VALUE OF ANTICARDIOLIPIN ANTIBODIES FOR MONITORING DISEASE-ACTIVITY IN SYSTEMIC LUPUS-ERYTHEMATOSUS AND OTHER RHEUMATIC DISEASES

The prevalence of anticardiolipin antibodies in active systemic lupus erythematosus (SLE) was compared with that in inactive SLE and other r heumatic and non-rheumatic diseases to determine the value of these au toantibodies in monitoring rheumatic diseases, Pairs of IgG-and IgM-aC L were measured by ELISA in 173 consecutive hospitalised patients, inc luding 141 with rheumatic diseases (18 active SLE, 21 inactive SLE, 19 rheumatoid arthritis, 13 reactive arthritis, 7 other spondyloarthropa thies, 16 vasculitis, 47 other autoimmune diseases) and 32 non-rheumat ic controls. A further 101 aCL pairs were determined during follow-up in 19 patients with SLE. Serum concentrations were analysed with respe ct to SLE activity and compared between the different patient groups, IgG-and IgM-aCL levels in excess of 10 GPL and 9 MPL respectively were considered positive, 30.6% of all patients (53/173) were found to be positive for IgG-aCL, as against only 9.8% (17/173) for IgM-aCL. IgG-a CL serum levels in active SLE differed significantly from all other gr oups, including inactive SLE (all p < 0.005). Median IgM-aCL levels we re below the cut off point in all groups, although measurable values w ere obtained almost exclusively in active SLE and Ri, In this study Ig M-aCL measurement was of less value in monitoring rheumatic diseases, IgG-aCL positivity in SLE was associated with a significantly higher o dds ratio (OR) for active disease (OR 16.0, 95% confidence interval: 2 .8-90.0). The results show that disease activity in SLE was accompanie d by significantly increased IgG-aCL, whereas no elevation was found i n other diseases. This parameter may therefore be useful in monitoring SLE activity.