ThehumanorganismreactswithaninflammatoryresponsetoattacksofinvADIngpathogens(microorganismsandviruses)ordamagedtissue(afteraccidentsorsurgery).Polymorphonuclear(PMN)granulocytesplayanimportantroleasprimarydefencecellsinthisinflammatoryreaction.Differentbloodstreammediators(cytokines,leukotrienes,complementfactors,bacterialendotoxins,clottingandfibrinolysisfactors)attractandstimulatethesecellstophagocytizeanddestroynotnaturallyoccurringagents.
PMNgranulocytesuseproteinasestodigesttheseagentsandtissuedebris.OneoftheseproteinasesisPMNelastasewhichislocalisedintheazurophilicgranulesofthepolymorphonucleargranulocytes.Duringphagocytosisofforeignsubstancestheseenzymesarealsopartiallyexcretedintotheextracellularsurrounding,wheretheactivityofPMNelastaseisregulatedbyinhibitors(esp.thealpha1-proteinaseinhibitor,alpha1-PI).AnoverwhelmingreleaseofPMNelastase,however,canexceedtheinhibitorypotentialofthea1-proteinaseinhibitor.Thus,enzymaticallyactivePMNelastase,togetherwithsimultaneouslyproducedoxidants(O2-radicals,H2O2,OH-radicals),cancauselocaltissueinjury.Duetothebloodstreamandlymphaticsystem,however,alpha1-PIisdeliveredsubsequentlyandeventuallyabletoformacomplexwithallexcretedelastase.Therefore,theconcentrationofthePMNelastase/alpha1-PIcomplexcorrelateswiththereleasedPMNelastaseandcanbeusedasameasurefortheactivityofgranulocytesduringaninflammatoryresponse.Primarily,determinationsofPMNelastasefinditsapplicationinobservationofthecourseoftrauma,shockandsepsis.Furtherindicationsaretheareasofhemodialysis,infectionsbyobstetrics,jointdiseases,effusionsofsportinjuries,intestinalaffection,pancreatitis,cysticfibrosisandmaleadnexaffections.

Synonyms:Elastase-2,leukocyteelastase,neutrophilelastase