Increased levels of interleukin-18 in patients with pulmonary sarcoidosis.
Interleukin-18 (IL-18) has recently been identified as an interferon-gamma (IFN-gamma)-inducing factor, and it plays an important role in T helper 1 (Th1) response. We measured the serum levels of IL-18 and IFN- gamma in 37 patients with pulmonary sarcoidosis and 25 healthy control subjects. We also measured the levels of IL-18 and IFN-gamma in 10-fold concentrated bronchoalveolar lavage (BAL) fluids of 19 patients with pulmonary sarcoidosis and 9 healthy control subjects (all lifelong nonsmokers). The levels of serum IL-18 and IFN-gamma were significantly increased in patients with sarcoidosis. The levels of BAL fluid IL-18 were significantly elevated in patients with sarcoidosis, however, the IFN-gamma levels of the patients and control subjects were all below sensitivity. Serum IL-18 levels significantly correlated with serum IFN-gamma levels and lysozyme activity. The patients positive for gallium-67 ((67)Ga) scan had significantly elevated serum IL-18 levels as compared with those of the negative patients. BAL fluid IL-18 levels significantly correlated with serum IL-18 levels in patients with sarcoidosis, and there was a significant correlation between IL-18 levels and lymphocyte proportions in sarcoid BAL fluids. In patients with sarcoidosis, IL-18 seems to induce IFN-gamma production and IL-18 levels in sera may reflect disease activity of sarcoidosis.
Shigehara
K
K
Third Department of Internal Medicine and First Department of Pathology, Sapporo Medical University School of Medicine, Hokkaido Branch of the Japan Anti-tuberculosis Association, Sapporo, Japan.
Shijubo
N
N
Ohmichi
M
M
Yamada
G
G
Takahashi
R
R
Okamura
H
H
Kurimoto
M
M
Hiraga
Y
Y
Tatsuno
T
T
Abe
S
S
Sato
N
N
D000328:Adult; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis / Q000097:blood; D020382:Interleukin-18 / Q000032:analysis* / Q000097:blood; D008297:Male; D008875:Middle Aged; D017565:Sarcoidosis, Pulmonary / Q000378:metabolism*
D020382:Interleukin-18; D007371:Interferon-gamma