Expression of membrane and soluble intercellular adhesion molecule-1 in Graves' disease

Key gene co-expression modules and functional pathways involved in the pathogenesis of Graves' disease

Graves' disease (GD) is a common autoimmune thyroid disease characterized by positive thyroid stimulating hormone receptor antibody. To better understand its molecular pathogenesis, we adopted the weighted gene co-expression network analysis to reveal co-expression modules of key genes involved in the pathogenesis of GD, protein-protein interaction network analysis to identify the hub genes related to GD development and functional analyses to explore their possible functions. Our results showed that 1) a total of 2667 differentially expressed genes in our microarray study and 16 different gene co-expression modules were associated with GD, and 2) the most significant module was associated with the percentage of macrophages, T follicular helper cells and CD4⁺ memory T cells and mainly enriched in immune regulation and immune response. Overall, our study reveals several key gene co-expression modules and functional pathways involved in GD, which provides some novel insights into the pathogenesis of GD.

Lymphocyte homing in xenotransplanted human thyroid tissue can be inhibited by LFA-1 and ICAM-1 antibodies

OBJECTIVES

Homing of lymphocytes is an important factor with respect to the initiation of the autoimmune process in Graves' disease (GD). As previously shown, human lymphocytes, particularly of intrathyroidal origin, derived from patients with GD, are able to migrate into normal xenotransplanted thyroid tissue and induce functional and histological changes. The aim of this study was to investigate the effect of LFA-1 and ICAM-1 antibodies on the homing of lymphocytes of different origin into xenografted human thyroid tissue.

METHODS

Eighty-five nude mice bearing 8-week-old xenografts of normal human thyroid tissue were treated twice with anti-CD 54 (anti-ICAM-1), anti-CD 11a (anti-LFA-1), a combination of both, or, serving as controls, iso-antibodies without specific binding capacity or saline. Thereafter, intrathyroidal (ITL) or peripheral blood lymphocytes (PBL) obtained from 4 patients with GD or saline were injected into the animals (i.v., 0.2 mL, 10(6) cells). After 48 hours the mice were sacrificed and transplants as well as mice thyroids were examined by immunohistochemical staining with Ki67, CD3, HLA-II (DAKO, Hamburg), IgG, CD44, ICAM-1, and VCAM-1 (Immunotech, Hamburg).

RESULTS

Pretreatment with anti-ICAM-1 and anti-LFA-1 decreased lymphocyte homing (CD3-staining), and expression of HLA-II, IgG, CD44, and VCAM-1 in the transplants.

CONCLUSION

Our data show that [ICAM-1/LFA-1 stimulated (induced)] lymphocyte homing and subsequently thyrocyte proliferation are inhibited by ICAM-1 and LFA-1 antibodies in xenotransplanted thyroid tissue. This suggests that ICAM1 and LFA-1 play an important role in the early steps of autoimmune thyroid disease. The inhibition/suppression of ICAM-1 and LFA-1 interaction by respective antibodies, as demonstrated in the present study, may provide a new concept for prophylaxis and therapy.

Expression of intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 and homing factor CD44 after engraftment of Graves' lymphocytes in xenotransplanted human thyroid tissue in athymic nude mice

The expression of adhesion molecules on thyrocytes and endothelium cells plays an important role in the pathogenesis of Graves' disease (GD). The intercellular adhesion molecule-1 (ICAM-1), the vascular cell adhesion molecule-1 (VCAM-1), and the homing receptor CD44 are responsible for the specific migration of lymphocytes in autoimmune thyroid diseases (AITD) (homing). Eight weeks after transplantation of thyroid tissue from 26 patients with nonautoimmune thyroid disease (nontoxic nodular goiter [NTG]) into nude mice, peripheral (PBL) and intrathyroidal lymphocytes (ITL) from 14 patients with NTG and 12 patients with GD were grafted into the animals. Two days after lymphocyte engraftment, the thyroid transplants were examined histologically (HE) and immunohistologically stained with monoclonal antibodies directed against ICAM-1, VCAM-1, and CD44. After injection of GD lymphocytes, thyroid transplants expressed significantly more ICAM-1, VCAM-1, and CD44 than after injection of NTG lymphocytes. This expression was even more pronounced after grafting of GD intrathyroidal lymphocytes. Our data demonstrate that only GD lymphocytes induce the expression of adhesion molecules and homing factor CD44, both of which play an important role in the migration of lymphocytes and induction of the autoimmune process.

