title: Immunoprecipitation assay for autoantibodies to steroid 21-hydroxylase in autoimmune adrenal diseases.
abstract: Adrenal autoantibodies characteristic of autoimmune Addison disease are directed towards steroid 21-hydroxylase (21-OH; EC 1.14.99.10). We describe a new assay to measure 21-OH autoantibodies (21-OH Abs), based on immunoprecipitation by the antibodies of 35S-labeled human 21-OH. Using this immunoprecipitation assay (IPA), we detected 21-OH Abs in 42 of 64 (66%) patients with Addison disease and in 14 of 19 (74%) patients with autoimmune polyendocrine syndromes type I and type II. No 21-OH Abs were detected by the IPA in any patients with Addison disease attributable to tuberculosis (n = 9) or adrenoleukodystrophy (n = 9) or in patients with autoimmune thyroid disease (n = 28), systemic lupus erythematosus (n = 10), myasthenia gravis (n = 10), rheumatoid arthritis (n = 10), or insulin-dependent diabetes mellitus (n = 12). None of the 26 sera from healthy normal blood donors was positive for 21-OH Abs by the assay. We found good agreement between 21-OH Abs measured by IPA and by Western blotting (r = 0.83, n = 123, P < 0.001). The inter- and intraassay CVs for IPA were well < 10% at high, medium, and low concentrations of 21-OH Abs. Overall, our studies indicate that the IPA provides a specific, sensitive, and convenient system for measuring 21-OH Abs.
authors.affiliation: FIRS Laboratories, RSR Ltd., Llanishen, Cardiff, UK.
authors.forename: J
authors.initials: J
authors.lastname: Colls
authors.forename: C
authors.initials: C
authors.lastname: Betterle
authors.forename: M
authors.initials: M
authors.lastname: Volpato
authors.forename: L
authors.initials: L
authors.lastname: Prentice
authors.forename: B R
authors.initials: BR
authors.lastname: Smith
authors.forename: J
authors.initials: J
authors.lastname: Furmaniak
mesh_terms: D000224:Addison Disease / Q000276:immunology; D000293:Adolescent; D000307:Adrenal Gland Diseases / Q000276:immunology*; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000276:immunology*; D015153:Blotting, Western; D002675:Child, Preschool; D005260:Female; D006111:Graves Disease / Q000276:immunology; D006801:Humans; D007163:Immunosorbent Techniques / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D016884:Polyendocrinopathies, Autoimmune / Q000276:immunology; D013255:Steroid 21-Hydroxylase / Q000276:immunology*; D013967:Thyroiditis, Autoimmune / Q000276:immunology
chemical_list: D001323:Autoantibodies; D013255:Steroid 21-Hydroxylase