Influence of thyroxine on serum soluble interleukin-2 receptor alpha levels in thyroid disorders

Thyroid stimulating immunoglobulin concentration is associated with disease activity and predicts response to treatment with intravenous methylprednisolone in patients with Graves' orbitopathy

Background

Thyroid stimulating immunoglobulins (TSI) play a central role in the pathogenesis of Graves' orbitopathy (GO), while soluble interleukin-2 receptor (sIL-2R) is a marker for T-cell activity. We investigated TSI and sIL-2R levels in relation to thyroid function, disease activity and severity and response to treatment with intravenous methylprednisolone (IVMP) in patients with GO.

Methods

TSI (bridge-based TSI binding assay), sIL-2R, TSH and fT4 levels were measured in biobank serum samples from 111 GO patients (37 male, 74 female; mean age 49.2 years old) and 25 healthy controls (5 male, 20 female; mean age 39.8 years old). Clinical characteristics and response to treatment were retrospectively retrieved from patient files.

Results

Higher sIL-2R levels were observed in GO patients compared to controls (p < 0.001). sIL-2R correlated with fT4 (r = 0.26), TSH (r = -0.40) and TSI (r = 0.21). TSI and sIL-2R concentrations were higher in patients with active compared to inactive GO (p < 0.001 and p < 0.05, respectively). Both TSI and sIL-2R correlated with total clinical activity score (CAS; r = 0.33 and r = 0.28, respectively) and with several individual CAS items. Cut-off levels for predicting active GO were 2.62 IU/L for TSI (AUC = 0.71, sensitivity 69%, specificity 69%) and 428 IU/mL for sIL-2R (AUC = 0.64, sensitivity 62%, specificity 62%). In multivariate testing higher TSI (p < 0.01), higher age (p < 0.001) and longer disease duration (p < 0.01) were associated with disease activity. TSI levels were higher in patients with a poor IVMP response (p = 0.048), while sIL-2R levels did not differ between responders and non-responders. TSI cut-off for predicting IVMP response was 19.4 IU/L (AUC = 0.69, sensitivity 50%, specificity 91%). In multivariate analysis TSI was the only independent predictor of response to IVMP (p < 0.05).

Conclusions

High TSI levels are associated with active disease (cut-off 2.62 IU/L) and predict poor response to IVMP treatment (cut-off 19.4 IU/L) in GO. While sIL-2R correlates with disease activity, it is also related to thyroid function, making it less useful as an additional biomarker in GO.

Causal relationship between inflammatory cytokines and autoimmune thyroid disease: a bidirectional two-sample Mendelian randomization analysis

Background

Autoimmune thyroid disease (AITD) ranks among the most prevalent thyroid diseases, with inflammatory cytokines playing a decisive role in its pathophysiological process. However, the causal relationship between the inflammatory cytokines and AITD remains elusive.

Methods

A two-sample Mendelian randomization (MR) analysis was performed to elucidate the causal connection between AITD and 41 inflammatory cytokines. Genetic variations associated with inflammatory cytokines were sourced from the FinnGen biobank, whereas a comprehensive meta-analysis of genome-wide association studies (GWASs) yielded data on Graves' disease (GD) and Hashimoto thyroiditis. Regarding the MR analysis, the inverse variance-weighted, MR-Egger, and weighted median methods were utilized. Additionally, sensitivity analysis was conducted using MR-Egger regression, MR-pleiotropy residual sum, and outliers.

Results

Seven causal associations were identified between inflammatory cytokines and AITD. High levels of tumor necrosis factor-β and low levels of stem cell growth factor-β were indicative of a higher risk of GD. In contrast, high levels of interleukin-12p70 (IL-12p70), IL-13, and interferon-γ and low levels of monocyte chemotactic protein-1 (MCP-1) and TNF-α suggested a higher risk of HD. Moreover, 14 causal associations were detected between AITD and inflammatory cytokines. GD increases the levels of macrophage inflammatory protein-1β, MCP-1, monokine induced by interferon-γ (MIG), interferon γ-induced protein 10 (IP-10), stromal cell-derived factor-1α, platelet-derived growth factor BB, β-nerve growth factor, IL-2ra, IL-4, and IL-17 in blood, whereas HD increases the levels of MIG, IL-2ra, IP-10, and IL-16 levels.

