Clinical correlation with the PA/plasmin system in septic arthritis of the knee.
Substantially more gelatinases appear in effusions of septic arthritis than in effusions of aseptic arthritis. We hypothesized there is greater plasminogen activator/plasmin activity in effusions of septic arthritis than aseptic arthritis. We examined the antigenic values of urokinase-type plasminogen activator and plasminogen activator inhibitor Type-1, cell counts, and levels of matrix metalloproteinase-2 and metalloproteinase-9 in 135 knee effusions from 80 patients with septic arthritis, rheumatoid arthritis, gouty arthritis, and osteoarthritis. Urokinase-type plasminogen activator and plasminogen activator inhibitor Type-1 antigenic values in effusions of septic arthritis were greater than those in effusions of aseptic arthritis. The increases of urokinase-type plasminogen activator and plasminogen activator inhibitor Type-1 antigenic values in effusions were associated with increased levels of prometalloproteinase-9 and the appearance of activated metalloproteinase-2. Antigenic values of urokinase-type plasminogen activator also correlated with the appearance of activated metalloproteinase-9. High plasminogen activator/plasmin activity, prometalloproteinase-9 levels, and the presence of activated metalloproteinase-2 and metalloproteinase-9 in effusions from replaced knees should increase suspicion of infection regardless of neutrophil counts. Joint aspiration reduces bacteria counts, endotoxins, proinflammatory cytokines, and matrix metalloproteinase. It also decreases the plasminogen activator/plasmin activity in effusions that may play a part in extracellular matrix destruction.


METHODS
Diagnostic study, Level III (study of nonconsecutive patients without consistently applied reference "gold" standard). See the Guidelines for Authors for a complete description of levels of evidence.
Hsieh
Yih-Shou
YS
Institute of Biochemistry, Chung Shan Medical University Hospital, Taichung, Taiwan.
Yang
Shun-Fa
SF
Lue
Ko-Huang
KH
Lu
Ko-Hsiu
KH
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001170:Arthritis, Infectious / Q000175:diagnosis*; D001172:Arthritis, Rheumatoid / Q000175:diagnosis*; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006403:Hematologic Tests; D006801:Humans; D007719:Knee Joint; D016014:Linear Models; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D008875:Middle Aged; D010960:Plasminogen Activators / Q000032:analysis / Q000378:metabolism*; D011379:Prognosis; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013582:Synovial Fluid / Q000737:chemistry; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis / Q000378:metabolism*
D015415:Biomarkers; D010960:Plasminogen Activators; D014568:Urokinase-Type Plasminogen Activator; D020778:Matrix Metalloproteinase 2