In vivo measurement of immunoglobulin accumulation in the pancreas of recent onset type 1 diabetic patients.
OBJECTIVE
The possibility to quantify in vivo the severity of the inflammatory process in the pancreas of patients with recent onset insulin dependent diabetes mellitus (IDDM) could be of great relevance for follow-up studies involving immunotherapy. Scintigraphy with radiolabelled human polyclonal immunoglobulins (99mTc-HIG) is currently used for the diagnosis and follow-up of several acute and chronic inflammatory diseases. In this longitudinal study we have investigated to what extent 99mTc-HIG accumulate in the pancreas of patients with recent onset IDDM and in subjects at risk to develop IDDM.


METHODS
Combined computerised tomography and gamma camera imaging were used to measure the radioactivity in the pancreatic region, as the pancreas/bone radioactivity 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.


RESULTS
Eight out of 15 newly diagnosed IDDM patients and 2/5 ICA+ve subjects showed a significant accumulation of radiolabelled HIG in the pancreas (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 were positive at diagnosis.


CONCLUSIONS
These results suggest that immunoglobulins home and bind to the pancreas of patients with recent onset IDDM and also in some ICA+ve individuals. This may reflect an increased vascular permeability of pancreatic capillaries as a consequence of the inflammatory process involving the islets. Thus, this technique may be useful for monitoring the efficacy of immune intervention at diagnosis.
Signore
A
A
Servizio Medicina Nucleare and Endocrinologia (I), University of Rome La Sapienza, Italy.
Barone
R
R
Procaccini
E
E
Annovazzi
A
A
Chianelli
M
M
Scopinaro
F
F
Ronga
G
G
Multari
G
G
Looman
W J
WJ
Pozzilli
P
P
D000293:Adolescent; D000328:Adult; D019412:Anatomy, Cross-Sectional / Q000379:methods; D001786:Blood Glucose / Q000032:analysis; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016756:Immunoglobulins, Intravenous; D007515:Islets of Langerhans / Q000276:immunology; D008297:Male; D010179:Pancreas / Q000000981:diagnostic imaging* / Q000473:pathology; D011868:Radioisotopes; D011877:Radionuclide Imaging; D013667:Technetium
D001786:Blood Glucose; D016756:Immunoglobulins, Intravenous; D011868:Radioisotopes; D013667:Technetium