Increased prevalence of antibodies to central nervous system tissue and gangliosides in Hashimoto's thyroiditis compared to other thyroid illnesses.

BACKGROUND: Previous studies point to central nervous system (CNS) alterations in euthyroid patients with Hashimoto's thyroiditis (HT). The aim of the present study was to investigate the prevalence and clinical significance of antibodies (Abs) against CNS tissue and gangliosides in female patients with HT compared to patients with other non-autoimmune thyroid disorders, comprising diffuse or nodular goitre and thyroid surgery for goitre.
METHODS: 58 HT patients (mean age: 46+/-17 years) and 89 patients with other thyroid disorders (mean age: 51+/-15 years) were recruited consecutively from our endocrine outpatient clinic. Serum Abs against CNS tissue and gangliosides were determined using an enzyme-linked immunosorbent assay (ELISA). In a subgroup of 23 HT patients, neurocognitive function was studied using established neuropsychological tests.
RESULTS: In HT patients, the prevalence of serum anti-ganglioside-Abs and anti-CNS-Abs were significantly higher compared to patients with other thyroid disorders (p<0.05 and p<0.005, respectively). In both cases, the number of Ab-positive HT patients was twice that of Ab-positive controls. Reactivity of IgM-Abs to gangliosides and IgG-Abs to CNS tissue was significantly higher in HT patients than in controls (p<0.05 and p<0.01, respectively). However, prevalence and reactivity of Abs to gangliosides and CNS tissue were associated neither with the prevalence of depression nor with impairment of neurocognitive function in HT patients.
CONCLUSION: Ab reactivity towards CNS tissue and gangliosides is markedly enhanced in patients with HT as compared to patients with other thyroid disorders. Whether these Abs could be of prognostic value to evaluate the risk of future neurocognitive impairment has to be investigated in longitudinal studies.