Increase of serum interleukin-10 in intractable Graves' disease

The multifaceted nature of IL-10: regulation, role in immunological homeostasis and its relevance to cancer, COVID-19 and post-COVID conditions

Interleukin-10 (IL-10) is a pleiotropic cytokine that has a fundamental role in modulating inflammation and in maintaining cell homeostasis. It primarily acts as an anti-inflammatory cytokine, protecting the body from an uncontrolled immune response, mostly through the Jak1/Tyk2 and STAT3 signaling pathway. On the other hand, IL-10 can also have immunostimulating functions under certain conditions. Given the pivotal role of IL-10 in immune modulation, this cytokine could have relevant implications in pathologies characterized by hyperinflammatory state, such as cancer, or infectious diseases as in the case of COVID-19 and Post-COVID-19 syndrome. Recent evidence proposed IL-10 as a predictor of severity and mortality for patients with acute or post-acute SARS-CoV-2 infection. In this context, IL-10 can act as an endogenous danger signal, released by tissues undergoing damage in an attempt to protect the organism from harmful hyperinflammation. Pharmacological strategies aimed to potentiate or restore IL-10 immunomodulatory action may represent novel promising avenues to counteract cytokine storm arising from hyperinflammation and effectively mitigate severe complications. Natural bioactive compounds, derived from terrestrial or marine photosynthetic organisms and able to increase IL-10 expression, could represent a useful prevention strategy to curb inflammation through IL-10 elevation and will be discussed here. However, the multifaceted nature of IL-10 has to be taken into account in the attempts to modulate its levels.

Toll-Like Receptors-2 and -4 in Graves' Disease-Key Players or Bystanders?

Graves’ disease (GD) is an autoimmune disease that affects the thyroid. The development of autoimmunity is associated with innate immune responses where the prominent role plays Toll-like receptors (TLRs). The aim of our study was to assess the relationship between the expression levels of TLR-2 and TLR-4 on CD4+ and CD8+ T as well as CD19+ B lymphocytes in patients with GD and selected clinical parameters. The study group consisted of 32 women with GD, the control group consisted of 20 healthy women. Immunophenotyping was performed using the flow cytometry and cytokines concentrations were assessed using ELISA assay. The mean percentage of CD4+/TLR-2+ and CD8+/TLR-2+ T cells in patients with GD was higher than in the control group (p < 0.0001). After obtaining euthyroidism, the mean percentage of CD4+/TLR-2+ T cells in patients with GD decreased (p < 0.0001). The expression level of TLR-2 on CD4+ T lymphocytes correlated with serum FT3 concentration in patients with GD (r = 0.47, p = 0.007). The mean percentage of CD8+/TLR-2+ T cells in patients with GD before treatment compared to patients with GD after obtaining euthyroidism was higher (p = 0.0163). Similar findings were found for TLR-4. Thus the TLR-2 and TLR-4 can be a prognostic marker for Graves’ disease.

Increased Human Interleukin-32 Expression Is Related to Disease Activity of Graves' Disease

