Diabetic immune markers in thyroid diseases. Preliminary studies on autoantibodies to glutamic acid decarboxylase (GADA)

A. VILLALBA; H. NIEPOMNISZCZE; M. SALA; S. GUAITA; A. L. VILLANUEVA; S. N. VALDEZ; M. P. SICA; M. E PRIMO; A. CARDOSO; E. POSKUS; O. D. BRUNO

Paris, Francia

Simposio; Journées Internationales d’Endocrinologie Clinique Henri-Pierre Klotz; 2002

Francaise d’Endocrinologie

The aim of this study was to investigate the prevalence of  humoral markers of antipancreatic autoimmunity in patients affected by thyroid disorders. They were divided in two subgroups: Autoimmune thyroid diseases (AITD) and non-autoimmune disorders (NAITD). GADA was assesed in 400 patients (375 WOMEN AND 25 MEN, AGED 14 TO 84) who consecutively consulted at our Division of Endocrinology. AITD involved patients with Graves’ disease (both, during hyperthyroidism or when attained euthyroidism or hypothyroidism after treatment) and Hashimoto’s thyroiditis in all its variants and associations (with other thyroid non-autoimmune diseases). The NAITD subgroup comprised all of the rest of thyroid diseases without thyroid autoimmunity. Out of the 400 patients, 76.3% were AITD and 23.7% were NAITD. GADA was assessed by the reference radiobinding assay using recombinant 35SGAD as a tracer. Cutoff valuesfor GADA determinations were obtained fron mean plus 3 SD of 30 normal controls, the prevalence of GADA in the normal argentinian population is < 0.5 %. Once excluded the patients with thyroid pathology and concomitant diabetes mellitus, in whom the frequency of positive GAD antibodies was elevated (8/25: 32 %) the results obtained were as follows: a) AITD patients (n= 284): GADA (+)= 6.3%; b) NAITD patients without DM [n=91]: GADA (+)= 2.2 %; It is concluded that the frequency of a positive GADA test appears to be higher in AITD than in NAITD, in non-diabetic patients with thyroid disorders.