IgG SUBCLASS DISTRIBUTION OF THYROID AUTOANTIBODIES: A ‘FINGERPRINT’ OF AN INDIVIDUAL'S RESPONSE TO THYROGLOBULIN AND THYROID MICROSOMAL ANTIGEN

Abstract

The IgG subclass distribution of autoantibodies to thyroglobulin and thyroid microsomal antigen was studied in 21 patients with Graves' disease during fluctuations in total IgG class autoantibody levels induced by various forms of therapy. In addition, changes in autoantibody subclass distributions were investigated during the natural course of Hashimoto's disease in seven patients taking thyroxine. The autoantibodies were principally of subclasses IgG1 and/or IgG4 in Graves' patients although IgG2 contributed significantly to thyroglobulin antibodies in 5/7 Hashimoto sera. In Graves' disease the distribution of microsomal and thyroglobulin antibodies among the IgG subclasses remained essentially unchanged over periods of 6 months-2 years whether autoantibody levels decreased during carbimazole therapy or increased transiently following 131Iodine treatment or subtotal thyroidectomy. Similar observations were made for thyroglobulin antibodies in Hashimoto patients studied over 2 1/2-4 years; furthermore, the IgG subclass distribution of microsomal antibodies was usually different from that of thyroglobulin antibodies in the same patient. These observations suggest that the microsomal and/or thyroglobulin antibody subclass distribution is characteristic for a particular individual and may be regarded as the 'fingerprint' of an individual's response to these thyroid autoantigens.

IgG subclass distribution of thyroglobulin antibodies in patients with thyroid disease

“…When the data were logarithmically transformed, to normalize the skewness to the right of the subclass distribution and the presence of outlying values, there was a significant positive correlation between these two variables: r = 0 79, P < 0 0001. [8,9,13]. We have also shown for the first time that the same pattern is present in patients with non-toxic goitre and thyroid carcinoma.…”

“…The early reports of Hay & Torrigiani [6] and Spiegelberg [7], using a co-precipitation radioimmunoassay with radiolabelled thyroglobulin and polyclonal rabbit anti-IgG subclass sera, showed that TgAbs in Hashimoto patients were not restricted to a particular subclass, but closely paralleled the relative amount of each subclass Correspondence: C. Lynne Burek, JHU School of Hygiene, MMI, 615 N. Wolfe St, Baltimore, MD 21205, USA. in normal serum. On the other hand, a second group of investigators [8][9][10][11][12] suggested a restriction to some IgG subclasses in response to thyroglobulin. Using an ELISA with a panel of mouse MoAbs directed against the four IgG subclasses, they reported that TgAbs in Hashimoto and also Graves' patients are restricted to IgGl and IgG4.…”

Distribution of immunoglobulin G subclasses of anti-thyroid peroxidase antibody in sera from patients with Hashimoto's thyroiditis with different thyroid functional status

“…Regardless of different thyroid functional status, the most represented IgG subclasses of TPOAb were IgG1 and IgG4, in agreement with some previous studies [16][17][18]. *P < 0·05 compared with E, **P < 0·05 compared with sH.…”

Autoreactive IgG elicited in mice by the non-dominant but pathogenic thyroglobulin peptide (2495–2511): implications for thyroid autoimmunty

“…Thus, the small molecular size and the nondominanl nature of the pathogenic TgPl peptide are not features that predispose induction of specific IgG with a hmited subclass distribution. Although it is possible that this subclass profile may change over time, evidence from Hashimoto's thyroiditis patients indicates an essentially unchanged subclass distribution of Tg-specific IgG over 2-5 4 years [18].…”