Recently, abnormal expression of interleukin-32 (IL-32) has been involved in various inflammatory or autoimmune diseases, but the level of IL-32 expression in Graves' disease (GD) is still unknown. This study is aimed to explore the human IL-32 expression in GD and the association of IL-32 expression with the disease activity of GD. A total of 125 GD patients and 97 normal controls (NC) were recruited in this study. We examined IL-32 mRNA level in peripheral blood mononuclear cells (PBMCs) of 43 GD patients and 41 controls using real-time polymerase chain reaction (RT-PCR). Serum IL-32 level of 40 GD patients and 34 controls was measured by enzyme linked immunosorbent assay (ELISA). In another cohort including 42 GD patients and 22 controls, we detected the percentages of IL-32α⁺ cells, CD4⁺IL-32α⁺T cells, and CD4^-IL-32α⁺ cells in PBMCs by flow cytometry. In GD patients, IL-32 mRNA expression was dramatically higher than that in controls (P < 0.001) and positively associated with FT3 (P = 0.036, r = 0.321). Subgroup analysis revealed that IL-32 mRNA level was elevated in both newly onset GD and refractory GD group (P < 0.01, P < 0.001, respectively) compared with controls. Furthermore, in refractory GD group, the IL-32 mRNA expression also positively correlated with FT3 (P = 0.019, r = 0.560). In addition, serum IL-32 level was notably higher in GD patients than that of controls (P < 0.01). Subgroup analysis also indicated that serum IL-32 level in both newly onset GD and refractory GD group was higher in comparison with controls (P = 0.015, P = 0.023, respectively) and serum IL-32 level in refractory GD patients positively correlated with TRAb (P = 0.043, r = 0.481). The percentages of IL-32α⁺ cells, CD4⁺IL-32α⁺ T cells, and CD4^-IL-32α⁺ cells were all significantly enhanced in GD patients compared with controls (P = 0.005, P = 0.017, P = 0.016, respectively). IL-32 and IL-32α⁺ cells may be associated with the pathogenesis of GD. IL-32 may become a promising target for the treatment of GD.

Comparative Assessment of Female Mouse Model of Graves' Orbitopathy Under Different Environments, Accompanied by Proinflammatory Cytokine and T-Cell Responses to Thyrotropin Hormone Receptor Antigen

We recently described a preclinical model of Graves' orbitopathy (GO), induced by genetic immunization of eukaryotic expression plasmid encoding human TSH receptor (TSHR) A-subunit by muscle electroporation in female BALB/c mice. The onset of orbital pathology is characterized by muscle inflammation, adipogenesis, and fibrosis. Animal models of autoimmunity are influenced by their environmental exposures. This follow-up study was undertaken to investigate the development of experimental GO in 2 different locations, run in parallel under comparable housing conditions. Functional antibodies to TSHR were induced in TSHR A-subunit plasmid-immunized animals, and antibodies to IGF-1 receptor α-subunit were also present, whereas control animals were negative in both locations. Splenic T cells from TSHR A-subunit primed animals undergoing GO in both locations showed proliferative responses to purified TSHR antigen and secreted interferon-γ, IL-10, IL-6, and TNF-α cytokines. Histopathological evaluation showed orbital tissue damage in mice undergoing GO, manifest by adipogenesis, fibrosis, and muscle damage with classic signs of myopathy. Although no inflammatory infiltrate was observed in orbital tissue in either location, the appearances were consistent with a "hit-and-run" immune-mediated inflammatory event. A statistically significant increase of cumulative incidence of orbital pathology when compared with control animals was shown for both locations, confirming onset of orbital dysimmune myopathy. Our findings confirm expansion of the model in different environments, accompanied with increased prevalence of T cell-derived proinflammatory cytokines, with relevance for pathogenesis. Wider availability of the model makes it suitable for mechanistic studies into pathogenesis and undertaking of novel therapeutic approaches.

Differential cytokine expression detected by protein microarray screening in peripheral blood of patients with refractory Graves' disease

OBJECTIVE

The prognosis of Graves' disease (GD) varies among patients. However, the immune pathogenesis of refractory GD is still unknown. The aim of this study was to explore the cytokine expression profile associated with refractory GD.

METHODS

Preliminary cytokine protein microarray screening was performed to detect differentially expressed cytokines in the plasma of four patients with refractory GD and four patients with stable GD. Some differentially expressed cytokines were then validated in plasma by enzyme-linked immunosorbent assay (ELISA) and in peripheral blood mononuclear cells (PBMCs) by quantitative real-time polymerase chain reaction (qRT-PCR) on another independent set of samples.

