The clinical study on secretory leukoprotease inhibitor (SLPI) in sera of patients with various pulmonary diseases

: It has been reported that secretory leukoprotease inhibitor (SLPI) can be a useful indicator for acute respiratory tract inflammation. In the present study, we attempted to measure automatically the serum concentration of SLPI by enzyme immunoassay (EIA) in patients with various pulmonary diseases. In this automatic measurement of SLPI, by which the results basically well-correlate with the manual method, we could measure many samples easily. Serum levels of SLPI in patients with various pulmonary diseases were significantly higher than those in healthy controls (50.5 +/- 9.8ng/ml). The serum concentration of SLPI in patients with inflammatory lung diseases correlated with that of C-reactive protein (CRP) or interleukin 6 (IL-6) significantly but not strongly. These results suggest that SLPI may be a useful indicator for local inflammation in respiratory tract. The serum concentration of SLPI in patients with lung cancer (71.1 +/- 10.8ng/ml), in particular adenocarcinoma, was significantly higher than that in healthy controls, but not correlated with other inflammatory markers.