Expression of TIGIT and FCRL3 is Altered in T Cells from Patients with Distinct Patterns of Chronic Autoimmune Thyroiditis.

Abstract

BACKGROUND:

Co-inhibitory receptors (IR), such as TIGIT and FCRL3, provide a checkpoint against highly destructive immune responses. Co-expression of TIGIT and FCRL3, in particular, has been linked to the HELIOS+ subset of regulatory CD4+FOXP3+T-cells. Of these, CD4+FOXP3-exon(E)2+ cells have higher expression of IR and exhibit strongest suppressive properties. Nevertheless, how the expression of TIGIT, FCRL3, HELIOS, and FOXP3E2 is regulated in chronic autoimmune thyroiditis (AT), is not known.

METHODS:

Thirty patients with AT [encompassing spontaneously euthyroid (euAT), hypothyroid-untreated and L-thyroxine-treated cases)] and 10 healthy controls (HC) were recruited. FCRL3, TIGIT, HELIOS and FOXP3E2 mRNA expression levels in peripheral blood (PB) T cells were measured via quantitative real-time PCR and compared to clinicopathological factors.

RESULTS:

The TIGIT and FCRL3 expression levels from T cells of AT cases were inversely related to the thyroid volume, and were significantly increased in hypothyroid patients (on+off L-thyroxine), but not euAT cases. The FCRL3 expression in PB T cells positively correlated with thyroid-peroxidase autoantibody levels; by contrast, T cells from aged AT patients and combined samples (AT+HC) accumulated more TIGIT mRNA. The patients with higher TIGIT mRNA levels had a greater prevalence of hypothyroidism, showing higher peak thyrotropin levels at diagnosis or at follow-up.

CONCLUSIONS:

Multiple IR, namely FCRL3 and TIGIT, but not the transcription factors HELIOS and FOXP3E2, showed increased mRNA levels in PB T cells from end-stage, long-standing and/or more aggressive AT, in proportion to disease severity. A relation with major clinical subphenotypes was observed, thereby identifying IR as potentially important players in AT.

• Authors: Mario Štefanić, Stana Tokić, Mirjana Suver-Stević, Ljubica Glavaš-Obrovac
• Journal: Experimental and clinical endocrinology & diabetes : official journal, German Society of Endocrinology [and] German Diabetes Association (Exp Clin Endocrinol Diabetes) Vol. 127 Issue 5 Pg. 281-288 (May 2019) ISSN: 1439-3646 [Electronic] Germany
• PMID: 29890552 (Publication Type: Journal Article)
• Copyright: © Georg Thieme Verlag KG Stuttgart · New York.

Chemical References

• FCRL3 protein, human
• FOXP3 protein, human
• Forkhead Transcription Factors
• IKZF2 protein, human
• RNA, Messenger
• Receptors, Immunologic
• TIGIT protein, human
• Ikaros Transcription Factor
• Thyrotropin

Topics

• Adult
• Age Factors
• Aged
• Female
• Forkhead Transcription Factors (metabolism)
• Gene Expression
• Humans
• Ikaros Transcription Factor (metabolism)
• Male
• Middle Aged
• RNA, Messenger (metabolism)
• Receptors, Immunologic (metabolism)
• Severity of Illness Index
• T-Lymphocytes (metabolism)
• Thyroiditis, Autoimmune (blood, classification, physiopathology)
• Thyrotropin (blood)