IN-VIVO MEASUREMENT OF IMMUNOGLOBULIN ACCUMULATION IN THE PANCREAS OFRECENT-ONSET TYPE-1 DIABETIC-PATIENTS

Objective. The possibility to quantify in vivo the severity of the inf lammatory process in the pancreas of patients with recent onset insuli n dependent diabetes mellitus (IDDM) could be of great relevance for f ollow-up studies involving immunotherapy. Scintigraphy with radiolabel led human polyclonal immunoglobulins (Tc-99m-HIG) is currently used fo r the diagnosis and follow-up of several acute and chronic inflammator y diseases. In this longitudinal study we have investigated To what ex tent Tc-99m-HIG accumulate in the pancreas of patients with recent ons et IDDM and in subjects at risk to develop IDDM. Methods. Combined com puterised tomography and gamma camera imaging were used so measure the radioactivity in the pancreatic region, as the pancreas/bone radioact ivity ratio (P/B). Patients with IDDM (n=15) were investigated at the time of diagnosis and after 1 year. Five pre-diabetic ICA+ve subjects and 8 age and sex matched normal subjects were also investigated. Resu lts. Eight out of 15 newly diagnosed IDDM patients and 2/5 ICA+ve subj ects showed a significant accumulation of radiolabelled HIG in the pan creas (P/B higher than the upper 1st centile of normal subjects). One year after the diagnosis a significant accumulation of immunoglobulins was still detectable in the pancreas of IDDM patients positive who we re positive at diagnosis. Conclusions. These results suggest that immu noglobulins home and bind to the pancreas of patients with recent onse t IDDM and also in some ICA+ve individuals. This may reflect an increa sed vascular permeability of pancreatic capillaries as a consequence o f the inflammatory process involving the islets. Thus, this technique may be useful for monitoring the efficacy of immune intervention at di agnosis.