Detection of Insulitis by Pancreatic Scintigraphy With 99mTc-Labeled IL-2 and MRI in Patients With LADA (Action LADA 10).

OBJECTIVE: Pancreatic scintigraphy with interleukin-2 radiolabeled with (99m)Tc ((99m)Tc-IL-2) is a technique used to image chronic inflammatory-mediated disorders. We used this method to detect a signal consistent with the presence of insulitis in patients with autoimmune diabetes. Positive and negative controls (patients with pancreatic carcinoma and type 2 diabetes, respectively) also were studied. RESEARCH DESIGN AND METHODS: We examined 25 patients with autoimmune diabetes (16 with recently diagnosed type 1 diabetes, 9 with latent autoimmune diabetes in adults [LADA]), 6 with type 2 diabetes, and 7 with pancreatic carcinoma (the latter two groups were used as negative and positive controls, respectively). All patients underwent (99m)Tc-IL-2 scintigraphy and contrast-enhanced MRI of the pancreas. To validate positive controls, samples were taken from patients with pancreatic carcinoma during surgery for histological and immunohistochemical investigations. RESULTS: Pancreatic accumulation of (99m)Tc-IL-2 was detected in patients with autoimmune diabetes (61% positive) and, notably, in 6 of 9 patients with LADA; semiquantitative evaluation of pancreatic uptake of (99m)Tc-IL-2 showed higher values in patients with autoimmune diabetes (both childhood and LADA) and pancreatic carcinoma than in those with type 2 diabetes (4.45 ± 1.99, 4.79 ± 1.1, and 4.54 ± 1.62 vs. 2.81 ± 0.63; P = 0.06, P = 0.01, and P = 0.04, respectively). In patients with pancreatic carcinoma, pancreatic interleukin-2 receptor expression correlated with pancreatic (99m)Tc-IL-2 uptake (r = 0.8; P = 0.01). In patients with LADA, (99m)Tc-IL-2 uptake inversely correlated with duration of disease (r = 0.7; P = 0.03). CONCLUSIONS: Autoimmune diabetes in adults is associated with increased pancreatic (99m)Tc-IL-2 uptake, indicating the presence of insulitis, particularly within 1 year of the beginning of insulin therapy, similar to type 1 diabetes at diagnosis. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.