Clinical Outcomes of Fetal Stem Cell Transplantation in Type 1 Diabetes Are Related to Alternations to Different Lymphocyte Populations

Background: In patients with diabetes, transplantation of stem cells increases C-peptide levels and induces insulin independence for some period. Today, this positive therapeutic outcome is widely attributed to the well-documented immunomodulatory properties of stem cells. The aim of this study was to report alternations (the trend of increase or decrease) in different lymphocyte populations in a stem cell clinical trial performed in our institute. Methods: Recorded data of a clinical trial conducted on 72 patients with type 1 diabetes who had received fetal stem cell transplantation several years ago and were regularly monitored before and after the procedure in 1, 3, 6, 12, 24 months were analyzed. In these regular follow-up visits, insulin demand, HbA1c, C-peptide, and alternation to B cell and T cell populations were analyzed and recorded. For the purpose of the current study, patients were retrospectively divided into 2 groups, namely, those with the positive response to treatment and patients without such response. Temporary positive therapeutic response was defined by 2 different indicators, namely, plasma C-peptide levels and insulin dose-adjusted A1C (IDAA1c), which was calculated as A1C (percent) + (4 × insulin dose (units per kilogram per 24 h). Data analysis was performed by means of SPSS Version 18. Results: Besides the short-term therapeutic effect, we observed remarkably significant alternations to the populations of B and T lymphocytes in the recipients. When patients were retrospectively assigned to 2 different groups of patients with a positive therapeutic response (based on C-peptide changes) and those without it, it was observed that alternations to different populations of B-cells and T-cells were significantly different in these 2 groups. Conclusion: Our results demonstrated that transplantation of stem cells leads to significant positive therapeutic outcomes in one group of patients who showed totally distinct patterns of alternation to different groups of lymphocytes.