RESULTS

We found that 21 cytokines were differentially expressed between patients with intractable GD and those in remission, including 18 upregulated and 3 downregulated cytokines with a fold change >1·30 and <0·77, respectively. Intractability-related elevation of three cytokines (IL-4, IL-6 and IL-10) was validated by ELISA in plasma on another GD cohort with 30 patients in recurrence and 14 in remission (t-test, P = 0·035, 0·033 and 0·041, respectively). Furthermore, mRNA expression of IL-4, IL-6 and IL-10 in PBMCs, detected by qRT-PCR, was significantly elevated in patients with refractory GD compared with those in remission (P = 0·039, 0·047 and 0·042, respectively).

CONCLUSION

The severity of GD is associated with the aberrant expression and secretion of several cytokines that may serve as potential biomarkers and predictors for disease prognosis. Targeting these cytokines or their receptors may also lead to a novel therapeutic intervention for GD.

An association of interleukin-10 gene polymorphisms with Graves' disease in two Chinese populations

Graves' disease (GD) is a common autoimmune disorder with a genetic predisposition. The cytokine interleukin-10 (IL-10) has a central role in mediating inflammation, which may affect the outcome of the patients with GD. To elucidate the impact of IL-10 gene polymorphisms, we performed a two-stage case-control association study of five single-nucleotide polymorphisms (SNPs) within the IL-10 gene as well as a meta-analysis of two SNP's rs1800896 and rs1800872 covering three previous studies from Iran, Taiwan, and the United Kingdom. The five SNPs were genotyped by SNPstream Genotyping and Taqman PCR. There was a significant increase of G allele of rs1800896 in the two cohorts (P (allele) = 2.6 × 10(-4) and 0.0082 for cohort Shanghai and Xiamen, respectively) compared with the controls. The meta-analysis showed the risk-increasing effects for the G allele of rs1800896 in GD (OR = 1.88; P < 0.00001). The allele and haplotype analysis results suggested that the polymorphisms of IL-10 were associated with GD susceptibility in the Chinese population.

The -112G>A polymorphism of the secretoglobin 3A2 (SCGB3A2) gene encoding uteroglobin-related protein 1 (UGRP1) increases risk for the development of Graves' disease in subsets of patients with elevated levels of immunoglobulin E

The human secretoglobin 3A2 (SCGB3A2) gene encoding secretory uteroglobin-related protein 1 (UGRP1) resides on the chromosome region 5q31-33 that harbors a susceptibility locus to several autoimmune and inflammatory diseases, including asthma and Graves' disease (GD). Recently, association between the marker rs1368408 (-112G >A), located in the promoter region of the SCGB3A2 gene, and susceptibility to GD was found in Chinese and UK Caucasians. The study aim was to evaluate whether this polymorphism confers GD susceptibility in a large population cohort comprising 1,474 Russian GD patients and 1,619 controls. The marker rs1368408 was studied using a TaqMan allele discrimination assay. Serum levels of UGRP1 and immunoglobulin E (IgE) were assessed using enzyme-linked immunosorbent assay (ELISA) analyses. Association between the allele A of SCGB3A2 and a higher risk of GD (odds ratio [OR] = 1.33, P = 2.9 × 10(-5)) was shown. Both affected and non-affected carriers of the higher risk genotype A/A had significantly decreased levels of serum UGRP1 compared to the subjects homozygous for G/G (93 ± 37 pg/ml vs. 132 ± 45 pg/ml, P = 0.0011 for GD patients; 77 ± 28 pg/ml vs. 119 ± 33 pg/ml, P = 0.0019 for controls). Serum IgE levels were significantly higher in non-affected subjects homozygous for A/A compared to control individuals homozygous for G/G (153 ± 46 IU/ml vs. 122 ± 40 IU/ml, P = 0.0095). Our data suggest that the carriage of the SCGB3A2 -112A/A variant increases the risk for GD in subsets of patients with elevated levels of IgE, a hallmark of allergic asthma. Therefore, the SCGB3A2 -112G >A polymorphism may be considered as a likely marker linking susceptibility to allergy/asthma and GD on chromosome 5q31-33.

