Microparticle-enhanced nephelometric immunoassay of anti-thyroid peroxidase autoantibodies in thyroid disorders

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 40; no. 3; pp. 442 - 447
• Main Authors: Harchali, AA, Montagne, P, Ruf, J, Cuilliere, ML, Bene, MC, Faure, G, Duheille, J
• Format: Journal Article
• Language: English
• Published: Washington, DC Am Assoc Clin Chem 01.03.1994; American Association for Clinical Chemistry
• Subjects: Autoantibodies - blood; Biological and medical sciences; Endocrinopathies; Epitopes - immunology; Graves Disease - immunology; Humans; Immunoassay - methods; Iodide Peroxidase - immunology; Medical sciences; Microspheres; Nephelometry and Turbidimetry; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Thyroid Diseases - immunology; Thyroid. Thyroid axis (diseases); Thyroiditis, Autoimmune - immunology; Endocrinopathy; Human; Immunopathology; Antigenic determinant; Enzyme; Hyperthyroidism; Thyroid diseases; Autoantibody; Autoimmune disease; Monoclonal antibody; Immunological method; Nephelometry; Specificity; Peroxidases; Hashimoto thyroiditis; Basedow disease; Peroxidase; Oxidoreductases; Diagnosis
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1093/clinchem/40.3.442

Crude thyroid peroxidase extracted from human thyroid microsomes was covalently bound onto polyacrylic and polyfunctional copolymerized microparticles. We observed agglutination of the thyroid peroxidase-microparticle conjugate with 13 monoclonal antibodies (mAbs) specific for epitopes on four different antigenic domains of human thyroid peroxidase (TPO; EC 1.11.1.7), after addition of anti-mouse immunoglobulins. We quantified agglutination by measuring with a specially designed nephelometer the light scattered by the conjugates. This allowed us to develop a microparticle-enhanced nephelometric immunoassay for human anti-TPO autoantibodies (aAbs) with defined epitopic specificity, based on the ability of aAbs to inhibit mAb-induced agglutination. Applied to patients with autoimmune thyroid diseases, this assay confirmed the polyclonality of anti-TPO aAbs and their preferential reactivity toward epitopes located on the A and B antigenic domains of the TPO molecule. The same specificities seem to be present in patients with Hashimoto thyroiditis or Graves disease.