Assessment of immunoglobulins A, M and G levels in the context of the administration of acellular cryopreserved biological agents in experimental autoimmune thyroiditis
Authors: Hladkykh F. V. 
Published: December 2024

Autoimmune diseases (ADs) are a heterogeneous group of more than 100 pathological conditions characterized by altered regulation of inflammatory processes against one or more autoantigens. The most common organ‑specific autoimmune disorder is autoimmune thyroid disease (AITD). The spectrum of AITD includes Graves’ disease and Hashimoto’s thyroiditis, presenting with two extreme clinical manifestations: hyperthyroidism and hypothyroidism. Our attention was drawn to the study of biotechnological drugs that do not contain cells exposed to low temperatures during their production (cryoextracts) or during long‑term storage. The object of the study was domestic acellular cryopreserved biological agents (ACBAs) — cryoextract of placenta (CEP), cryoextract of spleen (CES), and conditioned medium from mesenchymal stem cells (MSC‑CM).
Objective — to characterize the impact of CEP, CES, and MSC‑CM on the levels of immunoglobulins A, M, and G in rats with induced autoimmune thyroiditis.
Materials and methods. The effectiveness of ACBAs in AITD was studied on 42 male Wistar rats weighing 200—220 g. AITD was induced by administering a thyroid antigenic mixture to the rats, consisting of complete Freund’s adjuvant (Thermo Fisher Scientific, USA) and an antigen solution derived from the homogenate of allogeneic thyroid glands in a 1 : 1 ratio. The thyroid glands were homogenized in a 0.9% NaCl solution at a ratio of 1 mL/100 mg, filtered through a capron filter, and centrifuged for 5 minutes at 1000 rpm. The supernatant containing the thyroid antigen was collected and standardized for total protein content (1—1.5 mg/mL), which was determined by the biuret method. The levels of immunoglobulins (Ig) A, M, and G were determined using an enzyme‑linked immunosorbent assay (ELISA) with standard kits (Human GmbH, Germany) following the manufacturer’s instructions.
Results. In the control group, elevated levels of IgA, IgM, and IgG indicated autoimmune activity. The use of levothyroxine, cryoextracts (CEP, CES), and MSC‑CM led to a decrease in these immunoglobulin levels. Levothyroxine reduced IgA by 9.4% and IgM by 25%, but the effect was incomplete. CEP reduced IgA by 15.5%, while CES reduced it by 7.7%. The greatest decrease in IgA and IgM levels was observed in the group of rats treated with MSC‑CM (IgA by 19.2%, IgM by 39.3%). MSC‑CM demonstrated the greatest effectiveness in correcting autoimmune disorders.
Conclusions. The use of levothyroxine contributed to a reduction in IgA levels but did not lead to full normalization, while cryoextracts (CEP, CES) and MSC‑CM demonstrated the greatest therapeutic potential in reducing immunoglobulin levels and correcting autoimmune thyroiditis, outperforming levothyroxine and other CBAs. The highest effect in reducing IgM levels was achieved with MSC‑CM, where IgM levels were 39.9% lower than the control group. Furthermore, MSC‑CM demonstrated the most pronounced reduction in IgG levels, reducing them by 44.3% compared to the control group, confirming the high therapeutic potential of this drug in the treatment of autoimmune thyroiditis.