process in asthma through their regulatory role on eosinophil survival, differentiation and effector function.


OBJECTIVE
To examine the relationships between IL-3 and GM-CSF messenger (m) ribonucleic acid (RNA) expression in peripheral blood CD4+ cells and serum levels of eosinophil cationic protein (ECP), a marker of eosinophil activation, and disease activity in asthma.


METHODS
Venous blood was drawn from patients with acute severe asthma prior to the commencement of systemic steroid therapy (day 1) and 7 days afterwards (day 7), patients with stable disease and normal healthy volunteers. The capacity for expression of IL-3 and GM-CSF in ex vivo stimulated circulating CD4+ cells was assessed semi-quantitatively by reverse transcription-polymerase chain reaction (RT-PCR).


RESULTS
We found that the capacity for expression of IL-3 and GM-CSF was significantly higher in acute asthmatics prior to steroid treatment (n = 24) than those in stable disease (n = 38) and healthy subjects (n = 32, P < 0.001 for IL-3 and < 0.05 for GM-CSF), but no difference was observed between the latter two groups. Further assessment made in 15 of the 24 acute asthmatics 7 days after systemic steroid treatment revealed a significant reduction in GM-CSF expression (P < 0.05) but not for IL-3. At the same time, PEF also improved significantly from 30.4 +/- 3.5% of predicted value to 72.9 +/- 7.2% (P < 0.0001) and serum ECP concentration also fell from 19.9 +/- 5.9 micrograms/L to 4.3 +/- 2.0 micrograms/L (n = 10, P < 0.01).


CONCLUSIONS
Our data suggest both IL-3 and GM-CSF may be important in the pathogenesis of acute severe asthma.
Lai
C K
CK
Department of Medicine, Chinese University of Hong Kong.
Ho
S S
SS
Chan
C H
CH
Leung
R
R
Lai
K N
KN
D000208:Acute Disease; D000328:Adult; D001249:Asthma / Q000097:blood* / Q000503:physiopathology; D001798:Blood Proteins / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D047091:Eosinophil Granule Proteins; D005260:Female; D015870:Gene Expression; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000097:blood* / Q000235:genetics; D006801:Humans; D007377:Interleukin-3 / Q000097:blood* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012260:Ribonucleases
D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D007377:Interleukin-3; D012333:RNA, Messenger; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D012260:Ribonucleases