The Association of the Altered Interleukin-17 and Interleukin-21 Serum Levels with the Occurrence of Autoimmune Thyroid Diseases

Background: Autoimmunity denotes the abnormal attitude where an individual defenses act against its tissues. Objectives: The aim of the current study was to investigate the role of interleukin-17 (IL-17) and interleukin-21 (IL-21) in the occurrence of autoimmune thyroid diseases. Materials and Methods: Forty-five patients and forty-five controls were selected. The candidates were those suffering thyroid gland dysfunction. Clinical investigation was performed; the ones who fulfilled the diagnostic criteria were nominated. Cobas e411 was used for measuring serum thyroid stimulating hormone, T3 and (tetraiodothyronine) T4 levels, whereas anti-thyroid peroxidase (TPO) antibodies, IL-17, and IL-21 serum levels were measured by enzyme-linked immunosorbent assay. Results: The mean thyroid stimulating hormone serum levels (12.04 ± 2.76) of the patients differed statistically significantly from that of the controls (1.87 ± 0.15) ( P = 0.003). Whereas, the reported T3 and T4 mean serum levels were 2.05 ± 0.14, 100.66 ± 4.76 for the patients and 2.14 ± 0.07, 105.37 ± 2.92 for the control, respectively differed statistically non-significantly ( P = 0.57; P = 0.31, respectively). The mean serum concentration of anti-TPO antibody levels of the patients (259.08 ± 59.99) was significantly different ( P < 0.001) from that of the controls (8.71 ± 1.23). A statistically significant difference appeared when mean serum concentrations of IL-17 of the patients (44.05 ± 5.89) and the controls (29.43 ± 7.99) were compared ( P = 0.04). Moreover, a statistically significant difference ( P = 0.02) was observed when serum IL-21 level of the patients (57.03 ± 24.02) and controls (43.87 ± 18.48) were compared. Conclusion: The alterations in serum interleukins’ level can be a good marker to monitor the initiation and/or the progression of autoimmune thyroid diseases.