T Helper 22 Pathway Evaluation in Type 1 Diabetes and Its Complications

Abstract

A subset of CD4+ T cells named T helper (Th)22 cells play some pathogenic roles in some autoimmune disorders such as type 1 diabetes (T1D). We aimed to study the correlation between the circulatory number of these cells and serum levels of its related cytokines with T1D as well as diabetic complications including metabolic control, atherosclerosis, and nephropathy. Fortynine patients with T1D and 43 healthy controls underwent the assessment of circulatory number of Th22 cells (by flow cytometry), serum level of Th22 related cytokines including Interleukin-22 (IL-22), Interleukin-10 (IL-10), Transforming growth factor-β (TGF-β), Tumor necrosis factor-α (TNF-α) (by ELISA) and carotid intima-media thickness (cIMT) measurement (by doppler ultrasonography). In addition, fasting blood and urine samples were taken to measure levels of hemoglobin A1C, lipid profile, cell blood count (CBC), serum and urine creatinine and urine protein in all participants. Th22 frequency and serum levels of IL-22 and TNF-α in patients were significantly higher than those in controls (p<0.001). Serum levels of IL-10 and TGF-β in healthy individuals were higher than those in patients (p<0.001). None of the Th22 related markers had a significant correlation with diabetic complications. There was only a significant effect of IL-22 on HbA1C variations. Th22 pathway has a significant correlation with T1D but not with its complications of cIMT and Urine Albumin/Creatinine Ratio (UACR). We report that Th22 pathway is not a good prognostic as well as diagnostic marker of early macrovascular complications in T1D.

Keywords: Diabetes type 1; Diabetic nephropathy; Interleukin-10; Interleukin-22; Intima media thickness; T helper 22; Transforming growth factor-β; Tumor necrosis factor-α.