Effect of nonsteroidal antiinflammatory drugs on the neutrophil promoted inactivation of alpha-1-proteinase inhibitor

: We investigated the effect of some nonsteroidal antiinflammatory drugs (aspirin, naproxen and nimesulide) on the ability of neutrophils to oxidatively inactivate the alpha-1-proteinase inhibitor (A1PI). Nimesulide prevented the inactivation of A1PI by effectively scavenging the hypochlorous acid released by neutrophils. Aspirin and naproxen were completely ineffective. We suggest that the antiinflammatory effect of nimesulide may be due at least in part to the rescue of A1PI from neutrophil oxidative attack. The rescue of A1PI may in fact alter the elastase-A1PI balance in favor of the inhibitor, with resulting tissue protection.