Lymphocytes in peripheral blood and thyroid tissue in children with Graves' disease

"Lymphocyte population in peripheral blood in children and adolescents with graves disease. Potential predictive tool for severity of the disease"

PURPOSE

To date, few data are available on the prognostic role of lymphocyte subsets in pediatric Graves' Disease (GD). The aim of this retrospective study is to analyze the role of lymphocyte subtypes in predicting the severity of GD.

METHODS

Data of 10 pediatric subjects aged <18 years with GD onset in the period November 2017-April 2021 were collected. The lymphocyte population was assessed at the onset of GD as well as hormonal and clinical data. The follow-up period was 2.4 ± 0.8 years.

RESULTS

Pearson correlation coefficient between CD4+ /CD8+ ratio and fT3 levels and thyroid volume at diagnosis was 0.72 (p = 0.04) and 0.81 (p = 0.004) respectively; that between CD4+ /CD8+ ratio and the TRAb titer at diagnosis and after 6, 12 and 24 months was 0.89, 0.89, 0.73 and 0.77 respectively (p = 0.02, p = 0.01, p = 0.03 and 0.04). The correlation coefficient of anti-thyroid drug (ATD) dose after 6 and 12 months with CD4+ /CD8 ratio was 0.88 and 0.78 (p = 0.001 and p = 0.02 respectively). Patients with a higher CD4+ /CD8+ ratio at diagnosis displayed higher fT3 levels (28.73 ± 2.18 vs 13.48 ± 2.19 pmol/L, p = 0.03) and higher TRAb titers (28.9 ± 11.2 vs 4.88 ± 0.97, p = 0.01).

CONCLUSION

CD4+/CD8+ ratio appears as a promising predictive tool to be considered together with other prognostic factors to better manage pediatric GD. These preliminary data need to be confirmed over a longer follow-up period and in larger cohorts.

Clinical relevance of T lymphocyte subsets in pediatric Graves' disease

Objectives Graves' disease (GD) is an autoimmune disease involving intimate response of both T cells and B cells. Immunophenotyping of peripheral blood lymphocyte subsets in GD children with different clinical characteristics can provide further information of the pathogenesis of GD. Methods We studied the lymphocyte subsets in peripheral blood of 141 children with GD. We repeatedly divided the patients into two groups in accordance with different clinical characteristics (abnormal or normal alanine aminotransferase (ALT) levels, the presence or absence of Graves' orbitopathy (GO), and the presence or absence of hematuria. Then we compared the lymphocyte subsets measurements between two paired groups. Results We found that serum ALT levels correlated positively with CD3+CD8+ T cell percentages in children with GD. Moreover, we detected higher percentages of CD3-CD19+ cells and higher ratio of CD4/CD8 in patients with GO. However, no correlation was found between GO status and lymphocyte subsets after excluding confounding effect of TRAb. No difference of lymphocyte subset percentages was found between groups with or without hematuria. Conclusions Serum ALT levels correlate positively with cytotoxic T cell percentages in the peripheral blood of children with GD. The cytotoxic T cell may play a role in the pathogenesis of hepatic dysfunction in children with GD.

Interleukin-21 is associated with disease activity in patients with Graves' disease

Graves' disease (GD) is a common autoimmune disease mainly caused by thyroid-stimulating antibodies (TSAbs). Interleukin 21 (IL-21) has recently been reported to play a vital role in the production of pathogenic autoantibodies in several autoimmune diseases, but less is known about GD. This study aimed to investigate the serum levels of IL-21 in GD patients and to explore their association with disease activity. We performed a case-control association study of 152 patients with GD and 32 healthy controls. All patients were further classified into three subgroups: the GD-untreated group (n = 70), the GD-recurrence group (n = 41), and the GD-remission group (n = 41). Serum IL-21 levels were assayed with ELISA. TSAb activity was measured by an in vitro bioassay. Changes in serum IL-21 were also observed in 12 GD patients before and after treatment. Additionally, correlations among the serum IL-21 and free triiodothyronine (FT3), free thyroxine (FT4), thyrotropin (TSH), thyroperoxidase antibodies (TPOAb), thyroglobulin antibodies (TGAb), thyrotropin receptor antibody (TRAb), and TSAb were also analyzed. The serum IL-21 levels in all GD patients were significantly higher than those in the control group (P < 0.001), and specifically, both the GD-untreated and GD-recurrence groups had elevated serum IL-21 compared to the control group (P < 0.001). Moreover, serum IL-21 in newly diagnosed patients markedly decreased after treatment (P < 0.001). Additionally, the serum IL-21 levels in GD-goiter patients were higher than those of the GD-non-goiter patients (P < 0.001). However, no significant differences were found in the serum IL-21 levels in patients with or without Graves' ophthalmopathy. Importantly, serum IL-21 positively correlated with FT3, FT4, TPOAb, TGAb, and TRAb (r = 0.5053, r = 0.3266, r = 0.1792, r = 0.2445, and r = 0.4096, respectively; all P < 0.0001), and particularly with TSAb activity (r = 0.8171, P < 0.0001), negatively correlated with TSH (r = -0.2713, P < 0.0001). Serum IL-21 levels were significantly elevated in patients with GD and decreased after treatment; moreover, IL-21 may be associated with the clinical disease activity. These observations suggest that IL-21 may play an important role in the pathogenesis of GD.

