Serum lysozyme in sarcoidosis. Evaluation of its usefulness in determination of disease activity.

Serum lysozyme (LZM) determinations were done in 84 patients with clinically proven sarcoidosis. All patients were normocalaemic and had a normal renal function. An increased LZM activity was demonstrated in patients with pulmonary stage I and stage II disease, as well as in patients with extrapulmonary lesions. Treatment with corticosteroids rapidly normalized the LZM activity. A normal LZM activity was found in patients with cured sarcoidosis. The serum LZM activity seems to reflect the total mass of biologically active granulomas and is of great value in determining the activity of the disease. The dosage of corticosteroids can probably be administered according to the actual LZM level. Increasing LZM activity after stopping treatment may indicate progressive and uncured disease. Normal LZM activity in patients with even large pulmonary lesions seems to indicate inactive disease and unresponsiveness to treatment.