Serum lysozyme levels and clinical features of sarcoidosis

Serum lysozyme is used as a marker of sarcoidosis disease activity. In this study we examined the association between lysozyme levels and the clinical features of sarcoidosis and thus the clinical usability of this parameter in a large population. One hundred ten sarcoidosis patients from central Ja pan were examined for clinical features and serum lysozyme level at the fir st visit to our hospital and on a regular basis thereafter. The sensitivity of lysozyme for predicting sarcoidosis was 79.1%, whereas that of serum an giotensin-converting enzyme (ACE) was 59.0%. Even in the cases without an e levated serum ACE level, a value of 72.1% was obtained. The serum lysozyme level demonstrated a significant tendency to increase with the number of or gans involved (p < 0.01). There were significant differences among the four radiographic stages (p < 0.05). The maximum serum lysozyme levels of patie nts without a disappearance of abnormal shadows on chest radiography within 5 years were significantly greater than those of individuals with a disapp earance (p < 0.05). A positive correlation between serum lysozyme and serum ACE levels was observed. Because serum lysozyme is much less specific for sarcoidosis than serum ACE, its diagnostic value may be limited. However, t he sensitivity was high even when serum ACE levels were within normal limit s and correlated well with clinical features in sarcoidosis. Therefore, thi s parameter seems suitable for disease monitoring in proven cases.