Thyrocyte proliferation by cellular adhesion to infiltrating lymphocytes through the intercellular adhesion molecule-1/lymphocyte function-associated antigen-1 pathway in Graves' disease

Graves' disease (GD) is an autoimmune thyroid disease characterized by infiltration of lymphocytes into the thyroid, and intrathyroid lymphocytes are known to play an important role in the pathogenesis of GD. However, it remains to be understood how lymphocytes adhere to thyrocytes and regulate the thyrocyte function through cellular adhesion. We studied the mechanisms of T cell adhesion to thyrocytes using intrathyroid mononuclear cells (ITMC) and thyrocytes purified from the thyroids of patients with GD. The following novel features of cellular adhesion of ITMC to thyrocytes in the regulation of the thyrocyte function in GD were observed: 1) GD-ITMC expressed lymphocyte function-associated antigen (LFA)-1, which became an active adhesive configuration much higher than peripheral blood mononuclear cells (PBMC) from normal volunteers and GD patients; 2) GD-thyrocytes expressed a high quantity of intercellular adhesion molecule (ICAM)-1; 3) GD-ITMC adhered to GD-thyrocytes, whereas normal PBMC required activation stimuli by phorbol myriacetate, a pharmacological integrin-trigger, to adhere to GD- thyrocytes; 4) monoclonal antibody-blocking studies showed that the adhesion of the activated PBMC and ITMC to thyrocytes was mainly mediated by the LFA-1/ICAM-1 pathway; 5) the adhesion of GD-thyrocytes to the activated-PBMC or ITMC induced the proliferation of the thyrocytes, which was blocked by the addition of ICAM-1 and/or LFA-1 monoclonal antibodies; and 6) in GD thyrocytes of early cultures, ICAM-1 expression on GD-thyrocytes and its adhesion to LFA-1 on phorbol myriacetate-activated PBMC or ITMC were not modulated by the addition of interleukin-1beta or interferon-gamma, and proliferation of thyrocytes by the cellular adhesion via the ICAM-1/LFA-1 pathway was independent of the proliferative response of these cytokines. Taken together, these results suggest that lymphocytes infiltrating GD thyroid induce proliferation of GD-thyrocyte by the cellular adhesion to thyrocytes via ICAM-1/LFA-1, which may lead to the development of a goiter.

Longitudinal study of soluble intercellular adhesion molecule-1 (ICAM-1) in sera of patients with Graves' disease

Adhesion molecules, such as Intercellular Adhesion Molecule-1 (ICAM-1), play an important role during the autoimmune process of Graves' disease (GD). So the objective of the study was to evaluate the time-course of the soluble ICAM-1 (sICAM-1) in GD. Concentrations of sICAM-1, thyroid hormones and TSAb (thyroid-stimulating antibodies) were determined in sera from 30 healthy controls, 41 untreated GD patients and after 3, 6, 12, 18 months of carbimazole therapy (no.=30), at relapse (no.=11) or 2 years after the end of therapy when remission (no.=13). Mean sICAM-1 concentration was significantly higher in untreated GD patients than in controls (mean+/-SD: 371+/-108 ng/ml vs 243+/-47 ng/ml, p<0.0001) until 6 months of therapy (289+/-102 ng/ml; NS). The number of positive patients (sICAM-1 levels>mean of the controls+2 SD) declined from 56% (23/41) at the time of the diagnosis to 10% (3/29) at 18 months. At relapse, mean sICAM-1 level significantly increased compared to that at 18 months of therapy (288+/-65 vs 236+/-59 ng/ml, p=0.005). At remission mean sICAM-1 level was significantly lower than in relapse patients (240+/-48 ng/ml, p=0.04); no patient displayed sICAM-1 positive values. In conclusion, sICAM-1 concentrations were increased in sera of newly diagnosed GD patients, declined significantly during carbimazole therapy and could again be increased at relapse. sICAM-1 could reflect an ongoing immune process and help to affirm the presence of an autoimmunity notably in some cases of TSAb negative patients. However its precise interest in clinical practice remains to be determined in further studies.