title: [The association of complement with common connective tissue diseases - a review].
abstract: A strong association has been found between complement and common connective tissue diseases, such as systemic lupus erythema and Henoch Schoenlein Purpura. This has led to the notion that the pathogenesis of such diseases may involve a defect in the safe disposal of immune complexes, which is mediated by complement. To bring further light on this subject, a sensitive assay was developed to measure the ability of serum to prevent immune precipitation. This assay was then employed to study various Icelandic patient groups, and a defect in this function of complement was found to be common in patients with systemic lupus erythematosus and systemic sclerosis. Partial deficiency in complement C4A (C4A Q0) can not account for this defect, as it was not observed in patients with diabetes, gluten-sensitive enteropathy or autoimmune thyroiditis, in which C4A Q0 is common. The defect is strongly correlated with anti-C1q antibodies. Further studies are needed to test the possible role of anti-C1q antibodies in the pathogenesis of immune complex disease.
authors.affiliation: Onaemisfraedideild Landspitala, Hringbraut, 101 Reykjavik. garason@lsh.is
authors.forename: Gudmundur Johann
authors.initials: GJ
authors.lastname: Arason
mesh_terms: D001323:Autoantibodies / Q000097:blood; D003167:Complement Activation; D015922:Complement C1q / Q000276:immunology; D003165:Complement System Proteins / Q000276:immunology*; D003240:Connective Tissue Diseases / Q000276:immunology*; D006801:Humans; D007055:Iceland; D047468:Immunoprecipitation / Q000379:methods
chemical_list: D001323:Autoantibodies; D015922:Complement C1q; D003165:Complement System Proteins