Vitamin D administration in type 1 diabetes and its impact on T lymphocyte subsets

Purpose: To investigate the effect of vitamin D supplementation on glycated hemoglobin A1c (HbA1c); CD3+, CD4+, CD8+, CD4+/CD25+, and CD8+/CD25+ ratios. Methods: Thirty mice were equally assigned to three cohorts: control, untreated T1 diabetic (T1), and T1 diabetic treated with vitamin D for 4 months. Body weight, blood glucose levels, HbA1c percentages, and lipid profiles were measured in mice in each of the three groups. Additionally, total lymphocytes and CD4+, CD3+ cells, CD8+ cells, CD4+/CD25+, and CD8+/CD25+ ratios were assayed using flow cytometry in all mice. Results: Data showed significantly lower blood glucose levels, HbA1c levels, and lipid profiles (p < 0.0001); total lymphocyte counts (p < 0.05), and counts of CD3+ (p < 0.05), CD4+, and CD8+ cells (p < 0.0001) in vitamin-D-treated diabetic mice than in the untreated diabetic mice. In contrast, there were significantly higher CD4+/CD25+ and CD8+/CD25+ ratios in treated mice with diabetes (p < 0.01). Conclusion: Vitamin D may have promising immunomodulatory properties that could help mitigate the harmful effects of T1DM.