Conclusion

Our bidirectional MR analysis revealed a causal relationship between inflammatory cytokines and AITD. These findings offer valuable insights into the pathophysiological mechanisms underlying AITD.

Development of Graves' disease during drug-free remission of juvenile dermatomyositis

We report a Japanese boy with Graves' disease (GD) which developed during drug-free remission of juvenile dermatomyositis (JDM). He had been diagnosed with JDM at the age of 6 years by typical skin rashes, muscle weakness, elevated serum transaminase levels, and typical findings of both magnetic resonance imaging and muscle biopsy. Although anti-melanoma differentiation antigen 5 autoantibody was positive, there was no complication of interstitial lung disease. He showed good response to methylprednisolone pulse therapy followed by oral prednisolone in combination with weekly methotrexate (MTX) and achieved drug-free remission after 3.5 years of treatment. Nevertheless, serum levels of soluble interleukin-2 receptor (sIL-2R) gradually elevated to 3185 U/ml despite no signs of relapse or malignancy. Hyperactivity and attention deficit was also noted. One year and 3 months after the cessation of MTX, he presented with abdominal pain, tachycardia, and apparent goitre. Laboratory tests showed elevated free triiodothyronine, undetectable thyroid stimulating hormone (TSH), and positive anti-TSH receptor antibodies. 99mTc scintigraphy showed high levels of thyroid uptake. He was diagnosed with GD and treated with 15 mg/day of thiamazole. Although transient drug eruption was observed, his thyroid functions are currently well-controlled on 5 mg/day of thiamazole. In conclusion, to our knowledge, this is the first report in English literature describing complication of GD with JDM. Unexpected elevation of sIL-2R could be a clue to the diagnosis of GD during the follow-up of JDM.

Urinary neopterin levels in patients with thyroid cancer

Increased urinary neopterin concentrations have been described in many cancers. We aimed to evaluate the urinary neopterin levels in thyroid cancer. Sixty-nine patients with thyroid cancer, 76 patients with benign thyroid pathology and 33 healthy subjects were evaluated. First morning urine samples were collected from the patients and normal subjects for neopterin and creatinine measurement and stored at -80 °C until analysed. Neopterin levels were 149.3 (15.2-1,602.2) μmol/mol creatinine in the malignant group, 32 (5.2-275.6) μmol/mol creatinine in the benign group and 9.2 (2.7-78.7) μmol/mol creatinine in normal subjects (p ≤ 0.001). Urinary neopterin levels were significantly higher in patients with thyroid cancer than patients with benign thyroid pathologies and normal subjects. Also the patients with benign thyroid pathologies had a higher urinary neopterin level than the normal subjects. Malignant group was divided to two groups; patients with/without chronic thyroiditis (confirmed histologically). There were 22 (31.9 %) patients with and 47 (68.1 %) patients without chronic thyroiditis. Urinary levels of neopterin didn't differ in both groups (168.6 (21.3-716.8) μmol/mol creatinine and 135.3 (15.2-1,602.2) μmol/mol creatinine respectively; p = 0.381). Urinary neopterin levels are high in thyroid cancer patients independently from the presence of chronic thyroiditis.

Dense mapping of IL2RA shows no association with Graves' disease in Chinese Han population

OBJECTIVE

Associations between IL2RA and various autoimmune diseases have been reported in Caucasians. We investigated whether genetic polymorphisms at the IL2RA locus were associated with Graves' disease (GD) in the Chinese Han population.

