Deranged regulatory T-cells and transforming growth factor-β1 levels in type 1 diabetes patients with associated autoimmune diseases

Aim: This study was designed to enumerate regulatory T-cells (Tregs) and estimate transforming growth factor-β1 (TGF-β1) levels in type 1 diabetic (T1D) patients with respect to disease duration and associated autoimmune diseases. Methods: One hundred and fifty patients and twenty healthy controls were recruited in the study. The patients were subcategorized into eight categories on the basis of disease duration (new onset [NO] and long standing [LS]) and associated diseases, i.e., celiac disease (CD) and autoimmune thyroid disease (AiTD). Treg cells were assessed as CD4 + CD25 hi+ , FOXP3 + cells and serum TGF-β1 levels were assessed by ELISA. Results: The frequency of Tregs and levels of TGF-β1 were significantly increased in the patients compared to the healthy controls. Among the different categories of the patients, no significant differences were seen for TGF- β1 levels, but for Tregs in patients with T1D and AiTD ( P = 0.035). A significant correlation was also found between percentage count of Tregs and TGF-β1 levels in NO cases in all disease subcategories, but not in LS patients. Conclusion: Thus, there was an increased percentage of Tregs and serum levels of TGF-β1 in T1D patients, irrespective of the disease duration and associated autoimmune diseases. The significant correlation in these two parameters at the onset of the disease, but not in LS disease, indicates that the immunological milieu in LS autoimmune diseases is more complicated with disease-associated conditions such as prolonged hyperglycemia, insulin therapy, and/or continued gluten in diet. Treatment and modulation of these long-term complications for improving immunological parameters require further research.