Ratio of serum IgG3 to total IgG concentration and goiter size are independent factors in intractability of Graves' disease

Peripheral immunoglobulin (Ig) G(3)-secreting cells and serum concentrations of interleukin (IL)-10, a class-switching factor to IgG(3)-secreting cells, increase in patients with intractable Graves' disease (GD). However, they are not practical for laboratory tests. To find more stable and easily detectable markers of disease intractability or disease severity in patients with GD or Hashimoto's disease (HD), we examined the serum concentration of IgG(3) in 58 euthyroid GD patients who had been undergoing antithyroid drug treatment for more than 5 years but still must continue drug treatment to maintain a euthyroid state (intractable GD), 26 GD patients who had maintained a euthyroid state for more than 2 years without any treatment (GD in remission), 20 untreated, thyrotoxic GD patients, 40 euthyroid HD patients treated with thyroxine (5 men and 35 women), 13 untreated, euthyroid HD patients, and 39 healthy volunteers. Serum concentrations of IgG(3 )increased in euthyroid patients with intractable GD and in those with GD in remission, but serum concentrations of IgG were not altered. The ratio of serum concentrations of IgG(3) to total IgG (IgG(3)/IgG ratio) was higher in euthyroid patients with intractable GD than in those with GD in remission. Multiple logistic-regression analysis demonstrated that IgG(3)/IgG ratio and goiter size were independent factors in disease intractability of GD patients. These results suggest that IgG(3)/IgG ratio and goiter size may be used as independent markers associated with GD intractability.

Production of interleukin (IL)-5 and IL-10 accompanies T helper cell type 1 (Th1) cytokine responses to a major thyroid self-antigen, thyroglobulin, in health and autoimmune thyroid disease

Tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma exert detrimental effects in organ-specific autoimmune disease, while both destructive and protective roles have been demonstrated for interleukin (IL)-10, IL-4 and IL-5. We examined the production of these cytokines by peripheral blood mononuclear cells (PBMC) from patients with Hashimoto's thyroiditis (HT), Graves' disease (GD) and healthy controls, upon exposure to a thyroid self-antigen, human thyroglobulin (Tg), in the presence of autologous serum. Initially, TNF-alpha and IL-2 were produced in all three groups, accompanied by IL-10. Release of IFN-gamma, IL-4 and, notably, IL-5 ensued. Both patient groups exhibited increased TNF-alpha, IL-2, IFN-gamma and IL-10 responses, and PBMC from HT patients secreted lower amounts of IL-5 than male, but not female, controls. Enhanced TNF-alpha production by HT cells also occurred in the presence of pooled normal sera, indicating a dependency on intrinsic cellular factors. Conversely, higher production of TNF-alpha and IL-5 occurred in the presence of autologous sera than in the presence of pooled normal sera in both patient groups, indicating a dependency on serum constituents. Complement appeared to promote the production of IL-2 and particularly IL-5, the levels of which were reduced by neutralization of complement by heat- or zymosan treatment. The production of IFN-gamma and IL-2 of the three groups together correlated directly with the serum anti-Tg activity. Moreover, TNF-alpha, IFN-gamma, IL-5 and IL-10 responses were markedly inhibited by partial denaturation of Tg by boiling. We hypothesize that autoantibodies and complement may promote mixed Th1/Th2 cell cytokine responses by enhancing the uptake of autoantigens by antigen-presenting cells.