DESIGN

We performed a genome-wide association study (GWAS) in 1 536 GD patients and 1 516 controls. The 1000 Genomes Project data were adopted as references for imputation analysis. After forward and conditional logistic regressions, we found that rs11256313 was the major risk variant in the CD25/IL2RA region. Thus, we further genotyped rs11256313 in a replication cohort with 3 694 GD patients and 3 510 controls using ABI 7900HT TaqMan Real-Time PCR System.

RESULTS

Nine single nucleotide polymorphisms (SNPs) in the IL2RA block were nominally associated with GD in our GWAS (0·01 < P < 0·05). After imputation analysis, 13 imputed SNPs in the IL2RA block were weakly associated with GD (P ≤ 0·05). Logistic regression analysis suggested that the imputed rs11256313 could represent the IL2RA block (P = 0·003). However, we failed to replicate the association of rs11256313 in a larger cohort (P = 0·145). A subphenotype analysis of rs11256313 on thyroid hormone receptor antibody (TRAb) and gender showed that there was no association in any of the subphenotype groups (P > 0·05).

CONCLUSIONS

The results suggested that common genetic polymorphisms at IL2RA do not exert a significant genetic effect on the development of GD in the Chinese Han population. Previously reported associations between CD25/IL2RA and autoimmune diseases including GD in Caucasians again imply that heterogeneity exists in different ethnic populations.

A variant of the Il2ra / Cd25 gene predisposing to graves' disease is associated with increased levels of soluble interleukin-2 receptor

Alpha-subunit of the IL-2 receptor (IL-2Rα) encoded by the IL2RA/CD25 gene binds IL-2 that plays a pivotal role in the regulation of T cell function. Levels of a soluble form of IL-2Rα (sIL-2Rα) lacking the transmembrane and cytoplasmic domains were shown to be increased in several autoimmune diseases including Graves' disease (GD). Recent studies showed association between the IL2RA/CD25 gene variants and several autoimmune diseases including GD. In this study, we analyzed whether polymorphic markers rs2104286, rs41295061, and rs11594656 located at the IL2RA/CD25 locus confer susceptibility to GD and are related to increased concentrations of sIL-2Rα. A total of 1474 Russian GD patients and 1609 control subjects were genotyped for rs2104286, rs41295061, and rs11594656 using a Taqman assay. Concentrations of sIL-2Rα in sera of affected and non-affected individuals were measured using an ELISA test. A minor allele A of rs41295061 showed significant association with increased risk of GD [odds ratio (OR) = 1.43, P(c)  = 0.00102]. The allele A of rs41295061 and allele A of rs11594656 constitute a higher risk haplotype AA (OR = 1.47, P(c)  = 0.0477). Compared to carriers of the protective haplogenotype GT/GT, the carriage of two copies of the haplogenotype AA/AA was associated with elevated levels of sIL-2Rα in both GD patients (AA/AA versus GT/GT: 1.35 ± 0.47 ng/ml versus 1.12 ± 0.45 ng/ml, P = 0.0065) and healthy controls (AA/AA versus GT/GT: 0.67 ± 0.28 ng/ml versus 0.51 ± 0.33 ng/ml, P = 0.0098). This is the first report presenting correlation between the carriage of disease-associated variants of IL2RA/CD25 with increased levels of sIL-2Rα in GD.

Successful remission of Evans syndrome associated with Graves' disease by using propylthiouracil monotherapy

A 46-year-old woman with Graves' disease was admitted for anemia and thrombocytopenia. She had previously been treated with methimazole but she self-discontinued the treatment 6 months prior to admission. She was diagnosed with Evans syndrome associated with Graves' disease and treated with propylthiouracil without corticosteroids, which normalized her thyroglobulin level. Surprisingly, while Evans syndrome is characterized by frequent relapses, this patient has been in remission of Evans syndrome for approximately 4 years. The remission of Evans syndrome associated with Graves' disease in the absence of immunosuppressive therapy suggests that these 2 diseases have a common pathogenetic mechanism.