Serum Level of Soluble Molecules of Immune Response Checkpoints in Patients With Various Forms of Autoimmune Thyroiditis

Introduction : The prevalence of chronic autoimmune thyroiditis (AIT) is more than 5% of the world's population. Despite this, the tactics and methods of treating AIT have not undergone innovations in terms of therapy for many years, while the modern trend in the treatment of other autopathologies is to use monoclonal antibodies. However, it was noted that with the use of some immune checkpoint inhibitors for the treatment of oncopathology, various autoimmune diseases debuted in patients. This fact opens up the prospect of studying new links in the pathogenesis of AIT. Aim : determination of the level of sCD25, s4-1BB, sTim-3, sLAG-3, sGalectin-9 molecules in individuals suffering from various forms of AIT. Material and methods : The study involved 31 subjects aged 18 to 40 years, divided into four groups: I Healthy (n = 10); II Carriers of antibodies to thyroid peroxidase (ATkTPO) (n = 11); III Subclinical form of hypothyroidism AIT (n = 6); IV AIT with hypothyroidism, medically compensated (n = 4). Venous blood was collected to determine the ATkTPO level by ELISA, the concentration of thyroid-stimulating hormone and free thyroxine by immunochemiluminescence, the level of CD25, 4-1BB, Tim-3, LAG-3, Galectin-9 by flow cytofluorimetry. Statistical processing was performed using the Kruskal-Wallis one-way analysis of variance. Results: The sCD25 level decreased by almost 85% (P = 0,001) from the control 19,2 pg/ml (2,20; 29,9) in groups: II 2.83 pg/ml (2,24; 3,17), III 3,23 pg/ml (2,69; 45,8), and IV 3,05 pg/ml (2,31; 7,37). The concentration of 4-1BB increased threefold (P = 0,001) in groups: II 35,0 pg/ml (15,5; 39,8), III 31,9 (27,8; 44,4) from the control 11,8 pg/ml (4,96; 14,0). sTim-3 decreased by more than 98% (P = 0,001) from group I 280 pg/ml (13,7; 321) when compared with groups: II 5,22 pg/ml (2,13; 6,34), III 4,10 pg/ml (3,36; 5,34), IV 1,26 pg/ml (0,362; 2,45). The content of LAG-3 decreased by 66% (P = 0,001) when comparing group, I 51,1 pg/ml (20,1; 60,1) with II 20,1 pg/ml (2,23; 41,6). The concentration of Galectin-9 in group II 277 pg/ml (196; 378) is 5 times lower than in I 1377 pg/ml (1140; 1910) (P = 0,001). Conclusion : With the development of AIT, the concentration of CD25, Tim-3, LAG-3, Galectin-9 decreases, and the level of 4-1BB increases.