Effect of methimazole treatment for 2 years on circulating IL-4, IgE, TBII, and TSAb in patients with hyperthyroid Graves' disease

In this study we confirmed our previous findings on the importance of IgE in Graves' disease and further investigated the relationships existing among Graves' disease, IgE, and interleukin-4. Two hundred and thirty-two newly diagnosed Graves' disease patients were treated with methimazole for 2 years, and were classified into 3 groups according to their response to the therapy. Incidence of IgE elevation (IgE> or =170 IU/ml) before treatment was lowest, 23.8%, in the group who achieved remission without recurrence, while it was 41.7% in the group who achieved remission but recurrence occurred within 4 years. Incidence of IgE elevation before treatment was highest, 60.7%, in the group who failed to achieve remission, significantly higher than that of the group without recurrence. Incidence of IgE elevation before treatment in all these patients of Graves' disease were 35.3%, significantly higher than those of Hashimoto's thyroiditis (17.5%) and of simple goiter (7.0%). Serum IL-4 levels before treatment were significantly higher in the patients of Graves' disease with IgE elevation than in those without IgE elevation. Serum T4 concentration and TSAb titration before treatment were also significantly higher in elevated IgE group than in normal IgE group. These results support our previous findings and suggest that IL-4 may play important roles in the elevation of IgE, TBII, and TSAb in patients of Graves' disease, and that IL-4 and IgE may be involved in the development, progression, and maintenance of Graves' disease.

The effects of royal jelly on autoimmunity in Graves' disease

OBJECTIVE

Graves' disease is an organ-specific autoimmune disease with unknown etiology. TSHR Ab plays the most important role for the pathogenesis of Graves' disease. Recently, the role of cytokines for the pathogenesis of Graves' disease has been studied extensively. Royal jelly (RJ) is a creamy product secreted by young nurse worker bees (Apis mellifera), and it is synthesized in the hypopharyngeal and mandibular glands. RJ has been reported to have such pharmacological characteristics as antitumor, antibacterial, antihypercholesterolemic, antiallergic, antiinflammatory, and immunomodulatory properties. The major aim of the present study is to evaluate the effect of RJ on autoimmunity in peripheral lymphocyte culture and to establish the therapeutic doses.

RESEARCH DESIGN AND METHODS

In the first phase, lymphocyte cell isolation from four voluntary healthy subjects was performed to find the effective concentration of RJ on immunity. Serial dilutions of the RJ were prepared (0-5 mg/mL). All isolated lymphocyte cells were treated with the above diluted samples. MTT test was carried out after incubation of 72 h. In the second phase, six patients with Graves' disease, newly diagnosed by clinical and laboratory methods and admitted to my hospital and untreated were identified. RJ samples of 0 and 4 mg/mL were incubated in a culture medium for 72 h with isolated lymphocytes obtained from the patients. After incubation, MTT test in lymphocyte cell culture, Th1 cytokines IFN-gamma, TNF-alpha, and IL-12, and Th2 cytokines IL-4 and IL-10 levels by the enzyme amplified sensitivity immunoassay (EASIA) method and TSHR Ab by the radioreceptor method were determined.

RESULTS

The concentration causing lymphocytes to proliferate was found to be 4 mg/mL by MTT test after incubation of 72 h in cell culture medium. Of the cytokines produced and secreted from lymphocytes, IFN-gamma increased, whereas, other cytokines decreased in RJ concentration of 4 mg/mL. Significant differences were found only for IFN-gamma and TNF-alpha. IL-4 concentrations were kept near the level of significancy. Of Th1/Th2 ratios, IFN-gamma/IL-4 and IFN-gamma/IL-10 ratios also exhibited significant differences between 0 and 4 mg/mL. RJ treatment in lymphocytes from patients with Graves' disease shifted the Th1/Th2 cytokine ratio to the side of Th1 cytokine. Therefore, RJ using the treatment and establishing a remission of Graves' disease may be effective as an antithyroid drug treatment. TSHR Ab levels of lymphocyte cell culture supernatants treated with RJ showed significant decreases. Also, the result may suggest that RJ may exert an effect similar to an antithyroid drug for decreasing TSHR Ab levels.

CONCLUSIONS

RJ may be effective as an immunomodulatory agent in Graves' disease.