Increased percentage of L-selectin+ and ICAM-1+ peripheral blood CD4+/CD8+ T cells in active Graves' ophthalmopathy

DNA Methylation in Autoimmune Thyroid Disease

Graves disease and Hashimoto disease form part of the spectrum of autoimmune thyroid disease (AITD), to which genetic and environmental factors are recognized contributors. Epigenetics provides a potential link between environmental influences, gene expression, and thyroid autoimmunity. DNA methylation (DNAm) is the best studied epigenetic process, and global hypomethylation of leukocyte DNA is reported in several autoimmune disorders. This review summarizes the current understanding of DNAm in AITD. Targeted DNAm studies of blood samples from AITD patients have reported differential DNAm in the promoter regions of several genes implicated in AITD, including TNF, IFNG, IL2RA, IL6, ICAM1, and PTPN22. In many cases, however, the findings await replication and are unsupported by functional studies to support causal roles in AITD pathogenesis. Furthermore, thyroid hormones affect DNAm, and in many studies confounding by reverse causation has not been considered. Recent studies have shown that DNAm patterns in candidate genes including ITGA6, PRKAA2, and DAPK1 differ between AITD patients from regions with different iodine status, providing a potential mechanism for associations between iodine and AITD. Research focus in the field is moving from candidate gene studies to an epigenome-wide approach. Genome-wide methylation studies of AITD patients have demonstrated multiple differentially methylated positions, including some in immunoregulatory genes such as NOTCH1, HLA-DRB1, TNF, and ICAM1. Large, epigenome-wide studies are required to elucidate the pathophysiological role of DNAm in AITD, with the potential to provide novel diagnostic and prognostic biomarkers as well as therapeutic targets.

Effect of Prunella vulgaris polysaccharides on cultured orbit fibroblasts in vitro from patients with thyroid-associated ophthalmopathy

To observe the effect of Prunella vulgaris polysaccharides (PVP) on cultured orbit fibroblasts in vitro from patients with thyroid-associated ophthalmopathy (TAO). PVP at different concentrations were used to treat different groups of fibroblasts from TAO patients and normal persons. Dexamethasone (Dex) was used as a positive control drug, and interferon-γ (IFN-γ) was used as a positive stimulant. The effects of PVP on the proliferation of orbital fibroblasts, the secretion of hyaluronic acid (HA), the expression of intercellular adhesion molecule-1 (ICAM-1/CD54) and apoptosis in orbital fibroblasts were determined. The experimental results showed when the concentration of PVP was greater than 400 μg/mL, it could significantly inhibit the proliferation of orbital fibroblasts from patients with TAO (P < 0.05). However, no definite inhibitory effect was observed in the orbital fibroblasts from the normal people. Dex could significantly inhibit the proliferation of orbital fibroblasts from patients with TAO and the normal people (P < 0.05). In contrast, every concentration of IFN-γ could promote the orbital fibroblasts from patients with TAO and the normal people proliferation. No groups had statistically significant stimulatory effect on HA secretion by orbital fibroblasts from normal people (P > 0.05). But the Dex group, IFN-γ+PVP-1600 group and IFN-γ+Dex group could significantly inhibit the secretion of HA from orbital fibroblasts of TAO patients. And there were no groups had statistically significant stimulatory effect on the expression of ICAM-1/CD54 in orbital fibroblasts from TAO patients (P > 0.05). PVP and Dex at all concentrations could significantly promote orbital fibroblast co-cultured with IFN-γ apoptosis (P < 0.05). But without IFN-γ, PVP and Dex at all concentrations could only significantly promote orbital fibroblast from TAO patients apoptosis (P < 0.05). These results suggest that PVP exerts its therapeutic effect by inhibiting the proliferation of orbital fibroblasts and promoting the apoptosis of orbital fibroblasts in TAO patients. In addition, in this process, HA secretion is suppressed. But the participation of IFN-γ is required. This effect is similar to that of Dex. And in the MTT experiment, the efficacy of PVP showed selectivity for TAO patients. This is different from Dex. This may be a feature of PVP that deserves attention.

