Our data showed that the numbers of CD3+ and CD4+ T lymphocytes were reduced in 12 of 14 patients three months after WJ-MSC treatment, and there was a significant correlation between the changes in the levels of fasting C-peptide and the numbers of CD3+ T lymphocytes, suggesting that WJ-MSC transplantation may participate in the regulation of the immune process and reduce inflammation and insulin resistance, improving diabetic symptoms. Here, CD4 is linked to Insulin resistance.