title: Autoantibodies to CD59, CD55, CD46 or CD35 are not associated with atypical haemolytic uraemic syndrome (aHUS).
abstract: Autoantibody formation against Factor H (FH) is found in 7-10% of patients who are diagnosed with atypical haemolytic uraemic syndrome (aHUS). These autoantibodies predominately target the C-terminal cell binding recognition domain of FH and are associated with absence of FHR1. Additional autoantibodies have also been identified in association with aHUS, for example autoantibodies to Factor I. Based on this, and that there are genetic mutations in other complement regulators and activators associated with aHUS, we hypothesised that other complement regulator proteins, particularly surface bound regulators in the kidney, might be the target for autoantibody formation in aHUS. Therefore, we assayed serum derived from 89 patients in the Newcastle aHUS cohort for the presence of autoantibodies to CD46 (membrane cofactor protein, MCP), CD55 (decay accelerating factor, DAF), CD35 (complement receptor type 1, CR1; TP10) and CD59. We also assayed 100 healthy blood donors to establish the normal levels of reactivity towards these proteins in the general population. Recombinant proteins CD46 and CD55 (purified from Escherichia coli) as well as soluble CR1 (CD35) and oligomeric C4BP-CD59 (purified from eukaryotic cell media) were used in ELISA to detect high responders. False positive results were established though Western blot and flow cytometric analysis. After excluding false positive responders to bacterial proteins in the CD46 and CD55 preparations, and responses to blood group antigens in CD35, we found no significant level of patient serum IgG reactivity with CD46, CD55, CD35 or CD59 above that detected in the normal population. These results suggest that membrane anchored complement regulators are not a target for autoantibody generation in aHUS.
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Rachael
authors.initials: R
authors.lastname: Watson
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Wearmouth
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Amy-Claire
authors.initials: AC
authors.lastname: McLoughlin
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Arthur
authors.initials: A
authors.lastname: Jackson
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Sophie
authors.initials: S
authors.lastname: Ward
authors.affiliation: Division of Rheumatology, Washington University School of Medicine, St. Louis, MO, USA.
authors.forename: Paula
authors.initials: P
authors.lastname: Bertram
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Karim
authors.initials: K
authors.lastname: Bennaceur
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Catriona E
authors.initials: CE
authors.lastname: Barker
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Isabel Y
authors.initials: IY
authors.lastname: Pappworth
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: David
authors.initials: D
authors.lastname: Kavanagh
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, UK.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Lea
authors.affiliation: Division of Rheumatology, Washington University School of Medicine, St. Louis, MO, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Atkinson
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Timothy H J
authors.initials: TH
authors.lastname: Goodship
authors.affiliation: Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK. Electronic address: kevin.marchbank@ncl.ac.uk.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Marchbank
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000917:Antibody Formation / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology*; D065766:Atypical Hemolytic Uremic Syndrome / Q000097:blood / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D001782:Blood Donors; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004926:Escherichia coli / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D015703:Antigens, CD; D001323:Autoantibodies; D011994:Recombinant Proteins
keywords: Ahus; Autoantibodies; Complement; Surface regulators