Abstract: Objective The aim of this study was to assess the changes of thyroid hormone in patients with autoimmune liver diseases (AILD). Methods 52 patients with autoimmune hepatitis (AIH), 34 patients with primary biliary cholangitis (PBC) and 46 patients with AIH-PBC overlap syndrome (OS) were admitted to the Second Affiliated Hospital, Anhui Medical University between May 2016 and September 2022, and 52 healthy persons were selected as control. Serum free triiodothyronine (FT3), free thyroxine (FT4), T3, T4, thyroid stimulating hormone (TSH), thyrotrophin receptor antibody (TRAb), thyroid peroxidase antibody (TPOAb), anti-thyroglobulin antibody (TgAb), thyroxine-binding globulin (TBG) and thyroglobulin (Tg) were detected. Results Serum FT3 levels in patients with AIH, with PBC and with OS were 4.5(3.9, 5.0)pmol/L, 4.4 (4.0, 4.5)pmol/L and 4.1(3.7, 4.7)pmol/L, serum FT4 levels were 14.8(13.0, 16.5)pmol/L, 14.6(13.0, 16.0) pmol/L and 14.8(13.1, 15.9)pmol/L, all significantly lower than[4.8(4.5, 5.0)pmol/L and 15.7(14.5, 16.9)pmol/L, respectively, P<0.05] in healthy individuals; serum TSH level in patients with OS was 3.4(2.1, 6.4)mIU/L, much higher than[2.8(2.0, 3.3)mIU/L, P<0.05] in healthy control; the positive rates of serum TRAb, TGAb, TPOAb, TBG and Tg in patients with AIH were 5.4%, 21.6%, 29.7%, 8.1% and 0.0%, in patients with PBC were 6.9%, 13.8%, 17.2%, 10.3% and 3.4%, and in patients with OS were 12.5%, 18.8%, 21.9%, 0.0% and 3.1%, all not significantly different among them (P>0.05); the incidences of hypothyroidism and subclinical hypothyroidism in patients with AIH were 9.6% and 13.5%, in patients with PBC were 20.6% and 23.5%, and in those with OS were 6.5% and 30.4%, also not significantly different among them (P>0.05); at the end of six month treatment, 21 patients(41.2%) with AIH, 25 patients (73.5%) with PBC and 12 patients (26.7%) with OS responded to treatment, and there were no significant differences as respect to the response rates between patients with and without thyroid diseases(28.6% vs. 45.9%, 66.7% vs. 81.3% and 38.9% vs. 18.5%, respectively, all P>0.05). Conclusion Serum FT3 and FT4 levels decrease and serum TSH level increase in patients with AIH, PBC and OS, and the implication of concomitant thyroid diseases in this setting needs to be clarified.

Key words: Autoimmune liver diseases, Thyroid hormones, Anti-thyroid antibodies, Response