Relation between clinical stage of sarcoidosis and serum values of angiotensin converting enzyme and beta2-microglobulin.

We measured angiotensin converting enzyme (ACE) and beta2-microglobulin (beta 2M) in the serum of 107 patients with sarcoidosis in different clinical stages and in healthy subjects. In patients with acute sarcoidosis and erythema nodosum (EN) we found increased beta 2M values but low ACE activity. Patients with newly-detected sarcoidosis but without EN had increased ACE activity; however, their beta 2M-levels were normal or only slightly elevated. Patients with chronic active sarcoidosis had high ACE activity; however, their beta 2M-levels were normal in a stable phase, but significantly increased during clinical relapses. Patients with resolved sarcoidosis had normal ACE and beta 2M values. The results indicate that serum beta 2M concentrations are increased in connection with new granuloma formation-i.e. lymphocytic activation-whereas the serum ACE activity increases later on when active granulomas have been formed. In sarcoidosis, simultaneous determinations of serum ACE and beta 2M may be useful for describing the stage of the disease. The correlation between ACE and beta 2M will also be different, depending on the composition of the clinical series of sarcoidosis patients.