title: Standardisation of the factor H autoantibody assay.
abstract: The screening of all atypical haemolytic uraemic syndrome (aHUS) patients for factor H autoantibodies is best practice. However, there is no consensus assay for the reporting of factor H autoantibody titres. In this study, three European complement laboratories with expertise in the field of autoantibody testing address this by systematically evaluating several ELISA methods used for the detection of factor H autoantibodies. All methods tested adequately detect high titre samples. However, this study recommends the Paris method for the detection and reporting of factor H autoantibodies to be used when setting up a factor H autoantibody screen. The importance of individual sample background subtraction in these ELISA tests was established. The use of a relative or arbitrary unit index with a common positive and negative serum allowed for consistent comparison of findings from different test centres. Therefore, it is recommended that a standard arbitrary unit scale based on a titration curve from a common positive anti-serum be adopted to allow future establishment of the relative importance of particular titres of factor H autoantibodies in aHUS. Systematic assay for the presence of factor H autoantibodies in patients using the Paris method will provide the longitudinal analysis needed to fully establish the importance of factor H autoantibodies in disease. This will feed into additional research to clarify whether additional factors have a bearing on the phenotype/outcome of autoimmune aHUS.
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Rachael
authors.initials: R
authors.lastname: Watson
authors.forename: Susanne
authors.initials: S
authors.lastname: Lindner
authors.forename: Pauline
authors.initials: P
authors.lastname: Bordereau
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Hunze
authors.forename: Federico
authors.initials: F
authors.lastname: Tak
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Ngo
authors.forename: Peter F
authors.initials: PF
authors.lastname: Zipfel
authors.forename: Christine
authors.initials: C
authors.lastname: Skerka
authors.forename: Marie-Agnes
authors.initials: MA
authors.lastname: Dragon-Durey
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Marchbank
mesh_terms: D065766:Atypical Hemolytic Uremic Syndrome; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D017242:Complement Factor H / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods* / Q000592:standards*; D006463:Hemolytic-Uremic Syndrome / Q000097:blood / Q000175:diagnosis / Q000276:immunology; D006801:Humans; D008403:Mass Screening / Q000379:methods / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001323:Autoantibodies; D017242:Complement Factor H
keywords: AI-aHUS; AU; Autoantibody; Complement; ECGRD; ELISA; European Working Party on Complement Genetics in Renal Disease; Factor H; HRPO; IC; IgG; Kidney disease; SCR; aHUS; arbitrary units; atypical haemolytic uraemic syndrome; autoimmune atypical haemolytic uraemic syndrome; enzyme linked immunosorbent assay; horse-radish peroxidase; immune complex; immunoglobulin G; short consensus repeat