Increased levels of plasma galectin-9 in patients with influenza virus infection.
Galectin-9 (Gal-9) is a β-galactoside-binding protein involved in various biologic processes, including cell aggregation, adhesion, chemoattraction, and apoptosis. Little is known, however, about the regulation mechanisms of Gal-9 production. Recent studies reported high plasma Gal-9 levels in humans infected with human immunodeficiency virus-1 and dengue virus. Viral respiratory infections such as influenza are common human illnesses. A synthetic double-stranded RNA, polyinosinic-polycytidylic acid (PolyIC), mimics the effects of viruses in various cell types and induces the expression of Gal-9 in endothelial cells. To examine the potential link between viral infection and Gal-9 expression, we measured plasma Gal-9 concentrations in patients with influenza. Subjects were 43 patients with influenza virus infection, 20 with pneumococcal pneumonia, and 20 healthy adults. Gal-9 concentrations in the plasma and in culture supernatants of human airway epithelial cells were measured using an enzyme-linked immunosorbent assay. Plasma Gal-9 concentrations were higher in patients with influenza infection than in patients with pneumococcal pneumonia and healthy subjects (p < 0.05). Patients with influenza were effectively differentiated from those with pneumococcal pneumonia or healthy subjects, based on the plasma levels of Gal-9 (p < 0.0001). Furthermore, using a human airway epithelial cell line, we showed that the presence of PolyIC but not lipopolysaccharides increased the Gal-9 concentration in the culture medium (p < 0.05), suggesting that PolyIC enhanced Gal-9 production. These findings support our proposal that Gal-9 production is induced by influenza virus infection in humans. In conclusion, plasma Gal-9 could be a new biomarker for patients with influenza infection.
Department of Respiratory Medicine, Kawasaki Medical School.
Shigeki
S
Katoh
Masaki
M
Ikeda
Hiroki
H
Shimizu
Keiji
K
Mouri
Yasushi
Y
Obase
Yoshihiro
Y
Kobashi
Kiyoyasu
K
Fukushima
Mistuomi
M
Hirashima
Mikio
M
Oka
D015415:Biomarkers / Q000097:blood*; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D037161:Galectins / Q000097:blood* / Q000378:metabolism; D006801:Humans; D007251:Influenza, Human / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011018:Pneumonia, Pneumococcal / Q000097:blood; D011070:Poly I-C / Q000378:metabolism; D018709:Statistics, Nonparametric
D015415:Biomarkers; D037161:Galectins; C105032:LGALS9 protein, human; D011070:Poly I-C