Enhanced expression of interleukin-18 and its receptor in idiopathic pulmonary fibrosis.
Idiopathic pulmonary fibrosis (IPF)/usual interstitial pneumonia (UIP) is a major interstitial lung disease (ILD). Recently, we established a new mouse model for ILD in which daily administration of interleukin (IL)-18 with IL-2 induces lethal lung injury, suggesting that IL-18 is involved in the pathogenesis of ILD. Here, utilizing immunohistochemistry, we have analyzed IL-18 and IL-18 receptor (IL-18R) alpha expression in the lungs of 18 patients with IPF/UIP and 13 control subjects by using monoclonal anti-IL-18 antibodies and a new monoclonal antibody for IL-18Ralpha (H44). IL-18 was expressed in bronchoalveolar epithelium, alveolar macrophages, and the endothelium of small vessels in control subjects, and was abundantly expressed in the majority of pulmonary cells in patients with IPF. IL-18Ralpha was expressed in bronchoalveolar epithelium and alveolar macrophages in control subjects, and was strongly expressed in interstitial cells in patients with IPF, especially in the fibroblastic foci (FF). Interestingly, IL-18Ralpha expression was only weakly observed in areas showing established fibrosis. Semiquantitative analysis revealed that the histologic FF score was significantly correlated with the IL-18Ralpha expression level in FF lesions. Moreover, IL-18 levels in the serum and bronchoalveolar lavage fluid of patients with IPF were significantly higher than those in control subjects. Our findings suggest IL-18 and IL-18R are involved in the pathogenesis of IPF/UIP.
Department of Internal Medicine 1, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan.
Yasuhiko
Y
Kitasato
Tomoaki
T
Hoshino
Masaki
M
Okamoto
Seiya
S
Kato
Yoshiro
Y
Koda
Nobuhiko
N
Nagata
Masaharu
M
Kinoshita
Hideyuki
H
Koga
Do-Young
DY
Yoon
Hironobu
H
Asao
Hiroshi
H
Ohmoto
Takeharu
T
Koga
Toru
T
Rikimaru
Hisamichi
H
Aizawa
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000276:immunology; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D016207:Cytokines / Q000032:analysis / Q000097:blood; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D020382:Interleukin-18 / Q000097:blood / Q000378:metabolism*; D053727:Interleukin-18 Receptor alpha Subunit; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011658:Pulmonary Fibrosis / Q000378:metabolism* / Q000473:pathology; D018123:Receptors, Interleukin / Q000276:immunology / Q000378:metabolism*; D053724:Receptors, Interleukin-18
D000911:Antibodies, Monoclonal; D016207:Cytokines; C508572:IL18R1 protein, human; C508573:Il18r1 protein, mouse; D020382:Interleukin-18; D053727:Interleukin-18 Receptor alpha Subunit; D018123:Receptors, Interleukin; D053724:Receptors, Interleukin-18