CD19+CD24hiCD38hi regulatory B cells are associated with insulin resistance in type I Hashimoto's thyroiditis in Chinese females

Hashimoto's thyroiditis (HT) is typically associated with insulin resistance. The aim of the present study was to investigate the role of regulatory B cells (Bregs) in insulin resistance in patients with HT. A total of 52 female patients with type I HT and 35 matched healthy volunteers were enrolled. Demographic and laboratorial data were collected. A 75 g oral glucose tolerance test was performed on each subject. Flow cytometry was performed to evaluate the levels of CD19(+)CD24(hi)CD38(hi) Bregs in peripheral blood. Patients with HT exhibited significantly higher postprandial insulin levels (P<0.01), but normal glucose levels. The level of CD19(+)CD24(hi)CD38(hi) Bregs in patients with HT decreased significantly (P=0.0002) compared with the controls. Pearson's linear correlation model revealed a significant, negative association between anti-thyroid peroxidase antibodies (TPOAb) and homeostasis model assessment of beta cell (r=-0.313, P=0.014). The same correlation model revealed a significant, negative association between TPOAb and the disposition index (DI; r=-0.305, P=0.017), and between anti-thyroglobulin antibodies and DI (r=-0.321, P=0.013). Patients with a decreased ratio of CD19(+)CD24(hi)CD38(hi) Bregs to CD19(+) lymphocytes exhibited higher levels of total cholesterol and low-density lipoprotein cholesterol. A decrease in the ratio of CD19(+)CD24(hi)CD38(hi) Bregs to lymphocytes was a significant independent risk factor for hyperinsulinemia (odds ratio=1.372, P=0.035). A decrease in peripheral blood CD19(+)CD24(hi)CD38(hi) Bregs is associated with insulin resistance in HT patients, and was an independent risk factor for postprandial hyperinsulinemia. The present study provided a novel insight into the development of effective therapeutic strategies targeting immune mechanisms associated with HT.