Association of thyroid peroxidase antibodies with anti-neuronal surface antibodies in health, depression and schizophrenia - Complementary linkage with somatic symptoms of major depression

Association between hypothyroidism subtypes and major depression: A two-sample Mendelian randomization study

BACKGROUND

The causal relationship between different hypothyroidism subtypes and the risk of major depression (MD) is yet to be fully elucidated. This study aimed to determine if there's a causal relationship between various hypothyroidism subtypes (and related factors) and the risk of MD.

METHODS

This genetic association study utilized a two-sample Mendelian Randomization (MR) approach to explore the causal relationships between various hypothyroidism subtypes and MD risk. Genome-Wide Association Study (GWAS) summary statistics were obtained from the FinnGen and the UK Biobank. Instrumental variables (IVs) were chosen based on single nucleotide polymorphisms (SNPs).

RESULTS

Among the analyzed hypothyroidism subtypes and related factors, "Hypothyroidism, strict autoimmune" (HTCBSA) and "Hypothyroidism, levothyroxin purchases" (HT/LP) demonstrated a statistically significant positive causal relationship with MD, with odds ratios of 1.020 (95 % CI: 1.004-1.037) and 1.022 (95 % CI: 1.005-1.040), respectively. The sensitivity analysis supported the robustness of these findings, showing no significant horizontal pleiotropy and confirming the stability of results when individual SNPs were removed. "Congenital iodine-deficiency syndrome/hypothyroidism" (CIDS/HT), "Postinfectious hypothyroidism" (PHT), "Hypothyroidism due to medicaments and other exogenous substances" (HDTDM and OES), "Thyroid Stimulating Hormone" (TSH), "Thyrotropin-releasing hormone" (THRH), and "Hypothyroidism, strict autoimmune, 3 medication purchases required" (HTCBSA/3MPR) showed no significant causal relationship with MD.

LIMITATIONS

The study population was limited to individuals of European ancestry, and there may be certain genetic differences between different ethnic groups.

CONCLUSIONS

This MR study suggests a potential causal relationship between certain hypothyroidism subtypes (specifically HTCBSA and HT/LP) and an increased risk of MD.

Sera anti-neuronal antibodies in patients with irritable bowel syndrome and their correlations with clinical profiles

BACKGROUND

Immune factors were involved in the pathophysiology of irritable bowel syndrome (IBS). The aim of the study was to test anti-neuronal antibodies in sera of IBS patients and demonstrate their correlations with IBS profiles and psychological disorders.

METHODS

Patients with IBS met Rome III criteria and excluded organic diseases were enrolled. Controls included healthy subjects (HS), slow transit functional constipation, autoimmune diseases, and so on. Indirect immunofluorescence with monkey cerebellum and small intestine as substrates was used to detect anti-neuronal antibodies including anti-cerebral neuronal antibodies (ACNA) and anti-enteric neuronal antibodies (AENA).

RESULTS

A total of 293 IBS patients, 100 HS and 153 disease controls were included in this study. The ACNA positive rate of IBS patients was significantly higher than HS (14% vs. 6%, p = 0.033). The positive rate of ACNA was significantly lower than AENA (14.0% vs. 76.8%, p = 0.028) in IBS patients. The prevalence of headache and sleeping disorder were higher in ACNA-positive IBS patients than ACNA-negative IBS patients (61% vs. 42.9%, p = 0.03; 75.6% vs. 57.1%, p = 0.03, respectively). Among IBS patients, ACNA and AENA were both negative in 21.8% patients, ACNA negative and AENA positive in 64.2% patients, and ACNA and AENA were both positive in 12.6% patients. There were no significant differences of intestinal symptoms among the three groups, while the prevalence of headache (64.9% vs. 37.5% and 44.7%, p = 0.03) and sleeping disorder (78.4% vs. 50.0% and 59.6%, p = 0.02) were higher in patients with both ACNA and AENA positive than patients with both ACNA and AENA negative, patients with ACNA negative and AENA positive. There were no significant differences of the prevalence of depression and anxiety, HAMD, and HAMA scores among the three groups.

