Abstract 1517: Detection of CD4+ CD25+ foxp3+ Regulatory T-Cells in Atherosclerotic Carotid Artery Plaques
Atherosclerotic plaque typically contains an infiltrate of activated macrophages and T cells. The present study investigated potential anti-inflammatory processes in atherosclerotic lesions, focussing on regulatory T cells (Treg). Carotid artery plaque tissue was collected from 23 symptomatic and 19 asymptomatic patients undergoing endarterectomy. Quantitative PCR (Q-PCR) and immunohistochemistry were used for the analysis of plaques for markers of Treg (FOXP3, CD4, CD25) in conjunction with relevant cytokines and T cell activation markers. Results were correlated with clinical patient data. Immunohistochemistry demonstrated the presence of CD4+CD25+ T cells and CD4+CD25+FOXP3+ Treg in carotid artery plaques. Treg were present more frequently in lesions from asymptomatic patients than from symptomatic patients (75% of lesions vs. 35%, p< 0.01). Similarly, plaque samples from asymptomatic patients showed significantly higher levels of FOXP3 and the anti-inflammatory cytokine IL10 by Q-PCR compared to symptomatic patients. No significant differences between groups were found for expression of interferon-γ, TGF-β and ICOS by Q-PCR. Patients on statin therapy showed significantly higher expression of FOXP3 and IL10, while patients receiving aspirin (vs. clopidogrel or phenprocoumon) showed a trend towards higher expression of FOXP3 and lower expression of ICOS, a T cell activation marker. Regulatory T cells can be demonstrated in carotid artery atherosclerotic plaque and may represent an anti-inflammatory counter-regulatory principle. Regulatory T cells appear to be more frequent in carotid plaques of asymptomatic patients and patients receiving statins and/or aspirin.