Human neutrophil elastase in temporal (giant cell) arteritis: plasma and immunohistochemical studies.

Abstract

Few enzymes are able to attack the internal elastic lamina, which is destroyed in temporal arteritis (TA). Because human neutrophil elastase (HNE) is one of these, its role in the pathogenesis of TA was examined in patients undergoing temporal artery biopsy for suspected TA. Over a 6 month period, 33 patients undergoing temporal artery biopsy were prospectively included in the study. TA was diagnosed in 15 patients; 9 of them had positive temporal artery biopsy. The other 18 patients made up the non-TA group. Nineteen healthy age matched subjects (mean age 74 +/- 9 yrs) served as controls. Levels of plasma HNE bound to alpha1-antitrypsin (pHNE-alpha1AT) were measured by ELISA. The presence of HNE in the temporal artery wall of 7 TA and 7 non-TA patients was evaluated immunohistochemically. Age, neutrophil counts, and erythrocyte sedimentation rates were similar in TA and non-TA patients. The mean pHNE-alpha1AT concentration in the TA group (84 +/- 20 microg/l) was significantly higher (p < 0.001) than in the non-TA group (51 +/- 26 microg/l) or in healthy controls (52 +/- 23 microg/l). The diagnostic sensitivity of pHNE-alpha1AT > 50 microg/l was 100%. Immunohistochemistry detected no HNE within the temporal artery wall of any patient. High levels of pHNE-alpha1AT were associated with TA. Our preliminary results indicate this could be a diagnostic marker for TA. Further studies are needed to confirm its reliability. Because HNE was not detected locally, no conclusions can be drawn as to its pathogenic role in TA.