Immunoregulatory T cells, LFA-3 and HLA-DR in autoimmune thyroid diseases

AIM

The aim of the present study was to examine the changes in the expression of T-cell activation markers, namely CD4+ CD25+ and CD8+ in patients with AITD, namely Graves' disease and Hashimoto's thyroiditis as well as colloid nodular goitre. HLA-DR, LFA-3, and peripheral total lymphocytic count are also measured.

MATERIALS AND METHODS

We compared the expression of CD4, CD25, and CD8 surface markers in peripheral blood lymphocyte in Graves' disease and Hashimoto's thyroiditis as autoimmune thyroid diseases, as well as colloid goitre in comparison with healthy controls. Also, LFA-3 and HLA-DR were measured in the same groups using three-color flow cytometry. Total lymphocytic count in peripheral blood, thyroid function tests, antithyroid antibodies were also included in the laboratory investigations. The total number of participants was 65. All were recruited from endocrine clinics in a tertiary care hospital in the southern region of Saudi Arabia. All participants underwent history taking, clinical examination, laboratory workup, and radiological investigations. Neck ultrasound, technecium pertechnetate(ψψ) thyroid uptake, and fine-needle aspiration and cytology (FNAC) of the thyroid were done when indicated. The study was approved by the Hospital Research Isthics Committee and informed consents were obtained from all participants before enrollment in the study.

RESULTS

In comparison with thecontrol group, activation markers CD4, CD25, and CD8 were lower in the autoimmune thyroid diseases. Lymphocyte function antigen-3 (CD58) and total lymphocytic count were higher in the AIT diseases whereas HLA-DR was lower than that in the control group. The CD4/CD8 ratio was lower in the AITD compared with the healthy euthyroid subjects. No difference was found between patients with colloid nodular goitre and the healthy control in any of the study variables except for LFA-3 which was significantly higher in the colloid goitre group.

CONCLUSION

Our findings indicate downregulation of CD4+ CD25+ Treg as well as CD8+ T cells in autoimmune thyroid diseases. Downregulation of suppressor T lymphocytes helps initiation, progression, and maintenance of the autoimmune thyroid diseases. Lower HLA-DR and higher CD58 in AITDs indicate their role in the expression of the autoantigen and its escape from the immune surveillance. High levels of LFA-3 in colloid goitre indicate that the autoimmune process needs interacting factors, and not only the high level of LFA-3.

Interferon-gamma ELISPOT detecting reactivity of T cells to TSH receptor peptides in Graves' disease

OBJECTIVE

While thyrotrophin receptor (TSHR) is recognized as the main autoantigen in Graves' disease (GD), the actual antigen specificity of T cells that infiltrate the thyroid and the orbit is unknown. Identifying T cell responses to TSHR peptides has been difficult in the past due to the low frequency of autoreactive T cells and to the diversity of the putative epitopes identified by proliferation assays.

METHODS

We used the interferon-gamma ELISPOT assay to identify T cell reactivity to TSHR peptides in patients with GD. Peripheral blood T cells were exposed in vitro to four pools of 10 overlapping TSHR peptides.

RESULTS

T cells from 11 of 31 (35%) patients with GD and 1 of 22 (4%) healthy controls reacted to at least one peptide pool (P = 0·009). Mean time since diagnosis was 3·2 years in responder patients and 5·6 years in nonresponders (P = 0·07). In two patients, T cell reactivity was observed shortly after radioiodine treatment and not thereafter.

CONCLUSIONS

Our findings demonstrate that the ELISPOT assay is effective to test T cell reactivity in patients with GD and that patients with GD have significantly more interferon-gamma responses towards TSHR peptides than controls. The data suggest that screening for T cell responses in patients with GD might be more efficient in recent-onset disease or after radioiodine treatment.

The differences in T and B cell subsets in thyroid of children with Graves' disease and Hashimoto's thyroiditis

BACKGROUND

The differences between Graves' disease (GD) and Hashimoto's thyroiditis (HT) suggest that changes in the subsets of T cells may have an influence on the course of these reactions.

METHODS

This study included 90 children: 30 with GD, 30 with HT, and 30 healthy children as controls. After thyroidectomy, standard histological examinations and immunohistochemical reactions were performed in paraffin specimens with monoclonal antibodies against T cell markers CD3, CD4, CD8 as well as against CD79 alpha B cells. Ultrathin sections were examined under a transmission electron microscope.

RESULTS

Autoimmune reaction in GD consisted of an increased number of CD4+ T cells (3.17±4.27%) and plasma cells (22.89±8.61%) producing thyroidstimulating hormone-receptors and stimulating thyrocytes to activity. The number of CD8+ T cells was increased in children with HT (20.54±0.68%) as compared with the controls (0.65±0.30%). The autoimmune reaction in the HT children showed antibody dependent cytotoxicity with a low number of CD4+ T cells and an increased number of CD8+ T cells in the thyroid tissue in comparison with that in the GD children and the controls. Plasma cells (31.65±9.11%) in this situation produced the antibodies involved in cytotoxic reactions against thyrocytes.

CONCLUSIONS

Graves' disease is characterized by the increased number of CD4+ T cells and CD8+ T cells. Hashimoto's thyroiditis is characterized by the low number of CD4+ T cells and increased number of CD8+ T cells. CD8+ T cells have cytotoxic properties only in Hashimoto's thyroiditis.