99mTc-interleukin-2 scintigraphy for the in vivo imaging of vulnerable atherosclerotic plaques

Eur J Nucl Med Mol Imaging. 2006 Feb;33(2):117-26. doi: 10.1007/s00259-005-1899-4. Epub 2005 Oct 12.


Purpose: Several histopathological studies have demonstrated that vulnerable plaques are enriched in inflammatory cells. The aims of this study were: (1a) to test the ability of 99mTc-labelled interleukin-2 (99mTc-IL2) to bind to IL2R-positive (IL2R+) cells in carotid plaques and (1b) to correlate the plaque uptake of 99mTc-IL2, measured in vivo, with the number of IL2R+ cells within the plaque, measured ex vivo by histology (transversal study, TS), and (2) to evaluate changes in 99mTc-IL2 uptake in plaques, before and after treatment with a statin or a hypocholesterolaemic diet (longitudinal study, LS).

Methods: Ultrasound scan was performed for plaque characterisation and localisation. Fourteen patients (16 plaques) eligible for endoarterectomy were recruited for the TS and underwent 99mTc-IL2 scintigraphy before surgery. Nine patients (13 plaques) were recruited for the LS; these patients received atorvastatin or a standard hypocholesterolaemic diet and 99mTc-IL2 scintigraphy was performed before and after 3 months of treatment.

Results: The degree of 99mTc-IL2 uptake was expressed as the plaque/background (T/B) ratio. In patients from TS, T/B ratios correlated with the percentage of IL2R+ cells at histology (r = 0.707; p = 0.002) and the number of IL2R+ cells at flow cytometry (r = 0.711; p = 0.006). No correlations were observed between ultrasound scores and either scintigraphic or histological findings. In patients from the LS, the mean 99mTc-IL2 uptake decreased in statin-treated patients (1.75+/-0.50 vs 2.16+/-0.44; p = 0.012), while it was unchanged in the patients on the hypocholesterolaemic diet (2.33+/-0.45 vs 2.34+/-0.5).

Conclusion: 99mTc-IL2 accumulates in vulnerable carotid plaques; this accumulation is correlated with the amount of IL2R+ cells and is influenced by lipid-lowering treatment with a statin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Anticholesteremic Agents / therapeutic use
  • Atherosclerosis / diagnosis*
  • Atherosclerosis / diet therapy
  • Atherosclerosis / drug therapy
  • Atherosclerosis / metabolism*
  • Atorvastatin
  • Carotid Arteries / pathology
  • Diet, Atherogenic
  • Female
  • Heptanoic Acids / pharmacology
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / pharmacology
  • Inflammation / diagnosis
  • Inflammation / metabolism
  • Interleukin-2 / biosynthesis*
  • Male
  • Middle Aged
  • Pyrroles / pharmacology
  • Radionuclide Imaging / instrumentation
  • Radionuclide Imaging / methods*
  • Technetium*


  • Anticholesteremic Agents
  • Heptanoic Acids
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Interleukin-2
  • Pyrroles
  • Technetium
  • Atorvastatin