Infiltrating gamma/delta T-cell receptor-positive lymphocytes in Hashimoto's thyroiditis, Graves' disease and papillary thyroid cancer

Inhibition of IL-17A Protects against Thyroid Immune-Related Adverse Events while Preserving Checkpoint Inhibitor Antitumor Efficacy

Immune checkpoint inhibitor (ICI) immunotherapy leverages the body's own immune system to attack cancer cells but leads to unwanted autoimmune side effects in up to 60% of patients. Such immune-related adverse events (IrAEs) may lead to treatment interruption, permanent organ dysfunction, hospitalization, and premature death. Thyroiditis is one of the most common IrAEs, but the cause of thyroid IrAEs remains unknown. In this study, we use a new, physiologically relevant mouse model of ICI-associated autoimmunity to identify a key role for type 3 immune cells in the development of thyroid IrAEs. Multiple lineages of IL-17A-producing T cells expand in thyroid tissue with ICI treatment. Intrathyroidal IL-17A-producing innate-like γδT17 cells were increased in tumor-free mice, whereas adaptive Th17 cells were also prominent in tumor-bearing mice, following ICI treatment. Furthermore, Ab-based inhibition of IL-17A, a clinically available therapy, significantly reduced thyroid IrAE development in ICI-treated mice with and without tumor challenge. Finally, combination of IL-17A neutralization with ICI treatment in multiple tumor models did not reduce ICI antitumor efficacy. These studies suggest that targeting Th17 and γδT17 cell function via the IL-17A axis may reduce IrAEs without impairing ICI antitumor efficacy and may be a generalizable strategy to address type 3 immune-mediated IrAEs.

Association of increased eomesodermin, BCL6, and granzyme B expression with major clinical manifestations of Hashimoto's thyroiditis - an observational study

PURPOSE

Studies of cytotoxic T cells and their respective lineage master regulators have been limited in Hashimoto's thyroiditis (HT). It is unclear whether their transcriptomes are changed in HT patients and how these changes are associated with the thyroid damage, major clinical manifestations, and disease progression.

METHODS

We explored the gene expression patterns of selected transcription factors [eomesodermin (EOMES), BACH2, BCL6, TCF1] and cytolytic molecules [granzyme B (GZMB)] in peripheral blood (PB) T cells of 10 healthy controls and 30 HT patients of various subtypes (hypothyroid, untreated HT; L-thyroxine (T4)-treated HT, and spontaneously euthyroid HT) using real-time quantitative PCR.

RESULTS

EOMES (Mann-Whitney P = 0.044), GZMB (P = 0.028), and BCL6 mRNA (P = 0.001) were overrepresented in PB T cells from HT and showed levels varying by age, thyroid volume and disease severity. BCL6 transcripts were predominantly enriched in severely affected, hypothyroid cases, both on and off LT4. Increased EOMES RNA expression was associated with advancing age, lower thyroid volumes and higher peak adjusted TSH levels over the course of the disease. The body mass-adjusted, steady-state maintenance dose of LT4 increased with GZMB and BCL6 levels in PB T cells of hypothyroid cases, mostly postmenopausal women having long-standing, non-goitrous and atrophic disease form.

CONCLUSIONS

Our exploratory results suggest a role for GZMB, EOMES, and BCL6 in the context of HT, thyroid injury, and aggressive/advanced disease forms. Functions enriched within differentially expressed transcripts could be an important new target in understanding the pathogenesis of HT.

