Lenka Fialová1, Milada Petráčková1, Oliver Kuchař1. 1. Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
Abstract
BACKGROUND: Avidity of antiphospholipid antibodies may be clinically useful as a valuable additional characteristic. The aim of this study was to compare several ELISA modifications with different chaotropic agents and calculation of avidity indices for the determination of anticardiolipin antibody (aCL) avidity. METHODS: We examined 28 serum samples with positive IgG aCL by adapted ELISA using various concentrations of urea and sodium chloride as chaotropic agents and different dilution of sera. We tested these conditions of ELISA-a single diluted serum sample with fixed concentration of a chaotrope and a serially diluted serum in the constant concentration of a chaotropic agent. RESULTS: We demonstrated that ELISA method for avidity determination based on a single dilution of serum in the presence of fixed concentration of chaotrope is convenient for determination of IgG aCL antibody avidity. Concentrations 6 and 8 mol/L of urea or 1 and 2 mol/L of NaCl were suitable for sufficient dissociation of immune complexes during ELISA procedure. CONCLUSION: This way was in good agreement with more demanding procedures. Both urea and sodium chloride may be used as chaotropic agents. Reference values of avidity indices essential for interpretation of patients' results must be established individually for distinct assay conditions.
BACKGROUND: Avidity of antiphospholipid antibodies may be clinically useful as a valuable additional characteristic. The aim of this study was to compare several ELISA modifications with different chaotropic agents and calculation of avidity indices for the determination of anticardiolipin antibody (aCL) avidity. METHODS: We examined 28 serum samples with positive IgG aCL by adapted ELISA using various concentrations of urea and sodium chloride as chaotropic agents and different dilution of sera. We tested these conditions of ELISA-a single diluted serum sample with fixed concentration of a chaotrope and a serially diluted serum in the constant concentration of a chaotropic agent. RESULTS: We demonstrated that ELISA method for avidity determination based on a single dilution of serum in the presence of fixed concentration of chaotrope is convenient for determination of IgG aCL antibody avidity. Concentrations 6 and 8 mol/L of urea or 1 and 2 mol/L of NaCl were suitable for sufficient dissociation of immune complexes during ELISA procedure. CONCLUSION: This way was in good agreement with more demanding procedures. Both urea and sodium chloride may be used as chaotropic agents. Reference values of avidity indices essential for interpretation of patients' results must be established individually for distinct assay conditions.
Authors: S Miyakis; M D Lockshin; T Atsumi; D W Branch; R L Brey; R Cervera; R H W M Derksen; P G DE Groot; T Koike; P L Meroni; G Reber; Y Shoenfeld; A Tincani; P G Vlachoyiannopoulos; S A Krilis Journal: J Thromb Haemost Date: 2006-02 Impact factor: 5.824
Authors: Heather E Lynch; Shelley M Stewart; Thomas B Kepler; Gregory D Sempowski; S Munir Alam Journal: J Immunol Methods Date: 2013-12-04 Impact factor: 2.303