Anticardiolipin Antibodies in Patients on Regular Hemodialysis: An Epiphenomenon?

Dr. med. Thomas Sitter, Medizinische Klinik, Klinikum Innenstadt der Universität München, Ziemssenstr. 1, D-80336 München (FRG) was calibrated against an international standard from the Rayne Institute London. Results are expressed as units/milliliter, 1 U being defined as the cardiolipin-binding activity of 1 μg of affinity-purified IgG-aCL. Plasma samples giving 2 or more SD above the mean of normal controls were considered as positive ( > 15 U/ml). The proportion of subjects shown to have positive tests for IgG-aCL was significantly (p < 0.05) higher among patients undergoing regular hemodialysis (9 of 54) than in patients on CAPD (1 of 19) or in healthy blood donors (2 of 50; table 1). However, the mean aCL concentration of these three groups did not differ significantly. The prevalence of positive aCL did not differ between patients dia-lyzed exclusively with cellulose-based membranes (5 of 29) or with more biocompatible Hemodialysis (n = 54) 17* BiocompatibleMembrane (n = 25) 16 Cellulose-basedMembrane (n = 29) 17 ThromboticEpisode (n= 10) 10 Dear Sir, Patients with end-stage renal disease have been found to be associated with a higher frequency of raised anticardiolipin (aCL) antibodies than the general population [1^1]. The presence of these autoantibodies has been related to the occurrence of thrombotic complications [2-Q. However, the clinical significance of aCL antibodies as markers for a high risk of recurrent thrombosis and the therapeutic implications of this association are still far from established, and the data reported by several studies are discordant. The objectives of our investigations were (a) to characterize the aCL antibody status in patients with end-stage renal disease treated with different methods of dialysis; (b) to investigate possible causes of aCL antibody synthesis, and (c) to find out whether aCL of IgG isotype are additional risk factors for vascular events in dialysis patients. 73 patients with end-stage renal disease (26 females, 47 males, aged 25-86 years) were selected for the study, 50 healthy blood donors served as controls. The major causes of chronic renal failure were chronic glomerulo-nephritis in 38, diabetic nephropathy in 8 and interstitial nephritis in 7 patients; 54 patients with end-stage renal disease were maintained on hemodialysis, 19 patients were treated with continuous ambulatory peritoneal dialysis (CAPD). The two subgroups had comparable demographic characteristics and did not differ in the underlying cause of renal failure. None of the patients had systemic lupus ery-