The detection of up-regulated anti-thyroid antibodies and autoimmune thyroid diseases in patients with autoimmune encephalitis: a retrospective study of 221 patients

Abstract

Objective To investigate the potential detection rate of anti-thyroid antibodies' (ATAbs) positivity, thyroid dysfunctions, and autoimmune thyroid diseases (AITDs) in autoimmune encephalitis (AE) and to analyze whether thyroid autoimmunity/ dysfunction can affect the clinical course of AE. Methods Two hundred twenty-one AE patients and 229 age-and sex-matched controls were included in this study. We measured the levels of ATAbs (anti-thyroglobulin antibodies [TgAb], anti-thyroid peroxidase anti-bodies [TPOAb]) and thyroid hormones in all the individuals. In addition, the association of thyroid autoimmunity/dysfunctions with functional outcomes of AE was identified by using logistic regression and Kaplan-Meier analyses. ResultsThe prevalence of TPOAb-positive and TgAb-positive was significantly higher in AE patients (16.3% and 16.7%, respectively) as compared with controls (9.6% and 7.4%, respectively; P = 0.034 and P = 0.002, respectively). In addition, the free triiodothyronine (fT3) level was significantly lower in AE patients as compared to the controls (P < 0.001). However, the frequency of AITDs (Hashimoto's thyroiditis and Graves' disease) did not significantly differ between AE patients and control subjects. Importantly, low fT3 was found to be associated with poor functional outcomes at the 3-month follow-up in AE. Adjustment of potential confounders did not change the association. However, the presence of ATAbs did not significantly alert the disease course of AE. Conclusions ATAbs-positive and/or AITD patients with symptomatic encephalopathy should undergo proper surveillance for AE. Moreover, low fT3 could serve as a possible predictor of poor short-term outcome in AE, thereby suggesting that monitoring of thyroid function in AE may be necessary.

Contactin-associated protein-like 2 antibody-associated autoimmune encephalitis in children: case reports and systematic review of literature

“…One of them with low FT3 levels on admission, his symptoms were relieved after receiving first-line therapy, and his thyroid function and thyroid antibodies returned to normal before discharge. Our results are inconsistent with those of previous studies, indicating that low FT3 was associated with poor outcomes in this study for their 3-month follow-up assessments [ 41 , 42 ]. The role of thyroid antibodies and low FT3 levels in children with CASPR2 antibody-related AEs requires further investigation into the potential impact on prognosis.…”

“…Thyroid antibodies could be detected in roughly 1% of healthy individuals [ 40 ], with different ranges according to age and sex, so detecting anti-thyroid antibodies in patients with CASPR2 antibodies may be considered an occasional finding. A retrospective cohort study of 229 patients with AE revealed that TPO-Ab and Tg-Ab positivity were detected in 16.3% and 16.7% [ 41 ]. In this review, three patients were relieved of their symptoms after receiving immunotherapy.…”

Low triiodothyronine (T3) levels predict worse outcomes in autoimmune encephalitis—A meta‐analysis of current literature

“…Four studies (Ji et al, 2021;Lin et al, 2022;Ma et al, 2018;Qiao et al, 2022) reported data on this outcome. A statistically significant correlation was noted, where patients with low fT3 levels were 3.88 times more likely to experience central hypoventilation as opposed to the ones with non-low fT3 levels (OR = 3.88; 95% CI = 1.15-13.09; p = .03, S6).…”

“…Three (Ji et al, 2021;Lin et al, 2022;Ma et al, 2018) studies reported data for this outcome. No significant difference was obtained when patients with low fT3 and non-low fT3 were compared for experiencing autonomic dysfunction (OR = 1.48; 95% CI = .95-2.31; p = .09, I 2 = 0%) (Figure 5).…”

“…Five (Chen et al, 2021;Ji et al, 2021;Lin et al, 2022;Ma et al, 2018;Qiao et al, 2022) studies reported data on the presence of seizures.…”