Study objectives: The Fas-Fas ligand (FasL) pathway is
a representative system of apoptosis-signaling receptor molecules. We
previously described that this pathway may play an important role in
the pathogenesis of fibrosing lung diseases. In this study, we
hypothesized that soluble form of Fas (sFas) and FasL (sFasL) may also
be associated with this disorder.
results: We measured sFas and sFasL levels in BAL fluid (BALF)
from patients with idiopathic pulmonary fibrosis (IPF), interstitial
pneumonia associated with collagen vascular diseases (CVD-IP), and
bronchiolitis obliterans organizing pneumonia (BOOP), using
enzyme-linked immunosorbent assay. BALF from all patients was obtained
before prednisolone therapy. sFasL levels were relatively increased in
IPF patients (p = 0.084), and significantly increased in CVD-IP
patients (p < 0.05) and BOOP patients (p < 0.05), compared with
control subjects. BALF sFasL levels were elevated in the IPF or CVD-IP
subgroups with an indication for prednisolone therapy, compared with
those without an indication for therapy. The BALF sFasL level in IPF
patients was correlated with the number of total cells and lymphocytes.
The BALF sFasL level in BOOP patients was relatively or significantly
correlated with the number of total cells or lymphocytes, respectively.
The BALF sFas level was significantly increased in BOOP patients, but
not in IPF or CVD-IP patients.
conclude that BALF sFasL levels may be associated with the accumulation
of inflammatory cells and reflect the degree of lymphocyte alveolitis
in IPF. The elevation of sFasL may be associated with the deterioration
of IPF and CVD-IP. The elevation of the BALF sFas level may abrogate
the cytotoxicity of FasL in BOOP patients, which may be associated with
better prognosis of BOOP, compared with IPF or