Immunological Aspects of Graves' Ophthalmopathy

The body's autoimmune process is involved in the development of Graves' disease (GD), which is manifested by an overactive thyroid gland. In some patients, autoreactive inflammatory reactions contribute to the development of symptoms such as thyroid ophthalmopathy, and the subsequent signs and symptoms are derived from the expansion of orbital adipose tissue and edema of extraocular muscles within the orbit. The autoimmune process, production of antibodies against self-antigens such as TSH receptor (TSHR) and IGF-1 receptor (IGF-1R), inflammatory infiltration, and accumulation of glycosaminoglycans (GAG) lead to edematous-infiltrative changes in periocular tissues. As a consequence, edema exophthalmos develops. Orbital fibroblasts seem to play a crucial role in orbital inflammation, tissue expansion, remodeling, and fibrosis because of their proliferative activity as well as their capacity to differentiate into adipocytes and myofibroblasts and production of GAG. In this paper, based on the available medical literature, the immunological mechanism of GO pathogenesis has been summarized. Particular attention was paid to the role of orbital fibroblasts and putative autoantigens. A deeper understanding of the pathomechanism of the disease and the involvement of immunological processes may give rise to the introduction of new, effective, and safe methods of treatment or monitoring of the disease activity.

Markers of inflammation and fibrosis in the orbital fat/connective tissue of patients with Graves' orbitopathy: clinical implications

Purpose. To assess FGF-β, TGF-β, and COX2 expression and immunocompetent cells in the orbital tissue of patients with severe and mild Graves' orbitopathy. Patients and Methods. Orbital tissue was taken from 27 patients with GO: (1) severe GO (n = 18), the mean clinical activity score (CAS) being 8.5 (SD 2.5); and (2) mild GO (n = 9), the mean CAS being 2.2 (SD 0.8), and from 10 individuals undergoing blepharoplasty. The expression of CD4+, CD8+, CD20+, and CD68 and FGF-β, TGF-β, and COX2 in the orbital tissue was evaluated by immunohistochemical methods. Results. We demonstrated predominant CD4+ T cells in severe GO. CD68 expression was observed in the fibrous connective area of mild GO and was robust in severe GO, while the prominent TGF-β expression was seen in all GO. Increased FGF-β expression was observed in the fibroblasts and adipocytes of severe GO. No expression of COX2 was found in patients with GO. Conclusions. Macrophages and CD4 T lymphocytes are both engaged in the active/severe and long stage of inflammation in the orbital tissue. FGF-β and TGF-β expression may contribute to tissue remodeling, fibrosis, and perpetuation of inflammation in the orbital tissue of GO especially in severe GO.

Elevated percentage of HLA-DR⁺ and ICAM-1⁺ conjunctival epithelial cells in active Graves' orbitopathy

Background

To evaluate if conjunctival epithelial cells’ expression of HLA-DR and ICAM-1 could be helpful as early topical markers of inflammation in Graves’ orbitopathy (GO).

Methods

The ocular examination evaluated a clinical activity score (CAS) by assessment of clinical features, (e.g., eyelid or conjunctival inflammation, lid width, lid closure, proptosis, ocular motility). Conjunctival epithelial cell specimens for flow-cytometric evaluations of ICAM-I and HLADR expression were collected by impression cytology from ten eyes with active GO (CAS ≥ 4 and duration ≤ 12 months), from 15 eyes with Graves’ disease (GD) without active GO (CAS 0–2) and from 15 normal specimens without any ocular disorders.

Results

The percentage of HLA-DR + conjunctival epithelial cells was significantly elevated in patients with active GO comparing to GD without active GO and healthy controls, 10.7 % (8.5–17.7) and 7.78 % (3.92–10.1) (p < 0.05) vs. control 4.89 % (3.5–5.5) (p < 0.005), respectively. The expression of ICAM − 1+ conjunctival epithelial cells was greater only in patients with GO vs. controls, 5.5 % (4.8–7.03) and 1.46 % (0.69–2.51) (p < 0.005), respectively.

Conclusion

The percentage of HLA-DR⁺ and ICAM-1⁺ conjunctival epithelial cells in patients with the active GO may serve as a topical inflammation marker in Graves’ orbitopathy.