Lymphocyte transfusion in recent onset type I diabetes mellitus—A one-year follow-up of cell-mediated anti-islet cytotoxicity and C-peptide secretion

Abstract

In 19 patients with newly diagnosed Type I diabetes mellitus a single transfusion of 1.9 x 10(9) to 1.5 x 10(10) lymphocytes was performed. Fifteen Type I diabetic patients who did not receive a transfusion were used as controls. Anti-beta-cell cell-mediated cytotoxicity was measured using an insulin release assay. Stimulated C-peptide secretion (100 g glucose orally, 1 mg glucagon i.v.) was used to estimate residual beta-cell function. Both parameters were measured prior to transfusion and after 12 months. The transfusions were followed by a fall of cytotoxicity below the 95% confidence limit of the controls in 11 of the 19 patients ('responders') (15.7 +/- 1.7 ng insulin/islet/20 h vs 6.7 +/- 1.3 P less than 0.001), while the other eight transfused patients ('non-responders') (13.5 +/- 1.9 vs 17.1 +/- 2.9, ns) and the non-transfused control patients (11.6 +/- 1.1 vs 14.2 +/- 2.4, ns) displayed persistently high cytotoxicity levels. In the responder group a slight improvement in stimulated C-peptide secretion was observed (136 +/- 43 pmol/dl vs 148 +/- 38, ns) whereas in the non-responder (127 +/- 28 vs 106 +/- 25, ns) and in the control group (130 +/- 17 vs 97 +/- 19, P less than 0.05) the stimulated C-peptide responses declined during the 12-month follow-up. Thus, lymphocyte transfusion may have beneficial effects by suppressing anti-beta-cell cytotoxicity and preserving C-peptide secretion.