We wanted to evaluate residual insulin in newly manifested type-1 diabetics after one year of intensive insulin treatment. Nine adults (median 30.8 yrs) and six children (6.4 yrs) were included into the study. Control parameters were body weight, daily insulin, self-monitored blood glucose levels, HbA1c, glucagon stimulated C-peptide, islet cell antibodies (ICA) and insulin antibodies. Peripheral blood mononuclear cells were separated by Ficoll gradient and injected into CD-1 nu/nu mice. Mouse pancreas was subsequently examined for inflammatory infiltration of islets of Langerhans (insulitis). 6/9 (66%) adults were ICA positive, 2/9 (22%) had insulin autoantibodies. In 5 out of 7 (71%) cases human mononuclear cells caused pancreatic insulitis in the nude mice. After one year of intensive insulin therapy HbA1c was in the normal range. Glucagon stimulated C-peptide had increased by 80% from baseline in the adult patients. This increase was comparable to the effect of immunsuppressants like cyclosporin A. By contrast, no glucagon stimulated C-peptide improvement was found in the children after one year.
