Objective: (1) To confirm a previous observation that serum phospholipase A2 (PLA2) activity correlates with disease activity in rheumatoid arthritis (RA); and (2) to determine whether serum PLA2 activity changes after treatment with methotrexate (MTX), auranofin (AF), or a combination of the 2 (COMBO).
Methods: Sera obtained at baseline and after treatment from 100 patients with RA (40 MTX, 32 AF, and 28 COMBO) who participated in a multicenter, double blind trial were tested for PLA2 activity using an assay that measures the release of radiolabeled 14C oleic acid from the cell membrane of Escherichia coli. Detailed statistical analysis was performed using previously collected clinical data to determine whether correlations exist between RA disease activity and serum PLA2 activity; whether baseline serum PLA2 activity predicted a therapeutic response in any treatment group; and whether there was a significant change in serum PLA2 activity after treatment in patients who responded to the various drugs.
Results: Baseline serum PLA2 activity was significantly increased in patients with RA compared to healthy controls. No correlation between serum PLA2 activity and RA disease activity was noted at baseline. Mean serum PLA2 activity did not change significantly after treatment with MTX, AF, or COMBO in either treatment responders or nonresponders.
Conclusion: Serum PLA2 activity is increased in patients with RA compared to healthy controls, but does not correlate with disease activity in patients, nor does it predict a response to treatment with MTX, AF, or COMBO. Serum PLA2 activity also did not change significantly after treatment with any of the above agents.