Protease Inhibitors in Middle Ear Effusions

Abstract

As the presence of granulocytes in middle ear fluid in serous otitis media implicates a potential risk of extracellular release of granulocyte proteases, the main protease inhibitors in serum, α₁-antitrypsin, α₁-antichymotrypsin and α₂-macroglobulin, were immunochemically quantitated in such effusions. The mean concentration of α₁-antitrypsin was found to be higher in middle ear effusion and the mean concentration of α₁-antichymotrypsin slightly lower than in plasma. On comparison with albumin, however, lower values than expected were found in the middle ear fluid for the two inhibitors. The high molecular weight α₂-macroglobulin was significantly lower than in plasma. Furthermore a low molecular weight protease inhibitor, which is thought to be locally produced in the respiratory epithelium, was demonstrated in the effusion.