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

  • Alessio Annovazzi
  • Elena Bonanno
  • Marcello Arca
  • Calogero D’Alessandria
  • Antonella Marcoccia
  • Luigi G. Spagnoli
  • Francesco Violi
  • Francesco Scopinaro
  • Giorgio De Toma
  • Alberto Signore
Original Article



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).


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.


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).


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.


Carotid arteries Inflammation Interleukin-2 Plaque 



This study was partially supported by the Italian Ministry of Public Education, by the International Atomic Energy Agency (IAEA) and by GE-Amersham Healthcare. This paper was awarded with the 2004 Marie Curie award by the European Association of Nuclear Medicine (EANM).


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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Alessio Annovazzi
    • 1
  • Elena Bonanno
    • 2
  • Marcello Arca
    • 3
  • Calogero D’Alessandria
    • 1
  • Antonella Marcoccia
    • 4
  • Luigi G. Spagnoli
    • 2
  • Francesco Violi
    • 4
  • Francesco Scopinaro
    • 1
  • Giorgio De Toma
    • 5
  • Alberto Signore
    • 1
    • 6
    • 7
  1. 1.Nuclear Medicine, 2nd Faculty of MedicineUniversity La SapienzaRomeItaly
  2. 2.Department of Biopathology and Diagnostic ImagingUniversity Tor VergataRomeItaly
  3. 3.Department of Clinical and Applied Medical Therapy, 1st Faculty of MedicineUniversity La SapienzaRomeItaly
  4. 4.Medical Clinical Institute 1, 1st Faculty of MedicineUniversity La SapienzaRomeItaly
  5. 5.Department of Surgery Pietro Valdoni, 1st Faculty of MedicineUniversity La SapienzaRomeItaly
  6. 6.Department of Nuclear MedicineUniversity of GroningenGroningenThe Netherlands
  7. 7.Nuclear MedicineOspedale S. AndreaRomaItaly

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