γδ Τ cells enhance B cells for antibody production in Hashimoto's thyroiditis, and retinoic acid induces apoptosis of the γδ Τ cell

TCR γδ(+) Τ cells are important in the pathogenesis of inflammatory and autoimmune conditions. This study investigated the effect of γδ T cells on autoantibody production in patients with Hashimoto's thyroiditis (HT). A total of 148 subjects were enrolled, including 99 patients with HT, 5 with simple goiters, and 44 healthy controls. Peripheral blood and thyroid mononuclear cells were subjected to flow cytometric analysis. Thyroid tissues underwent immunofluorescent staining and immunohistochemistry for γδ T cells and anti-thyroid antibody detection. Antibody production was measured by ELISA and automated chemiluminescent immunoassays. And activation and apoptosis of peripheral blood γδT cells and B cells were measured by flow cytometric analysis. The percentage of γδ T cells were greater in thyroid tissue from HT patients than that of goiter patients (n = 5, 5.33 ± 1.20 vs. 2.07 ± 0.44 %; P < 0.05), with the Vδ1(+) γδ T cell subset especially dominant. Frequencies of CD69 (8.42 ± 1.08 vs. 1.60 ± 0.38 %, P < 0.001), HLA-DR (58.12 ± 6.36 vs. 37.82 ± 3.70 %, P < 0.05), CD40L (1.58 ± 0.35 vs. 0.15 ± 0.05 %, P < 0.01), and ICOS (2.78 ± 0.66 vs. 0.28 ± 0.13 %, P < 0.01) expressed on γδ T cells from HT patients (n = 19) were significantly increased compared with those of healthy controls (n = 15). More importantly, γδ T cells from HT patients enhanced B cells for antibody production, and all-trans retinoic acid (ATRA) treatment inhibited the effect by inducing apoptosis of γδ Τ cells. γδ Τ cells appear to play an important role in the pathogenesis of HT, and ATRA might be an effective regulator for HT patients.

Thyroid organoid formation in simulated microgravity: influence of keratinocyte growth factor

The generation of artificial human thyroid tissues in suspension (low-shear environment, present in simulated microgravity [MG] and generated by a rotary cell culture system [RCCS]), was enhanced by increasing medium kinematic viscosity with a (3% v/v) suspension of extracellular matrix (basement membrane extract [BME]) in serum-free medium to generate artificial human thyroid organoids. Recombinant human keratinocyte growth factor (KGF, 7 ng/mL) facilitated human thyrocyte aggregation and three-dimensional (3-D) differentiation. There was an MG-associated decrease in extractable DNA that was reversed after addition of keratinocyte growth factor (KGF). In simulated MG, the increase in extractable DNA after KGF addition was up to 170% over non-KGF control cultures. In contrast, monolayer cultures in unit gravity showed a maximum DNA increase of 39% after KGF addition. Morphologically, differentiated thyroid neofollicles displayed polarization and were located in close proximity after 2 weeks of culture. Immunogold labeling with antibody to human thyroglobulin (Tg) revealed staining of follicular lumina and secretory vesicles, and a time-dependent increase in human Tg was detected in the culture media. Culture under simulated MG thus allowed direct visualization of KGF-facilitated thyrocyte/extracellular matrix interaction. Such artificial human thyroid organoids-generated in MG and in the presence of KGF-structurally resembled natural thyroid tissue. The above findings may have implications for autoimmune thyroid disease where KGF (if, for example, secreted locally by intraepithelial gammadelta T cells among other cells) may contribute to thyroid cell growth.

Serial analysis of circulating T gamma/delta lymphocyte subpopulations in Graves' disease

In the present paper the distribution of peripheral blood T gamma/delta lymphocytes in Graves' disease patients is analyzed in order to correlate them with disease activity and with prognosis. Eighteen patients with Graves' disease, 24 patients with Hashimoto's thyroiditis and 32 sex- and age-matched healthy control subjects were studied. Peripheral blood CD3+ alpha/beta and gamma/delta T lymphocytes as well as CD4+ and CD8+ T cells, and CD19 (B) lymphocytes were analyzed by cytofluorometry. At diagnosis, patients who required a radical treatment for thyrotoxicosis control showed a significant decrease of T gamma/delta lymphocytes and an increase of B cells when compared with those who maintained the euthyroid state after methimazole. No correlation was detected between the percentages of these subpopulations and serum free thyroxine. This decreased proportion did not normalize after methimazole or radical treatments. These results suggest that the cytotoxic T gamma/delta compartment of the immune system is altered in patients with Graves' disease.