CONCLUSIONS AND INFERENCES

Anti-neuronal antibodies in sera of IBS patients were mainly targeted to enteric neurons and in a small part to cerebral neurons. ACNA were closely related to headache and sleeping disorder but unrelated to intestinal symptoms, depression, or anxiety of IBS patients.

Steroid-responsive encephalopathy associated with autoimmune thyroiditis presenting as cortisone sensible psychosis with reversible leukoencephalopathy

INTRODUCTION

Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT) is a frequently discussed neuropsychiatric syndrome with elevated thyroid antibodies in the context of various clinical neuropsychiatric phenotypes. MRI abnormalities are usually nonspecific and treatment can be complex.

CASE STUDY

We present a case of a woman in her sixties with SREAT whose psychosis kept worsening under cortisone tapering. After three years with cortisone side effects, therapy was changed to plasmapheresis and rituximab treatment with an excellent initial response, subacute unexplained deterioration with extensive leukoencephalopathy on MRI shortly after, and full recovery with regression of leukoencephalopathy afterwards.

DISCUSSION

SREAT varies in clinical and diagnostic presentation. Its precise pathophysiology is unknown, as are the best treatment protocols. The case illustrates that some patients with SREAT syndrome might end up in constellations, in which it proves difficult to wean off steroid treatment and illustrates treatment alternatives such as plasmapheresis and/or rituximab. In addition, it highlights leukoencephalopathy as possible MRI finding in the context of SREAT. Further research is necessary to fully comprehend the (potentially different) pathomechanisms and courses of SREAT.

Gender differences in the prevalence and clinical correlates of thyroid dysfunction in patients with first-episode and drug-naïve major depressive disorder with comorbid suicide attempts: a large cross-sectional study

BACKGROUND

Gender differences in patients with major depressive disorder (MDD) are commonly reported; however, gender differences in first-episode and drug-naïve (FEDN) MDD patients with comorbid suicide attempts have not been reported. This study aimed to examine potential gender differences in the prevalence and clinical correlates of comorbid abnormal thyroid function (ATF) in FEDN MDD patients with comorbid suicide attempts.

METHODS

A cross-sectional study of 1718 FEDN MDD patients was conducted. The demographic and clinical data were collected. The Hamilton Depression Scale (HAMD), the Hamilton Anxiety Scale (HAMA) and Positive and Negative Syndrome Scale (PANSS) were used to assess depression, anxiety and psychotic symptoms, respectively. Thyroid function parameters and blood glucose levels were measured.

RESULTS

There was no gender difference in the prevalence of ATF between male (78.6%, 88/112) and female MDD patients (74.8%, 175/234) with comorbid suicide attempts. In the male and female subgroups, duration of disease, HAMD score, HAMA score, anti-thyroglobulin (TgAb), thyroid peroxidases antibody (TPOAb), diastolic blood pressure (DBP), systolic blood pressure (SBP), glucose level and the rate of psychotic symptoms were higher in patients with ATF than those without ATF in MDD with comorbid suicide attempt (all P < 0.05). There was a gender main effect only on SBP (F = 7.35, P = 0.007). Furthermore, binary logistic regression analysis showed that HAMD score, DBP and glucose levels were independently with ATF in both male and female MDD patients with comorbid suicide attempts. However, anxiety symptoms, psychotic symptoms and TPOAb levels were significantly associated with ATF only in female MDD patients with comorbid suicide attempts.

CONCLUSION

Our study showed no gender differences in the prevalence of ATF in FEDN MDD patients with comorbid suicide attempts. Depression, DBP and glucose levels were associated with ATF in both male and female MDD patients with comorbid suicide attempts, whereas anxiety, psychotic symptoms and TPOAb level were correlated with ATF only in female MDD patients with suicide attempts.

