Determination of lysozyme activity by fluorescence polarization in rheumatoid synovial fluids and release of lysozyme from polymorphonuclear leukocytes by chemotactic factors.

A new method for the measurement of lysozyme activity, which is rapid, quantitative and sensitive, was established and applied to clinical material obtained from arthritis patients. The method is based on fluorescence polarization with the use of fluorescein isothiocyanate-labeled peptidoglycan. Using this method, we found that the synovial fluids obtained from rheumatoid arthritis contained more lysozyme activity than similar samples from osteoarthritis patients (P less than 0.001). Furthermore, we found that chemotactic factors and lysozyme-depleted rheumatoid synovial fluids could induce the release of lysozyme from human polymorphonuclear leukocytes in vitro. It is therefore suggested that lysozyme present in rheumatoid synovial fluids may derive in part from polymorphonuclear leukocytes and the action of chemotactic factor(s) within the fluids.