The authors determined both the numbers of T lymphocyte subpopulations in peripheral blood and the concentration of C-peptide in serum before experimentation at 15 days

1 month

6 months

and 1 year after islet transplantation in tripterygii totorum (T II) group in which 30 insulin dependent diabetes mellitus (IDDM) patients were given T II and the control group in which 24 IDDM patients did not use any immunosuppressive agents

and 20 healthy individuals were used as the healthy group. Results: Before transplantation

the numbers of T lymphocyte subpopulations such as CD2

CD4 in the two groups were lower than those in the healthy group (P<0.01); the ratio of CD4/CD8 was between 1.2 and 2.0. After transplantation the numbers of CD2

CD4 in the two groups were elevated

particulary in T II group the numbers of CD2

CD4 were close to those in the healthy group (P>0.05). The ratio of CD4/CD8 in the control group was more than 2.0. The average dose of insulin reduced by 84.2% in 19 patients of the T II group

2 cases stopped insulin; the peak value of C-peptide was 3.24±1.2 ng/ml. In the control group the average dose of insulin and the peak value of C- peptide was similar to that in the T II group in the first 6 months after transplantation (P>0.05)

then the dose of insulin was gradually increased and the concentration of C-peptide began decreasing. One year after transplantation both the dose of insulin and the concentration of C-peptide were close to those before transplantation. The study suggests that T II have immunosuppressive effects in islet transplantation and prolong the survival time of grafts in IDDM patients.