Identification of inflamed atherosclerotic plaque using 123 I-labeled interleukin-2 scintigraphy in high-risk peritoneal dialysis patients: a pilot study.

BACKGROUND: Patients with end-stage renal disease (ESRD) suffer from markedly increased cardiovascular morbidity and mortality. Common carotid artery (CCA) intima-media thickness (IMT) assessment and CCA plaque identification using ultrasound are well-recognized tools for identification and monitoring of atherosclerosis. A new method for monitoring the inflammatory status of plaque, namely radiolabeled interleukin-2 (IL-2) scintigraphy, was proposed recently. The aim of this pilot study was to perform (123)I-labeled-IL-2 carotid plaque scintigraphy in ESRD patients treated with peritoneal dialysis and to correlate obtained results with ultrasound assessment of CCA and selected inflammatory markers. METHODS: CCA-IMT was measured and CCA plaques were identified by ultrasound in 10 patients (5 women, 5 men; mean age 62.4 +/- 10.4 years; median peritoneal dialysis duration 32.5 months, range 12 - 55 months) with advanced cardiovascular comorbidity. Following CCA ultrasound, (123)I-labeled IL-2 carotid plaque scintigraphy was performed. Several biomarkers of inflammation and atherosclerosis were also measured in all patients. RESULTS: Mean target/non-target ratio for focal (123)I-IL-2 uptake within the plaque was 3.15 +/- 0.54, and mean IMT from the site of the scintigraphy analysis was 0.975 +/- 0.337 mm. Highly significant correlation was found between CCA-IMT and a target/non-target ratio for focal (123)I-IL-2 uptake in a corresponding artery (R = 0.92, p = 0.01). However, no significant correlations were found between target/non-target ratio for focal (123)I-IL-2 uptake and levels of measured biomarkers. CONCLUSIONS: Our preliminary results suggest potential for identification of an inflamed (vulnerable) plaque using IL-2 scintigraphy in ESRD patients with cardiovascular comorbidities.