Changes in the level of immune checkpoints in patients with various forms of autoimmune thyroiditis

Background. Autoimmune thyroiditis (AIT) affects more than 5 % of the world’s population.

The aim. To determine the level of sPD-1, sPD-L1, sCTLA-4 and sB7.2 molecules in individuals suffering from various forms of autoimmune thyroiditis.

Methods. The study included 31 individuals aged 18 to 40 years. They were divided into four groups: group I – healthy individuals (n = 10); group II – carriers of antibodies to thyroid peroxidase (n = 11); group III – individuals with AIT accompanied with subclinical form of hypothyroidism (n = 6); group IV – individuals with AIT complicated by compensated hypothyroidism (n = 4). Venous blood was collected to determine the level of antibodies to thyroid peroxidase using enzyme immunoassay, the concentration of thyroid stimulating hormone and free thyroxine – using chemiluminescence immunoassay, and the levels of sPD-1, sPD-1L, sCTLA-4, and sB7.2 – using flow cytofluorometry. Statistical processing was performed using the Kruskal – Wallis one-way analysis of variance.

Results. When comparing the level of sPD-1L in groups I (54.1 (28.7; 67.6) pg/ml) and II (4.36 (2.36; 18.0) pg/ml), the decreased in this indicator was 91.94 % (p = 0.001). When comparing the sPD-1 level in the group of healthy individuals (16.6 (13.6; 37.2) pg/ml) and group IV (7.28 (5.18; 11.1) pg/ml), werecorded a decrease of 56.14 % (p = 0.001). The sB7.2 concentration decreased by 65.03 % in group II (16.4 (15.6; 32.7) pg/ml) compared to the control group (46.9 (39.3; 54.4) pg/ml) (p = 0.001). In group III, the sCTLA-4 level was 3.22 (3.06; 3.33) pg/ml and decreased by 88.66% compared to the control group (p = 0.001).

Conclusion. The development of autoimmune thyroiditis is accompanied with the decrease in the concentration of sPD-1, sPD-1L, sCTLA-4 and sB7.2.

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