Severe psychiatric disorders and general medical comorbidities: inflammation-related mechanisms and therapeutic opportunities

Individuals with severe psychiatric disorders, such as mood disorders and schizophrenia, are at increased risk of developing other medical conditions, especially cardiovascular and metabolic diseases. These medical conditions are underdiagnosed and undertreated in these patients contributing to their increased morbidity and mortality. The basis for this increased comorbidity is not well understood, possibly reflecting shared risks factors (e.g. lifestyle risk factors), shared biological mechanisms and/or reciprocal interactions. Among overlapping pathophysiological mechanisms, inflammation and related factors, such as dysbiosis and insulin resistance, stand out. Besides underlying the association between psychiatric disorders and cardiometabolic diseases, these mechanisms provide several potential therapeutic targets.

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

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.

RESULTS

The 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.

Redefining the Cut-Off Ranges for TSH Based on the Clinical Picture, Results of Neuroimaging and Laboratory Tests in Unsupervised Cluster Analysis as Individualized Diagnosis of Early Schizophrenia

Thyroid abnormalities, including mild forms of hypothyroidism and hyperthyroidism, are reported as risk factors for the development of a number of neuropsychiatric disorders, including schizophrenia. The diagnostic process still takes into account the extreme ranges of the accepted reference values for serum TSH since the concentration of free thyroxine in the serum does not change by definition. TSH mU/L cut-off values in psychiatric patients are currently clinically considered in the case of extremely high serum TSH levels (>4.0 mU/L). The results obtained in this study suggest that the clinically significant value has a lower TSH cut-off point with an upper limit of 2–2.5 mU/L. The criteria for the differential diagnosis of patients with schizophrenia, however, mainly take into account statutory reference ranges without a background related to the history of thyroid diseases in the family. The results indicate the need to lower the upper cut-off values for TSH among patients with early psychosis, which is related to the potential clinical significance of the obtained values both in the field of clinical evaluation and neuroimaging and laboratory evaluation parameters. The cut-off points obtained with the prior available knowledge coincided with the values established in the unsupervised clustering method, which further confirms the legitimacy of their use in the individualized diagnosis strategy of schizophrenia.

Amino acid sequence homology between thyroid autoantigens and central nervous system proteins: Implications for the steroid-responsive encephalopathy associated with autoimmune thyroiditis

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Alpha-enolase, aldehyde reductase-I and dimethylargininase-I are SREAT autoantigens.

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Molecular mimicry between thyroid and CNS autoantigens is hypothesized in SREAT.

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Homology with TSH-R, Tg and TPO exists for 6, 27 and 47 of 46,809 CNS-proteins.

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The above homologies are often in epitope-containing parts of thyroid autoantigens.

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Most of the above proteins are expressed in CNS regions which are altered in SREAT.

A few patients with Hashimoto’s thyroiditis or Graves’ disease develop a multiform syndrome of the central nervous system (CNS) termed Hashimoto’s encephalopathy or steroid-responsive encephalopathy associated with autoimmune thyroid disease (HE/SREAT). They have high levels of thyroid autoantibodies (TgAb, TPOAb and/or TSH-R-Ab) in blood and cerebrospinal fluid. Autoantibodies against alpha-enolase, aldehyde reductase-I (AKRIA) and/or dimethylargininase-I (DDAHI), proteins expressed in the CNS among other tissues, were detected in the blood and, when searched, in the cerebrospinal fluid of HE/SREAT patients. Recently, we reported that alpha-enolase, AKRIA and DDAHI share local sequence homology with each of the three autoantigens (TgAb, TPOAb, TSH-R-Ab), often in epitope-containing segments of the thyroid autoantigens. We hypothesized that there might be additional CNS-expressed proteins homologous to thyroid autoantigens, possibly overlapping known epitopes of the thyroid autoantigens. We used bioinformatic methods to address this hypothesis.

Six, 27 and 47 of 46,809 CNS-expressed proteins share homology with TSH-R, Tg and TPO, respectively. The homologous regions often contain epitopes, and some match regions of thyroid autoantigens which have homology with alpha-enolase, AKRIA and/or DDAHI. Several of the aforementioned proteins are present in CNS areas that show abnormalities at neuroimaging in HE/SREAT patients. Furthermore, autoantibodies against some of the said six, 27 and 47 proteins were reported to be associated with a number of autoimmune diseases.

