Serum secretory leukoprotease inhibitor levels to diagnose pneumonia in the elderly.
In pneumonia in the elderly, one occasionally encounters difficulties in evaluation with respect to both clinical observation and treatment. Thus a simple serum indicator is indicated. We measured secretory leukoprotease inhibitor (SLPI) concentrations in sera to see whether this can provide a useful indicator for pneumonia, especially in the elderly. Serum samples from patients over 65 yr of age, with (n = 54) or without (n = 87) pneumonia, and from healthy, young (n = 16) and aged (n = 188) control subjects were assayed using ELISA for human SLPI. Comparisons were made between groups with clinical diagnoses of either definite or probable pneumonia and among cases with various other respiratory diseases, including bronchial asthma, chronic obstructive pulmonary disease, and lung cancer. The mean SLPI concentration in patients with pneumonia was significantly higher than in patients without pneumonia or in healthy controls. The data suggest that the measurement of SLPI can provide a useful indicator for pneumonia to be used in clinical evaluation.