IL-10 as a Potential Immunomodulatory Marker in Hashimoto's Thyroiditis with Latent Toxoplasma gondii Infection: A Cross-Sectional Study

Background: Hashimoto's thyroiditis (HT) is an autoimmune thyroid disorder characterized by lymphocytic infiltration and thyroid autoantibodies. Latent toxoplasmosis, caused by Toxoplasma gondii, may influence autoimmune diseases (ADs) through mechanisms including the modulation of cytokine production. Interleukin-10 (IL-10), an anti-inflammatory cytokine with complex immunomodulatory roles, is implicated in autoimmune thyroid diseases. Objective: To evaluate serum IL-10 levels in HT patients with and without latent T. gondii infection, and the correlations of IL-10 with thyroid hormones (TSH, T3 and T4) and thyroid autoantibodies (anti-TPO and anti-TG) in patients with Hashimoto’s thyroiditis (HT) in these two groups of patients. Methodology: A cross-sectional study was conducted on 78 patients with HT (68 females and 10 males). Patients were divided into two groups based on the presence or absence of latent toxoplasmosis (anti-Toxoplasma IgG seropositivity). Thyroid hormones (TSH, T3 and T4), thyroid autoantibodies (anti TPO, anti TG), anti-Toxoplasma IgG and IL-10 levels were measured. Results: Serum IL-10 levels were significantly higher in HT patients with latent toxoplasmosis compared to those without toxoplasmosis. IL-10 levels were positively correlated with TSH and thyroid autoantibodies (anti-TPO and anti-TG) levels in the anti-Toxoplasma IgG seropositive group, but not in the seronegative group. Conversely, IL-10 levels were negatively correlated with T3 and T4 levels in both groups. Conclusion: IL-10 may serve as a potential immunomodulatory marker in HT patients with latent toxoplasmosis. Further research is warranted to elucidate the precise mechanisms by which T. gondii influences IL-10 production and its impact on the pathogenesis of HT.