Not only we validated our hypothesis, but we think that such a variety of potential CNS targets for thyroid Ab against epitopes contained in regions that have local homology with CNS proteins may explain the polymorphic phenotypes of HE/SREAT. Only when elevated amounts of these Ab are synthesized and trespass the blood-brain barrier, HE/SREAT appears. This might explain why HE/SREAT is so relatively rare.

An observational study on the association of anti-thyroid autoantibodies with clinical, EEG, MRI, FDG-PET, cerebrospinal fluid and anti-neuronal antibody findings in 530 patients with schizophreniform and affective disorders

INTRODUCTION

Although the link between autoimmune thyroiditis and mental illnesses is well established, the precise underlying pathophysiology and the influence of anti-thyroid antibodies on diagnostic findings require further research.

PATIENTS AND METHODS

A total of 530 patients with schizophreniform and affective syndromes were screened for anti-thyroid antibodies against thyroid peroxidase (TPO), thyroglobulin (TG), and thyroid-stimulating hormone receptor (TSH-R). The patient group analyzed here is a patient subgroup of a previously published cohort (Endres et al., 2020, Translational Psychiatry). The anti-thyroid antibody positive (N = 91) and negative (N = 439) patients were compared in terms of various clinical parameters, routine cerebrospinal fluid (CSF) findings, and the number of positive anti-neuronal antibodies in serum and/or CSF, as well as electroencephalography (EEG), magnetic resonance imaging (MRI), and ^[18 F]fluorodeoxyglucose positron emission tomography (FDG-PET) findings.

RESULTS

Anti-TPO antibodies were increased in 17%, anti-TG antibodies in 15%, and anti-TSH-R antibodies in 2% of all patients. In CSF, higher protein concentrations (p = 0.018) and albumin quotients (p = 0.008) were found in the anti-thyroid antibody positive patient group. Also, there were more patients with elevated age-corrected albumin quotients in this group (p = 0.031). FDG-PET hypometabolism was significantly more frequent and the number of positive anti-neuronal intracellular antibodies was significantly higher in patients with anti-thyroid antibodies (p = 0.048, N = 29 and p = 0.032, N = 497 respectively). In addition, there was a trend for higher white blood cell (WBC) counts in all patients with anti-thyroid antibodies (p = 0.090). In the patient subgroup with anti-TPO antibodies this difference was statistically significant (p = 0.027). No relevant differences were found in the other CSF routine parameters, the number of anti-neuronal antibodies against cell surface antigens in serum and/or CSF, EEG and MRI findings.

DISCUSSION

The present study provides evidence of impaired blood CSF barrier (BCSFB) function in patients with anti-TPO and anti-TG antibodies. An influence of anti-TG antibodies on BCSFB structures has been shown in previous laboratory studies, which reported that the antibodies bind to vascular smooth muscle cells. Due to BCSFB breakdown anti-thyroid antibodies might lead to increased autoimmune susceptibility. The alterations in the FDG-PET, WBC count, and anti-neuronal antibody findings against intracellular structures indicate that it could be useful to extend diagnostic investigations in patients with anti-thyroid antibodies. Further studies should investigate whether anti-thyroid antibodies can also act as "drivers of disease".

Potential Cross-Links of Inflammation With Schizophreniform and Affective Symptoms: A Review and Outlook on Autoimmune Encephalitis and COVID-19

Based on current implications of the SARS-CoV-2 pandemic with regards to mental health, we show that biological links exist between inflammation and mental illness in addition to psychoreactive effects. We describe key principles of the biological interaction of the immune system and the mind, as well as the possible routes of viral entry into the brain. In addition, we provide a stepwise scheme for the diagnosis and therapy of autoimmune-encephalitis with schizophrenia-like symptomatology as a general guide for clinical practice and in the specialized scenario of infections, such as those caused by the SARS-CoV-2 virus.