Serum Levels of Platelet Released CD40 Ligand Are Increased in Early Onset Occlusive Carotid Artery Disease

OBJECTIVE Soluble CD40 ligand (sCD40L) has been suggested as a key mediator between inflammation and atherosclerosis, and the CD40-CD40L interaction has a role in atherosclerotic lesion progression. We evaluated if platelet released serum sCD40L and sCD40 levels differ between patients with early onset occlusive carotid artery disease and age-matched controls. METHODS sCD40L and sCD40 levels were measured in serum samples of 60 patients with occlusive carotid artery disease and 30 age-matched controls using ELISA. Degree of stenosis of the internal carotid artery (ICA), and intima-media thickness (IMT) in the common carotid artery were measured by high resolution ultrasound. Values are given as mean +/- SD. RESULTS Mean age was 50.9 +/- 3.5 and 50.1 +/- 3.5 years in the patient and control groups. IMT was significantly thicker in patients than in controls (0.89 +/- 0.14 vs. 0.78 +/-0.12 mm, p=0.0003). Serum levels of sCD40L were significantly higher (6.9 +/- 5 vs. 4.5 +/- 3.0 ng/mL, p=0.038) in patients, whereas sCD40 did not differ significantly between patients and controls (85 +/- 56.9 vs. 79.3 +/- 18.7 pg/mL, p=0.34). IMT did not correlate with sCD40L or sCD40 levels (R=-0.03, p=0.77; and R=0.109, p=0.308, respectively). CONCLUSIONS sCD40L but not sCD40 levels are significantly higher in patients with occlusive carotid artery disease. Platelet derived sCD40L may be a key mediator among inflammation, thrombosis and atherosclerosis.