title: Cathepsin G and elastase in synovial fluid and peripheral blood in reactive and rheumatoid arthritis.
abstract: The purpose of the study was to evaluate the involvement of serine proteinases cathepsin G and elastase on pathomechanisms in synovial fluid (SF) of patients with reactive (ReA) and rheumatoid, (RA) arthritis. Cathepsin G, elastase, and their endogenous inhibitors alpha1-antichymotrypsin (alpha1-ACT) and alpha1-proteinase inhibitor (alpha1-PI) were identified immunohistochemically from SF and peripheral blood (PB) of patients with ReA and RA. Cathepsin G and elastase activities in SF and PB were measured spectrophotometrically. Dot-immunostaining was used to identify cathepsin G, elastase, but also alpha1-ACT and alpha1-PI from SF and PB. Cathepsin G and elastase-like activities (IU/I) were slightly elevated in ReA SF compared to the corresponding peripheral blood values (11.4 +/- 9.2 vs 4.8 +/- 1.7, NS, and 5.1 +/- 2.8 vs 2.3 +/- 2.2, NS), which was similar to what was seen in RA (16.4 +/- 6.2 vs 0.53 +/- 0.4, p < 0.05, and 6.51 +/- 1.8 vs 1.22 +/- 0.58, p < 0.05). Although some samples did not contain cathepsin G and/or elastase-like activities, all samples contained immunoreactive enzyme, but also alpha1-ACT and alpha1-PI. In ReA SF, in contrast to monocytes, all polymorphonuclear (PMN) cells contained cathepsin G and elastase. Cathepsin G and elastase activities correlated with each other (r = 0.78, p < 0.05) suggesting PMN / primary granules as their likely source. There was a closer association between the cathepsin G or elastase and SF leukocyte count in ReA than in RA. In ReA and RA SF elevated cathepsin G and elastase activities are detected compared to activity levels in PB suggesting local production mainly from PMNs. The co-existence of highly cellular SF and cathepsin G and elastase activity in the documented presence of endogenous inhibitors in ReA SF together with the, known, usually self-remitting clinical course of ReA, suggest a brisk and even exaggerated local PMN serine proteinase release; sparing of joints does not seem to be due to lack or inhibition of PMN responses but rather to a successful down-regulation or cessation of the responses initially elicited.
authors.affiliation: Department of Medicine, Helsinki University Central Hospital, Finland.
authors.forename: D
authors.initials: D
authors.lastname: Nordstrom
authors.forename: O
authors.initials: O
authors.lastname: Lindy
authors.forename: Y T
authors.initials: YT
authors.lastname: Konttinen
authors.forename: A
authors.initials: A
authors.lastname: Lauhio
authors.forename: T
authors.initials: T
authors.lastname: Sorsa
authors.forename: C
authors.initials: C
authors.lastname: Friman
authors.forename: T
authors.initials: T
authors.lastname: Pettersson
authors.forename: S
authors.initials: S
authors.lastname: Santavirta
mesh_terms: D000328:Adult; D000368:Aged; D016918:Arthritis, Reactive / Q000201:enzymology* / Q000503:physiopathology; D056649:Cathepsin G; D002403:Cathepsins / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D007150:Immunohistochemistry / Q000379:methods; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010196:Pancreatic Elastase / Q000097:blood / Q000378:metabolism*; D000091402:Prohibitins; D012697:Serine Endopeptidases / Q000097:blood / Q000378:metabolism*; D013582:Synovial Fluid / Q000378:metabolism
chemical_list: C000717331:PHB2 protein, human; D000091402:Prohibitins; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase