Significance of anticardiolipin and anti-beta(2)-glycoprotein I antibodiesin lupus nephritis

Objective. To investigate whether anticardiolipin (aCL) and anti-beta(2)-gl ycoprotein I (anti-beta(2)GPI) antibodies are associated with lupus nephrit is (group 11 patients), and whether there are differences in the prevalence of these two autoantibodies between group II patients and patients with no n-nephritis SLE (group I) and primary antiphospholipid syndrome (PAPS) pati ents (group III). Methods. Ige and IgM aCL were measured in 31 patients and anti-beta(2)GPI i n 30 patients with systemic lupus erythematosus (SLE) nephritis and 25 with out SLE nephritis and in 36 PAPS patients by validated enzyme immunoassays. Relationships of anti-double-stranded DNA (anti-dsDNA) antibodies and anti bodies to the collagenous region of C1q (anti-C1q) with SLE nephritis were also examined. Results. The prevalence and levels were higher for aCL, but not for anti-be ta(2)CPI, antibodies in group II than in group I patients. Absolute values of aCL and anti-beta(2)GPI in all three patient groups correlated with each other. The prevalences of aCL, anti-dsDNA and anti-C1q antibodies were sig nificantly higher in group II than in group I and group III patients. Conclusion. The observations in this paper suggest that raised levels of aC L antibodies are associated with lupus nephritis. We were not able to demon strate an association between anti-beta(2)GPI antibodies and kidney disease either in patients with lupus or in patients with primary antiphospholipid syndrome. In SLE, we demonstrated that the presence of anticardiolipin ant ibodies in conjunction with elevated levels of anti-dsDNA and anti-C1q anti bodies is highly specific for glomerulonephritis in patients with lupus.