Characteristics of Leukocyte Subtypes in Graves' Disease

Background: Graves' disease (GD) is the most common cause of hyperthyroidism, and isa part of extensive autoimmune thyroid disease, involving both innate and adaptive immunity. However, connections between these immune components are complex and need to be fully understood. The purpose of this study was to determine the clinical characteristics of the subtypes of leukocytes associated with Graves' disease (GD) at different pathological stages. Methods: In this study, 2290 patients were enrolled and divided into 3 groups: graves disease (1586 patients), subacute thyroiditis (SAT, 443 subjects), and subacute thyroiditis hypothyroidism (261 patients) groups. The collected data included the clinical symptoms and hormonal results. Related data from 167 healthy individuals served as normal control parameters. Two correlation analyses were performed for categorical variables and some valid factors using logistic regression analysis (LRA). Results: Compared to the patients in SAT group, higher counts and percentage of lymphocytes (p < 0.001) were detected in GD group, coupled with the lower counts and percentage of neutrophils (p < 0.001). Compared to the patients with hypothyroidism, lymphocyte counts (p < 0.001), monocyte counts (p < 0.001), and their percentage (p < 0.001) were higher in GD group, while the counts (p < 0.001) and percent of neutrophils (p = 0.009) and eosinophils were lower (p < 0.001). LRA revealed that in GD group, total thyroxine (TT4) was positively correlated with lymphocyte count (p = 0.021) and its percentage (p = 0.019), and negatively correlated with neutrophil count (p = 0.026) and its percentage (p = 0.006). Moreover, in the hypothyroid group, TT4 was positively correlated with eosinophil count (p = 0.017) and its percentage (p = 0.015), and negatively correlated with lymphocyte count (p = 0.018) and its percentage (p = 0.027). Conclusions: Circulating leukocyte parameters are related to thyroid function, and there is an interaction between thyroid hormones and immune responses in GD patients. Clinical manipulation of immune functions could be applied as potential therapeutic strategy to modulate thyroid hormone levels.