FIGURE 4.

Major findings in summary. (1) Having AIA in a knee joint was associated with increased A1M concentrations locally in synovial fluid (sf) and systemically in serum (s). With area under the ROC curve of close to 0.8, A1M was a biomarker for AIA in both synovial fluid and serum. (2) Independent of disease, cell-free Hb and heme within a knee joint triggered an increased synovial concentration of A1M that appeared to be protective of oxidative damage measured as sf-Carbonyl. The net amount of local oxidative damage (sf-Carbonyl) was dependent not only on the absolute concentrations of oxidative Hb and heme, or antioxidative A1M, but the ratio between pro- and antioxidative molecules appeared as important. (3) In knee injured there was a similar temporal pattern in the synovial concentrations of both oxidants (Hb and heme) and antioxidants (A1M), which were highest early after injury, without a corresponding temporal change in oxidative damage (sf-Carbonyl).