Evaluation of soluble IL-6 receptor concentration in serum and epithelial lining fluid from patients with interstitial lung diseases.
We measured soluble IL-6 receptor (sIL-6R) levels in serum and bronchoalveolar lavage fluids (BALF) from patients with interstitial pneumonia of unknown etiology (IP) (n = 17), sarcoidosis (n = 8) and normal control subjects (n = 10), to investigate its role in pulmonary diseases. Soluble IL-6R was determined by an ELISA. The volume of epithelial lining fluid (ELF) in BALF was estimated using an urea method. We found that levels of sIL-6R in serum, BALF, and ELF from patients with IP or sarcoidosis were significantly higher than those from normal subjects. Furthermore, levels of sIL-6R in BALF or ELF were significantly correlated with those of albumin, indicating that sIL-6R, together with albumin, may enter ELF as a result of the increased permeability caused by pulmonary inflammation. Thus most of the sIL-6R in ELF would be from serum, and relatively small amounts of it might be produced locally. However, sIL-6R levels in ELF, but neither serum nor BALF, were significantly correlated with levels of C-reactive protein in patients with IP. These results suggest that both systemic and local production of sIL-6R are increased, and raised sIL-6R is involved in the modulation of systemic and local inflammatory responses in patients with IP and sarcoidosis.
Yokoyama
A
A
Second Department of Internal Medicine, Ehime University School of Medicine, Japan.
Kohno
N
N
Hirasawa
Y
Y
Kondo
K
K
Abe
M
M
Inoue
Y
Y
Fujioka
S
S
Fujino
S
S
Ishida
S
S
Hiwada
K
K
D000328:Adult; D001992:Bronchoalveolar Lavage Fluid; D004848:Epithelium / Q000378:metabolism; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D008171:Lung Diseases / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018123:Receptors, Interleukin / Q000737:chemistry / Q000378:metabolism*; D019947:Receptors, Interleukin-6; D012995:Solubility
D015850:Interleukin-6; D018123:Receptors, Interleukin; D019947:Receptors, Interleukin-6